Freshwater Biology and Pollution Ecology: Training Manual


 EPA-430/ 1-75-005
  FRESHWATER BIOLOGY AND
  POLLUTION ECOLOGY
TRAINING MANUAL
u
 S. ENVIRONMENTAL PROTECTION AGENCY
WATER PROGRAM OPERATIONS

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                                       EPA-430/1-75-005
                                       April 1975
       FRESHWATER BIOLOGY
This course is designed as an introduction to aquatic
biology for sanitary engineers,  scientists, and others
who are involved in freshwater pollution studies,
surveillance,  and control.  Biologists new to the field
of aquatic biology and pollution problems may find it
useful for orientation.
                     AND
  FRESHWATER POLLUTION ECOLOGY
This course is offered for aquatic biologists or persons
with comparable experience concerned with and/or
involved in the application of biological principles,
techniques and parameters to pollution studies and
abatement programs.
  ENVIRONMENTAL PROTECTION AGENCY
      Office of Water  Program Operations
          TRAINING   PROGRAM

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                                      CONTENTS                             •   ,



Title or Description                                • -                    Outline. Number

Survey of the Biota

   The Aquatic Environment                                                    1

   Types of Algae                                                              2

   Production of Excess Organic Material in Freshwater                         3

   Aquatic  Macrophytes                                                        4

   An Artificial Key to Some Common Aquatic Plants                             5
    (Freshwater,  Estuarine,  and Marine)

   Key to Selected Groups of Freshwater Animals                                6

   Biota of Wastewater Treatment Plants (Microscopic                           7
    Invertebrates)

   Biology  of Zooplankton Communities                                         8

   Macro Invertebrates                                                         9

   Fishes                                                                    10

   Fungi and the "Sewage Fungus" Community                                  11

Freshwater Pollution Ecology

   Biological Aspects of Natural Self Purification                               12

   The Interpretation of Biological Data with Reference to                       13
    Water  Quality

   Effects  of Pollution on Aquatic Life                                         14

   Global Deterioration and Our Environmental Crisis                          15

   Fundamentals of the Toxicity Bioassay                                      16

   Biological Field Methods                                                   17

   Stream Invertebrate Drift                                                   18

   Artificial Substrates                                                        19

   Attached Growths (Periphyton or Aufwuchs)                    '              20



 140.4.75

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                                        Contents
Title or Description                                      '                 Outline Number





   Application of Biological Data                                                 21




   Using Benthic Biota in Water Quality Evaluation                          '     22

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                SURVEY  OF  THE BIOTA
The first half of this manual is a synoptic review of the components
of the aquatic community to aid the observer in recognizing many
common types of organisms encountered both in the field, laboratory,
and treatment facilities.

A comprehension of the system of biological nomenclature and
ecological classifications, is basic to an understanding of aquatic
life communities.  The first exercise in ecology is systematics.
Application of systematics will depend on one's background, present
limitations,  and program objectives.

Systematics, broadly defined, is the study of the diversity of organisms.
In connotation it is a wedding between taxonomy and ecology.  In applied
biology or ecology,  good systematics is indispensable and is an immensely
useful system of information storage and retrieval.  The following
definitions are basic.
SYSTEMATICS:  "The scientific study of the kinds and diversity of
organisms and of any and all relationships among them. "

CLASSIFICATION:  "The ordering of organisms into groups (or sets)
on the basis of their relationships; that is, of their associations by
contiguity, similarity,  or both."

TAXONOMY: "The theoretical study of classification, including its
bases, principles, procedures,  and rules."

IDENTIFICATION:  "The use of a key (or key substitute like an expert)
to place an unknown organism into a specific taxonomic rank."

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                                    THE AQUATIC ENVIRONMENT

                              Part 1:  The Nature  and Behavior of Water
I  INTRODUCTION

The earth is physically divisible into the
lithosphere or land masses, and the
hydrosphere which includes the oceans,
lakes,  streams,  and subterranean waters.

A  Upon the hydrospere are based a number
   of sciences which represent different
   approaches.  Hydrology is  the general
   science of water itself with its various
   special fields such as hydrography,
   hydraulics,  etc.  These in  turn merge
   into physical chemistry and chemistry.

B  Limnology and oceanography combine
   aspects of all of these,  and deal not only
   with the physical liquid water and its
   various naturally occurring solutions and
     forms, but also with living organisms
     and the infinite interactions that occur
     between them and their environment.

  C  Water quality management, including
     pollution control, thus looks to all
     branches of aquatic science in efforts
     to coordinate and improve man's
     relationship  with his aquatic environment.
 II   SOME FACTS ABOUT WATER

  A  Water is the only abundant liquid on our
     planet.   It has many properties most
     unusual for liquids, upon which depend
     most of the familiar aspects  of the  world
     about us as we know it.  (See Table 1)
                                               TABLE 1
                                      UNIQUE PROPERTIES OF WATER
                           Property
         Significance
                   Highest heat capacity (specific heat) of any
                   solid or liquid (except NH3>
Stabilizes temperatures of organisms and
geographical regions
                   Highest latent heat of fusion (except
Thermostatic effect at freezing point
                  Highest heat of evaporation of any substance
Important In heat and water transfer of
atmosphere
                  The only substance that has its maximum
                  density as a liquid (40 C)
Fresh and brackish waters have maximum
density above freezing point.  This is
important In vertical circulation pattern
In lakes.
                  Highest surface tension of any liquid
Controls surface and drop phenomena,
important In cellular physiology
                  Dissolves more substances In greater
                  quantity than any other liquid
Makes complex biological system possible.
Important for transportation of materials
In solution.
                  Pure water has the highest di-electrlc
                  constant of any liquid
Leads to high dissociation of Inorganic
substances In solution
                  Very little electrolytic dissociation
Neutral, yet contains both H+ and OH ions
                  Relatively transparent
Absorbs much energy In Infra red and ultra
violet ranges, but little in visible range.
Hence "colorless"
  BI.  21e. 1.74
                                                                                                   1-1

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The Aquatic Environment
B  Physical Factors of Significance

   1  Water substance

      Water is not simply "HgO" but in
      reality is a mixture of some 33
      different substances involving three
      isotopes each of hydrogen and oxygen
      (ordinary hydrogen H1, deuterium H2,
      and tritium H^; ordinary  oxygen O  ,
      oxygen 17, and oxygen 18) plus  15
      known types  of ions.   The molecules
      of a water mass tend to associate
      themselves as polymers rather than
      to remain as discrete units.
      (See Figure 1)
     SUBSTANCE OF PURE WATER
                 TABLE 2

 EFFECTS OF TEMPERATURE ON DENSITY
        OF PURE WATER AND ICE*

 Temperature (°C)          Density

                   Water         Ice**
-10
- 8
- 6
- 4
- 2 .
0
2
4
6
8
10
20
40
60
80
100
.99815
.99869
.99912
.99945
.99970
.99987 	
.99997
1.00000
.99997
.99988
.99973
.99823
.99225
.98324
.97183
.95838
.9397
.9360
.9020
.9277
.9229
.9168










                   Ftfure 1
 *  Tabular values for density,  etc., represent
    estimates by various workers rather than
    absolute values,  due to the variability of
    water.

**  Regular ice  is known as "ice I".  Four or
    more other "forms" of ice are known to
    exist (ice  II, ice III,  etc.), having densities
    at 1 atm.  pressure ranging from 1.1595
    to 1.67.  These are of extremely restricted
    occurrence and may be ignored in most
    routine operations.
   2  Density

     a  Temperature and density:  Ice.
        Water is the only known substance
        in which the solid state will float
        on the liquid state.  (See Table 2)
           This ensures that ice usually
           forms on top of a body of water
           and tends to insulate the remain-
           ing water mass from further loss
           of heat. Did ice sink,  there
           could be little or no  carryover of
           aquatic life, from season to season
           in the higher latitudes.  Frazil or
           needle ice forms colloidally at a
           few thousandths of a degree
           below 0° c.   It is adhesive and
           may build up on submerged objects
           as "anchor ice", but it is still
           typical ice (ice I).
1-2

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                                                      The Aquatic Environment
1) Seasonal increase in solar
   radiation annually warms
   surface waters in summer
   while other factors result in
   winter  cooling.  The density
   differences resulting establish
   two classic layers:  the epilimnion
   or surface layer, and the
   hypolimnion or lower layer, and
   in between is the thermocline
   or shear-plane.

2) While for certain theoretical
   purposes a "thermocline" is
   defined as a zone in which the
   temperature changes one
   degree centigrade for each
   meter of depth, in practice,
   any transitional layer between
   two relatively stable masses
   of water of different temper-
   atures  may be regarded as a
   thermocline.

3) Obviously the greater the
   temperature differences
   between epilimnion and
   hypolimnion arid  the sharper
   the  gradient in the thermocline,
   the  more stable will the
   situation be.

4) From information given above,
   it should be evident that while
   the  temperature  of the
   hypolimnion rarely drops
   much below 4° C, the
   epilimnion may range from
   0° C upward.

5) When epilimnion and hypolimnion
   achieve the same temperature,
   stratification no  longer exists.
   The entire body of water behaves
   hydrologically as a unit, and
   tends to assume  uniform chemical
   and physical characteristics.
   Even a light breeze may then
   cause the entire  body of water
   to circulate.  Such events are called
   overturns, and usually result in
   water quality changes of consider-
   able physical,  chemical, and
   biological significance.
        Mineral-rich water from the
        hypolimnion, for example,
        is mixed with oxygenated
        water from the epilimnion.
        This usually triggers a
        sudden growth or "bloom"
        of plankton organisms.

     6) When stratification is present,
        however,  each layer behaves
        relatively independently, and
        significant quality differences
 =       may develop.

     7) Thermal stratification as
        described above has no
        reference to the size of the
        water mass; it is found in
        oceans and puddles.

  b  The  relative densities of the
     various isotopes of water
     influence its molecular com-
     position.  For example, the
     lighter O16 tends to go off
     first in the process of evaporation,
     leading to the relative enrichment
     of air by O16 and the enrichment
     of water by O17 and O18.   This
     can lead to a measurably higher
     OIB  content in warmer climates.
     Also, the temperature of water
     in past geologic ages can be
     closely estimated from the ratio
     °f QIQ  in the carbonate of mollusc
     shells.

  c  Dissolved and/or suspended solids
     may also affect the density of
     natural water masses (see Table 3)

            TABLE 3
EFFECTS OF DISSOLVED SOLIDS
           ON DENSITY
Dissolved Solids
(Grams per liter)
0
1
2
3 •
10
35 (mean for sea water)
Density
(at 40 C)
1.00000
1.00085
1.00169
1,00251
1.00818
1.02822
                                                                               1-3

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The Aquatic Environment
      d Types of density stratification

        1) Density differences produce
           stratification which may be
           permanent,  transient, or
           seasonal.

        2) Permanent stratification
           exists for example where
           there is a heavy mass of
           brine in the deeper areas of
           a basin which does not respond
           to seasonal or other changing
           conditions.

        3) Transient stratification may
           occur with the recurrent
           influx of tidal water in an
           estuary for example,  or the
           occasional influx of cold
           muddy water into a deep lake
           or reservoir.

        4) Seasonal stratification is
           typically thermal in nature,
           and involves the annual
           establishment of the epilimnion,
           hypolimnion, and thermocline
           as described above.

        5) Density stratification is not
           limited to two-layered systems;
           three, four, or even more
           layers may be encountered in
           larger bodies  of water.

      e  A "plunge line" (sometimes called
        "thermal line") may develop at
        the mouth of a stream.  Heavier
        water flowing into a lake or
        reservoir plunges below the
        lighter water mass of the epiliminium
        to flow along at a lower level.  Such
        a line is usually marked by an
        accumulation of floating  debris.

      f  Stratification may be modified
        or entirely suppressed in some
        cases when deemed expedient, by
        means of a simple air'lift.

      The viscosity of water is  greater at
      lower temperatures (see Table 4).
        This is important not only in situations
        involving the control of flowing water
        as in a sand filter, but also since
        overcoming resistance to flow gen-
        erates heat, it is significant in the
        heating of water-by internal friction
        from wave and current action.
        Living organisms more easily support
        themselves in the more viscous
        (and also denser) cold waters of the
        arctic than in the less viscous warm
        waters of the tropics.  (See Table 4).

                   TABLE 4

VISCOSITY OF WATER (In millipoises at 1 atm)
Temp, o c
-in
- 5
0
5
. 10
30
1UU
Dissolved solids in g/L
0
OA n
21.4
17.94
15.19
13.10
8.00
. 84
5



18.1
15.3
13.2
8.1

10



18.24
15.5
13.4
8.2

30



18.7
16.0
13.8
8.6

     4  Surface tension has biological as well
        as physical significance.  Organisms
        whose body surfaces cannot be wet by
        water can either ride on the surface
        film or in some instances may be
        "trapped" on.the surface film'and be
        unable to re-enter the water.

     5  Heat or energy

        Incident solar radiation is the prime
        source of energy for virtually all
        organic and most inorganic processes
        on earth.  For the earth as a whole,
        the total amount (of energy) received
        annually must exactly balance that
        lost by reflection and radiation into
        space if climatic and related con-
        ditions are to remain relatively
        constant over geologic time.
 1-4

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                                                            The Aquatic Environment
   a For a given body of water,
     immediate sources of energy
     include in addition to solar
     irradiation:  terrestrial heat,
     transformation  of kinetic energy
     (wave and current action) to  heat,
     chemical and biochemical
     reactions,  convection from the
     atmosphere, and condensation of
     water vapor.

   b The proportion of light  reflected
     depends on the angle  of incidence,
     the temperature, color, and other
     qualities of the water; and the
     presence or absence  of films
     of lighter liquids such as oil.
     In general,  as the depth increases
     arithmetically, the light tends to
     decrease geometrically.  Blues,
     greens,  and yellows tend to
     penetrate most deeply while  ultra
     violet, violets, and orange-reds
     are most quickly absorbed.  On
     the order of 90% of the  total
     illumination which penetrates the
     surface  film is absorbed in the
     first 10  meters of even the clearest
     water, thus tending to warm the
     upper layers.

6  Water movements

   a Waves or rhythmic movement

     1)  The best known are traveling
        waves caused by wind.  These are
         effective only against objects near
        the surface.  They have little
         effect on the movement of large
        masses of water.

     2)  Seiches

         Standing waves or seiches occur
        in lakes,  estuaries,  and other
         enclosed bodies of water, but are
         seldom large enough to be
        observed.  An "internal wave or
         seich" is an oscillation in a
         submersed mass of water such
        as a hypolimnion,  accompanied
        by compensating oscillation in the
        overlying water so that no
      significant change in surface
      level is detected.  Shifts in
      submerged water masses of
      this type  can have severe effects
      on the biota  and also, on human
      water uses where withdrawals
      are  confined to a given depth.
      Descriptions and analyses of
      many other types and sub-types
      of waves  and wave-like movements
      may be found in the literature.

b  Tides

   1) Tides are the longest waves
      known, and are responsible  for
      the once or twice a  day rythmic
      rise and fall of the ocean level
      on most shores around the world.

   2) While part and parcel of the
      same phenomenon,  it is often
      convenient to refer  to the rise
      and  fall of the  water level as
      "tide, " and to  the^resulting
      currents  as  "tidal currents. "

   3) Tides are basically caused by the
      attraction of the sun and moon on
      water masses, large and small;
      however, it  is only  in the oceans
      and  possibly certain of the larger
      lakes that true tidal action has
      been demonstrated.  The patterns
      of tidal action  are enormously
      complicated by local topography,
      interaction with seiches, and other
      factors.  The  literature on tides
      is very large.

c  Currents (except  tidal currents)
   are steady arythmic water movements
   which have had major  study only in
   oceanography although they are
   most often observed in rivers and
   streams.   They  are primarily
   concerned with the translocation of
   water masses.  They may be generated
   internally by virtue of density changes,
   or externally by wind or terrestrial
   topography.   Turbulence phenomena
   or eddy currents  are largely respon-
   sible for lateral mixing in a current.
   These are of far  more importance
   in the economy of a body of water than
   mere laminar flow.
                                                                                    1-5

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The Aquatic Environment
       d  Coriolis force is a result of inter-
         action between the rotation of the
         earth, and the movement of masses
         or bodies on the earth.  The net
         result is a slight tendency for moving
         objects to veer to the right in the
         northern hemisphere, and to the
         left in the southern hemisphere.
         While the result in fresh waters is
         usually negligible,  it may be con-
         siderable in marine waters. For
         example, other factors permitting,
         there is a tendency in estuaries for
         fresh waters to move toward the
         ocean faster along the right bank,
         while salt tidal waters tend to
         intrude farther inland along the
         left bank.  Effects are even more
         dramatic in the open oceans.

       e  Langmuir circulation (or L. spirals)
         is the interlocking rotation of
         somewhat cylindrical masses of
         surface water under the influence
         of wind action.  The axes of the
         cylinders are parallel to the
         direction of the wind.
                               To somewhat oversimplify the
                               concept, a series of adjoining cells
                               might be thought of as chains of
                               interlocking gears in which at every
                               other contact the teeth are rising
                               while at the alternate contacts, they
                               are sinking.(Figure 2).

                               The result is elongated masses of
                               water rising or sinking together.
                               This produces the familiar  "wind
                               rows" of foam, flotsam and jetsam,
                               01- plankton often seen streaking
                               windblown lakes or oceans.  Certain
                               zoo-plankton struggling to maintain
                               a position near the surface tend to
                               collect in the down current between
                               two Langmuir  cells, causing such
                               an area to be called the "red dance",
                              .while the clear upwelling water
                               between is the "blue dance".

                               This phenomenon may be important
                               in water or plankton sampling on
                               a windy day.
               b
                                      b
_WATER
SURFACE
            WATER
            RISING
WATER
SINKING
                  Figure 2.  Langmuire  Spirals
                  b.  Blue  dance,  water  rising, r.  Red
                  dance,  water  sinking,  floating  or
                  swimming  objects  concentrated.
 1-6

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                                                               The Aquatic Environment
   6   The pH of pure water has been deter-
       mined between 5. 7 and 7. 01 by various
       workers.  The latter value is most
       widely accepted at the present time.
       Natural waters of course vary widely
       according to circumstances.

C  The elements of hydrology mentioned
   above represent a selection of some of
   the more conspicuous physical factors
   involved in working with water quality.
   Other items not specifically mentioned
   include: molecular structure of waters,
   interaction of water and radiation,
   internal pressure,  acoustical charac-
   teristics, pressure-volume-temperature
   relationships,  refractivity, luminescence,
   color, dielectrical characteristics and
   phenomena,' solubility,  action and inter-
   actions of gases, liquids and solids,
   water vapor, phenomena of hydrostatics
   and hydrodynamics in general.
REFERENCES

1  Buswell, A. M. and Rodebush,  W. H.
       Water. Sci. Am.  April 1956.

2  Dorsey, N. Ernest.  Properties of  '
       Ordinary Water - Substance.
       Reinhold Publ.  Corp. New York.
       pp. 1-673.  1940.

3  Fowle, Frederick E.  Smithsonian
       Physical Tables.  Smithsonian
       Miscellaneous Collection, 71(1),
       7th revised ed.,  1929.

4  Hutcheson, George  E.  A Treatise on
       Limnology.  John Wiley Company.
       1957.

This outline was prepared by H. W. Jackson,
Chief Biologist,  National Training Center,
Water Programs Operations, EPA, Cincinnati,
OH 45268.
                                                Descriptors:
                                                Aquatic Environment, Estuarine Environment,
                                                Lentic Environment, Lotic Environment,
                                                Currents,  Marshes,  Limnology, Water
                                                Properties
                                                                                   1-7

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                              THE AQUATIC ENVIRONMENT

                    Part 2:  The Aquatic Environment as an Ecosystem
 I  INTRODUCTION
                                        •. •
 Part 1 introduced the lithosphere and. the
 hydrosphere. Part 2 will deal with certain
 general aspects of the biosphere, or the
 sphere of life on this earth, which photo-
 graphs from space have shown is a finite
 globe in infinite space.

 This is the habitat of man and the other
 organisms.  His relationships  with the
 aquatic biosphere are our common concern.
II   THE BIOLOGICAL NATURE OF THE
    WORLD WE LIVE IN

 A  We can only imagine what this world
    must have been like before there was life.

 B  The world as we know it is largely shaped
    by the forces of life.

    1   Primitive forms of life created organic
       matter and  established soil.

    2   Plants cover the lands and enormously
       influence the forces of erosion.

    3   The nature  and rate of erosion affect
       the redistribution of materials
       (and mass)  on the surface of the
       earth (topographic changes).

    4   Organisms  tie  up vast quantities of
       certain chemicals, such as carbon
       and oxygen.

    5   Respiration of plants and animals
       releases carbon dioxide to the
       atmosphere in influential quantities.

    6   CO? affects the heat transmission of
       the atmosphere.

 C  Organisms respond to and in turn affect
    their environment. Man is one  of the
    most influential.
Ill.. ECOLOGY IS THE STUDY OF THE
    INTERRELATIONSHIPS BETWEEN
    ORGANISMS, AND BETWEEN ORGA-
    NISMS AND THEIR ENVIRONMENT.

 A The ecosystem- isrthe basic functional
    unit of ecology.  Any area of nature that
    includes living'Organisms and nonliving
    substances interacting to produce an
    exchange of materials between the living
    and nonliving parts constitutes an
    ecosystem. (Odum,  1959)

    1  From a structural standpoint, it is
       convenient to recognize four
       constituents as composing an
       ecosystem (Figure 1).

       a  Abiotic NUTRIENT  MINERALS
          which are the physical  stuff of
          which living protoplasm will be
          synthesized.

       b  Autotrophic (self-nourishing) or
          PRODUCER organisms.  These
          are largely the green plants
          (holophytes),  but other minor
          groups must also be included
          (See Figure 2). They assimilate
          the nutrient minerals,  by the use
          of considerable energy, and combine
          them into living organic substance.

       c  Heterotrophic (other-nourishing)
          CONSUMERS (holozoic). are chiefly
          the animals.  They ingest  (or eat)
          and digest organic matter, releasing
          considerable energy in the process.

       d Heterotrophic REDUCERS are chiefly
          bacteria  and fungi that return
          complex organic compounds back to
          the original abiotic mineral condition,
          thereby releasing the remaining
          chemical energy.

    2  From a functional standpoint,  an
       ecosystem has two parts (Figure 2)
 BI.2le.l.74
                                                                                   1-9

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The Aquatic Environment
                                CO  NSUMERS
        PRO DUCERS
              REDUCERS
                                    NUTRIENT
                                    MINERALS
                                      FIGURE 1
     a  The autotrophic or producer
        organisms, which construct
        organic substance.

     b  The heterotrophic or consumer and
        reducer organisms which destroy
        organic substance.

   3  Unless the autotrophic and hetero-
     trophic phases of the cycle approximate
     a dynamic equilibrium, the ecosystem
     and the environment will change.

   Each of these groups includes simple,
   single-celled representatives, persisting
   at lower levels on the evolutionary stems
   of the higher organisms. (Figure 2)

   1  These groups span the gaps between the
     higher kingdoms with a multitude of
     transitional forms.  They are collectively
     called the PROTISTA.
    2  Within the protista, two principal sub-
       groups can be defined on the basis of
       relative complexity of structure.

       a  The bacteria and blue-green algae,
         lacking a nuclear membrane may
         be considered as the lower protista
         (or Monera).

       b  The single-celled-algae and
         protozoa are best referred to as
         the Higher Protista.

    Distributed throughout these groups will
    be found most of the traditional "phyla"
    of classic biology.
IV  FUNCTIONING OF THE ECOSYSTEM

 A  A food chain is the transfer of food energy
    from plants through a series of organisms
    with repeated eating and being eaten.
    Food chains are not isolated sequences but
    are interconnected.
  1-10

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                                                          The Aquatic Environment
RELATIONSHIPS  BETWEEN  FREE  LIVING AQUATIC  ORGANISMS

          Energy Flows from Left to Right, General Evolutionary Sequence is Upward

    PRODUCERS    |

 Organic Material Produced,
 Usually by Photosynthesis I
                             CONSUMERS
                         Organic Material Ingested or
                                Consumed
                             Digested Internally
     REDUCERS
Organic Material Reduced
by Extracellular Digestion
and Intracellular Metabolism
to Mineral Condition
     ENERGY STORED
                            ENERGY RELEASED
                                                          ENERGY RELEASED
Flowering Plants and
Gymnosperms
Club Mosses, Ferns
Liverworts, Mosses
Multicellular Green
Algae
Red Algae
Brown Algae
Arachnids
Insects
Crustaceans
Segmented Worms
Molluscs
Bryozoa
Rotifers
Roundworms
Flatworms
Mammals
Birds
Reptiles
Amphibians
Fishes
Primitive
Chordates
Echinoderms

Coelenterates
Sponges
Basidiomycetes

Fungi Imperfect!
Ascomycetes

Higher Phycomycetes
         DEVELOPMENT OF MULTICELLULAR OR COENOCYTIC STRUCTURE

               H  I  G" H  E  R      P  R 0  T  I~S  T  A
Unicellular Green Algae
Diatoms
Pigmented Flagellates
Protozoa
Amoeboid Cilliated
Flagellated, Suctoria
(non-pigmented)
Lower
Phycomycetes
(Chytridiales, et. al. )
                     DEVELOPMENT OF A NUCLEAR MEMBRANE
                LOWER      PROTISTA
                                or:_  Monera)

                                                          Actinomycetes

                                                      Spirochaetes
Blue Green Algae



       Phototropic Bacteria



              Chemotropic Bacteria
                                   I  I
                                            Saprophytic
                                            Bacterial
                                            Types
 BI.ECO.pl. 2a. 1.69
                               FIGURE 2
                                                                              1-11

-------
The Aquatic Environment
B  A food web is the interlocking pattern of
   food chains in an ecosystem.  (Figures 3, 4)
   In complex natural communities, organisms
   whose food is obtained by the same number
   of steps are said to belong to the same
   trophic (feeding) level.

C  Trophic Levels

   1  First - Green plants (producers)
      (Figure 5)  fix biochemical energy and
      synthesize basic organic substances.
      This is 'primary production .
   2  Second - Plant eating animals (herbivores)
      depend on the producer organisms for
      food.

   3  Third - Primary carnivores, animals
      which feed on herbivores.

   4  Fourth - Secondary carnivores feed on
      primary carnivores.

   5  Last- - Ultimate carnivores are the last
      or ultimate level of consumers.
D Total Assimilation

   The amount of energy which flows through
   a trophic level is distributed between the
   production of biomass (living substance),
   and the demands of respiration (internal
   energy use by living organisms) in a ratio
   of approximately 1:10.
E Trophic Structure of the Ecosystem

   The interaction of the food chain
   phenomena (with energy loss at each
   transfer) results in various communities
   having definite trophic structure or energy
   levels. Trophic structure may be
   measured and described either in terms
   of the standing crop per unit area or in
   terms  of energy fixed per unit area per
   unit time at successive trophic levels.
   Trophic structure and function can be
   shown  graphically by means of ecological
   pyramids (Figure 5).
        Figure 3. Diagram of the pond ecosystem. Basic units are as follows:' I, abiotic substances-basic inorganic and
        organic compounds; HA, producers-rooted vegetation; IIB, producers—phytoplankton; IU-1A, primary consumers
         (herbivores)-bottom formi; Ill-IB, primary consumers (herbivores)-zooplankton; III-2, secondary consumers (or*
        oJvoru); III-3. tertiary consumers (secondary carnivores); IV, decomposers-bacteria and fungi of decay.
 1-12

-------
                                                               The Aquatic Environment
        .•••// \ Light .':;;;_	
    .•   /  •  \  •.  s. •.    ••..              	     vT   —————=»_
   Nutrient
   supply
    Bacterial
     action
                        A
Death and decay
 \
Predatory
animals
Figure 4.  A  MARINE ECbSYSTEM (After Clark,  1954 and Patten, .1966).
                                                                      1-13

-------
 The Aquatic Environment

1






\r<
(a)
Decomposers II Carnivores (Secondar
[| Carnivores (Primary
1 [ Herbivores
Producers ]
*
1 1
1 1
(c)
.. rl~l •
(•-U777TT7T
f U/V ///////// 1
' '/ /" / 1 1 1 1 1 1 1 1 1 1 1 1 1 I I 1 1
 Figure 5.  HYPOTHETICAL PYRAMIDS of
 (a) Numbers of individuals, (b) Biomass, arid
 (c) Energy (Shading Indicates Energy Loss).
V  BIOTIC COMMUNITIES

A Plankton are the macroscopic and
   microscopic animals, plants,  bacteria,
   etc., floating free in the open water.
   Many clog filters, cause tastes, odors,
   and other troubles in water supplies.
   Eggs and larvae of larger forms are
   often present.

   1  Phytoplankton are plant-like.  These
      are the dominant producers of the
      waters, fresh and salt, "the grass
      of the seas".

   2  Zooplankton are animal-like.
      Includes many different animal types,
      range in size  from minute protozoa
      to gigantic marine jellyfishes.

B  Periphyton (or Aufwuchs) - The communities
   of microscopic organisms associated with
   submerged surfaces of any type or depth.
    Includes bacteria, algae,  protozoa, and
    other microscopic animals, and often the
    young or embryonic stages of algae and
    other organisms that normally grow up
    to become a part of the benthos (see below).
    Many planktonic types  will also adhere
    to surfaces as periphyton;  and some
    typical periphyton may break off and
    be collected as plankiers.

  C Benthos are the plants and animals living
    on, in, or closely associated with the
    bottom.  They include  plants and
    invertebrates.

  D Nekton are the community of strong
    aggressive swimmers  of the open waters,
    often called pellagic.   Certain fishes,
    whales, and invertebrates such as
    shrimps and squids are included here.

  E The marsh community is based .on larger
    !!higher" plants, floating and emergent.
    Both marine and freshwater marshes are
    areas of enormous biological production.
    Collectively known as "wetlands",  they
    bridge the gap between the waters  and the
    dry lands.

VI  PRODUCTIVITY

  A The biological resultant of all physical
    and chemical factors in the quantity of
    life that may actually be present.  The
    ability to produce this  "biomass" is
    often referred to as the "productivity"
    of a body of water.  This is neither good
    nor bad per se.  A water of low pro-
    ductivity is a "poor" water biologically,
    and also a relatively "pure" or "clean"
    water; hence desirable as a water  supply
    or a bathing beach. A productive water
    on the other hand may  be a nuisance to
    man or highly desirable.  It is a nuisance
    if foul odors and/or weed-chocked
    waterways result,  it is desirable if
    bumper crops of bass, catfish,  or
    oysters are produced.  Open oceans have
    a low level of productivity in general.
   1-14

-------
                                                              The Aquatic Environment
REFERENCES

1  Clarke.  G. L.   Elements of Ecology.
      John Wiley & Sons, New York.   1954.

2  Cooke, W.B.  Trickling Filter Ecology.
      Ecology 40(2):273-291.   1959.

3  Hanson,  E.D.   Animal Diversity.
      Prentice-Hall,  Inc., New Jersey.  1964.

4  Hedgpeth,  J. W.  Aspects of the Estuarine
      Ecosystem.  Amer. Fish. Soc., Spec.
      Publ. No. 3.   1966.
 5  Odum, E.P.  Fundamentals of Ecology.
      W.B. Saunders Company,
      Philadelphia and London.   1959.

 6  Patten, B.C.   Systems Ecology.
      Bio-Science.   16(9).   1966.

 7  Whittaker, R.H.  New Concepts of
      Kingdoms. Science 163:150-160. 1969.
This outline was prepared by H. W. Jackson,
Chief Biologist,  National Training Center,
Water Programs Operations, EPA,
 Cincinnati,  OH  45268.
                                                Descriptors:
                                                Aquatic Environment, Estuarine  Environment,
                                                Lentic Environment,  Lotic Environment,
                                                Currents, Marshes,  Limnology, Water Properties
                                                                                  1-15

-------
THE AQUATIC ENVIRONMENT

Part 3. The Freshwater Environment .
I INTRODUCTION

The freshwater environment as considered
herein refers to those inland waters not
detectably diluted by ocean waters, although
the lower portions of rivers are subject to
certain tidal flow effects.

Certain atypical inland waters such as saline
or alkaline lakes, springs, etc., are not
treated, as the main objective here in typical
inland water.

All waters have certain basic biological cycles
and types of interactions most of which have
already been presented, hence this outline
will concentrate on aspects essentially
peculiar to fresh inland waters.
H PRESENT WATER QUALITY AS A
FUNCTION OF THE EVOLUTION OF
FRESH WATERS

A The history of a body of water determines
its present condition. Natural waters have
evolved in the course of geologic time
into what we know today.

B Streams

Inthe-course of their evolution, streams
in general pass through four stages of
development which may be called: birth,
youth, maturity, and old age.

These terms or conditions may be
employed or considered in two contexts:
temporal, or spatial. In terms of geologic
time, a given point in a stream may pass
through each of the stages described below
or: at any given time, these various stages
of development can be loosely identified
in successive reaches of a stream traveling
from its headwaters to base level in ocean
or major lake.
1 Establishment or birth. This
might be a "dry run" or headwater
stream-bed, before it had eroded
down to the level of ground water.

During periods of run- off after a
rain or snow-melt, such a gulley
would have a flow of water which
might range from torrential to a
mere trickle. Erosion may proceed
rapidly as there is no. permanent
aquatic flora or fauna to stabilize
streambed materials. On the other
hand, terrestrial grass or forest
growth may retard erosion. When
the run-off has passed, however,
the "streambed" is dry.

2 Youthful streams. When the
streambed is eroded below the
ground water level, spring or
seepage water enters, and the
stream becomes permanent. An
aquatic flora and fauna develops
and water flows the year round.
Yout hful streams typically have a
relatively steep gradient, rocky beds,
with rapids, falls, and small pools.

3 Mature streams. Mature streams
have wide valleys, a developed
flood plain, are deeper, more
turbid, and usually have warmer
water, sand, mud, silt, or clay
bottom materials which shift with
increase in flow. In their more
favorable reaches, streams in this
condition are at a peak of biological
productivity. Gradients are moderate,
riffles or rapids are often separated
by long pools.

4 In old age, streams have approached
geologic base level, us,ually the
ocean. During flood stage they scour
their beds and deposit materials on
the flood plain which may be very
broad and flat. . During normal flow
the channel is refilled and many
shifting bars are developed.
BI. 21e.l.74
1-17

-------
 The Aquatic Environment
         (Under the influence of man this
         pattern may be broken up,  or
         temporarily interrupted.  Thus an
         essentially "youthful" stream might
         take on some of the characteristics
         of a "mature" stream following soil
         erosion,  organic enrichment,  and
         increased surface  runoff.  Correction
         of these conditions might likewise be
         followed by at least a partial reversion
         to the "original" condition).

C Lakes and Reservoirs

   Geological factors which significantly
   affect the nature of either a stream or
   lake include the following:

   1  The geographical location of the
      drainage  basin or watershed.

   2  The size and shape of the drainage
      basin.

   3  The general topography, i.e.,
      mountainous or plains.

   4  The character of the bedrocks and
      soils.

   5  The character,  amount, annual
      distribution, and rate of precipitation.

   6  The natural vegetative cover of the
      land, is, of course, responsive to and
      responsible for many of the above
      factors and is also severely subject
      to the whims of civilization.  This
      is one of the major factors determining
      run-off versus soil absorption, etc.

D Lakes have a developmental history which
   somewhat parallels that of streams.  This
   process is often referred to as natural
   eutrophication.

   1  The methods of formation vary greatly,
      but all influence the character and  '
      subsequent history of the lake.

      In glaciated areas, for example, a
      huge  block of ice may have  been covered
      with till.   The glacier retreated,  the
      ice melted, and the resulting hole
1-18
   became a lake.  Or,  the glacier may
   actually scoop out a hole.   Landslides
   may dam valleys, extinct volcanoes  may
   collapse, etc., etc.

2  Maturing or natural eutrophication of
   lakes.

   a  If not already present shoal areas
      are developed through erosion
      and deposition of the shore material
      by wave action and undertow.

   b  Currents produce bars across bays
      and thus cut off irregular areas.

   c  Silt brought in by tributary streams
      settles out  in the quiet lake water

   d  Algae grow attached to surfaces,
      and floating free as plankton.  Dead
      organic matter begins to accumulate
      on the bottom.

   e  Rooted aquatic plants grow on
      shoals and  bars, and in doing so
      cut off bays and contribute to the
      filling of the lake.

   f  Dissolved carbonates and other
      materials are precipitated in the
      deeper portions of the lake in part
      through the action of plants.

   g  When filling is well advanced,
      mats of sphagnum moss may extend
      outward from the shore.  These
      mats are followed by sedges and
      grasses which finally convert the
      lake into a  marsh.

3  Extinction of lakes.  After lakes reach
   maturity, their progress toward
   filling up is accelerated.   They become
   extinct through:

   a  The downcutting of the outlet.

   b  Filling with detritus eroded from
      the shores  or brought in by
      tributary streams.

   c  Filling by the accumulation of the
      remains of vegetable materials
      growing in  the lake itself.
      (Often two or three processes may
      act concurrently)

-------
                                                                 The Aquatic Environment
III  PRODUCTIVITY IN FRESH WATERS

 A Fresh waters in general and under
    natural conditions by definition have a
    lesser supply of dissolved  substances  ;
    than marine waters, and thus a lesser
    basic potential for the  growth of aquatic
    organisms.   By  the same token, they
    may be  said to be more sensitive to the
    addition of extraneous  materials
    (pollutants, nutrients,  etc.) The
    following notes are directed toward
    natural  geological and  other environ-
    mental factors as they affect the
    productivity of fresh waters.

 B Factors Affecting Stream Productivity
    (See Table 1)

                TABLE 1

    EFFECT OF SUBSTRATE ON STREAM
                PRODUCTIVITY*

    (The productivity of sand bottoms is
    taken as 1)
         Bottom Material
  Sand
  Marl
  Fine Gravel
  Gravel and silt
  Coarse gravel
  Moss on fine gravel
  Fissidens (moss) on coarse
    ;   gravel
  Ranunculus (water buttercup)
  Watercress
  Anacharis  (waterweed)
Relative
Productivity
     1
     6
     9
    14
    32
    89
   111

   194
   301
   452
 ^Selected from Tarzwell 1937

    To be productive of aquatic life, a
    stream must provide adequate nutrients,
    light, a suitable temperature, and time
    for growth to take place.

    1 Youthful streams, especially on rock
      or sand substrates are low in essential
      nutrients.  Temperatures in moun-
      tainous regions are usually low,  and
      due to the steep gradient,  time for
      growth is short.  Although ample
      light is available, growth of true
      plankton is thus greatly limited.
       2  As the stream flows toward a more
          "mature" condition, nutrients tend to
          accumulate, and gradient diminishes
         . and so time of flow increases, tem-
          perature tends to increase, and
          plankton flourish..

          Should a heavy load of inert silt
          develop  on  the other hand, the
          turbidity would reduce the light
          penetration and consequently the
          general  plankton production would
          diminish.

       3  As the stream approaches base level
          (old age) and the time available for
          plankton growth increases, the
        •  balance  between turbidity, nutrient
          levels,  and temperature and other
          seasonal conditions,  determines the
          overall  productivity.

  C Factors Affecting the Productivity of
    lakes (See Table  2)

        1  The size,  shape, and depth of the
          lake basin.  Shallow water is more
          productive  than deeper water since
          more light  will reach the bottom to
          stimulate rooted plant growth.  As
          a corollary,  lakes with more shore-
          line, having more shallow water,
          are in general more productive.
          Broad shallow lakes and reservoirs
          have the greatest production potential
          (and hence  should be avoided for
          water supplies).

                TABLE 2

         EFFECT  OF SUBSTRATE
        ON LAKE PRODUCTIVITY *

(The productivity of sand bottoms is taken as 1)
Bottom Material
Sand
Pebbles
Clay
Flat rubble
Block rubble
Shelving rock
Relative Productivity
1
4
8
9
11
77
                   * Selected from Tarzwell 1937
                                                                                       1-19

-------
 The Aquatic Environment
    2  Hard waters are generally more
      productive than soft waters as there
      are more plant nutrient minerals
      available.  This is often greatly in-
      fluenced by the character of the soil
      and rocks in the watershed and the
      quality and quantity of ground water
      entering the lake.  In general, pH
      ranges of 6. 8 to 8. 2 appear to be
      most productive.

    3  Turbidity reduces productivity as
      light penetration is reduced.

    4  The presence or absence of thermal
      stratification with its semi-annual
      turnovers affects productivity; by
      distributing nutrients throughout the
      water mass.

    5  Climate, temperature, prevalence of
      ice and snow, are also of course
      important.

    Factors  Affecting the Productivity  of
    Reservoirs

    1  The productivity of reservoirs is
      governed by much the same principles
      as that of lakes, with the difference
      that the water level is much more
      under the control of man.   Fluctuations
      in water  level can be used to de-
      liberately increase or decrease
      productivity.  This can be demonstrated
      by a comparison of the TVA reservoirs
      which practice a summer drawdown
      with some of those in the west where
      a winter  drawdown is the rule.

    2  The level at which water is removed •
      from a reservoir is important to the
      productivity of the stream below.
      The hypolimnion may be anaerobic
      while  the epilimnion is aerobic,  for
      example, or the epilimnion is poor in
      nutrients while the hypoli'mnion is
      relatively rich.

   3  Reservoir discharges also profoundly
      affect the DO, temperature, and
      turbidity  in the stream below a dam.
      Too much fluctuation in flow may
      permit sections of the stream to dry,
      or provide inadequate dilution for
      toxic waste.
IV CULTURAL EUTROPHICATION

 A The general processes of natural
   eutrophication, or natural enrichment
   and productivity have been briefly out-
   lined above.

 B When the activities of man speed up
   these enrichment processes by intro-
   ducing unnatural quantities of nutrients
   (sewage, etc.) the result is often called
   cultural eutrophication.  This term is
   often extended beyond its original usage
   to include the enrichment (pollution) of
   streams, estuaries, and even oceans, as
   well as lakes.
V CLASSIFICATION OF LAKES AND
   RESERVOIRS

A The productivity of lakes and impound-
   ments is such a1 conspicuous feature that
   it is often used as a convenient means of
   classification.

   1  Oligotrophic lakes are the younger,
      less productive lakes, which are deep,
      have clear water, and usually support
      Salmonoid fishes in their deeper waters.

   2  Eutrophic lakes  are more mature,
      more turbid, and richer.  They are
      usually shallower.  They are richer
      in dissolved solids; N,  P, and Ca are
      abundant.  Plankton is abundant and
      there is often a rich bottom fauna.

   3  Dystrophic lakes, such as bog lakes,
      are low in Ph,  water yellow to brown,
      dissolved solids, N, P,  and Ca scanty
      but humic materials abundant, bottom
      fauna and plankton poor,  and fish
      species are limited.

B Reservoirs may also be classified as
   storage, and run of the river.

   1  Storage reservoirs have a large
      volume in relation to their inflow.

   2  Run of the river reservoirs have  a
      large flow-through in relation to their
      storage value.
1-20

-------
                                                                The Aquatic Environment
  C According to location, lakes and
    reservoirs may be classified as polar,
    temperate, or tropical.   Differences in
    climatic and geographic conditions
    result in differences in their biology.
VI  SUMMARY

 A A body of water such as a lake, stream,
    or estuary represents an intricately
    balanced system in a state of dynamic
    equilibrium.  Modification imposed at
    one point in the system automatically
    results in compensatory adjustments at
    associated points.

 B The more thorough our knowledge of the
    entire system, the better we  can judge
    where to impose control measures to
    achieve a desired result.
 6   Tarzwell,  Clarence M.  Experimental
      Evidence on the Value of Trout 1937
      Stream Improvement in Michigan.
      American Fisheries Society Trans.
      66:177-187.  1936.

 7   U. S. Dept. of Health, Education, and
      Welfare.  Public Health Service.
      Algae and Metropolitan Wastes.
      Transactions of a seminar held
      April 27-29,  1960 at the Robert A.
      Taft Sanitary Engineering Center.
      Cincinnati, OH. No.  SECTRW61-3.

 8   Ward and Whipple. Fresh Water
      Biology. (Introduction).  John
      Wiley Company.  1918.
 REFERENCES

 1  Chamberlin,  Thomas C. and Salisburg,
       Rollin P.  Geological Processes and
       Their Results.  Geology 1: pp i-xix,
       and 1-654. Henry Holt and Company.
       New York. 1904.

 2  Frey,  David  G.  Limnology in North
       America.   Univ.  Wise. Press.  1963.

 3  Hutcheson, George E.  A Treatise on
       Limnology Vol. I  Geography, Physics
       and Chemistry.  1957.  Vol. II.
       Introduction to Lake Biology and the
       Limnoplankton.  1115pp.  1967.
       John Wiley Co.

 4  Hynes, H.B.N.  The Ecology of Running
       Waters.  Univ. Toronto Press.
       555 pp.  1970.

 5  Ruttner,  Franz.   Fundamentals of
       Limnology.  University of Toronto
       Press,  pp. 1-242.  1953.
 This outline was prepared by H. W.  Jackson,
 Chief Biologist, National Training Center,
 Water Programs Operations, EPA,  Cincinnati,
 OH 45268.
 Descriptors:
Aquatic Environment, Estuarine  Environment,
Lentic Environment, Lotic Environment,
 Currents, Marshes, Limnology, Water
 Properties
                                                                                     1-21

-------
THE AQUATIC ENVIRONMENT
Part 4. The Marine Environment and its Role in the Total Aquatic Environment
TABLE i
I INTRODUCTION

A The marine environment is arbitrarily
defined as the water mass extending.
beyond the continental land masses,
including the plants and animals harbored
therein. This water mass is large and
deep, covering about 70 percent of the
earth's surface and being as deep as
7 miles. The salt content averages
about 35 parts per thousand. Life extends
to all depths.

B The general nature of the water cycle on
earth is well known. Because the largest
portion of the surface area of the earth
is covered with water, roughly 70 percent
of the earth's rainfall is on the seas.
(Figure 1)
>*w
SE« SURFACE

Figure 1. THE WATER C1CLE
Since .roughly one third of the
rain which falls on the land is again
recycled through the atmosphere
(see Figure 1 again), the total amount
of water washing over the earth's surface
is significantly greater than one third of
the total world rainfall. It is thus not
surprising to note that the rivers which
finally empty into the sea carry a
disproportionate burden of dissolved and
suspended solids picked up from the land.
The chemical composition of this burden
depends on the composition of the rocks
and soils through which the river flows,
the proximity of an ocean, the direction
of prevailing winds, and other factors.
This is the substance of geological erosion.
(Table 1)

BI. 21e.l.74
PERCENTAGE COMPOSITION OF THE MAJOR IONS
OF TWO STREAMS AND SEA WATER

(Data from Clark, F.W., 1924, "The Composition of River
and Lake Waters of the United States", U.S. Geol. Surv.,
Prof. Paper No. 135; Harvey, H. W., 1957, "The Chemistry
and Fertility of Sea Waters", Cambridge University Press,
Cambridge)
Ion
Na
K
Ca
Mg
Cl
•so4
C03
Delaware River
at
Lambertville, N. J.
6.70
1.46
17.49 ,
4.81
4.23
17.49
32.95
Rio Grande
at
Laredo, Texas
14.78
.85
13.73
3.03
21.65
30. 10
11.55
Sea Water
30.4
1. 1
1.16
3.7
55.2
7.7.
•mco, 0.35
o
C For this presentation, the marine
environment will be (1) described using
an ecological approach, (2) characterized
ecologically by comparing it with fresh-
water and estuarine environments, and
(3) considered as a functional ecological
system (ecosystem).
H FRESHWATER, ESTUARINE, AND
MARINE ENVIRONMENTS

Distinct differences are found in physical,
chemical, and biotic factors in going from
a freshwater to an oceanic environment.
In general, environmental factors are more
constant in freshwater (rivers) and oceanic
environments than in the highly variable
and harsh environments of estuarine and
coastal waters. (Figure 2)

A Physical and Chemical Factors

Rivers, estuaries, and oceans are
compared in Figure 2 with reference to
the relative instability (or variation) of
several important parameters. In the
oceans, it will be noted, very little change
occurs in any parameter. In rivers, while
"salinity" (usually referred to as "dissolved
solids") and temperature (accepting normal
seasonal variations) change little, the other
four parameters vary considerably. In
estuaries, they all change.
1-23

-------
  The Aquatic Environment
Type of environment
and general direction
 of water movement
Salinity
                                     Degree of instability
Temperature
 Water
elevation
Vertical
 strati-
 fication
 Avail-
 ability
   of
nutrients
(degree)
Turbidity
 Riverine
    Oceanic
       Figure2 .  RELATIVE VALUES OF VARIOUS PHYSICAL AND CHEMICAL FACTORS
                  FOR RIVER, ESTUARINE, AND OCEANIC ENVIRONMENTS
 B  Biotic Factors

    1 A complex of physical and chemical
      factors determine the biotic composi-
      tion of an environment.  In general,
      the number of species in a rigorous,
      highly variable environment tends to be
      less than the number in a more stable
      environment (Hedgpeth, 1966).

    2 The dominant animal species (in
      terms of total biomass) which occur
      in estuaries are often transient,
      spending only a part of their lives in
      the estuaries.  This results in better
      utilization of a rich environment.
                           C Zones of the Sea

                             The nearshore environment is often
                             classified in relation to tide level and
                             water depth.  The nearshore and offshore
                             oceanic regions together, are often
                             classified with reference to light penetra-
                             tion and water depth.  (Figure 3)

                             1  Neritic - Relatively shallow-water
                                zone which extends from the high-
                                tide mark to the edge of the
                                continental shelf.
  1-24

-------
                                               The Aquatic Environment
                       MARINE ECOLOGY
                                   _____ _ ___ _/-„
                                                            "
                              S//S/SSSSSS/JSSSSS':"
                                     wsssssssssss
      opt/Of*

BENTHIC (Bottom)
  Supro-IIMorol
  Littorol 0/MarfiJal)
  Subliftarot
    Inntr
    Ovt«r
            FIGURE 3—Classification of marine environments
   a  Stability of physical factors is
      intermediate between estuarine
      and oceanic environments.

   b  Phytoplankters are the dominant
      producers but in some locations
      attached algae are also important
      as producers.

   c  The animal consumers are
      zooplankton, nekton, and benthic
      forms.

2  Oceanic - The region of the ocean
   beyond the continental shelf.  Divided
   into three parts, all relatively
   poorly populated compared to the
   neritic zone.

   a  Euphotic zone -  Waters into which
      sunlight penetrates (often to the
      bottom in the neritic zone).  The
      zone of primary productivity often
      extends to 600 feet below the surface.
                                         1) Physical factors fluctuate
                                            less than in the neritic zone.

                                         2) Producers are the phyto-
                                            plankton and consumers are
                                            the zooplankton and nekton.

                                      b  Bathyal zone - From the bottom
                                         of the euphotic zone to about
                                         2000 meters.

                                         1) Physical factors relatively
                                            constant but light is absent.

                                         2) Producers are absent and
                                            consumers are scarce. '

                                      c  Abyssal zone - All the sea below
                                         the bathyal zone.

                                         1) Physical factors more con-
                                            stant than in bathyal zone.

                                         2) Producers absent and consumers
                                            even less abundant than in the
                                            bathyal zone.
                                                                       1-25

-------
  The Aquatic Environment
III  SEA WATER AND THE BODY FLUIDS

 A Sea water is a remarkably suitable
    environment for living cells, as it
    contains all of the chemical elements
    essential to the growth and maintenance
    of plants and animals.  The ratio and
    often the concentration of the major
    salts of sea water are strikingly similar
    in the cytoplasm  and body fluids of
    marine organisms.  This similarity is
    also evident, although modified somewhat
    in the body fluids of fresh  water and
    terrestrial animals.  For example,
    sterile sea water may be used in
    emergencies as a substitute for blood
    plasma in man.

 B Since marine organisms have an internal
    salt  content similar to that of their
    surrounding medium (isotonic condition)
    osmoregulation poses no problem.  On the
    other hand,  fresh water  organisms are
    hypertonic (osmotic pressure of body
    fluids is higher than that of the surround-
    ing water).  Hence, fresh water animals
    must constantly expend more energy to
    keep water out (i.e.,  high osmotic
    pressure fluids contain more salts, the
    action being then to dilute this concen-
    tration with more water).

    1  Generally, marine invertebrates are
       narrowly poikilosmotic, i.e.,  the salt
       concentration of the body fluids changes
       with that of the external medium. This
       has  special significance in estuarine
       situations where salt  concentrations
       of the water  often vary considerably
       in short periods of time.

    2  Marine bony fish (teleosts) have lower
       salt content internally than the external
       environment (hypotonic). In order to
       prevent dehydration, water is ingested
       and  salts are excreted through special
       cells in the gills.
IV FACTORS AFFECTING THE DISTRI-
   BUTION OF MARINE AND ESTUARINE
   ORGANISMS

 A Salinity.  Salinity is the single most
   constant and controlling factor in the
   marine environment, probably followed
   by temperature.  It ranges around
   35, 000 mg. per liter,  or  "35 parts per
   thousand" (symbol: 35%0) in the language
   of the oceanographer.  While variations
   in the open ocean are relatively small,
   salinity decreases rapidly as one
   approaches shore and proceeds through
   the estuary and up into fresh water with
   a salinity of "0 %„ (see Figure  2)

 B Salinity and temperature as limiting
   factors in ecological distribution.

   1  Organisms differ in the salinities
      and temperatures in which they
      prefer to live, and in the variabilities
      of these parameters which they can
      tolerate.  These preferences and
      tolerances often change with successive
      life history stages,  and in turn often
      dictate where the organisms live:
      their "distribution."

   2  These requirements or preferences
      often lead to extensive migrations
      of various species for  breeding,
      feeding, and growing stages.  One
      very important result of this is that
      an estuarine environment is an
      absolute necessity for  over  half of
      all coastal commercial and  sport
      related species of fishes and invertebrates,
      for either all  or certain portions of their
      life histories. (Part V, figure 8)

   3  The Greek word roots  "eury"
      (meaning wide) and "steno"  (meaning
      narrow) are customarily combined
      with such words as "haline" for salt,
      and "thermal" for temperature,  to
      give us  "euryhaline" as an adjective
      to characterize an organism able to
      tolerate a wide range of salinity, for
      example; or "stenothermal" meaning
      one which cannot stand much change
      in temperature. "Meso-" is a prefix
      indicating an intermediate capacity.
   1-26

-------
The Aquatic Environment
Marine, estuarine, and fresh water
organisms. (See Figure 4)
Fresh Water
Stenohaline
Marine
Stenohaline
Salinity
ca.;35
Figure 4. Salinity Tolerance of Organisms

1 Offshore marine organisms are, in
general, both Stenohaline and
stenothermal unless, as noted above,
they have certain life history require-
ments for estuarine conditions.

2 Fresh water organisms are also
Stenohaline, and (except for seasonal
adaptation) meso- or stenothermal.
(Figure 2)

3 Indigenous or native estuarine species
that normally spend their entire lives
in the estuary are relatively few in
number. (See Figure 5). They are
generally meso- or euryhaline and
meso- or eurythermal..
10
15 20 25 30 35
lity
Figure 5. DISTRIBUTION OF
ORGANISMS IN AN ESTUARY
a Euryhaline, freshwater
b Indigenous, estuarine, (mesohaline)
c Euryhaline, marine
4 Some well known and interesting
examples of migratory species which
change their environmental preferences
with the life history stage include the
shrimp (mentioned above), striped bass,
many herrings and relatives, the salmons,
and many others. None are more
dramatic than the salmon hordes which
lay their eggs in freshwater streams,
migrate far out to sea to feed and grow,
then return to the stream where they
hatched to lay their own eggs before
dying.

5 Among euryhaline animals landlocked
(trapped), populations living in lowered
salinities often have a smaller maximum
size than individuals of the same species
living in more saline waters. For
example, the lamprey (Petromyzon
marinus) attains a length of 30 - 36"
in the sea, while in the Great Lakes
the length is 18 - 24".

Usually the larvae of aquatic organisms
are more sensitive to changes in
salinity than are the adults. This
characteristic both limits and dictates
the distribution and size of populations.

D The effects of tides on organisms.

1 Tidal fluctuations probably subject
the benthic or intertidal populations
to the most extreme an'd rapid variations
of environmental stress encountered
in any aquatic habitat. Highly specialized
communities have developed in this
zone, some adapted to the rocky surf
zones of the open coast, others to the
muddy inlets of protected estuaries.
Tidal reaches of fresh water rivers,
sandy beaches, coral reefs and
mangrove swamps in the tropics; all
have their own floras and faunas. All
must emerge and flourish when whatever
wate'r there is rises and covers or
tears at them, all must collapse or
retract to endure drying, blazing
tropical sun, or freezing arctic ice
during the low tide interval. Such a
community is depicted in Figure 6.
1-27

-------
The Aquatic Environment
®
    SNAILS

    Littorina neritoides
    L. rudis
    L. obtusata
    ' L. littorea

    P,AiWACLES

    Chthamalus .stellatus
    Balanus balanoides
    R. pert'oratus
                                  ^Avv
^&m^*^^^  ,.
"t*^W:V^\^-5^r^k€:?,c
& »$W;/ v::\;;fe.;:C;^:^  «
) * « o  %t;^:,;;:.\v^)y/;c;;::^fe-v-;:i
           J^^^^N^^fc^i"
          tfe^ "1 - W .
                                    Figure'6

            Zonation of plants, snails, and barnacles on a rocky shore.  While
            this diagram is based on the  situation on the southwest coast of
            England, the general idea of  zonation may be applied to any  temper-
            atf rocky ocean shore,  though the species will differ.  The gray
            zone consists largely of lichens.  At the left is the zonation  of rocks
            with exposure too extreme to support algae; at the right, on a  less
            exposed situation, the animals are mostly obscured by the algae.
            Figures at the right hand margin refer to the percent of time that
            the zone is exposed to the air, i. e.,  the time that the tide is out.
            Three major zones can be  recognized: the Littorina zone (above the
            gray zone);  the Balanoid zone (between the gray zone and the
            laminarias); and the Laminaria zone.  a. Pelvetia canaliculata;
            b. Fucus spiralis; c. Ascophyllum nodosum; d. Fucus serratus;
            e. Laminaria digitata. (Based on Stephenson)
  1-28

-------
                                                              The Aquatic Environment
V  FACTORS AFFECTING THE
   PRODUCTIVITY OF THE MARINE
   ENVIRONMENT

A  The sea is in continuous circulation.  With-
   out circulation, nutrients of the ocean would
   eventually become a part of the bottom and
   biological production would cease.  Generally,
   in all oceans there exists a warm  surface
   layer which overlies the colder water and
   forms a two-layer system of persistent
   stability.  Nutrient concentration is usually
   greatest in the lower zone. Wherever a
   mixing or disturbance of these two layers
   occurs biological production is greatest.

B  The estuaries are also a mixing zone of
   enormous importance.  Here the fertility
   washed off the land is mingled with the
   nutrient capacity of seawater,  and many
   of the would1 s most productive waters
   result.

C  When man adds his cultural contributions
   of sewage, fertilizer,  silt or toxic waste,
   it is no wonder that the dynamic equilibrium
   of the ages is rudely upset, and the
   environmentalist cries,  "See what man
   hath wrought"!
ACKNOWLEDGEMENT:

This outline contains selected material
from other outlines prepared by C. M.
Tarzwell, Charles L. Brown, Jr.,
C. G. Gunnerson,  W. Lee Trent, W.  B.
Cooke, B. H. Ketchum, J.  K.  McNulty,
J. L.  Taylor, R. M. Sinclair, and others.
REFERENCES

1  Harvey,  H.  W.  The Chemistry and
      Fertility of Sea Water (2nd Ed.).
      Cambridge Univ. Press,  New York.
      234pp.   1957.

2  Hedgpeth, J. W. (Ed.).  Treatise on
      Marine Ecology and Paleoecology.
      Vol. I.  Ecology Mem.  67 Geol.
      Soc. Amer.,  New York.   1296pp.
      1957.

3  Hill, M. N. (Ed.).  The Sea. Vol. II.
      The Composition of Sea Water
      Comparative  and Descriptive
      Oceanography.  Interscience Publs.
      John Wiley & Sons,  New York.
      554pp.   1963.

4  Moore, H. B. Marine Ecology..  John
      Wiley & Sons, Inc.,  New York.
      493 pp.   1958.

5  Reid, G. K.  Ecology of Inland Waters
      and Estuaries.  Reinhold Publ.
      Corp.  New York.  375pp.  1961.

6  Sverdrup, Johnson, and Fleming.
      The Oceans.  Prentice-Hall, Inc.,
      New York.  1087 pp.   1942.
This outline was prepared by H. W.  Jackson,
Chief Biologist, National  Training Center,
Water Programs Operations, EPA, Cincinnati,
OH. 45268.

Descriptors:
Aquatic Environment, Estuarine Environment,
Lentic Environment, Lotic Environment,
Currents, Marshes, Limnology, Water Properties
                                                                                    1-29

-------
THE AQUATIC ENVIRONMENT

Part 5: Wetlands
I INTRODUCTION

A Broadly defined, wetlands are areas
which are "to wet to plough but too
thick to flow. " The soil tends to be
saturated with water, salt or fresh,
and numerous channels or ponds of
shallow or open water are common.
Due to ecological features too numerous
and variable to list here, they comprise
in general a rigorous (highly stressed)
habitat, occupied by a small relatively
specialized indigenous (native) flora
and fauna.

B They are prodigiously productive
however, and many constitute an
absolutely essential habitat for some
portion of the life history of animal
forms generally recognized as residents
' of other habitats (Figure 8). This is
particularly true of tidal marshes as
mentioned below.

C Wetlands in toto comprise a remarkably
large proportion of the earth's surface,
and the total organic carbon bound in
their mass constitutes an enormous
sink of energy.

D Since our main concern here is with
environment, primary
emphasis will be directed toward a
description of wetlands as the transitional
zone between the waters and the land, and
how their desecration by human culture
spreads degradation in both directions..
II TIDAL MARSHES AND THE ESTUARY (=--
B Estuarine pollution studies are usually
devoted to the dynamics of the circulating
water, its chemical, physical, and
biological parameters, bottom deposits, etc.

C It is easy to overlook the intimate relation-
ships which exist between the bordering
marshland, the moving waters, the. tidal
flats, subtidal deposition, and seston
whether of local, oceanic, or riverine
origin.

D The tidal marsh (some inland areas also
have salt marshes) is generally considered
to be the marginal areas of estuaries and
coasts in the intertidal zone, which are
dominated by emergent vegetation. They
generally extend inland to the farthest
point reached by the spring tides, where
they merge into freshwater swamps and
marshes (Figure 1). They may range in
width from nonexistent on rocky coasts to
many kilometers.
"There is no other case in nature, save
in the coral reefs, where the adjustment
of organic relations to physical condition
is seen in such a beautiful way as the
balance between the growing marshes
and the tidal streams by which they are
at once nourished and worn away. "
(Shaler, 1886)
Flfuro 1. Zoiuttoo In > positive Now England Mtturr. 1. Spring lido le»«l 1. Mewl hljh lUs.
3. Mean low tlda, 4. Dog hole, 5. Ice cleavage pool, 6. Chunk of Spartlna turt deposited by ice.
. , . , . , .
7. Organic ooce with •MOctated community, 8. velfraia (ZoBlere)
cUm Inural • mud «iull (Mjurel commviUtt. 10. 3«» lettuce |Ulv»>
.
(ZoBlere), 9. Ribbed muafel* (motttolu*)*
BI, 21e.l.74
1-31

-------
The Aquatic Environment
III MARSH ORIGINS AND STRUCTURES

A In general, marsh substrates are high in
organic content, relatively low in minerals
and trace elements. The upper layers
bound together with living roots called
turf, underlaid by more compacted peat
type material.

1 Rising or eroding coastlines may
expose peat from ancient marsh
growth to wave action which cuts
into the soft peat rapidly (Figure 2).
Such banks are likely to be cliff-like,
and are often undercut. Chunks of
peat are often found lying about on
harder substrate below high tide line.
If face of cliff is well above high water,
overlying vegetation is likely to be
typically terrestrial of the area.
Marsh type vegetation is probably
absent.

Low lying deltaic, or sinking coast-
lines, or those with low energy wave
action are likely to have active marsh
formation in progress. Sand dunes
are also common in such areas
(Figure 3). General coastal :
configuration is a factor.
Figure 2. Diagrammatic section of eroding peat cliff
MHW HI iiootec
MHWO' I9SOIAD
Figure 3
Development of a Massachusetts Marsh since 1300 BC, Involving an
18 foot rise In water level. Shaded area indicates sand dunes. Note
meandering marsh tidal drainage. A: 1300 BC. B: 1950 AD.
1-32

-------
The Aquatic Environment
Rugged or precipitous coasts or
slowly rising coasts, typically
exhibit narrow shelves, sea cliffs,
fjords, massive beaches, and
relatively less marsh area (Figure 4).
An Alaskan fjord subject to recent
catastrophic subsidence and rapid
deposition of glacial flour shows
evidence of the recent encroachment
of saline waters in the presence of
recently buried trees and other
terrestrial vegetation, exposure
of layers of salt marsh peat along
the edges of channels, and a poorly
compacted young marsh turf developing
at the new high water level (Figure 5).
Figure 4 A River Mouth on a Slowly Rising Coast. Note absence
of deltaic development and relatively little marshland.
although mud flats stippled are extensive.
Figure 5 Some general relationships in a northern fjord with a rising water level. 1. mean low
water, 2. maximum high tide, 3. Bedrock, 4. Glacial flour to depths in excess of
400 meters, 5. Shifting flats and channels, 6. Channel against bedrock, 7. Buried
terrestrial vegetation, 8. Outcroppings of salt marsh peat.
Low lying coastal plains tend to be
fringed by barrier islands, broad
estuaries and deltas, and broad
associated marshlands (Figure 3).
Deep tidal channels fan out through
innumerable branching and often
interconnecting rivulets. The
intervening grassy plains are
essentially at mean high tide level.
1-33

-------
  The Aquatic Environment
          Tropical and subtropical regions
          such as Florida, the Gulf Coast,
          and Central America, -are frequented
          by  mangrove swamps.  This unique
          type of growth is able to establish
          itself in shallow water and move out
          into progressively deeper areas
          (Figure 6).  The strong deeply
          embedded  roots enable the mangrove
          to resist considerable wave action
          at times,  and the tangle of roots
          quickly accumulates a deep layer of
          organic sediment.  Mangroves
          in the south may be considered to
          be  roughly the equivalent of the
          Spartina marsh  grass in the north
          as  a land builder.  When fully
          developed, a mangrove  swamp is an
          impenetrable thicket of  roots over
          the tidal flat affprding shelter to an
          assortment of semi-aquatic organisms
          such as various molluscs and
          crustaceans,  and providing access
          from the nearby land to predaceous
          birds, reptiles, and mammals.
          Mangroves are not restricted to
          estuaries,  but may develop out into
          shallow oceanic lagoons, or upstream
          into relatively fresh waters.
  Figure 6   Diagrammatic transect of a mangrove swamp
            showing transition from marine to terrestrial
            habitat.
      tidal marsh is the marsh grass,  but very
      little of it is used by man as grass.
      (Table 1)

      The nutritional analysis of 'several
      marsh grasses as compared to dry land
      hay is  shown in  Table 2.
'TABLE 1. General Orders of Magnitude of Gross Primary Productivity in Terms
             of Dry Weight of Organic Matter Fixed Annually
      Ecosystem
    gms/M /year      . r
(grams/square meters^year)
                                            Iba/acre/year
 Land deserts, deep oceans        Tens
 Grasslands, forests, cutrophlc     Hundreds
   lakes, ordinary agriculture
 Estuaries, deltas, coral reefs.     Thousands
   intensive agriculture (sugar
   cane, rice)
                       Hundreds
                       Thousands

                       Ten-thousands
      TABLE 2. Analyses of Some Tidal Marsh Grasses
                                                         T/A
                                                        Dry Wt.
                 Perccntaj?e Composition
           Protein   fal      Fiber    Water
                                         Ash
                                                N-free Eitract
 Oitlichlit spicata (pure stand, dry)
   2.8       5.3     1.7      32.4      8.2      6.7        45.5
 Short Spartina-allcrniflora and Salicornia curopaea {in standing water)
   1.2       7.7     2.5      31.1      8.8      12.0        37.7
 Spartina atlcrnitlora (tall, pure stand in standing water)
   3.5       7.S     2.0      29.0      8.3      15.5        37.3
 Spartina patent 'purr: stamj, rlry)
   3.2       >,t)
   2.2       &8     2.4      30.4      8.7      13.3        36.3
Comparable Analyses (or Hay
 IstMjt      fi.O     2.0      36.2      6.7      4.2        44.9
 in.J.ul     11.0     1.7      20.5      10.4      5.9        30.5

   Analyses performed by Roland W. Gilbert, Department
   of Agricultural Chemistry, U.R.I.
IV  PRODUCTIVITY OF  WETLANDS

 A  Measuring the productivity of grasslands
    is not easy,  because  today grass is seldom
    used directly as such by man.  It is thus
    usually expressed as production of meat,
    milk,  or in the case of salt marshes, the
    total crop of animals that obtain food per
    unit of area.  The primary producer in a
  1-34

-------
                                                               The Aquatic Environment
The actual utilization of marsh grass is
accomplished primarily by its decom-
position and ingestion by micro organisms.
(Figure 7) A  small quantity of seeds and
solids is consumed directly by birds.
   Figure  7  The nutritive composition of
   successive stages of decomposition of
   Spartlna marsh grass, showing increase
   in protein and decrease in carbohydrate
   with Increasing age and decreasing size
   of detritus particles.

   The quantity of micro invertebrates
   which thrive on this wealth of decaying
   marsh has  not been estimated, nor has
   the actual production of small  indigenous
   fishes and invertebrates such as the
   top minnows (Fundulus),  or the  mud
   snails (Nassa), and others.

   Many forms of oceanic life migrate
   into the estuaries, especially the
   marsh areas,  for important portions
   of their life histories as is mentioned
   elsewhere (Figure 8).  It has been
   estimated that in excess of 60% of the
   marine commercial and sport fisheries
   are estuarine or marsh dependent in
   some way.
                                                      Figul-e 8  Diagram of the life cycle
                                                      of white shrimp (after Anderson and
                                                      Lunz 1965).
3  An effort to make an indirect
   estimate of productivity in a  Rhode
   Island marsh was made on a single
   August day by recording the numbers
   and kinds of birds that  fed on a
   relatively small area (Figure 9).
   Between 700 and 1000 wild birds of
   12 species,  ranging from  100 least
   sandpipers to uncountable  numbers
   of seagulls were  counted.  One food
   requirement estimate for three-
   pound poultry in the confined inactivity
   of a poultry yard is approximately one
   ounce per pound of bird per day.
                                                      Greater yellow legs (left)
                                                        and black duck
                                                                    Great blue heron
                                                   Figure 9  Some Common Marsh Birds
                                                                                     1-35

-------
The Aquatic Environment
      One-hundred black bellied plovers
      at approximately ten ounces each
      would weigh on the order of sixty
      pounds.  At the same rate of food
      consumption, this would indicate
      nearly four pounds of food required
      for this species alone.  The much
      greater activity of the wild birds
      would obviously greatly increase their
      food requirements,  as would their
      relatively  smaller size.

      Considering the range of foods con-
      sumed, the sizes of the birds, and the
      fact that at certain seasons, thousands
      of migrating ducks and others pause
      to feed here, the enormous productivity
      of such a marsh can be better under-
      stood.
V  INLAND BOGS AND MARSHES

A  Much of what has been said of tidal
   marshes also applies to inland wetlands.
   As was mentioned earlier, not all inland
   swamps are salt-free, any more than all
   marshes affected by tidal rythms are
   saline.

B  The specificity of specialized floras to
   particular types  of wetlands  is perhaps
   more spectacular in freshwater wetlands
   than  in the marine, where Juncus,
   Spartina, and Mangroves tend to dominate.

   1  Sphagnum,  or peat moss, is
      probably one of the most widespead
      and abundant wetland plants on earth.
      Deevey (1958) quotes an estimate that
      there is probably upwards of 223
      billions (dry weight) of tons of peat
      in the world- today, derived during
      recent geologic time from Sphagnum
      bogs.  Particularly in the northern
      regions, peat moss tends to overgrow
      ponds and shallow depressions,  eventually
      forming the vast tundra plains and
      moores of the north.

   2  Long lists of other bog and marsh plants
      might be cited, each with its own
      special requirements, topographical,
      and geographic distribution,  etc.
      Included would be the familiar cattails,
      spike rushes, cotton grasses, sedges,
      trefoils, alders,  and many, many
      others.

C  Types of inland wetlands.

   1   As noted above (Cf:  Figure 1)
      tidal marshes often  merge into
      freshwater marshes and bayous.
      Deltaic tidal swamps and marshes
      are often saline in the seaward
      portion, and fresh in the landward
      areas.

   2   River bottom wetlands differ from
      those formed from lakes, since wide
      flood plains subject to periodic
      inundation are the final stages of
      the erosion of river  valleys,  whereas
      lakes in general tend to be eliminated
      by the geologic processes of natural
      eutrophication  often involving
      Sphagnum and peat formation.
      Riverbottom marshes in the southern
      United States, with favorable climates,
      have luxurient growths such as the
      canebrake of the  lower Mississippi,
      or a characteristic timber growth
      such as cypress.

   3   Although bird life is the most
      conspicuous animal element in the
      fauna (Cf:  Figure 9), many mammals,
      such as muskrats, beavers,  otters,
      and others  are  also marsh-oriented.
      (Figure 12)
      Figure 12
1-36

-------
The Aquatic'Environment
VI POLLUTION

A No single statement can summarize the
effects of pollution'on marshlands as
distinct from effects noted elsewhere on
other habitats.

B Reduction of Primary Productivity

The primary producers in most wetlands
are the grasses and peat mosses.
Production may be reduced or eliminated
by:

1 Changes in the water level brought
about by flooding or drainage.

a Marshland areas are sometimes
diked and flooded to produce fresh-
water, ponds. This may be for
aesthetic reasons, to suppress the
growth of noxious marsh inhabit at ing
insects such as mosquitoes or biting
midges, to construct an industrial
waste holding pond, a thermal or a
sewage stabilization pond, a
"convenient" result of highway
causeway construction, or other
reason. ' The result is the elim-
ination of an area of marsh. A
small compensating border of
marsh may or may not develop.

b High tidal marshes were often
ditched and drained in former days
to stabilize the sod for salt hay or
"thatch" harvesting which was highly
sought after in colonial days. This
inevitably changed the character
of the marsh, but it remained as
essentially marshland. Conversion
to outright agricultural land has
been less widespread because of the
necessity of diking to exclude the
periodic floods or tidal incursions,
and carefully timed drainage to .
eliminate excess precipitation.
Mechanical pumping of tidal marshes
has not been economical in this
country, although the success of
the Dutch and others in this regard
is well known.
2 Marsh grasses may.also be eliminated
by smothering as, .for example, by
deposition of dredge spoils, or the
spill or discharge of sewage sludge.

3 Considerable marsh area has been ..
eliminated by,industrial construction
activity such as wharf and dock con-
struction, oil well construction and
operation, and the discharge of toxic
brines and other chemicals.

Consumer production (animal life) has
been drastically reduced by the deliberate
distribution of pesticides. In some cases,
this has been aimed at nearby agricultural
lands for economic crop pest control, in
other cases the marshes have been sprayed
or dusted directly to control noxious
insects.

1 The results have been universally
disastrous for the marshes, and the
benefits to the human community often
questionable.

2 Pesticides designed to kill nuisance
insects, are also toxic to other
arthropods so that in addition to the
target species, such forage staples as
the various scuds (amphipods), fiddler
crabs, and other macroinvertebrates
have either been drastically reduced
or entirely eliminated in many places.
For example, one familiar with fiddler
crabs can traverse miles of marsh
margins, still riddled with their burrows,
without seeing a single live crab.

3 DDT and related compounds have been
"eaten up the food chain" (biological
magnification effect) until fish eating
and other predatory birds such as herons
and egrets (Figure 9), have been virtually
eliminated from vast areas, and the
accumulation of DDT in man himself
is only too well known.
1-37

-------
The Aquatic Environment
D  Most serious of the marsh enemies is
   man himself.  In his quest for "lebensraum"
   near the water, he has all but killed the
   water he  strives to approach.  Thus up to
   twenty percent of the marsh--estuarine
   area in various parts of the  country has
   already been utterly destroyed by cut and
   fill real estate developments (Figures
   10,  11).
Swimming birds such as ducks,  loons,
cormorants,  pelicans, and many others
are severely jeopardized by floating
pollutants such as oil.
                     Figure 10.  Diagrammatic representation of cut-and-fill for
                                 real estate development,  mlw = mean low water
                     Figure 11.  Tracing of portion of map of a southern
                                 city showing extent of cut-and-fill real
                                 estate development.
 1-38

-------
                                                               The Aquatic Environment
VII SUMMARY

 A Wetlands comprise the marshes, swamps,
    bogs, and tundra areas of the world.
    They are essential to the well-being of
    our surface waters and ground waters.
    They are essential to aquatic life of
    all types living in the open waters.  They
    are essential as habitat for all forms of
    wildlife.

 B The tidal marsh is the area of emergent
    vegetation bordering the ocean or an
    estuary.

 C Marshes are highly productive areas,
    essential to the maintenance of a well
    rounded community of aquatic life.

 D Wetlands may be destroyed by:

    1  Degradation of the life forms of
       which it is  composed in the name of
       nuisance control.

    2  Physical destruction by cut-and-fill
       to create more land area.
5  Morgan,  J.P.  Ephemeral Estuaries of
      the Deltaic Environment in: Estuaries,
      pp.  115-120. Publ. No. 83,  Am.
      Assoc. Adv. Sci.  Washington,  DC. 1967.

6  Odum,  E.P.  and Dela Crug, A. A.
      Particulate Organic Detritus in  a
      Georgia Salt Marsh - Estuarine
      Ecosystem,  in:  Estuaries, pp.  383-
      388, Publ. No. 83,  Am. Assoc.  Adv.
      Sci. Washington, DC.  1967.

7  Redfield, A.C.  The Ontogeny of a Salt
      Marsh Estuary, in: Estuaries,  pp.
      108-114.  Publ. No. 83, Am.  Assoc.
      Adv. Sci.  Washington, DC.  1967.

8  Stuckey,  O. H.  Measuring the Productivity
      of Salt Marshes.  Maritimes (Grad
      School of Ocean., U.R.I.) Vol.  14(1):
      9-11.  February  1970.

9  Williams, R. B. Compartmental
      Analysis of Production and Decay
      of Juncus reomerianus.   Prog.
      Report,  Radiobiol. Lab., Beaufort, NC,
      Fiscal Year  1968, USDI, BCF,  pp.  10-
      12.
  REFERENCES

  1  Anderson, W. W.  The Shrimp and the
        Shrimp Fishery of the Southern
        United States.  USDI,  FWS, BCF.
        Fishery Leaflet 589.   1966.

  2  Deevey, E.S., Jr.  Bogs. Sci. Am. Vol.
        199(4):115-122.  October  1958.

  3  Emery, K. O.  and Stevenson.  Estuaries
        and Lagoons.   Part n, Biological
        Aspects by  J. W.  Hedgepeth,  pp.  693-
        728. in: Treatise on Marine Ecology
        and Paleoecology.  Geol.  Soc. Am.
        Mem. 67.   Washington, DC.   1957.

  4  Hesse, R., W. C. Allee, and K. P.
        Schmidt. Ecological Animal
        Geography.   John Wiley & Sons.  1937.
This outline was prepared by H.  W.  Jackson,
Chief Biologist, National Training Center,
Water  Programs Operations, EPA, Cincinnati,
OH   45268.
Descriptors:  Aquatic Environment, Estuarine
Environment,  Lentic Environment  Lotic
Environment,  Currents, Marshes,  Limnology
                                                                                    1-39

-------
                                      TYPES OF ALGAE
 I   INTRODUCTION
 A   Algae in general may be defined as small
     pigmented plant-like organisms of rela-'
     tively simple structure.  Actually the
     size range is extreme:  from only a
     few microns to over three hundred
     feet in length.  Commonly observed
     examples include the greenish pond
     scum or frog spittle of freshwater
     ponds, much of the golden brown
     slime covering rocks in a trout stream,
     and the great marine kelps and sea-
     weeds.  Large freshwater forms as
     Nitella and Chara or stonewort are also
     included.

 B   Algae approach ubiquity in distribution.
     In addition to the commonly observed
     bodies of water,  certain algae also
     live in such unlikely places as thermal
     springs, the surface of melting snow,
     on the hair of the three toed sloth in
     Central America, and in conjunction
     with certain  fungi to form lichens.
II   ALGAE WILL BE GROUPED FOR THE
     SAKE OF CONVENIENCE INTO FOUR
     GENERAL TYPES:
     Blue-greens (See plate: Blue-Green
     Algae, Cyanophyceae).  This is a valid
     technical group.  The size range is not
     very great, some being so small as to
     approach the size range  of the bacteria.

     1  These are the only algae in which
        the pigments are not localized  in
        definite bodies but dissolved through-
        out the cell.  Blue, red, or other
        pigments are present in addition to
        chlorophyll thus giving the cells a
        bluish green, -yellow,  or red color,
        at least enmasse.
   2  The nucleus lacks a nuclear membrane.

   3  Tend to achieve nuisance concentrations
      more frequently in the warm summer
      months and in the richer waters.

   4  Vegetative reproduction, in addition
      to cell division,  includes the forma-
      tion of  "hormogones, " or short specif-
      ically delimited sections of trichomes
      (filaments).

   5  Spores of three types are encountered:

      a Akinetes are usually larger,  thick
        walled resting spores.

      b Heterocysts appear like empty
        cell walls,  but are actually filled
        with protoplasm,  have occasionally
        been observed to germinate.

      c Endospores, also called "gonidia"
        or conidia, are formed by repeated
        division of the protoplast within a
        given  cell wall. Present in only a
        few generaj
   6  Some common examples of blue
        green algae are:

      Anacystis (Microcystis or
      Polycystis). Anabaena, Aphani-
      zomenon, and Oscillatoria.
B  The. Pigmented flagellates '("in contrast
   to the non-pigmented or animal-like
   flagellates) are a heterogeneous
   collection of motile forms from several
   different algal groups (See plate:
   Flagellated algae).

   1  There may be one, two, four, or
      more flagella  per cell.

   2  There  is a well organized nucleus.

   3  A light-sensitive  red eyespot usually
      present.
BI. MIC.cla. 19a.8.69
                                   2-1

-------
Types of Algae
   4  The chlorophyll is contained in one
      or more distinctive bodies called
      plastids.

   5  Two or more cells may be associated
      in a colony.

   6  Non-motile life history stages may
      be encountered.

   7  Masses of stored starch-called
      pyrenoid bodies are often conspicuous.

   8  Some examples of pigmented flag-
      ellates are: Euglena,  Phacus,
      Chlamydomonas. Gonium, Volvox,
      Peridinium, Ceratium Mallomonas,
      Synura  and Oinobryon.
C The Non- motile green algae constitute
   another heterogeneous assembly of un-
   related forms (See plate: Non-Motile
   Green Algae)

   1  Like the flagellates they have well
      organized nuclei and  chloroplasts.
      The shape of the chloroplast is often
      distinctive.

   2  They lack' flagella or  any other loco-
      motor device.

   3  There is extreme  structural variation
      among the group.

   4  Some  types tend to occur as a general
      planktonic mass or "bloom, " often
      in  combinations of two or more species.

      Some  examples are: Sphaerocystis;
      Pediastrum,  Scenedesmus, and the
      desmid  Cosmarium.

   5  Threadlike (filamentous) green algae may
      form masses or blankets, cutting off
      light,  and reducing water circulation.
      They also add considerably to the total
      mass  of organic matter.  Some examples
      of  this type are: Spirogyra, Hydrbdictyon,
      Cladophora, Oedogonium,  and Chara.
D The Diatoms constitute another valid
   technical group (See plate: Diatoms-
   Bacillariophyceae).

   1  In appearance,  they are geometrically
      regular in shape.'  The presence  of a
      'brownish  pigment in addition to the
      chlorophyll gives them a golden to
      greenish color.

   2  Motile forms have a distinctive
      hesitating progression.
      The  most distinctive structural
      feature is the two-part shell
      (frustule )  composed of'silicon
      dioxide (glass). '

      a  One  part fits inside the other as
         the two halves of a pill box, or a
         petri dish.

      b  The surface of these shells are
         sculptured with minute pits and
         lines arranged with geometrical
         perfection.

      c  The  view  from the side is  called
         the "girdle view, " that from above
         or below,  the  "valve view. "

      There are two general shapes of
      diatoms, circular (centric)  and
      elongate (pennate).   The elongate
      forms may be motile,  the circular
      ones  are not.

      Diatoms may associate in colonies
      in various ways.

      Examples of diatoms frequently en-
      countered are: Stephanodiscus
      Cyclotella, Asterionella, Fragilaria.
      Tabellaria,  Synedra,  and Nitzschia.
This outline was prepared by H. W.  Jackson,
Chief Biologist, National Training Center,
Water Programs Operations, EPA, Cincinnati,
 OH 45268.
  2-2

-------
                                                                          Types of Algae	
            KEY FOR IDENTIFICATION OF GROUPS OF FRESHWATER A LGAE
               Beginning with "la" and "ib", choose one of the two contrasting
               statements  and follow this procedure with the  "a" and "b" state-
               ments of the number given at the end of the chosen statement.
               Continue until the name of the algal group is given instead of
               another key number.
               la.   Plastid (separate color body) absent; complete protoplast
                    pigmented; generally blue-green; iodine starch test*
                    negative	Blue-green algae

               Ib.   Plastid or plastids present; parts of protoplast free of some
                    or all pigments; generally green, brown, red, etc.,  but not
                    blue-green; iodine starch test* positive or negative	2
               2a.   Cell wall permanently rigid (never showing evidence of
                    collapse), and with regular pattern of fine markings
                    (striations,  etc.); plastids brown to green; iodine starch test*
                    negative; flagella absent; wall of two essentially similar halves,
                    one placed over the other as a cover	Diatoms

               2b.   Cell wall, if present, capable of sagging,  wrinkling, bulging
                    or rigidity,  depending on existing turgor pressure of cell
                    protoplast; regular pattern of fine markings on wall generally
                    absent; plastids green,  red,  brown,  etc.;  iodine starch test*
                    positive or negative;  flagella present or absent; cell wall
                    continuous and  generally not of two parts	3
               3a.   Cell or colony motile; flagella present (often not readily visible);
                    anterior and posterior ends of cell different from one another in
                    contents and often in shape	Flagellate algae

               3b.   Non-motile; true flagella absent; ends of cells often not
                    differentiated	•	Green algae and associated forms
*Add one drop Lugol's (iodine) solution, diluted 1-1 with distilled water.  In about 1 minute,
 if positive,  starch is stained blue and, later black.  Other structures (such as nucleus,
 plastids, cell wall) may also stain,  but turn brown to yellow.

                                                                                    2-3

-------
 Types of Algae
 CMP
                COMPARISON OF FOUR MAJOR GROUPS OF ALGAE

Color
Location
of pigment
Starch
Slimy
coating
Nucleus
Flagellum
Cell Wall
"Eye "spot
Blue-Green
Blue-Green
(Brown)
Throughout
cell
Absent
Present
Absent
Absent
Inseparable
from slimy
coating
Absent
Pigmented
flagellates
Green
Brown
In plastids .
Present or
Absent
Absent
in most
Present
Present
Thin or
Absent
Present
Greens
Green
In plastids
Present
Absent
in most
Present
Absent
Semi-rigid
smooth or
with spines .
. Absent
Diatom s
Brown
(Light-Green)
In plastids
Absent
Absent
in most
Present
Absent
Very rigid,
with regular
markings
Absent
2-4

-------
                                  Name '
                Production of Excess Organic
                  Material in Freshwater
  1.  What is  it?.
  2.  Through sensory perception characterize at  least
      five things about it which could be  significant?
      a .

      b.

      c .

      d .

      e .
  3.  If present in excessive amounts  in water  courses  or
      water bodies, what would be  its  significance?

      a .

      b.

      c .
  4.  How do you account for  the contrast  in  color  of  the
      two samples?
AT. TW. 5. 8. 74                                                3-1

-------
                          This   alga   using    the   key   below
                          (Circle   the  correct   number   in
                          choice   between   the   two)
                               is	
                               each  pair   as   you   make   a
     Th* tailoring key it designed to aid in the recognition of alffM In thtlr nature)
 habitat*.  The decision* to  he  made will depend upon the features of  th« habitats
 •nd upon the gross structure of the algae. A  hand lens may be  helpful but it IB not
 essential.                                                       '
     The key includes  only those  algae which are  macroscopic  and with  a  definite,
 organization, or those which have distinguishing features because of numbers present.
 The users judgement prevludrs the necessity for minutely describing each habitat.

                  FIELD KEY TO SOME GENERA OF ALGAE

  1.  Living  hi or upon animals    	  j
  1.  \ot living in such association with animals 	  6
     2. On  shell* of snapping turtles (also on Viripona
        m«ttrot*i Reeve in L.  Erie); filamrnious, tuftsd,
        rosn«              .   •	
     2. Not oa turtle shells         .  .  .	'.	
  3.  Forming a hard green coating on snail shells 	
  3-  Not on snail shells            	
     4. Green masws attached to  anterior and posterior
        append*nets  of fairy shrimp or to eopepod*	
     •1. Nut attached to fairy  shrimp or copepod•  	
  5.  In old egg masses .of the  salamander Ambyitoma; dark green
 S.  Living within green Hydro or green planaria 	
    Baslcladia
   	3
  . Gongrosira
  	  4
21.
23.
23.
27.
27.
29.
39.
ai.
11.
     6.  Aquatic, submerged or nearly so  	
     6.  Not aquatic; on soil, rock, concrete, wood, or bark 	
  7.  On soil,  rock, or concrcu 	
  7,  On wood or bark .      ,      	„	
     8.  On shaded side of tre* trunks,
        or on weathered siding of old buildings	
     8.  On rotting logs  or pilings, pale greta 	  .  ...:

  9.  On rock or concrete	.'	.-.	
  9.  On soil .      	
     10.  A lra I mass orange or reddish; on "dry" cliff or quarry faces
     10.  A Iral majs dark olive to black; slimy (peeling if dry) ... ....
 31.  Algal  ma»« filamentous; often in greenhouses  	
 ]1.  Algal mass not filamentous or fe)t-)ike; location* various	
     12,  Dark  green; felt-like, coarsely branched ...'	
     12.  Yellow green,  tawny or olive-brown 	
 13.  Ytllow green; filmy         	
 13.  Tawny or olive brown;  velvet or felt-Kkt	
     14.  Alga] mass jelly-like, ipherical or in expanded sheets 	
     14.  Aliril mass globular, l-2mm  in diameter;
         shining, with white flakes	
 15.  Running water, lake shores, or in spray; attached 	
 15.  Standing or very alow moving water;  attached or net  	
     If,.  Water cold; late winter, early spring, or spring fed  	
     1C.  Water cool to warm; late spring, summer, autumn  	
.  .  Ch tract en*
 	   ft
	   OophiUa
 . .  Chlorella
 (ZoocMorella)
	16
	7
	„	9
	8


. .. Ho r mid ion
  Stichococcns
	10
	11
.,. TrentepoMJa
... OacillstorU
	12
	14
  ... Vagcheria
	13
   Hormfdlara
... Scytonetna
	Nostoc

	Botrydtnm
	16
	34
	17
	27
	•  ...18
	  	 24
	 Vancherla
Algal mass filamentous 	
Algal ma» not filamentous  ,	
18.   Algal mass a felt-like mat 	
18.   Alga] mass not a felt-like mat 	

Plants not branched         -'	".....10
Plants profusely branched (bushy)	 Jl
20.   Plant* short; slippery; bright green    	 Ulothrlx
20.   Plants noduiosv; i-urtilagenous; ulive    	 	Lenanea
Plants emb«4cfccl in a jvijy-likc ma*s                	  22
Plants not gelatinous, "dry," coarse; often in very swift water   ..   Cladophora
22.   Olive.green to rt-d-purptv             .         ...    Batrachoipermum
22.   Brilliant green                        .       	   23
Gelatinous mass soft, in.l»-finite, lateral branches long	Stifftoe Ionium
Gelatinous mass firm, definite, lateral branches  short
and mostly at right anglva to main axis
24*   Colony brown, jr?Iatin» not filani*:ntous                   	 ...
28.  Filaments  branj I f*-cti. silky, gn-tn;  mus* tough  .          Khltoclunium
, .Draparnaldia
  . .. Diatoms
 .   ..     25
Enteromorpha
          20
  ManoKtroma
.  . Tctraspora
  	   28
	  32-
	   29
  	31
    Vaueherla
          30
   Cladophora
      Ionium
                 33.
                 33.
                35.
                33.
                37.

                37.
39.
39.
                 41.


                 41.
                43.
                43.
                 45.
                 45.
                47.
                47.
                49.


                49.
                51.
                51.
                                                                              S3.
                                                                              53.
                                                                              55.
                                                                              55.
                 57.
                 57.
                                                                              69.
                                                                              59.
                                                                              (11.

                                                                              61.
    32. Colonies "shot-like," olive to black; on  ruck        .. ..  .
    32. Coloniej not "jhot-liJc*-," some shade of green
    Grten incrustation  on rocks and sticks; cslean-out     ..  .
    Colonies grwn, gvlulinous pads or saca            	
    34. Cold water; late winter or early spring       	
    34. Cool to warm  water:  late spring, summer, autumn
    Woodland pool.*, leaf litter  bottom                 	.'.....
    Open ponds, lake margin*, pools, "cut-offs"     .     	
    3d. Algal mo.*s yellow-green, filamentous,  itlky         .  .
    3ft. Green, motile  sphere* visible in * glass jar of the water .
    Plants tree-like, often calcareous, attached to bottom  	
                                                                                        31
                                                                               Calorol'liom
                                                                                Tetraspora
                                                                                        35
                                                                                        40
                                                                                ...       36
                                                                                        37
                                                                               .. Tribafrema
                                                                               ..  .  Volt 01
                                                                                    Chara
                                                                                    Ntte Ma
                                                                                        as
                                                                                Oedoreoivm
                                                                                        39
                                                                                 Spirogjra
                                                                              Filamentous      .                         .    . ............
                                                                              30.  Attached to dead or living sticks, weeds and grass
                                                                              38.  Free' floating
                                                                              Brilliant green, slippery; ends of mass curling when held aloft
                                                                              Bright to light green, less slippery; ends of mass not distinctly curling   Zygnemj
                                                                                                                                          Moageotia
                                                                              40.  Temporary bodies of water           ...............................   41
                                                                              40.  Permanent  or semipermanent bodies of water  . ................................ 44 '
                                                                              Bird baths, urn», limestone shoreline depressions;
                                                                              reddish scum on bottom and sides          ...................... Sphaerorystia
                                                                                                                                    (Haema tococrvs )
                                                                              Puddles, cow tracks, ruts, manure water pools     ...........................         42
                                                                              42.  Blue-green, olive, black; slimy, membranareous, often on mud   Oscillatoria
                                                                              42.  Green or red; living in or on the water        ........................    43
                                                                              Forming a red or preen *cum on the surface of th« water ......     .  Cujtlena
                                                                              Water uniformly green throughout     .............................. Ctilamydamunas
                                                                                                                                          Pandorina
                                                                                                                                           Eudorina
                                                                              44.  Aquaria, bo t tits and culture dishes in laboratory  or greenhouse .        45
                                                                              44.  Ponds, lakes,  lake  margins, "cut-offs"       .. .   . .............. ... .      46
                                                                              As a green film on the  pins* wall* ............................................... Chlorella
                                                                              Water uniformly green throughout    ................. ........................ Scenedesmiu
                                                                                                                                     Ankfstrodeaaiu
                                                                              46.  On wet soil at margin* [[[ ! .................................... 4?
                                                                              46.  Aquatic, floating or submerged ................... . [[[ *8
                                                                              Globular, gelatinous colonies [[[ Noatoe
                                                                              Slimy, membranareous colonies, blue-green,  olive,  black ................... Oscillatoria
                                                                              48.  'Submerged  and attached   [[[ <*
                                                                              48.  Free  floating, or enmeshed In other aquatics .................................. > ................. 53
                                                                              Plant* tree-like; often calcareous; growing on bottom mud,
                                                                              scarcely submerged to 30 feet
                                                                    Chara
                                                                   Nitella
                                                                       50
    Plants not tree-like; not calcareous 	
    50.  Filamentous  	'-	51
    50.  Not  filamentous   ...              	    52
    Filaments dichotomously branched; crowing on bottom  mud   Dtchotomoslphon
    Filaments not trenched; attached to stick:., vrrj and grass stems     Oedrf>Konlum
    52.  Small hemispherical or branched gelatinous colonies;
        green; atUrhed to weed*, sti.-ks, or st&nes      	       Cftaetophora
    52.  Flat green discs, often attached to dead cattail
        or water lily leaves   	"...       ColeochaeU
    Algal  mass forming a net	        Ilydrodlctyon
    Algal  maun not net-Hke     ...      	   	 54
    54.  Alk'al man* a tough, membranaceous, paper-likt sheet;
        gri-*-n to olive-green ....     	    Lyngbya
    54.  Altai mass not a membranaceous sheet	   ...".  -      55
    Algal  rnafii filamentous; green 	•-	   59
    Algal  ma** not filamentous	     56
    .r>tt.  Green motile sphere*  visible in a glass jar of tht  water 	    VoKot
    />£.  Alcnl mttrn  nonmotile, definitely mscroscoplc  	      .         57
    Aliral  nin"8 irrvirular, gel«tinnu!i  tump*; yellow to tawny     ..    f>lo#otrkMa
    Alcal  particlfff blur.preen; dii-pvrM-d throughout the waUr,
    or floating as a bluish scum; sticky in mass	
    58.  Particles appearing as "chopped grans" In tht water
    58.  Particles of irregular  shape and sist  	
    FUamei.ts coarse, branched, not slippery  	
    Filament.*  silky, unbranched,  slippery
    CO.  filament* with well defined, ^altered, dark, swollen areas
    60.  Filaments without  dork, swollrn  areas   	
    Bright gret-n to  yellowish,  very Mipprry If green; tnds of
    mass  curling if  held aloft              	
    Green to yellowish, only slightly slippery;
    and* of mass not curling 		
                                                                             Aphafllsomenoa
                                                                                  Anabaena
                                                                                  Aaaryntis
                                                                               {Mferorystu)
                                                                                        60
                                                                             .  .         Cl
                                                                                 PltKophnrs
                                                                                 Cladophora

                                                                                  Splrogyra

                                                                                  Zygntm*
                   6.     Classification   of   this   alga   is:
                           Kingdom
                           Phylum
                           Class
                           Order
                          Family
                          Genus

-------
                                 AQUATIC MACROPHYTES
I  INTRODUCTION

A  This non-taxonomic description of aquatic
   plants includes not only the higher vascular
   plants, but also the larger algae like
   Chara and Lemanea and the mosses and
   liverworts.  Many manuals on higher
   aquatic plants will also include the larger
   algae and lower plants for  ecological
   convenience.

B  Ecologically they are primary producers
   as are the phytoplankton.  Their role in
   detrital cycles is considerable.

C  The littoral zone of lakes and estuaries
   are often dominated by this group while
   in streams they fill important niches in
   both the riffles and shallow pool areas.

   Water depth determines the adjustment
   of aquatic seed plants into three principal
   categories.

   1  Surface or floating weeds generally
      grow in deeper water at the front of
      (oftentimes commingling with) the
      emersed weeds.  The larger floating
      weeds are waterlilies that may be
      rooted in the mud of the bottom and bear
      large leaves that float upon the surface.
      Smaller types such as the duckweeds
      are free-floating.

   2  Emersed weeds are those that occupy
      shallow water, are rooted in bottom
      mud, and support foliage, seeds and
      mature fruit one or more feet above
      the water 'surface.  Cattails, rushes,
      and the marsh grasses are familiar
      examples.

   3  Submersed aquatic growths often form
      a belt or zone of herbage farthest from
      shore. Except for those forms that
      dwell in quiet waters,  they are rooted
      to the bottom.  Depth varies considerably
      within this zone and may extend down
      to the limits of effective light penetration.
 D In the long-term cycle of the change in the
   aquatic terrain there is a  continuing
   tendency for the land to encroach upon
   shallow ponds and shallow areas of lakes,
   decrease their size, make them more
   shallow and eventually return them to dry
   land.  Rooted and other aquatic vegetation
   plays a prominent role in  this gradual
   process by:

   1  Invading shallow water areas through
      entrapment of particulate matter that
      is carried into lakes and ponds.  The
      rooted vegetation will continue to
      spread as water areas  become more
      shallow and the bottom mud provides
      suitable anchorage for  roots.
      Mangrove growths in estuaries and
      along seashore areas have made
      swamps out of once open water areas.

   2  Plants contribute also to the filling in
      of lakes and estuaries through both
      the precipitation of calcium carbonate
      and the accumulation of their remains
      upon death and decay; e.g.,  marl and
      peat moss.

 E While these lake invasions by higher
   aquatic plants may sometimes be
   sufficiently rapid to be recognized by
   those who habitually use the lake,  the
   common objections to rooted vegetation
   stem from their immediate  interference
   with recreational use euch as boating and
   encroachment on navigation channels and
   swimming beaches.
II  MACROPHYTE GROUPS

 A Division Algae

   The green alga Chara (and related genera
   Nitella and Tolypella) may form "weed
   beds" (in lakes, ponds, streams, and
   estuaries) as extensive as higher plants
   and grossly similar.  Other algae such
   as  Lemanea may form dense mats in
 BI.PL. lb.3.70
                                                                                     4-1

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Aquatic Macrophytes
   riffle areas of streams or springs.  In
   marine waters the larger marine algae
   may form dense mats.

B Division Bryophyta (Liverworts and Mosses)

   These are relatively small plants which
   lack flowers and conducting tissues
   (xylem and phloem).

   1  The Life Cycle consists of two phases:

      a The leafy green gametophyte which
        produces  motile gametes.

      b The sporophyte generation producing
        spores.

   2  This is a freshwater group consisting
      of less than 50 genera.  About one
      fourth of these are liverworts.

      a The liverworts (Class Hepaticae) are
        small flattened green plants, which
        may lack  stems and leaves. Riccia
        is a slender, branched surface form
        growing in loose clusters of flat
        slender sprays. Fragments of these
        are often  taken in plankton samples.
        Ricciocarpus is a notched oval form
        about one centimeter in diameter that
        is often found in the same environ-
        ment.

      b The true mosses (Class Musci) have
        distinct leaves and stems.  Sphagnum
        forms extensive bogs in some areas.
        In cooler  streams Fontinalis may
        occupy large areasl  One species of
        the latter has been found resistant
        to a variety of complex wastes,
        including  zinc.
             i
      c In swamps and along lake shores
        many species pass from an aquatic
        to terrestrial environment without
        showing specific morphological
        changes.

C  Vascular Plants (Division Tracheophyta)
   include the aquatic fern or fern-like plants
   (Class Pteridophyta).
   1  The aquatic lower tracheophytes are
      primarily freshwater.  The Quillworts
      (Isoetaceae) are related to the club
      mosses and may form numerous
      rosettes on the silt-sand bottoms of
      lakes.

      Division Tracheophyta - .This division,
      like the preceding one (Bryophyta) has
      the life cycle of alternation of
      gametophyte and sporophyte.  In this
      group, however, the sporophytes
      always become free living,  independent
      plants with possession of conducting
      or vascular tissues (xylem and phloem).
      The aquatic lower Tracheophyta are .
      primarily freshwater and only repre-
      sented by a few species.

   2  Included in the higher Tracheophyta
      are ferns (Class Filicinae) containing
      aquatic genera, Azolla, Salvinia,
      Marsilea, Ceratopteris.

      a  Azolla and Salvinia form floating
        masses sometimes interspersed
        with Duckweed.   The former often
        forms a red carpet.

      b  Marsilea occupies the area between
        high and low water of stream and
        bayou margins.

      c  Ceratopteris is  a floating form
        often of nuisance locally.

D  Vascular Plants (Division Tracheophyta,
   Class Angiospermae)

   1  Structural modification - all aquatic
      plants are characterized by certain
      specific morphological features relative
      to adaptation for the aquatic habitat.

      a  Many heterophyllous - submerged
        leaves may be narrow or incised.
        Surface leaves have simple com-
        pact blades.

      b  Root system only an anchor,  with
.        adsorption of dissolved salts taking
        place over entire plant surface,
        lacking root hairs.
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                                                                Aquatic Macrophytes
   c  Stomata present only on upper side
      of leaves in floating plants.

   d  Chloroplasts located in the epidermis.

   e  Flower clusters may be above water
      and pollinated by wind  or insects or
      pollen suspended in the water and
      pistils pollinated under water.

   f  Vegetative reproduction predominates.
      Small fragments  (turions or winter
      buds) or root stocks (tubers) may be
      sufficient for propagation.

   g  A variety of plants are associated
      with the aquatic environment making
      a clear distinction between terrestrial
      and true hydrophytes difficult.
      Aquatic plants have been defined by
      Reid as "those whose seeds germinate
      in either the water phase or the
      substrate.. .and must  spend part of
      their life  cycle in water. "  This,
      therefore, includes submersed as
      well as emersed.

2  Classification  - Around fifty families
   of Angiosperms are primarily aquatic,
   including thirty estuarine species.

3  Dicotyledons

   a  Family Nymphaceae -  the water
      lilies, Nuphar and Nymphaea
      Watershield, Brasenia; and
      Cabomba.

   b  Family Ceratophyllaceae - includes
      one genera Ceratophyllum (Coontail
      or HornwortTI  The stems which are
      entirely under water may sometimes
      be stfff with a coat of lime.

   c  Family Trapaceae - the water
      chestnut or caltrop, Trapa. The
      sharp spine d fruits are a staple
      crop in parts of Asia.  Colonies of
      connected rosettes of this plant
      quickly form surface floating mats
      which may impede navigation in the
      littoral region of lakes and in slow-
      moving rivers.  Examples  - Africa,
      Rumania,  and Massachusetts.
d  Family Haloragidaceae - includes
   two genera Proserpinica and
   Myriophyllum.  The latter is found
   up to 15 parts per 1000 salinity and
   has been a serious nuisance in
   Chesapeake Bay and the Tennessee
   Valley.  In the former area, a virus
   has reduced populations as much as
   95 percent.

e  Podostemaceae - primarily a
   tropical family which is highly
   adapted to life'in rushing water,
   even in torrential areas over rocks
   worn smooth by the water and
   impenetrable by roots.  This is
   made possible by haptera
   (attachment organs) which cement
   the plant to the substrate.
   Morphologically and ecologically
   they bear resemblances to certain
   attached algae. This group also
   shares the characteristics of other
   aquatic plants,  but in addition
   possesses quantities of silica in the
   cell.  Where the current in the
   stream is  less vigorous the
   Podostemum will be replaced by
   mosses and algae. Podostemum
   communities are a challenge in
   quantitative sampling of the
   associated macroinvertebrates.

f  Family  Lentibulariaceae -
   Bladderworts, Utricularia, have
   small bladders which keep the stems
   afloat and  also serve as traps  for
   the capture of small organisms.

g  Family Rhizophoraceae -
   Rhizophora mangle.  The red man-
   grove.
h  Family Combretaceae -
   Combretaceae - Laguncularia
   racemosa.  The white mangrove.
i  Family Verbenaceae - Avincennia
   nitida. The black mangrove
   The three mangrove families listed
   above are widespread on both the
   East and West Coasts.   They support
   a unique algal vegetation,  mainly of
   certain red algal genera.
                                                                                 4-3

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Aquatic Macrophytes
   4  Monocotyledons

      a  Family Butomaceae - Butomus
        umbellatus is Eurasian in origin,
        and has spread rapidly in the
        St. Lawrence River Basin and
        around the Great Lakes.

      b  Family Hydrocharitaceae - includes
        the well known Elodea  (= Anacharis)
        Hydrilla.  Egej
and Vallisneria
        plus two marine genera Halophila
        and Thalassia (T. testudinum,
        Turtle Grass.) The former fresh
        water genera also extend into
        brackish water.

      c  The water plantain family
        (Alismaceae) is a large group of
        emerged marsh plants and sub-
        mersed aquatics.  Sagittaria
        subulata is found in both fresh and
        estuarine areas.  In the latter it
        matures without much change in
        shape or size  of leaves (ribbon  leaf
        form) and the  plant  and flowers may
        be under water at high tide.

      d  Family Zosteraceae

        1) Zostera marina or Eel Grass is
           found on both coasts from Alaska
           to California and Hudson Bay to
           North Carolina.  In the early
           thirties, there were great
           mortalities of Eel Grass over
           extensive areas,  particularly the
           East Coast. Since that time  there
           has been considerable recovery
           in the east.

        2) Phyllospadix scouleri or Surf
           Grass is found from British
           Columbia to California.  The
           "sea grasses" include the above
           four genera and two others
           (discussed in the families
           Hydrocharitaceae and
           Zannichelliaceae.  They are
           stenohaline and probably do not
           occur where salinities are below
           25 7oo for considerable periods.
           The remaining genera of this
       family are primarily fresh
       water although.many have  species
       extending into brackish water.

e  Family Potamogetonaceae

   Potamogeton includes over forty
   species and is recognized generally
   as a difficult group to key out.

f  Family Ruppiaceae

   Ruppia maritima or Widgeon Grass
   is found from alkali to fresh water
   and salt to fresh coastal water.

g  Family Zannichelliaceae

   1)  Zannichellia palustris is found
      from fresh water and fresh  to
      brackish coastal water.

   2)  Cymodoceae  - Syringodium
      filiforme (= Cymodocea
      manatorum) or Manatee Grass
      is found from Texas to Florida.
      The leaves are round in cross-
      section and flowers are common.

   3)  Halodule wrightii (=  Diplanthera)
      or Shoal Grass is found in North
      Carolina and from Texas to
      Florida.  Leaves are flat in
      cross-section and have a three
      pointed tip.

h  Family Najadaceae - includes the
   one genus Najas, approximately
   35 species.  Southern Naiad has
   long been one of the most trouble-
   some submersed aquatic weeds in
   Florida.  It infests irrigation and
   drainage canals.

i  Family Pontederiaceae - includes
   Eichornia crassipes, waterhyacinth.
   It is a native of tropical America
   and was probably introduced in the
   United States  as an ornamental.  As
   an escapee it  has become an
   exceedingly troublesome species
   by clogging waterways of the
   Southern States.  Its attractive
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                                                               Aquatic Macrophytes
   blue-purple flowers and charac-
   teristic bulbous leaf stem with
   rounded leaf blade make it easy to
   identify.  The plant is usually found
   floating on the surface of ponds and
   quiet streams and growing on.mud-
   banks. This plant spreads
   vegetatively by horizontal stem
   growth and rooting at the nodes to
   produce new plants that develop into
   mats covering large areas.  The
   capsulelike fruits contain many
   seeds that provide for extensive
   spread of the species in suitable
   climates.

j  Family Acanthaceae - Dianthera
   (= Justicia) or Water Willow forms
   large beds at the margins of streams.

k  Marsh and shore zones are inhabited
   by Bulrushes or Sedges (Family
   Cyperaceae), Rushes (Faniily
   Juncaceae), and Grasses
   (Gramineae).  The latter includes
   wild rice (Zizania)and Cord Grass
   (Spartina).

1  Faniily Amaranthaceae - includes
   Alternanthera philoxeroides or
   Alligator Weed.

m Family Lemnaceae - The Duck weed
   family includes the smallest known
   flowering plants,  all of which are
   free floating.  Wolffia and Wolffiella
   are without roots  and Lemna and
   Spirodela both possess them.

n  Family Typhaceae - one genus
   Typha.  Cattail or tule.

o  Family Iridaceae  - Iris pseudacoris
   is another European plant becoming
   widely established in North America.

p  Family Araceae - Acorus calamus,
   sweet flag,  is an Eurasian plant
   which has become widely established
   in North America.
Ill  TYPICAL AQUA TIC PLANT
    COMMUNITIES

 A Ponds and lakes not only have a charac-
    teristic plant zonation, but over a period
    of years exhibit a distinct succession of
    aquatic  plant communities.

 B Intertidal salt marshes are so distinctive
    that in one state, regulations  preventing
    the disruption of the ecology of salt
    marshes, are defined on the basis of the
    specific plants involved.  A typical
    estuarine shore (from seaward in) might
    have successive zones dominated by:

    1  Suaeda (alkali seepweed)

    2  Spartina (cord grass)

    3  Halimione  (sea purslane)

    4  Puccinellia (alkaligrass) and others

    5  Juncus (rush)

 C Mangrove vegetation replaces salt marshes
    in tropical and subtropical regions.  Two
    most  widespread genera  are:

    1  Rhizophora, the red mangrove
       occupies  the outer pioneer zone.
       Roots are borne on downward curving
       branches or rhizophores.  The
       resulting tangle  reduces tidal currents
       and promotes deposition of solids.

    2  Avicennia, the black mangrove,
       usually forms a  shoreward zone.
       It depends on aerial roots, which
       emerge from the ground a short
       distance from the tree, rather than
       prop roots.

    3  Examples have been given of open
       shoal areas being transformed into
       thick swamp forest in some 30 years
       through this process.
                                                                               4-5

-------
 A quatic Ma crophytes
    Sea grass communities, whether composed
    of Zostera (eel grass) in Northern waters
    or Thalassia (turtle grass) or Cymodocea
    (Manatee grass) in the tropics,  are
    recognizable as an entity wherever found.
    A soft substratum near low water is
    required,  and each has a similar distinct
    assemblage of molluscs, crustacenas,
    and other  invertebrates.

    1  The destruction of this community by
       bulkheading and filling has far-reaching
       effects on the stability of such bottom
       areas.

    2  Destruction of these plants by disease,
       such as the epidemics which decimated
       the Zostera eel grass community in the
       thirties created both erosion problems
       and also brought about far-reaching
       biotic community changes which only
       became reestablished with the return
       of the eel grass.
IV  In comparison to other living organisms
 the aquatic plants or macrophytes have been
 seriously neglected. Man's increased
 activities have favored some plants (which
 we call "weeds") through eutrophication and
 diminished others (which we call a valuable
 resource loss) through dredging and filling
 operations.  These events demand
 reassessment of knowledge about the ecology
 of these plants and increased contributions
 toward increasing that information.
 ECOLOGICAL REFERENCES

 1  Bay ley, Suzanne; Rubin,  Harvey, and
       Southwick,  Charles H.   Recent Decline
       in the Distribution and Abundance of
       Eurasian Milfoil in Chesapeake Bay.
       Chesapeake Science 9 (3):173-181.
       1968.

 2  Bickel,  David.   The Role of Aquatic
       Plants and Submerged Structures in the
       Ecology of a Freshwater Pulmonate
       Snail.  Physa integra Hald.
       Sterkiana 18:17-20.   1965.
 3  Blackburn,  Robert D.,  White,  P.E. and
      Weldon,  L. W.   Ecology of  Submersed
      Weeds in'South Florida Canals.
      Weed Science 16 (2):261-266.   1968.

 4  Dawson, Elmer Y.  Marine Botany.
      Holt-Rhinehart & Winston, New York.
      pp. 371.   1966.

 5  Holm, L.G.,  Weldon, L.W. and
      Blackburn, R.D.  Aquatic Weeds.
      Science 166:699-709.   1969.
      (An excellent summary and  review of
      "the rampart growth of.weeds has
      become one of the symptoms of our
      failure to manage our resources".)

 6  Kormandy,  Edward J.  Comparative
      Ecology of Sandspit Ponds.  Am.  Mid.
      Nat.  82:28-61.   1969.

 7  Lawrence, J.M.  Aquatic Herbicide
      Data.  USDA Handbook No.  231,
      pp. 133.   1962.

 8  Mackenthun, Kenneth M.   A Review of
      Algae, Lake  Weeds,  and Nutrients.
      J.WPC Fed.  34:1077-1085.   1962.

 9  Mackenthun, Kenneth M.   Nitrogen and
      Phosphorus in Water.   An Annotated
      Selected Bibliography of Their
      Biological  Effects, USPHS Pub. No.
      1305, pp. 111.  1965.

10  Mackenthun, Kenneth M.  and Ingram,
      William M.  Biological Associated
      Problems in  Freshwater Environ-
      ments, FWPCA, pp. 287.   1967.

11  Neel, Joe Kendall.  Seasonal Succession
      of Benthic Algae and their Macro-
      invertebrate  Residents in a  Headwater
      Limestone Stream, Jour. Water Poll.
      Cont. Fed.,  40  (2) Part 2: R10-30.
      1968.

12  Nelson, Daniel J. and Scott, Donald C.
      Role of Detritus in the Productivity
      of a Rock-Outcrop Community in a
      Piedmont Stream,  Limn,  and Ocean.
      7(3):396-413.   1962.
   4-6

-------
                                                                     Aquatic Macrophytes
13  Peltier, W.H.  and Welch,  E.B.
      Factors Affecting Growth Rooted
      Aquatic Plants, TVA, Chattanooga,
      Tennessee,.pp. 45.   1968.

14  Rawls, Charles K.,  Jr.   Reefoot Lake
      Waterfowl Research,  Tenn.  Game
      & Fish Comm., pp. 80.   1954.

15  Smith,  Gordon E. and Isom,  Billy G.
      Investigation of Effects of Large-
      Scale Applications on 2, 4-D on
      Aquatic Fauna and Water Quality,
      Pest. Monit. Journal 1 (3):16-21.  1967.

16  Westlake, D. F.   The Biology of A quatic
      Weeds in  Relation to their Management.
      Proc. 9th Brit. Weed Conf.  pp. 372-
      381.  1968.

17  Zeiger,  C. F.   Biological Control of
      Alligatorweed with A ga sides n. sp.
      in Florida, Hyacinth Cont. Jour.,
      6:31-34.  1967.
 IDENTIFICATION REFERENCES

 1  Arber, Agnes.  Water Plants, Wheldon
      and Wesley, Lt. and Hafner Pub. Co.,
      New York, pp.  436.  1963.

 2  Blackburn,  Rotiert D.  and Weldon,  Lyle
      W.  Eurasian Watermilfoil-Flprida's
      new underwater menace.. Hyacinth
      Cont. Jour. 6:15-18.  1967.

 3  Conard, Henry S.   How to Know the
      Mosses, Wm. C. Brown,  Dubuque,
      Iowa, pp. 166.   1944.

 4  Dawes, Clinton J.  Marine Algae in the
      vicinity of Tampa Bay, University S.
      Florida.  1967.  (includes Angiosperms)

 5  Eyles,  C. E. and Robertson,  J. L.
      A  Guide and Key to the Aquatic Plants
      of the Southeastern United States,
      USPHS Bull. No.  286, 151 pp.   1944.
      (Reprinted as Circular 158,  U.S. Bur.
      Sport Fisheries and Wildlife, 1963).
 6  Fassett, N. C.   A Manual of Aquatic
      Plants (with Revision Appendix by
      Eugene G. Ogden).   University of
      Wisconsin Press, Madison,  405 pp.
      1960.               '

 7  Fernald,  M. L.   Gray's Manual of
      Botany.  8th ed.  Amer. Book Co.
      1632 pp.  1950.

 8  Hotchkiss, N.   Pondweeds and Pondweed-
      like Plants of Eastern North America,
      U. S. Fish and Wildlife Service,
      Circular 187,  pp. 1-30.   1964.

 9  Hotchkiss, N.   Bulrushes and Bulrush-
      like Plants of Eastern North America,
      U. S. Fish and Wildlife Service.
      Circular 221,  pp. 1-19.   1965.

10  Hotchkiss, N.  Underwater and Floating-
      Leaved Plants of the U. S. and Canada,
      U. S. Fish and Wildlife Service,
      Resource Publ.  No.  44, pp. 124.  1967.

11  Humm, H. J.   Seagrasses of the Northern
      Gulf Coast,  BuU. Mar. Sc. Gulf &
      Caribbean 6 (3): 305-308.

12  Muenscher, W. C.  Aquatic Plants of the
      United States, Comstock Publishing
      Company, Ithaca, New York, 374 pp.
      1944.

13  Otto, N. E. and Bartley, T.R.   Aquatic
      Pests on Irrigation Systems,
      Identification Guide,  U.S. Bur. of
      Reclamation Water Resources.Tech.
      Publ., pp. 72.  1965.

14  Stewart, Albert W., Dennis, LaRue J.,
      and Gilkey,  Helen M.  Aquatic Plants
      of the Pacific Northwest.   Oregon
      State Monographs, Corvallis,
      Second Edition,  261pp.   1963.

15  Weldon, L.W., Blackburn,  R.D.,and
      Harrison, D. S.   Common Aquatic
      Weeds, USDA Agriculture Handbook
      No. 352, 43 pp.  1969.
                                                                                     4-7

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 Aquatic Macrophytes
16  Winterringer, Glen S.  and Lopinot, Alvin       	;	'  '.	
       C.  Aquatic Plants, of Illinois, Illinois       This outline was prepared by R.M. Sinclair,
       State Museum Popular  Science Series,        Aquatic Biologist. National Training Center,
       Vol.  VI, pp. 142.   1966.                    Water Programs Operations,  EPA, Cincinnati,
                                                   OH 45268.
17  Correll, Donovan S. and Correll, Helen B.
       Aquatic and Wetland Plants of Southwestern                     '
       United States.  Water Pollution Control
       Research  Series.  16030 DNL 01/72.
       Environmental Protection Agency.
       Research  and Monitoring, Wash., D. C.                                         •
       1777pp. 1972.
   4-8

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                 AN ARTIFICIAL KEY TO SOME COMMON AQUATIC PLANTS

                         (Freshwater,  Estuarine, and Marine)
I  Specific identification of aquatic plants
often requires microscopic examination of
parts which may not always be available to
the investigator (for example, fruiting bodies
and/or seeds which are seasonal or produced
only rarely).

Because of this, some groups are more
difficult to identify.  Potamogeton is a varied
and difficult genus, although  Ogden's Key
gives help where only vegetative parts are
available.  Najas and Myriophyllum are often
difficult.

In the Hydrocharitaceae, Hydrilla, Egeria.
and Elodea (Ana char is is an obsolete name
for the latter two) are sometimes confused,
and the serious student may need to turn to
the specialist in this group (see Blackburn
et al for a discussion of this  problem.

For a detailed list of references on classification
see Sculthorpe  (p. 16-20) where these are
listed by family. The following key will aid
the common plant groups.  It is divided as
follows:

A)    Plants floating on water surface.

B)    Plants submersed beneath water surface.
C)
D)
Plants erect and emersed; rooted to the
substratum and extending upward out
of water.
Submersed "sea grasses".
Manuals with descriptive comments and
figures for specific identification are listed
in part under references.

To use the key,  select the proper group
(A, B, C, D) and read the description in the
first couplet.  The description that best fits
the unknown specimen will indicate either the
plant group or genus to which the specimen
may belong or an additional couplet, in which
case the process is repeated until the descrip-
tion for a particular plant or genus best fits
the unidentified specimen.  An asterisk *
indicates that distribution may include
brackish or salt water.  Common names
used here (with few exceptions) are those
of:  Subcommittee on Standardization of
Common and Botanical Names of Weeds,
reprinted from Weeds  14 (4):347-386 (1966).

A  PLANTS FLOATING ON WATER  SURFACE

1. Plants very small; seldom  2
   over a centimeter along
   any dimension.

1. Plants large; usually        8
   measuring at least 0.5
   decimeter along some
   dimension.

   2.  Plant body dichotomously 3
      2-lobed, or  repeatedly
      dichotomously branched.

   2.  Plant body not dichoto-   4
      mously branched and if
      2-lobed not equally so.

3. Divisions of plant body fine  Riccia
   and many; plant body usuallyfluitans L.
   floating below surface.

3. Divisions of plant body      Ricciocarpus
   coarse, 2-lobed; floating    natans L.
   on surface.

   4.  Plants floating on        5
      surface.

   4.  Plants floating just      WolffieUa
      below water surface;     floridana Sm.
      plant body made  up of
      a clump of short
      filaments.

5. Plant body of small over-   Azolla
   lapping scales.

5. Plant body simple or        6
   compound, made up of
   rounded floating
   leaves.
BI.PL.2b.2.70
                                                                                      5-1

-------
 An Artificial Key to Some Common Aquatic Plants
    6. Plants simple,  extremely
       minute, appearing as
       grains on surface of
       water.

    6. Plants compound, made
       up of several rounded-
       oblong disk-like bodies,
       floating on surface of
       water.
watermeal      13.  Plant body repeatedly     Riccia
Wolffia             dichotomously branched,  fluitans

                13.  Leaves not dichoto-       14
                    mously branched.
7
                   14. Leaves entire not      Elodea
                      dissected or bearing •
                      bladders, and
                      whorled.
 7. Plant body inconspicuously
    nerved, rootlets 1 per disk.

 7. Plant body conspicuously
    nerved, rootlets 2 to
    several per  disk.

    8.  Leaves broad and blade-
       like, sometimes inflated
       near base.

    8.  Leaves (plant body in
       Riccia) narrow  or finely
       divided.

 9. Leaves large and dilated
    with inflated petioles.

 9. Leaves normally expanded.

   10.   Leaves bearing plantlets
        around the margin.

   10.   Leaves not bearing
        plantlets.

11. Floating-leafed plants with
    leaves  attached to  the
    bottom by a bare unbranched
    stem of varying length.

11. Roots usually suspended
    free in the water,  with no
    connection to lake  bottom;
    capable of drifting.

   12.  Leaves wide to  the base,
       without petioles.

   12.  Leaves mostly differ-
       entiated into blades
       and  petioles.
star duckweed
Lemna

giant duckweed
Spirodela
polyrhiza L.

9
12
waterhyacinth
Eichhornia
crassipes Mart.
11

floating fern
Ceratopteris

11
15
12
water lettuce
Pistia
stratiotes L.
frogbit
Limnobium
spongia Base.
   14.  Leaves dissected and
       bearing bladders..

15. Stem attached to middle
    of leaf.

15. Stem attached at the
    summit of a deep notch
    in the leaf.

   16.  Leaves oval,  not
       more than 3 inches
       wide, with supple
       stem attached to the
       middle of the  leaf.

   16.  Circular leaf  with a
       long, fairly rigid
       stem attached to the
       middle of the  leaf,  .
       leaves 6 inches or
       more wide some-
       times supported by
       the stem above the
       water level.

17. Circular or heart-
    shaped leaf with  the
    veins radiating from
    the mid-rib nearly to
    the margin without
    forking; floating  yellow
    flowers.

17. Circular leaf with much-
    forked veins radiating to
    the margin, white,  or
    pink floating flowers.
bladderwort
Utricularia

16
17
watershield,
Brasenla schreberi
Gmelin
american lotus
Nelumbo
yellow pond lily
Nuphar
                                             *white water lily
                                             Nymphaea
   5-2

-------
An Artificial Key to Some Common Aquatic Plants
* green alga,
muskgrass,
Chara
B PLANTS SUBMERSED BENEATH WATER
SURFACE

1. Plant body made up of
stems bearing whorled,
smooth, brittle branches,
easily snapped with a
slight pressure; plants
with a musky odor, no
roots, often with a limy
encrustation.

1. Plant body not as
described.

2. Plant attached to sub-
strate by holdfasts or
haptera, not rooted.

2. Plant not so attached.

3. Plant attached to stones
•by haptera (roots not
attached) and tough
stems forming a dull-
green tangle. .

3. Plants single shoots
attached to substrate
by holdfasts.

4. Without true roots,
flowers or vascular
bundles.
riverweed,
Podostemum
c eratophyllum
red alga
Lemanea
4. Usually with true
roots and with
vascular bundles.
5. Leaves without midrib,
arranged in two opposite
rows, usually with a
part folded under.

5. Leaves most often with
midrib, usually arranged
equally around the stem,
not curved under.
Division Bryophyta,
Mosses and
Liverworts
5

Division
Angiospermae.
True flowering
plants
6

Order Junger-
manniales,
Porella
Order Musci,
Leptodictyum,
Fontinalis, and
Fissidens
11
*w»ter milfoil
Myriophyllum
6. Submerged leaves bladderwort
bearing small . Utricularia
bladders, leaves
irregularly forked.

6. Submerged leaves 7
not bladder bearing.

7. Submerged leaves com- 8
pound, made up of
narrow segments or
leaflets.

7. Submerged leaves
simple, made up of
a single narrow blade.

, 8. Submerged leaves
with one central
axis, leaves feather-
like, branches in
whorls about the
stem, stems
, usually very lax.

8. Submerged leaves
irregularly forking.

9. Submerged leaves
singly and alternately
or irregularly borne;
leaves many branches,
irregularly forked and
appearing as tufts of
numerous thread-like
projections attached
to the center stem.

9. Submerged leaves
borne opposite each
other on stem or
whorled.

10. Leaves stalked, fan-
like, extending from
opposite sides of the
stem; leaflets not
toothed.

10. Stems with whorls of
stiff, forked leaves;
leaflets with toothed
or serrated margins
(small barbs) on one
side; plant without
true roots.
*water buttercup
Ranunculus
10
fanwort
Cabomba
caraliniana Gr.
coontail
Ceratophyllum
5-3

-------
 An Artificial Key to Some Common Aquatic Plants
                             12
                             22
11.  Submerged leaves long
    and ribbon-like,  at
    least 1/10 inch wide.

11.  Submerged leaves not
    ribbon-like; often
    thread-like but if wider
    than I/10 inch, less
    than 1 inch long.
   12.  Leaves scattered along 13:
       the stem.
17".  Upper submerged leaves
    with long stalks.
   12.  Leaves all borne from
       one point.

13. Leaves with mid-ribs   *
    evident when held against
    bright light, many
    species with great
    diversity in leaf forms.

13. Leaves without mid-ribs
    evident when held against
    bright light.

   14.  Plants with both
       floating and submerged
       leaves, the floating
       leaves with expanded
       blades and differing
       from those  submerged.

   14.  Plants with all leaves
       alike and submerged.

15. Floating leaves, heart-
    shaped at the base,  1 to
    4 inches long,  waxy in
    appearance.

15. Floating leaves rounded
    at the base.
                             21
                             pondweed
                             Potamogeton
                             14
                             water star grass
                             Heteranthera
                             15
                             18
                             floating pondweed
                             Potamogeton
                             natans  L.
                             16
   16. Floating leaves with
      30 to 50 nerves;
      submerged leaves
      about three times
      as long as broad.

   16. Floating leaves with
      less than 30 nerves.
                             large leaf pondweed
                             Potamogeton
                             amplifolius
                             Tuckerman
                             17
17.  Submerged leaves not
    as above but with an
    abrupt awl-shaped
    tip.

   18. Margins of the thin
      leaves crimped and
      toothed, the marginal
      serrations visible to
      the naked eye.

   18. Margins of leaves
      not visibly toothed.

19.  Leaves minutely toothed
    on the margins, visible
    when magnified; leaves
    extending stiffly in
    opposite directions so
    that whole plant appears
    flat; only midvein
    prominent.

19.  Not as above

   20. Stems much flattened
      and winged, about as
      wide as the leaves;
      leaves 1/12 to 1/5
      inch wide.

   20. Leaves threadlike,    *
      long, rounded, and
      slender, rarely
      exceeding 1/10 inch
      wide, oriented into
      a lax,  diffuse,
      branched spray.  The
      "bunched" appearance
      of the threadlike
      rounded leaves as they
      float in the water
      readily distinguished
      sago pondweed from
      others of group.
 American
 pbndweed-
 Potamogeton
 nodosus
 Poiret

 pondweed
 Potamogeton
 angustifolius
 Berchtold

* curlyleaf
 pondweed
 Potamogeton
 crispus L.
  19
 Robbins
 pondweed
 Potamogeton
 robbinsii
 Oakes
  20

  flatstem
  pondweed
  Potamogeton
  zosteriformls
  Fernald

  sago pondweed
  Potamogeton
  pectinatus L.
  5-4

-------
An Artificial Key to Some Common Aquatic Plants
21. Leaves very long and * Vallisneria
ribbonlike; when
examined with hand
lens, showing a central
dense zone and a
peripheral less dense
zone; flowers borne on
a long stem that forms
a spiral after fertili-
zation.
21. Leaf, when examined
with hand lens not
showing zones as above.

22. Leaves whorled, 3-8
in upper whorls.

22. Leaves alternate or
opposite.

23. Leaves alternate, leaf- *
base apparently
inflated.

23. Leaves opposite.

24. All leaves long
and narrow.

24. Upper leaves shorter
and broader.

25. Leaves dilated at base. *

25. Leaves with narrow
bases.
waterplantains,
Alismataceae
Elodea, Egeria,
Hydrilla

23
widgeongrass,
Ruppia maritima L.
24

25
waterstarwort,
CaUitriche
horned pondweed,
Zannichiellia
palustris L.
2. Base of stem tri-
angular in cross
section, the three
angles in some cases
so rounded as to make
the stem appear al-
most round.

2. Base of stem not
triangular. •

3. Three cornered seeds,
usually straw colored,
enclosed within a loose
elongated sac; a low-
growing grasslike plant.

3. Seeds not enclosed in a
loose elongated sac.

4. A single flower or
seed-bearing struture
on the tip of the stem.
sedge, Carex
spikerush,
Eleocharis
Stem with one or more *bulrush,
leaves extending beyond Scirpus
the spike or seed-
bearing structure.
(The hardstem bulrush
has long, hard, slender,
dark olive-green stems,
1/8 to 3/8 inch at the
base, extending 3 to 5
feet above the water
surface; the softstream
bulrush has soft stems
of light green color,
3/10 to 1 inch thick
at the base.)
C PLANTS ERECT AND EMERSED; ROOTED
TO THE SUBSTRATUM AND EXTENDING
UPWARD OUT OF THE WATER.

1. Leaves more than 10 2
times as long as broad.
1. Leaves less than 10
times as long as broad.
12
5. Leaf with a collar like
appendage, membranous
or composed of hairs at
the junction of the leaf
blade and that part of the
leaf that is wrapped
around the stem.

5. Leaf without collarlike
appendage mentioned
above.
6
5-5

-------
An Artificial Key to Some Common Aquatic Plants
                               common reed,
                               Phragmites
   6. Seed or flower-bear ing    Cutgrass,
      structure composed of    Leersia
      scales with fringed
      margins and over-
      lapping in a single row.

   6. Flower-bearing struc-    7
      ture not as above.

7. Flowering heads composed
   of small seeds with long
   silky hairs,  appearing as a
   silky mass.  The root-
   stocks are stout, making
   it a difficult plant to pull
   up. Plants are 6 to 12 feet
   tall.

7. Flowering heads not         8
   appearing as a silky
   mass.

   8. Flowering part of         wildrice,
      plant much branched,      Zizania
      but not as closely         aquatica L.
      packed as in Phragmites.
      Seeds much larger,
      about  3/4 inch long.
      Plants with short
      roots and easily pulled
      up.

   8. Spikelets, 6 mm long      *cordgrass,
      or more appressed        Spartina
      along one side of
      rachis, grass growing
      in clumps or solid
      stands.

9. None of the veins more       10
   prominent than others.

9. Midvein more prom-         11
   inent than others.

  10. Flowers borne in closely  Cattail, Typha
      packed cylindrical spikes,
      seeds very small. (The
      common cattail has flat
      leaves about 1 inch
      wide; the narrow-leaved
      cattail has leaves some-
      what rounded on the back
      that are 1/8 to 7/8 inch
      wide.)
                                                  10. Flowers in spherical  burreed,
                                                      heads, seeds larger,  Sparganium
                                                      up to size of corn
                                                      kernel; leaves
                                                      shallowly  and
                                                      broadly triangular
                                                      in cross-section.

                                                11. Plants aromatic when    sweetflag
    crushed.

11.  Plants not aromatic
    when crushed,
    flowers large and
    showy.

   12.  Leaves arising at
       intervals along the
       stem.

   12.  Leaves arising at
       base of the plant.

13.  Plants with jointed
    stems,  swollen at the
    joints, or with creeping
    rootstocks; stems with
    alternate, simple
    leaves.

13.  Stems prostrate or
    creeping, branched,
    and often jointed and
    rooted at the joints;
    leaves opposite;
    spreading plant,
    often forming floating
    mats over extensive
    water areas crowding
    out other plants;
    broken off branch frag-
    ments root readily,  and
    stems may elongate as
    much as 200 inches  in
    one season.
A corus
calamus L.
yellow iris
Iris
pseudacorus L.
                                                                           13
                                                                           14
                                                                           smartweed,
                                                                           Polygonum
                                                                           alligatorweed,
                                                                           Alternanthera
                                                                           philoxeroides
                                                                           Mart.
                                                                           15
   14. Fleshy or tuber-
      bearing rootstocks
      and rosettes of sheathing
      basal leaves.

   14. Not as above, floating 16
      plants.
  5-6

-------
An Artificial Key to Some Common Aquatic Plants
15. None of the veins more *arrowhead
prominent than others. Sagittaria

15. Midvein and those arrow arum
descending into the Peltandra
lobes more prominent Virginia L.
than others.

16. Plants floating with waterhyacinth
fibrous, branched roots Eichhornia
and rosettes of stalked crassipes
leaves, the leaf stalks Mart.
often inflated and
bladder-like.
16. Plants with floating
rosettes of stalked
leaves, commonly
several rosettes
produced on branches
of the same plant at
the end of flexible,
cardlike, sparsely-
branched submerged
stems; plant thrives
at depths of 2 to 5
feet and favors muddy
bottoms with high
organic content; leaf
stalks inflated, but
not as conspicuously
as in waterhyacinth.
D SUBMERSED "SEA GRASSES"
water-
chestnut,
Trapa natans L.
1. Leaves round in cross
section.

2. Leaves flat.

3. Leaves widest at or
above the middle.

3. Leaves uniform width.

4. Leaf tip blunt.

4. Leaf tip pointed.

5. Leaf tip single.
manateegrass,
Cymodocea
manatorum
Halophila
turtlegrass,
Thalassia
testudinum
eelgrass,
Zostera marina
5. Leaf tip 3-pointed.
ACKNOW LEDGMENT:
shoalgrass,
Diplanthera
wrightii
This outline was adapted from Keys of
Mackenthun and Ingram (1967); Robertson
and Eyles (1963); and Humm (1956). The
figures are from Eyles and Robertson and
Hotchkiss (1967).
REFERENCES

1 Blackburn, R.D., Weldon, L.W., Yeo,
R.R., and Taylor, T.M.
Identification and Distribution of
Certain Similar-Appearing Submersed
Aquatic Weeds in Florida. Hyacinth
ControlJour.8:17-21. 1969.

2 Eyles, Don E. and Robertson, J. L.
Guide and Key to the Aquatic Plants
of the Southeastern United States.
USFWS Circular 158, 151pp. 1963.

3 Hotchkiss, Neil. Underwater and
Floating-Leaved Plants of the United
States and Canada. USDI. Fish and
Wildlife Service Resource Publication
Number 44. 124 pp. 1967.

4 Humm, H.J. Sea Grasses of the
Northern Gulf Coast, Bull. Mar. Sci.
Gulf and Carlb. 6 (4):305-308. 1956.

5 Mackenthun, Kenneth M. and Ingram,
William M. Biological Associated
Problems in Freshwater Environments.
FWPCA. 287 pp. 1967.

6 Ogden, E.G. Key to the North American
Species of Potamogeton. Circ. N.Y.
State Museum. 31:1-11. 1953.

7 Prescott, G.W. How to Know the Aquatic
Plants. Wm. C. Brown. 1969.

8 Sculthorpe, C. D. The Biology of Aquatic
Vascular Plants. St. Martin's Press.
New York. 610pp. 1967.
5-7

-------
An Artificial Key to Some Common Aquatic Plants
   Ward, H.B. and Whipple,  G.C.              10   Weldon, Lyle W.   Common Aquatic
      (Edited by W.T. Edmondson) 1959,               Weeds.   USDA.   Agricultural
      Fresh Water Biology, John Wiley and             Handbook 352,  43pp.   1969.
      Sons,  New York, 1248 pp.  (includes
      chapters Aquatic Bryophyta by Conrad       This outline was prepared by R.M. Sinclair,
      and Vascular Plants by Muensher.           Aquatic Biologist, National Training Center,
                                                Water Programs Operations, EPA, Cincinnati,
                    '                             OH 45268.
  5-8

-------
                                 An Artificial Key to Some Common Aquatic Plants
          Riccia
        Azolla
                               Group A
                          FLOATING PLANTS
Ricciocarpus
                                   of
                                 Salvinia
                                                      Ceratopteris
Lemna minor    Wolffiella
  Limnobium
                              Eichornia
                                                           Pistia
                Elodea
                                                 Ultricularia

-------
An Artificial Key to Some Common Aquatic Plants
                                         Group A
                                FLOATING PLANTS (Cont.)
                          Nelumbo
Nymphaea
                                     seedling,  life-size
                                            Nuphar

-------
                            An Artificial Key to-Some Common Aquatic Plants
                          Group B
                        SUBMERSED
Egeria
Sagittaria

-------
An Artificial Key to Some Common Aquatic Plants
                                          Group B
                                     SUBMERSED (Cent.)
            Ceratophyllum

-------
                   An Artificial Key to Some Common Aquatic Plants
                  Group B
            SUBMERSED (Cont.)
 P.  pectinatus
POTAMOGETON
                                                               stem
                                                               detail
                                N. guadalupensis

-------
An Artificial Key to Some Common Aquatic Plants
                                           Group C
                                         EMERSED
                     Scirpus

-------
                           An Artificial Key to Some Common Aquatic Plants
Diplanthera
   Group D
SEA GRASSES
                                                        Phyllospadix
                                     Cymodocea

-------
An Artificial Key to Some Common Aquatic Plants
                  AQUATIC MACROPHYTES - ALGAE AND BRYOPHYTES
                   Chara
                   Division ALGAE
                                                            Nitella
                                  "Liverworts"
                                 Class Hepaticae
                                                          Riccia
                Porella
   w
 W
4
                                        "Mosses"
                                       Class Musci
                       Leptodictyum.

                               Sphagnum
                        Division BRYOPHYTA

-------
                                   An Artificial Key to Some Common Aquatic Plants
             AQUATIC VASCULAR PLANTS - TRACHEOPHYTA
Class
    Equisetinae
                                                     Equisetum
                                                                  Azolla
   Isoetes
Ceratopteris
Marsilea
                               Class Angiospermae
 Nymphoides
            Myrlophyllum

           DICOTYLEDONS

     Thalassia
             Potamogeton

           MONOCOTYLEDONS
                                                                 Lemna

-------
                 KEY TO SELECTED GROUPS OF FRESHWATER ANIMALS
The following key is intended to provide            animal as a member of the group. Phylum
an introduction to some of the more                PROTOZOA.  If you selected "Ib , proceed
common freshwater animals.  Technical           to the couplet indicated.  Continue this
language is kept to a minimum.                    process until the selected statement is .
                                                 terminated with the name of  a group.
In using this key, start with the first
couplet (la, Ib), and select the alternative          If you wish more information about the
that seems most reasonable. If you               group, consult references.   (See reference
selected "la" you have identified the               list.)
 BI.AQ.21b.5.71

-------
 Key to Selected Groups of Freshwater Animals
 la    The body of the organism comprising
       a single microscopic independent
       cell, or many similar and indepen-
       dently functioning cells associated
       in a colony with little or no differ-
       ence between the cells, i. e. ,  with-
       out forming tissues; or body com-
       prised of masses of multinucleate
       protoplasm.  Mostly microscopic,
       single celled animals.

           Phylum PROTOZOA

. Ib    The body of the organism com-
       prised of many cells of different
       kinds, i.e.,  forming tissues.
       May be microscopic or macro-
       scopic.

 2a    Body or colony usually forming
       irregular masses or layers some-
       times cylindrical, goblet shaped,
       vase shaped, or tree like. Size
       range from barely visible to
       large.

 2b    Body or colony shows some type
       of definite symmetry.

 3a    Colony  surface rough or bristly
       in appearance under microscope
       or hand lens.  Grey, green, or
       br own.   Sponge s.
           Phylum PORIFERA (Fig.   1)

 3b    Colony surface relatively smooth.
       General texture of mass gelatinous,
       transparent.  Clumps of minute
       individual organisms variously
       distributed.  Moss animals,
       bryozoans.
           Phylum BRYOZOA (Fig. 2)

 4a    Microscopic.  Action of two
       ciliated (fringed) lobes  at an-
       terior (front) end in life often
       gives appearance of wheels.
       Body often segmented,  accordian-
       like. Free swimming or attached.
       Rotifers or wheel animalcules.
           Phylum TROCHELMINTHES
           (Rotifera) (Fig.  3)

 4b    Larger,  wormlike, or having
       strong skeleton or shell.
5a  Skeleton or shell present.  Skel-      15
    eton may be external or internal.

5b  Body soft and/or wormlike.            6
    Skin may range from soft to
    parchment -like.

6a  Three or more pairs of well          19
    formed  jointed legs present.
         Phylum ARTHROPODA (Fig. 4)

6b  Legs or appendages,  if present,        7
    limited  to pairs  of bumps or hooks.
    Lobes or tenacles,  if present,
    soft and fleshy,  not jointed.

7a  Body strongly depressed or            8
    flattened in cross section.

7b  Body oval, round, or shaped like      10
    an inverted "U"  in cross section.

8a  Parasitic inside bodies of higher
    animals.  Extremely long and flat,
    divided  into sections like a Roman
    girdle.   Life history may involve
    an intermediate  host.  Tape worms.
         Class  CESTODA (Fig.  5)

8b  Body a  single unit.  Mouth and         9
    digestive system present, but no
    anus.

9a  External or internal parasite of
    higher animals.   Sucking  discs
    present for attachment.  Life his-
    tory may involve two or more in-
    termediate hosts or stages.  Flukes.
         Class  TREMATODA

9b  Free living.  Entire body covered
    with locomotive  cilia. Eye areas
    in head  often appear "crossed".
    Free living flatworms.
         Class  TURBELLARIA (Fig.  6)

lOa Long, slender, with snake-^like
    motion  in life.  Covered with glis-
    tening cuticle.  Parasitic or free-
    living.  Microscopic to six feet in
    length.   Round worms.
         Phylum NEMATHELMINTHES
         (Fig. 7)

lOb Divided into sections or segments     11
   6-2

-------
Key to Selected Groups of Freshwater Animals
lOc Unsegmented, head blunt, one
or two retractile tentacles.
Flat pointed, tail.

lla Head a more or less well-formed,
hard, capsule with jaws, eyes,
and antennae.
Class INSECTA order DIPTERA
(Figs. 8A, 8C)

lib Head structure soft, except
jaws (if present). Fig. 8E.)
18 sucking parasites on higher animals,
often found unattached to host.
Leaches.
Class HIRUDINEA (Fig. 9B)

15a Skeleton internal, of true bone. 40
(Vertebrates)
12
12a Head conical or rounded, lateral
appendages not conspicuous or
numerous.

12b Head somewhat broad and blunt.
Retractile jaws usually present.
Soft fleshy lobes or tentacles,
often somewhat flattened, may be
present in the head region. Tail
usually narrow. Lateral lobes
or fleshy appendages on each
segment unless there is a large
sucker disc at rear end.
Phylum ANNELIDA (Fig. 9)

13a Minute dark colored retractile
jaws present, body tapering
somewhat at both ends, pairs or
rings of bumps or "legs" often
present, even near tail.
Class INSECTA Order DIPTERA
(Fig. 8)

13b No jaws, sides of body generally
parallel except at ends. Thicken-
ed area or ring usually present
if not all the way back on body.
Clumps of minute bristles on most
segments. Earthworms, sludge-
worms.
Order OLIGOCHAETA

14a Segments with bristles and/or fleshy
lobes or other extensions. Tube
builders, borers, or burrowers.
Often reddish or greenish in
color. Brackish or fresh water.
Nereid worms.
Order POLYCHAETA (Fig. 9A)

14b Sucker disc at each end, the large
one posterior. External blood-
13
14
15b Body covered with an external 16
skeleton or shell.
(Figs. 10, 13, 17, 18, 24,
25, 28)

16a External skeleton jointed, shell 19
covers legs and other appendages,
often leathery in nature.
Phylum ARTHROPODA

16b External shell entire, not jointed, 17
unless composed of two clam-
like halves.
(Figs. 10, 11, 12)

17a Half inch or less in length. Two
leathery, clam-like shells. Soft
parts inside include delicate,
jointed appendages. Phyllopods
or branchiopods.
Class CRUSTACEA, Subclasses
BRANCHIOPODA (Fig. 12)
and OSTRACODA (Fig. 11)

17b Soft parts covered with thin 18
skin, mucous produced, no jointed legs.
Phylum MOLLUSCA
14 18a Shell single, may be a spiral cone.
Snails.
Class GASTROPODA (Fig. 13)

18b Shell double, two halves, hinged
at one point. Mussels, clams.
Class BIVALVIA (Fig. 10)

19a Three pairs of regular walking 29
legs, or their rudiments. Wings
present in all adults and rudiments
in some larvae.
Class INSECTA (Figs. 22, 24D,
25, 26, 28, 29)
19b More than three pairs of legs
apparently present.

20a Body elongated, head broad and flat
20
6-3

-------
Key to Selected Groups of Freshwater Animals
      with strong jaws.  Appendages follow-
      ing first three pairs of legs are round-
      ded tapering filaments.  Up to  3
      inches long. Dobson fly and fish fly
      larvae.
          Class INSECTA Order
          MEGALOPTERA (Fig.  14)
        25a Appendages leaflike, flattened,
            more than ten pairs.
                Subclass BRANCHIOPODA
                (See 22 a)
20b   Four or more pairs of legs.

21a   Four pairs of legs.  Body rounded,
      bulbous, head minute.  Often
      brown or red.  Water mites.

          Phylum ARTHROPODA, Class
          ARACHNIDA,  Order ACARI
          (Fig. 15)

21b   Five or more pairs of walking
      or swimming legs; gills, two
      pairs of antennae.  Crustaceans.
          Phylum ARTHROPODA,  ,
          Class CRUSTACEA

22a   Ten or more pairs of flattened,
      leaflike swimming and respiratory
      appendages.  Many species swim
      constantly in life; some swim
      upside  down.  Fairy shrimps,
      phyllopods,  or branchipods.
          Subclass BRANCHIOPODA
          (Fig. 16)

22b   Less than ten pairs of swimming     23
      or respiratory appendages.

23a   Body and legs inclosed in bi-         24
      valved  (2 halves) shell which may
      or may not completely hide them.

23b   Body and legs not enclosed in         26
      bivalve shell.  May be large or
      minute.
          (Figs.  17, 18, 19)
24a  One pair of branched antennae
     enlarged for locomotion, extend
     outside of shell (carapace).
     Single eye usually visible.
     "Water fleas"
          Subclass CLADOCERA (Fig. 12)

24b  Locomotion accomplished by
     body legs,  not by antennae.
        25b Animal less than 3 mm, in length.
            Appendages more or less slender
            and jointed; often used for walking.'
21          Shells opaque.  Ostracods.
                '(Fig.  11)  Subclass OSTRACODA

        26a Body a series  of six or more         27
            similar segments, differing
            mainly in size.

        26b Front part of body enlarged into      28
            a somewhat separate body unit
            (cephalothorax) often covered
22          with a single piece of shell (cara-
            pace).  Back part (abdomen) may be
            relatively small,  even folded
            underneath front part. (Fig-  19b)

        27a Body compressed laterally,  i.e.,
            organism is tall and thin.  Scuds.
            amphipods.  ..  •                    .
                Subclass AMPHIPODA (Fig. 17)

        27b Body compressed dorsoventrally,
            i. e., organism low and broad.
            Flat gills contained in chamber
            beneath tail.  Sowbugs.
                Subclass ISOPODA (Fig.  18)
        28a Abdomen extending straight out
            behind,  ending in two small pro-
            jections. One or two  large masses of
            eggs are often attached to female.
            Locomotion by means of two enlarged,
            unbranched antennae, the only large
            appendages on the body.  Copepods.
                Subclass COPEPODA (Fig. 19)

        28b Abdomen extending out behind ending
            in an expanded "flipper" or swim-
            ming paddle.  Crayfish or craw fish.
            Eyes on movable stalks.  Size range
            usually from one to six inches.
                Subclass DECAPODA
        29a Two pairs of functional wings,        39
            one pair may be more or less har-
25          dened as protection for the other
            pair.  Adult insects which normally
            live on or  in the water. (Figs. 25, 28)
  6-4

-------
Key to Selected Groups of Freshwater Animals
29b No functional wings, though 30
pads in which wings are develop-
ing may be visible. Some may
resemble adult insects very
closely, others may differ ex-
tremely from adults.

30a External pads or cases in which 35
wings develop clearly visible.(Figs.
24,16,27)
30b More or less wormlike, or at . 31
least no external evidence of
wing development.

31a No jointed legs present. Other
structures such as hooks, sucker
discs, breathing tubes may be
present. Larvae of flies,
midges, etc.
Order DIPTERA (Fig. 8)

31b Three pairs of jointed thoracic 32
legs, head capsule well formed.

32a Minute (2-4mm) living on the
water surface film. Tail a
strong organ that can be hooked
into a "catch" beneath the
thorax. When released animal
jumps into the air. No wings
are ever grown. Adult spring-
tails.
Order COLLEMBOLA (Fig. 20)

32b Larger (usually over 5 mm) 33
wormlike, living beneath the
surface.

33a Live in cases or webs in water.
Cases or webs have a silk
foundation to which tiny sticks,
stones, and/or bits of debris
are attached. Abdominal segments
often with minute gill filaments.
Generally cylindric in shape.
Caddisfly larvae.
Order TRICHOPTERA (Pig. 21)

33b Free living, build no cases. 34

34a Somewhat flattened in cross
section and massive in appear-
ance. Each abdominal segment
with rather stout, tapering, lateral
filaments about as long as body
is wide. Alderflies, fishflies, and
dobsonflies.
Order MEGALOPTERA (Fig. 22, 14)

34b Generally rounded in cross section.
Lateral filaments if present tend
to be long and thin. A few forms
extremely flattened, like a suction
cup. Beetle larvae.
Order COLEOPTERA (Fig. 23)

35a Two or. three filaments or other 37
structures extending out from
end of abdomen.

35b Abdomen ending abruptly, unless 36
terminal segment itself is extended
as single structure.(Figs. 24A, 24C)

36a Mouth parts adopted for chewing.
Front of face covered by extensible
folded mouthparts often called a
"mask". Head broad, eyes widely
spaced. Nymphs of dragonflies
or darning needles.
Order ODONATA (Figs.24A. 24C, 24E)

36b Mouthparts for piercing and sucking.
Legs often adapted for water lo-
comotion. Body forms various.
Water bugs, water scorpions, water
boatmen, backswimmers, electric
light bugs, water striders, water
measurers, etc.
Order HEMIPTERA (Fig. 25)

37a Tail extensions (caudal filaments)
two. Stonefly larvae.
Order PLECOPTERA (Fig. 26)
37b Tail extensions three, at times
greatly reduced in size.

38a Tail extensions long and slender.
Rows of hairs may give extensions
a feather-like appearance.
Mayfly larvae.
Order EPHEMEROPTERA
(Fig. 27)

38b Tail extensions flat, elongated
plates. Head broad with widely
spaced eyes, abdomen relatively
long and slender. Damselfly
nymths.
Order ODONATA (Fig.
38
6-5