PB81-204109
 Water Quality and Mangrove Ecosystem  Dynamic;
 Rosenstiel School  of Marine and  Atmospheric
 Science, Miami,  FL
Prspared for


Environmental. Research Lab
Gulf Breeze. FL
Apr 81
                 U.S. DEPARTMENT OF COMMERCE
               National Technical Information Service
                             Nnns,

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              United States                   _„„ ,„„,, „, „_„
              Environmental Protection              EPA-600/J-81-022
              Agency                     April 1981
4MEPA       Research and
              Development

              Water Quality and
              Mangrove Ecosystem Dynamics
              Prepared for

              Office of Pesticides
              and Toxic Substances
              Prepared by

              Environmental Research
              Laboratory
              Gulf Breeze FL 32561

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20. SECUA1TY CLASS (ThizpagflJ 22. PRICE
UNCLASSIFIED
TECHUICAL REPORT DATA
(Pk e read Instracuosu OR the repent before COmNIWvRJ
1. REPORT NO. 2.
EPA-600/4-81-022
3. AECIPIENrS ACCESSION NO.
4. TITLE AND SUBTITLE
Water Quality and Mangrove Ecosystem Dynamics
6. REPORT DATE :
ADril 1981.
6. PERPORMING ORGAN 1ZAflON CODE
7. AUTHOR(S)
Samuel C. Snedakar and Melvin S. Brown
I. PERPORMING ORGANIZATION REPORT NO.
LPERFORMING ORGANIZATION NAME ANOADORESS -
Division of Biology and Living Resources
osenstiel School. of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway Miami, Florida 33149 USA•
1O.PRO RAM ELEMENT NO.
A87!1A
11. CONTRACT/GRANT No.
.
R803340
t2. SPONSORING AGENCY NAME AND 400RESS
Gulf Breeze Envir’onmen aJ. Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Gulf Breeze, Florida 32561
13. TYPE OF REPORT AND PERIOD COVERED
.
14. SPONSORING AGENCY CODE
..
EPA/600/04
15. SUPPLEMENTARY NOTES
lB. ABSTRACT .
Field studies were made to determine the relationship between, general-water
uality parameters, with emphasis on pesticides and metal. poUutanta, and the
functioning of, th halophytic mangroves. It .w s, .conc3.uded,. .from a,.broad ange gf
ecological sample Rat 1yaes, that mangroves are relatively insensitive to toxic
materials in the - 1 parts per million range and’ lower. Further, they do not
significantly concentrate ynthetic organics or metals to levels which could be
considered haimful to-detritus feeders, although it is not known whether further
biological concentration occurs during decomposition enrichment. Observed large
differences ‘in mangrove production and structure do appear to be related to:
(1) terrestrial runoff and its entrained nutrients, (2) periodic inundation
by runoff andjor tidal activity, and (3) depŕsita of organic matter in the -
substrate.
—
17. ‘ KEY WORDS AND DOCUMENT ANALYSIS
a. OESCRWTORS
b.IOEMTIPERS/OPEN ENDED TERMS
C. COSATIl ietd/Cco sp
mangroves, wate quality, pesticides,
metals, salinity.
florida, Puerto Rico,
litterfall, peat
06/C; 06/F; 06/t
.
P ,aPfl, - —- - e.. .flfle .w -
.. . .
.y r UT ON
Raieased
o
pubiic
(This Rapwi,
.
2t 4O. O AO
u pages
Pot , ,, 222O— (R. .4 77) PR v ,OU$ Or QM SOG5oL T

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NOTICE
THIS DOCUMENT HAS BEEN REPRODUCED
FROM THE BEST COPY FURNISHED US BY
THE SPONSORING AGENCY. ALTHOUGH IT
IS RECOGNIZED THAT CERTAIN PORTIONS
ARE ILLEGIBLE, IT IS BEING RELEASED:
IN THE INTEREST OF MAKING AVAILABLE
AS MUCH INFORMATION AS POSSIBLE.

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WATER QUALiTY AND MANGROVE ECOSYSTEM DYNAMICS
by
Samuel C. Snedaker
and
Melvin S. Brown
Division of Biology and Living Resources
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, Florida 33l 9
EPA Grant NuniberR8O4355
(formerly R803340)
Project Officer
Gerald E. \Vaish
Gulf Breeze Environmental Research Laboratory
U.S. Environmental Protection Agency
Gulf Breeze, Florida 32561
ENVIRONIMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
GULF BREEZE, FLORIDA 32561
Lb

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DISCLAIMER
This report has been reviewed by the Gulf Breeze Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and policies
of the U.S. Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
11

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FOREWORD
The protection of our estuarine and coastal areas from damage caused by toxic
organic pollutants required that regulations restricting the introduction of these
compounds into the environment be formulated on a sound scientific basis. Accurate
information describing dose-response relationships for organisms and ecosystems under
varying conditions is required. The Environmental Research Laboratory, Gulf Breeze,
contributes to this information through research programs aimed at determining:
• the effects of toxic organic pollutants on individual species and communities
of organisms;
• the effects of toxic organics on ecosystem processes and components;
• the significance of chemical carcinogens in the estuaririe and marine
environment.
The purpose of this research was to relate selected water quality parameters to
functional indices of the relative vigor of mangrove ecosystems. This. was done by
generation of empirical field data that distinguished ecosystem responses to chemical
pollutants, thermal loading, nutrient enrichment, tidal flushing and hydrope-iod
dynamics, and mechanical perturbations. Qualitative interpretive models and detailed
computer models, suitable for analog and digital computer simulation, were designed as
tools for prediction of effects of pesticide and heavy metal loading in the mangrove
ecosystem. / I, 1 n
Henr . Enos
Director
Environmental Research Laboratory
Gulf Breeze, Florida
‘it

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PREFACE
Since the late 1960b, when the value of coastal mangrove forests in the southern
part of the United States became widely publicized, interest has been shown in
elucidating the relationship between water quality and the dynamics of the mangrove
ecosystem. To a large extent, this broad initiative was based on the presumed
dependency of mangroves on suitable quality water for their sustained productivity and
growth, and on the ability of mangroves to improve the quality of the water to which
they are exposed. Imbedded in this broad initiative was also the concern for pollutants
entrained in the water circulating within a mangrove forest. Like many water-
entrained nutrients, would the pollutants too be taken up in the living tissues of the
mangroves only to exert a physiological stress and exhibit a debilitation of the health
of the forest? Or, could mangroves detoxify polluted waters without experiencing the
kinds of pollution-induced stress exhibited by so many other forms of life? It was
apparent that although advances were being made in the &u derstanding of the
mangrove ecosystem, many of the key mechanisms which permit the mangroves to
thrive in a saline environment were poorly known. it was also apparent that a better
understanding of these mechanisms, or relationships, was required if mangrove
ecosystems were to be protected and conserved for the value they have for estuarine
dependent fisheries.
In 1974, the work described here was initiated as part of a three-year study of
the relationship between water quality and m ngrove ecosystem dynamics which was
envisioned to result in computer simulations of those relationships. However, the work
was cut short forcing an emphasis to be placed on the analysis and interpretation of
the existing data. Only minor field work was continued beyond that point and those
efforts were restricted to completing and refining the existing data base. This proved
to be highly useful insofar as it was possible to place greeter attention on the work
completed and on its interpretation in the context of the published literature. What
resulted, and what is reported here, is a highly pragmatic derstanding of the cited
relationship; pragmatic in the sense that it lays a firm basis for resource managers and
decision makers whose responsibility includes the mangroves of the southern coastline
of the United States.
iv

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R
CON i ENT5
Page
Foreword
Preface iv
Abstract. vi
Figures vii
Tables viii
Abbreviations and Symbois ix
Acknowledgments xi
1. Introduction . . . . . . . .
2. Objectives . . . . . 4
3. Conclusions . . . . 7
4. Recommendations. . . . . . . . 11
5. Study Areas . . . . 12
6. Methods . . . . . 16
7. Results and Discussion. . . . . 21
References 54
Appendices
A. Rhizophora mangle L. leaf lengths, widths and ratios 61
B. Conceptual mode! parameterized for copper 68
V

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ABSTRACT
This research project was initiated to define the reciprocal relationship between
water quality and mangrove ecosystem dynamics, and the role of water borne
pollutants within that relationship.
Field studies were conducted in southern Florida and in Puerto Rico with the
intent of locating mangrove communities stressed by either synthetic organic
compounds or metal pollutants. None of the twenty-seven sites examined and sampled
showed evidence of pollution affecting mangroves, nor were any synthetic organic
compounds found in mangrove tissues despite a low level presence in certain areas. Jt
is suggested that mang roves do. not actively take up these organic pollutants.
The metals chromium, copper, iron, manganese, nid
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GURES
Number Page
1 Location of mangrove sampling sites in southern Florida
and Puerto Rico 13
2 Location of mangrove sampling sites in Marismas Nacionales,
Mexico 14
3 Location of mangrove sampling sites in Costa Rica, Central
America 15
4 General process model for heavy metaLs 22
5 Litter production by compartments for fringe forest #37
located in southeast Florida 38
6 Litter production by compartments for hammock forest 1/30
located in southeast Florida 39
7 Litter production by compartments for dwarf forest #30
located in southeast Florida 40
8 Litter production by compartment for dwarf forest //23
located in southeast Florida 41
9 Litter production by compartment for fringe forest #5-
11 located in southwest Florida 42
10 Litter production by compartments for overwash forest /13—
7 located in southwest Florida 43
11 Litter production by compartments for riverine forest 116-
14 located in southwest Florida 44
12 Litter production by compartments for riverine forest #6-
15 located in southwest Florida 45
13 Litter production by compartments for basin forest located
in southwest Florida 46
A-I Relationship between the length and width of red mangrove
leaves shown superimposed over the linear regression
(solid line) of the two variables bounded by + 1 standard
error (dotted lines) 63
B-i Conceptual mode! for copper 69
vii

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TABLES
Number
I Percentage Recovery for Rohm and Haas XAD -2 Resin. IS
2 Forest Type, Location and Number of Collections at Each
Litter Production Site 19
3 References in the Literature to Mangroves Being Maintained
in Freshwater 26
4 in situ Soil Water Salinities 28
5 Elemental Composition of Red Mangrove Tissues and
Peat in Puerto Rico and Southeast Florida 31
6 Additional Elements of Interest for the Red Mangrove
in Southeast Florida 32
7 Elemental Composition by Compartment for Black Mangrove
in Southeast Florida 33
8 Elemental Composition by Compartment for White Mangrove
in Southeast Florida 34
9 Elemental Composition of Maturing Red Mangrove Leaves
From the Bud Through Senescence 35
10 Summary of Mangrove Forest Community Litter Production
in Southern Florida 47
11 Elemental Composition of Red Mangrove Leaf Litter
by Month for the Dwarf Forest, Southeast Florida 49
12 Elemental Composition of Mangrove Leaf Litter, for 1974
by Month for the Hammock Forest 1/30, Southeast Florida . . . . 50
A-i Mean lengths and widths of red mangrove leaves for 34
locations from Puerto Rico, west Mexico, Haiti, southwest
and southeast Florida 62
A-2 Comparison of leaf area (LA) and rectangular area (RA) for
tendencies toward oblate and lanceolate leaf shape. 65
B-i Values obtained from the literature to parameterize copper
cycling in a mangrove ecosystem based on the conceptual
model presented in Figure B—I 70
v i i i

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LIST OF ABBREVL TJONS AND SYMBOLS
ABBREVIATK NS
DOT Dichlooaiphenyl tridiloroethane
DD E l,l Dichloro-2, 2-bis -chlorophenyl) ethylene
DOD Dichlot -odiphenyldichloroethane
PCB Polychiorinated biphenyl
B.C. Before Christ
cm centimeter
g gram
m meter squared
ml 2 milliliter
mm milirneter squared
m meter
micrograms per Liter
2 parts per million
mg/rn miligrams per meter squared
kcal/ m kilocalaries per centimeter cubed
ng/m nanograms per meter cubed
ug/g 2 micrograms per gram
m grams per meter squared
ppt parts per thousand
0.0. Dissolved Oxygen
p.s.i. pounds per square inch
APDC ammonit.n-t pyrolidine dithiocarbonate
MI I3K methyl iso-butyl ketone
TCA Total Carbon Analyzer
S.E. Standard Etror
r correlation coefficient
RA Rectangular Area
LA Leaf Area
ND None Detected
NA Not Analyzed
Aik Alkalinity
SYMBOLS
less than
> greater than
n sample size
C carbon
N nitrogen
H hydrogen
Al aluminum
ix

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Sr CTION 1
1NTR0DUCnDN
Mangroves and water quality have been asSociated in the literature since the
first report in the Chronicle of Nearchus in 325 BC t.Bowman 1917) because of unusual
morphological adaptations and their apparent restriction to the tropical marine
environment. The thread of continuity in the relationship has always been the “salt” in
seawater and its relationship to the anatomical and physiological adaptations which
ostensibly allow them to maintain reproducing populations in a saline environment.
The majority of the literature which reports on this relationship focuses on site-
specific observations between salinity graaients and the distribution and abundance of
the mangrove species. It was early recognized that the gradient in interstitial soil
water salinity corresponaeo to predictable patterns in the zonation of the mangrove
species (ci. Davis 1940) and that the control of salinity levels was related to the
surface hydrology, specifically “Inundation classes” (Watson .9 8) and “Tidal factors”
(see review by Chapman 1976). Based on this u derstanding, the zonation of
mangroves has been studied in great detail (Watson 1928, DeHaan i931, Walter and
Steiner 1936, Davis 1940, Chapman 1944, Chapman and Ronaldson 1958, MacNae 1968,.
Baltzer 1969, Cf. reviews by Walsh 1974, and Lugo and Snedaker 1974). The
correspondence of results from widely differing areas of the world (e.g., Malay
Peninsula, Watson 1928, South Africa, Day et al. 1953, southern Florida, Davis 1940)
largely confirms the importance of the salinity component in water quality. However,
the major emphasis on the dassilication of mangroves has largely remained tixed on
species assemblages and physiognomy, and aside from salinity and zonation, has
focused on geomorphological features of the coastal zone.
Chapman U 976) observed that “tidal factors” may not be the controlling mechan-
isms because similar patterns of species zonation occur in areas with high and low tidal
ranges. I-Us observation seemed to reflect site to site differences which might better
oe attributable to differing classes of substrates, which has also been used to
distinguish and classify mangrove vegetation. For example, Watson (1928) recognized
differences between “accretive snores” ana “sand” Troll and Dragenoorff U 931) and
Walter and Steiner (1936) described mangroves on “reef” and “mud” sthstrates;
Chapman (1944) distinguished oetween “peat” and “sand”; and Thom (1967) and Thom,
Wright and Coleman (1975) described the control of plant habitats by lanQ form
changes, particularly in active deltas. Thus, much of the voluminous work on
mangroves (Cf. van Tine and Snedaker’s 1974 bibliography of 2005 titles) views water as
a factor in mangrove dynamics dominated by salinity and water as a physical force
which alters the coastal geomorphology. Furthermore, the published experimental
work on mangroves is dominated b work on plant-water relations and the major cation
species (e.g. Na , K , Ca , Mg ) and chloride (see, for example Walter and Steiner
1936, Chapman 1944, Chapman and Ronaldson 1958, Atkinson et a! 1967, Chapman
1966, Clarke and Hannon 1969, Corinor 1969, Carter et al. 1973, and Hicks and Burns
1.

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197)). The overall quality of the waters associated with mangroves had heretofore not
been stuOted to tie point tnat the general relationship between water quality and
mangrove ecosystem dynamics could be stated.
In the early 1970’s i-ieaid (1971) ano W.E. O um (i971) published their now
classical works showing tnat mangroves we prolific prociucers of leaf detritus and
that this cietritus formed a major fraction Of &ie food base for estuarine life forms.
ir e cramanc realization of the eco!og ca1 value of mangroves coupled with the
envtronmental fervor of me late 60’s inspired others to restudy the mangrove
ecosystem from a more holistic viewpoint shari nau been used in tIe earlrer works.
Two of those efforts yielded resu1ts which laid the basis for further work on mangrove
dynamics and water quality. Carter et a!. (1973) reported some e 1oratory work
showing that the metabolism of rnangroves correlated to chlormnitl relative to its rate
of change, and thus tie rate of exchange between surface and interstitial soil water.
They also showed that ambient nutrient concentrations in mangrove waters were
related to the time-changing ratio between seawater and freshwater inputs. Lugo et
aL (1975) corroborated the work of Carter et al. (1973) and developed the “metabolic
basis of zonanon” in rnarigroves as it relates to the frequency of inundation and its
control over the interstitial soil water chiorinity. This interpretation served to e)ç 1ain
the mechanism controlling the distribution of each mangrove species relative to one
another and could be considered to be a general model applicable to marigroves
woildwide. Later, Lugo etai. (1976) combined the aata from Carter eta!. (1973) and
Snedai ’ier and Lugo (l97 ) to develop a computer simulation model which upon
simulation showed the importance of water borne nutrieii s in controlling the
productivity of mangroves. Basea on this collective pool of research findmgs, it
seemed reasonable to conclude that: (1) salinity controlled the distribution of
rnangroves according to the local gradient, t2) the availability of nutrients controlled
the community productivity, and (3) salinity and nutrients as indices of water qualty
were’ controlled by the surface hydrology in some quasi-known manner.
The relative importances of hydrology and water quality were also demonstrated
through parallel studies which attempted to find a basis f a- distinguishing discrete
mangrove forest types covering large areas of southern Florida in which species
zonation was not apparent (Snedaker and Lugo 1973). This resultel in tie recognition
of characteristic mangrove forest types based on physiognomy, topography, frequency
of inundation, pattern of on-site circulation patterns, and water quality. These were
identified by the following type names: fringe, overwash, riverine, basin, hammock
and dwarf (Lugo and Snedaker 1974). Since then, independent studies with other
objectives have largely confirmed the validity of these types and the environmental
bases for their appearance as discrete types (see Pool, Sneoaker and Lugo 1977 and
Cintronetal. 1978).
Despite what might be considered significant advances in mangrove ecology in
the Caribbean ,ckted above), the knowledge gained was not considered to be uniformly
applicable to rnarigroves in other regions of the world. Specifically, the majority of
the Florida research cited above was performed in an organic-rich environment
centering in the Evergl es National Park and the contiguous Ten Thousand Islands.
Subsequent research in carbonate environments revealed disturbing anomalies; vigorous
mangroves in poor environments, and mangroves showing severe growth restrictions in
ostensibly optimum environments. Substrate dominance over these characteristics,
however, could not be initially accepted because the variations were observed to e 
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quality, as it dill erentiaUy related to the reduction of allochthonous/autochthonous
organic matter, precipitation of carbonates, and mass transport of dastic materials,
also dominated the local variations in mangrove structure and fuictioning...but how?
How could water quality change so sharply over such small oistances to create and
maintain two contiguous and contrasting mangrove forest types? This gap in our
knowledge prompted part of the research reported here.
Trroughout all of the preceding studies, water quality in its largest context was
never really evaluated with respect to the dynamics of functioning of mangroves. With
the singular exception of the field analyses reported in Carter et al. (1973) and Lugo et
al. (1975), and the computer simulation on nutrients (Lugo et a!. 1976); water quality
remained a general concept, subject to speculation, in the field of mangrove ecology.
In 1974, this project was initiated to fill the apparent gap in our knowledge of water
quality and mangroves, and to incorporate considerations of the role of water-borne
pollutants in the mangrove ecosystem within the overall project. Following so d ely
the then completed work described above (Carter et a!. 1973 and Snedaker and Lugo
1973), it was possible to build upon and continue several aspects of the earlier work in
this study.
3

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Section 2
OBJECTiVES
Tue purposes of this project were to ciefine the empirical relationship which
exists between water quality end mangrove ecosystem dynamics, and to evaluate that
relationship as a two-way interaction. In otner woros, how does water quality
influence tne functioning of inangroves and conversely, how co mangroves through
their normal functioning influence the quality of the water? The many ramifications
of this overall purpose are detailed below as specific working objectives.
Objective I: Use the existing literature and information on rnangroves to
develop the hypothetical relationship between water quality and mangrove dynamics as
an overall guiding hypothesis for the specific research tasks.
Objective 2: Define the quality of those waters assu’ ated with the highest
quality mangrove ecosystems and conversely, the quality associated with the poorest
mangr ores.
Objective 3: Evaluate the fates of selected organic and metal-based toxic
material within the mangrove ecosystem, and report the concentrations of Such
pollutants in mangrove ecosystems in relation to water quality.
Objective 4: Select and evaluate a key parameter of mangrove ecosystem
dynamics that can be related in an emp:ricai manner and used as an index relative to
water quality and me potential productivity of the environment.
Objective 5: Identify and evaluate the most critical factor or factors associated
with, and contributing to, water quality that have the greatest influence on the
dynamics of the mangrove ecosystem.
These objectives are discussed in greater detail to lay the basis for the
presentation of the research. Because the objectives are so closely related with one
another they are discussed collectively as they relate to the key aspects of both water
quality and mangroves.
BACKGROUND AND DISCUSSION OF THE OBJECTIVES
Objective I : Use the existing literature and information on mangroves to develop the
hypothetical relatiorship between water quality and mangrove dynamics
as an overall guiding hypothesis for the specific research tasks.
Much of the analytical work on pollutant compounds in the environment is based on
sampling routines designed simply to establish background concentrations in environ-
mental materials. With the notable exception of tro iic transfers through food chains,
4

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sampling designs are seldom predicated on the functional relationships linking the
major compartments of an ecosystem into a single functioning unit. The first task in
this project was to develop a generalized mangrove ecosystem model containing all of
the major compartments coupled in the most realistic functional relationship. The
manner in which each of the compartments is coupled, defines, with some degree of
realism, the major pathways through which materials are exchanged or transferred.
Once the conceptual mode! was deveiu d, it then served as a sampling design to
ensure that all compartments were examined and subsequently interpreted in the
context of the system. The second step in this process was to use the conceptual
model as a guide for reviewing the literature and collating data on the materials of
interest. If values were reported in the literature they were recorded as such. In the
absence of data, estimates were developed, cr calculations made, to assess the best
probable values. Not only did data in this context serve as a ready reference for
quality control, they also established a basis for making mass balance calculations
using the more reliable data developed from the research. To guide this research, a
single conceptual model was developed and used to assemble the best available data on
the heavy metals. It was early established that too few literature data existed for the
synthetic organic compounds to warrant any attempt to pararneterize the model for
this class of materials.
Objective 2 : Define the quality of those waters associated with the highest quality
mangrove ecosystems and conversely, the quality associated with the
poorest mangroves.
If there is a demonstrable relationship between water quality and mangrove ecosystem
dynamics, then one should be able to examine a large gracient of water quality
conditions and observe differences in the structure and functioning of the associated
mangroves. The guiding hypothesis would be that the best structured forests and t ose
with the highest productivities would occur in association with water of the highest
quality. Conversely, the opposite should also be true. To find the required range in
habitat conditions, it is necessary to compare widely differing watersheds in several
different dimatic environments to establish the normal background conditions.
Against this background then, any anomalous conditions such as might be associated
with polluted waters would become apparent and could be assessed in that context. A
part of this task was the attempt to identify the componentor components of water
quality which are most strongly associated with the observed condition(s) of the
mangrove ecosystem. The component of water quality could be either chemical or
physical or their interaction, and the initial examination had to take this into account
lest some pertinent factor be overlooked.
Objective 3 : Evaluate the fates of selected organic and metal-based toxic material
- within the mangrove ecosystem, and report the concentrations of such
pollutants in mangrove ecosystems in relation to water quality.
- Since the mangrove ecosystem has become recognized as a net producer of detritus
which is utilized in estuarine food webs, it is necessary to know the extent to which
deleterious or toxic compounds become incorporated in that flux of material.
Frequently, biological processes concentrate pollutants above background
concentrations and through trophic transfer they become further concentrated at the
top of food webs. This is particularly true for lipid-soluble compounds such as certain
of the chlorinated hydrocarbons like DDT. Should either synthetic organic compounds
or metals be taken up and concentrated in mangroves, particularly the leaf
5

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compartment, then a direct link s established with estuarine fooc webs. Likewise,
however, if processes occur :n the environment which remove these compounds from
the water column and sequestet them in the sediments, then they might represent d
significant threat only to benthic organisms. Of course, they could also become
permanently sequestered depending upon specittc circumstances of the environment.
A major part of the question of poilutant in the nearshore mangrove environment
concerns whether or not the mangroves concentrate pollutants in leaf detritus or if
some aspect of the overall environment mitigates against the potential impact of
water borne pollutants. That was considered to be one of tne major aspects cf the
project work.
Objective 4 : Select and evaluate a key parameter of mangrove ecosystem dynamics
that can be related in an empirical manner and used as an index relative
to water quality and the potential productivity of the environment.
One of the primary working objectives fi.ridamental to the overall project work was the
selection of a specific mangrove-related parameter whicn could: (I) serve as a
caflbrdted index of. mangrove procuctivity, (2) reflect at least the broad
characteristics of the physical environment, and (3) be easily evaluated in a highly
repruoucible manner. Because of the observed variations in the physiognomy of
mangrove forests, even within a relatively small area, an index of comm unity s -ucture
would represent one possible index of both the relative vigor of the mangroves and the
quality of the environment. Many useful techniques are reported in the literature, and
it would be necessary to pid< the most conveniently-employed technique that would
provioe the desired information. From a completely different perspective, some
integrating measure of leaves might also be useful as it is known that the mor ol y
of leaves frequently reflects nutritional status, water stress, and the general climate.
Also, the leaf litter production rate, coupled with morç oi ical information, cc ld
give better empirical definition to the relative vigor of mangrove systems. Selection
of the most appropriate indexing parameter, would require several to be tested on a
comparative basis for sites which are documented and thus can be used for calibration
purposes. This search for a single parameter of ecosystem health is not unique to this
project but as yet no foolproof measire has been found, including meast.res of
diversity.
Objective 5 : Identify and evaluate the most critical factor or factors associated with,
and contributing to, water quality that have the greatest influence on the
dynamics of the mangrove ecosystem.
Based on the vast mangrove literature and the recent works by Carter et a!. (1973) and
Lugo and Sniedaker (1974), a suite of critical factors have been identified and related,
at least in a qualitative fashion, to mangrove productivity. In general, these are
salinity, the availability of nutrients, and related to them, the dynamics of tidal
flushing and surface water circulation. Although each of these factors can be
expected to show interactior affecting mangroves, the specific mechanisms are
known only in a semi-quantitative way, and as yet there is no e erimental proof that
any c x - all are not just simply autocorrelates of some other unknown factor. If the
critical factor(s) could be so identified, then it would be easier to refine our
understanarng of the dynamics of the mangrove system and we woula be able to
deso-ibe txw certain pollutants behave relative to mangroves. Although mangrove
researchers are inn fair agreement on the environmental requirements of mangroves,
the stQpocting base of research is not wholly convirxalnng.
6

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Section 3
CON L I DNS
MANGROVE MODEL - OBJECTIVE 1
Sufficient information exists within the literature to assemble a variety of
conceptual models portraying the general structure and functioning of the mangrove
ecosystem or specific processes therein. Eighteen such models have been developed
and reported, from which a general model was constructed to guide the research on
this project. In contrast to the rather complete qualitative knowledge of the structure
and functioning of the mangrove ecosystem, reliable, quantitative data are almost non-
existent. Such data are also poorly documented and are expressed in units which make
their incorporation into a model very dif±iailt. In this limited hard data pool, more
quantitative information exists on state variables (structural features) than on flow
variables (time dependent functions expressed as rates). The temperate salt-marsh
literature contains si tificantly more hard data on the type useful to the understanding
of the ecosystem; but it too, is deficient in flow variables. Specifically, in the
sibtropical portion of the United States, there exist little data from which conclusions
can be drawn to develop a quantitative understanding of the mangrove ecosystem and
the consequences of water quality changes, or pollution, therein. An example of the
data deficiency is apparent in the parameterization of the element copper (see
Appendix B).
WATER QUALITY AND SALINITY - OBJECTIVE 2
During the course of this study, mangrove ecosystems were visited in a variety of
environments and climates in southern Florida, Puerto Rico, Bahamas, Mexico, Costa
Rica, and nearing the completion of the study in such areas as Western Australia (Port
Hediand area), Pakistan (Indus River delta), Bangladesh tGanges-Brahmaputra River
delta), and Thailand (Phuket Province). Overall, the structure of the mangrove forests
and perceptions of their functioning are remarkably uniform despite large aifferences,
particilarly in water quality. The poorest developed structures (low stand density,
short stature of mature trees, relatively open canopy and absence of surface leaf
litter), and therefore inferred poorest dynamics (low rate of community metabolism
and specifically a low rate of net primary productivity), are consistently found only in
arid climates (low rainfall), environments with insufficient ground water or fresh
surface water, ano in sedimentary carbonate environments. The best Un the sense of
high density of individuals, tall stature, closed canopy, and cons aious leaf litter
suggestive of a high rate of net primary productivity) mangrove forests tend to be
fwnd where there are moderate soil salinities due to the availability of freshwater and
to tidal amplitude that ensures frequent and extensive inundation and flushing.
Marginal environments are those with either uniformly high or low annual salinity
regimes, exposure to excessive silt loading, and/or in areas in which the tidal
7

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—2 ,a::Ipl Ituae s normally s rmil or hn been attenuatec by natural or man-induced forces.
in the mergiflal arm poor qu it env rornnerits, vigorous stands of mangroves,
evertrieias can be observed n assuc at1on with anaerobic organic soils, or underlying
pear ooa es. in general, rnar1 ,roves appear to be remarkably tolerant of a wide range
of water quality cond tiors, as if water quality we e not a controlling factor.
Certainl , a review of the literature now dvrronstrates that mangroves are Dasically
freshwater plant forms possessing a unique ability to tolerate salt better than other
plant species. In tn s regard. normal salinity regimes are the factors which prevent
invasion by, and competition from, freshwater species, thus allowing mangroves to
majnta n competitive dominance in the ntect dal zone. One key aspect of water
quality management 10 tnii en ironment s the maintenance of salinity and tidal
flushing patterns to perpetuate the domination arid high proauctivity of mangroves.
POLLUTANTS Ii W A.NGROVE ENVIRONMENT - OBJECTIVE 3
Samoles of water, sediment, and mangrove tissues were analyzed for ten
synthetic organ!c compounas (aidrin, dieidrin, DOT, DDE, DOD, linaane, heptachior,
mirex. parathion, and PCB ’s). The compounds were not detected in the 180 samples
collected from IS stations in southern Florida and 9 stations in Puerto Rico. UnKnown
compounds in certain groups of the samples were subsequently identified as the active
ingredients in a corn,riercial insect repellent used by the field crew. The ability to
detect traces of the contaminant but not the synthetic organic compounds of interest,
suggests that they are not present in any detectable quantity in the 27 mangrove areas
sampled. As a result, this phase of the investigation was concluded and the emphasis
shitted to me heavy metals.
The metals, copper, criroiniun, iron, lead, manganese and zinc, were detected in
tt majority of environmental and biological samples taken in this study. in .his
regaro, low to moderate concentrations of metals appear to be ubiquitous components
of the mangrove study areas in southern Florida and Puerto Rico. Compared to the
concentration of metals in I al waters, metals appear to be concentrated several
orders of magnitude in mangrove sediments and up to 6 to 7 orders of magnitude more
concentrated in mangrove tissues. With respect to the general environmental
concentrations of metals in the mangrove environment, the observed variations reflect
the geochemistry of the regional watershed. For example, metals in general are higher
in concentration in Puerto Rico than in southern Florida where there are no geologic
sources for metals in drainage and leachate water entering the coastal zone. Highest
concentrations of metals in Florida mangroves can be associated with fossil-fuel
- ) burning power plants, agricultural usage, and highway runoff. Des te the magnitude
of biological concentration no evidence was found to suggest that the absolute levels
constituted a toxic hazard to the health of mangroves. Kowever, the appearance of
bioIc icalty-conCentrated metals in the leaf litter destined to become part of detrital
foodwebs raises a question concerning dose rates and body burdens in riearshore marine
animals. Although the greatest concentrations of metals in the physical environment
were found in the sediments, no evidence was obtained concerning whether mangroves
take up metals from the sediment versus the ambient water. It is likely that the
metals are sequestered as sulfides in the anaerobic environment in which case they are
unavailable for uptake so long as salinity, pH and redox potential remain constant.
Water quality rianagernent again emphasizes the maintenance of site-specific salinity
regimes (through normal mixing of fresh and marine waters) and temporal and spatial
patterns of tidal inundation.
S

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INDEX OF MANGROVE DYNAMICS - OBJECTiVE 4
The complexity index (Holc ic e 1967 and Ho1dric e et al. 1971), mangrove leaf
wiath:length ratios, and leaf litter production were evaluated as key inaices of overall
gçpy ynamics associated with environmental and water quilT onditions. The
corn pie xity index proved highly Usoful iii comparative tüdies of mangrove areas of the
western hemisphere but it was julged unsuitable foe the purposes of this project. A
full description of this part of the sturly was reported by Pool et at. (1977), as it did
yield new and valuable information on the structure of mangrove ecosystems.
Mangrove leaf measurements were made at 34 sites in Mexico, Florida, Haiti and
Puerto Rico, using an average of 139 sun leaves of Rhizophora mangle from each site.
Although there was a great variation in size, e.g., 14.7 an to 6.4 cm in length and 8.9
to 3.0 cm in width, the length:width ratio always approximated 2.1 :1. The cause of the
variation in absolute size is not understood but it is believed to reflect both population
isolation (mangroves of the Pacific coast of Mexico had consistently larger leaves than
those of the Caribbean area) and the variation in the local climatic character of
regional environments. Because the reason fat- leaf-size differences could not be
established without a prohibitively expensive re-sampling program, this index was
deleted from further consideration.
Tne index which proved to be most reliable in reflecting general considerations
of the mangrove ecosystem is the biweekly rate of leaf litter production because it
(1) can serve as a calibrated index of mangrove net procl”ctivity, (2) reflects the
broad characteristics of the physical environment and integrates both physical and
biological measures, and (3) appears to be a precise and accurate measure of
mangrove dynamics. A leaf 1itter production record for 9 stations in southern Florida
maintained over a period ranging from 18 months to 6 years, was evaluated in this
project. The record shows that the type descriptions of mangrove forests published by
Lugo and Snedaker (1974) represent broadly differing structures and functioning, and
that the differences do reflect variations in the physical environment. Based on this
parameter, productivity indices of six forest types can be ranked:
Forest Type Litter Production gjm 2 .year
Riverine 1120
Fringe 1032
Overwash 1024
Hammock 750
Basin (flushed) 741
Dwarf (scrub) 220
Basin (impounded) 0
The most pertinent interpretation of the leaf litter production record arose from
the comparison of rates for fringe forests in two contrasting environments: one in
southwestern Florida in a nutrient-rich moderate salinity environment arid the second
in southeastern Florida in a relatively nutrient-poor high salinity environment. The
original hypothesis stated that the former would show a consistently higher rate of leaf
litter production than the latter. in fact, the record showed the reverse was true and
led to the explanation given above of the importance of sulphate reduction in
anaerobic sibsurf ace peats. The litter production samples are still being taken (by
volunteers) and the appropriate records maintained. It is expected that whenever the
fill! synoptic record is rigorwsly analyzed it will yield new insights into the functioning
9

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of the mangroves of southern Florida.
WATER QuALrrY AND MANGROVE ECOSYSTEM DYNAMIC - OB ECTJVE 5
Water quality is associated with the structure and dynamics of mangrove
ecosystems although several of the mechanisms remain poorly elucidated. The portion
of trie work reported by Pool et al. (1977) associated the best developed structure with
mooerate salinity (i.e., a source of freshwater to dilute sea water), water borne
nutrients and optimum tidal circulation and flushing. In addition, two components 01
marine water quality are suggested to be similarly related and, in addition, provide a
basis for understanding the mechanisms involved. These are nitrate and sulfate, the
latter of which is abundant in marine water. Specifically, nitrate may derive its
greatest importance as an oxidant involved the anaerolic decomposition of reduced
organic matter accompanied by the release of nutrients in the rhizosphere and the
creation of ammonia. Likewise, sulfate may be highly important, not as a source of
elemental sulfur, but also as an oxidant able to penetrate deep into anaerobic
sediments during flushing sec ences. Like nitrate, sulfate is involved in the anaerot c
decomposition of organic matter and in the formation of sulfides which can combine
with metals rendering them unavailable fcx uptake by mangroves. Irrespective of the
precise role of either compound, their positive interaction in the mangrove
environment depends on: U) the availability of a source such as the sulfate iii
seawater, (2) tidal action as the dominant mechanism promoting mixing of fresh and
salt water, and inundation of the mangrove environment, (3) a relatively permeable
substrate facilitating the exchange of surface and interstitial water, and (1 ) the
presence of reduced organic matter in the rhizosphere. This bio1 i lly mediated
regeneration of nutrients appears to be able to au ent the relatively low
concentrations of primary plant nutrients in marine waters.) In general, it is th?se
factors which serve to maintain and perpetuate mangroves over a very wide range of
natural vfronmental conditions and in instances of low level water pollution involving
either metals and/or synthetic organic compounds. However, in this latter regard, we
continue to know little about the role of mangroves as concentrating and transfer
agents relative to the shunting of pollutants into estuarine food webs.
10

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Section 4
RECOMMENDATiONS
1. Research on the mangrove environment will be most profitable if orientation is
on the functional relationships of the ecosystem with full quantification.
2. With respect to water quality in the coastal zone relative to the natural
dynamics of the mangrove ec ystem, there are two important aspects: a normal
pattern of mixing of fresh and saltwater and periodic inundation of the tidelands,
and the entrained solutes which either serve directly as primary plant nutrients
or failitate the in situ regeneration. In addition, the salinity component
controls the distribution of species and preserves the haophytlc nature of the
mangrove cŕastŕi zone. Although these aspects are generally known and
accepted, there is an absence of a quantitative understanding which could be
used in the management of water quality and the mangt ve community. Further
research on these mechanisms should yield profitable new insights into water
quality and mangrove ecosystem dynamics useful in management and
conservation.
3. The apparent tolerance or resistence of mangroves to water borne pollutants
should not be interpreted as meaning that mangroves are immune to their toxic
effects; threshold levels need to be determined and related to the acute and
chronic response by mangroves. More important, although mangroves may be
resistent, the associated fauna is not. It is unknown to what extent the biolngical
concentration of metals by mangroves and their transfer to detrital foodwebs
represent a potential danger to marine and estuarine animals.
4. Further quantification with regard to hydrolc y and chemistry of natural waters
in the coastal zone -will greatly affect regulation of man’s activities and the
conservation of productivity of the coastal environment.
11

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Section
STUDY AREAS
In this research project, sites were visited and sampled regularly in southern
Flori a (Fig. 1), and at least one time in Puerto Rico (Fig. 1), Mexico (Fig. 2) and Costa
Ri (Fig. ,). Al! of these sites are Ldentitied and fully described by Pool et a!. (1977).
in acoition, some oc these sites have been described in greater detail by the fo1Io ng
authors: southern Florioa (Lugo, Sell arid Snedaker, 1976); Rookery Bay (Lugo et at.
1975); Ten Thousand lslanz!s (Snedaker and Lugo 1973, Carter et at. i973, Pool et at.
1975); Turkey Point (Snedaker, Cottreil and I3rown, ms in prep3 Puerto Rico kCintron
etal. 1978) and Mexiw (Curray, Emmel and Crarnpton, 1969, also see Rollet 1974).
The majority of the fLeid work was performed at the southern Florith sites and
the observatior made there fonn the basis for the major conclusions. Sampling, for
the purpose of identifying and intensively studying the effects of pollutant loading, was
performed in southern Florida and Puerto Rico. All of the sites were visited during the
initial efforts to isolate and define an integrative parameter of mangrove dynamics.
This part of the research is reported in Pool et a!. (1977) and Appendix A of this
report. In addition to the work cited here research by the principal author in Western
Australia, Pakistan, Bangladesh and Thailand in the eastern hemisphere, and Jie
Bahamas, Colombia and Panama in the western hemisphere (Snedaker, unpubl. ms. and
repo. ts) stpport the conclusions.
U

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S200
ROOK Y
BAY
2000
A
- 2 3D0
THOUSAND
ISLANDS
OF
MEXICO
0 3 10 ‘3 20 MI&(S
- j
0 S I? 23 3) S tOU*TISS
Figure 1. Location of mangrove sampling sites in southern Florida and Puerto Rico.
FLORIDA
GULF
MIAMI
.
/
TUB NC V
ATLANTIC
OCEAN
- V 30
ATLANTIC OCEAN
•000
0 2 , 1 MII3
_________ CARIBBEAN SEA
0 0 20 30 (ILON1T1PS
13

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Figure 2. Location of mangrove sampling sites in Marismas Nacionales, Mexico.
14

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Figure 3. Location of mangrove sampling sites in Costa Rica, Central America.

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Sect on 5
MEIL -IODS
Alt ato r ic absorption analysis was cone by either the Analytia l Research
Laboratory, University of Florina, Ga nesvi1le, Fioriaa or the Rosenstiel School of
Marine and Atmos ieric Science, University of Miami, Miami, Florida wider the
supervision at Dr. i-LL. breland and Dr. E.F. Corcoran, respectively. All analyses were
done on Perkin-Elmer atomic absorption spectrometers using the flame methods
desc ibed in EPA (1971).
Water samples analyzea for NH 3 —N, NO. 2 —N, ortho P, total P and SO—S were
cone by ‘lechnicon CSM6 Autoanalyzer. Analy is was done by either Mr. L. 1 hesney,
Department of Environmental Engineering, University of Florida or Mr. T. Mendez,
Water Analysis Laboratory, Rosensnel School of Marine anr’ Atm pheric Science,
Uriiversityol Miami.
Organic compounds were anlayzec at the University of Florida, Pesticide
Research Laboratory under the super viston of Dr. W.B. Wheeler. Analysis was done
using a Beckman gas chro;natograph.
Organic and Inorganic carbon analyses of the water samples and carbon, hydrogen
and nitrogen analysis of the biological material were done in-house. Carbon analysis of
the water samples was cone using a Beckman Model 915 Total Carbon Analyzer.
Carbon, nycrogen and nitrogen cieterrn iations of the biological material were
determined using a Perkiri—Elrner Model 240 Elemental Anr lyzer.
WATER ANALYSiS
Water samples were collected and analyzed for heavy metals, synthetic organic
compounds, major nutrients, and salinity.
Heavy Metals
Water samples f or heavy metal analyses were collected in one liter polyethyl e
containers. Sarnpl es were preserved by acidification to a pH < 2 with a known amount
of nitric acid immediately upon collection (EPA 1971). The samples were then
prepared for atomic absorption analysis by a chelation, solvent extraction procedure.
The organics in the water sample were removed by oxidizing the sample with
1.0 g of potassium persulfate and autoclaving for one hour at 15 psi. The pH of the
sample was then adjusted with ammoniian hydroxide to the appropriate level for the
metals of interest (see Parker 1972). The metals in the sample were then chelated
16

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with organic ligands and extracted with a solvent. This procedure not only
concentrates the metals but also removes many of the interfering matrices. The
chelating, solvent-extraction procedure used was the standard arnmonium pyrolidine
dilhioc rbonate (APOC) - methyl iso-butyl ketone (MIBK) system (see Christian 1969;
and Parker 1972 for details). After extraction with M1BK, the sa nples were
transferred to silica flasks and evaporated to dryness using mild heat (70 C) sipplied
from a bank of heat lamps. The sampler were then returned to solution with 20 in! of
2 N nitric acid and analyzed by flame atomic absorption following the
recommendations described in EPA (1971).
Nutrients
- Water samples for nutrient analyses were collected in one liter plastic bottles,
fixed immediately with 40 mg m ercuric chloride and stored on ice until they could be
placed under refrigeration at 4 C. Aliquots of 25 ml were acidified to a p1-1 <2 and
cagested by the addition of 3.75 ml of potassium persuif ate (5 g of potassium persuif ate
dissolved in 100 ml of distilled water) and autoclaved for one hour at 15 psi. The
samples were then analyzed for Al, Ca, Mg, Mn, Md and Sr by flame atomic absorption
(see EPA 1971 for details).
An additional 300 ml aliquot was taken and analyzed for NH —N, N0 ,-N,
ortho P, total P and 504—5. Analysis was done using autoanalyzer fechnique as
described in 1 PA (1971).
Organic and inorganic carbon were determined using a Beckman Model 915 Total
Carbon Analyzer (TCA). The TCA consists of two channels one for the determination
of total carbon, the. other for inorganic carbon. Organic carbon is determined by
difference (total carbon - inorganic carbon = organic carbon). The method and
operating procedures are described in detail by EPA (1971) and Taras et al. (1971).
Synthetic Organic Compounds
• The organic compounds of interest were isolated from the sample by sorption on
macroreticular resin. One liter samples were collected in glass containers and passed
through Rohm and Haas XAD —2 macroreticiilar resin immediately after collection.
Teflon and glass globe type 125 ml separatory funnels with a stem length of 12 au and
inside diameter of 1 cm were packed with the resin. Glass wool plugs were used at
both enas of the stem to contain the column. After the sample had been allowed to
pass through the funnel it was sealed and returned to the laboratory. The organic
compounde were then eluted with ethyl ether, concentrated by evaporation,
fractionated by use of a Florisil column and analyzed by gas chromatography. For
details concerning the Florisil fractionation see Thompson (1977). Table I lists the
percentage recovery of the compounds of interest using the above procedure.
Salinity
Salinities were determined using a Golcberg T/C ref ra tomet r, Model 10419.
The instrument is 5elf-compensating for temperatures from 16 to 38 C by means of a
hollow glass prism filled with a temperature stable liquid. The maximum error at the
extremes of the instrument and temperature ranges is 0.1%. But this error is much
-less over the most useful portion of the scale.
17

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TABLE 1. PERCENTAGE RECOVERY FOR ROHM AND HAAS XAD 2 RESIN
Organic Compound
51
Aldrin
Dielann
92
DOT
95
DDE
83
ODD
86
Lindane
95
Heptach lor
90
Mirex
88
Parathion
96
PCB ’s
78
BK)LOGICAL MATERIAL
Biological material, sediments and peat were analyzed for heavy metals,
synthetic organic compounds and major nutrients.
Heavy Metals
Samples were collected in clean plastic containers 0 and returned to the lab as
soon as possible for analysis. Samples were dried at 70 C in a drying oven until a
constant weigrit was obtained and then ground into a homogeneous sample using a
rno tar and pestle or a Wiley Intermediate Grinding Mill. Samples were then reciried
and an aliquot of known weight was uigeste i using the following wet oxidauon
procedure. An aliquot was placed in a silica flask, known amounts of nitric acid were
added and mild heat (70°C) was applied from a bank of heal lamps. The sample was
allowed to evaporate to dryness arid was brought back into solution with 20 ml 2 N
nitric acid. Samples were stored in 25 ml plastic screw cap vials. Samples were
analyzed by flame atomic absorption as described in EPA (1971).
Nutrients
Preparation of biological samples for major nutrient analyses incorporated an
ash-digestion procedure modified from Isaac and lcties (1972) and Piper (1950). Sample
collection, drying and grinding procedures are the same as described in the above
heavy metals section. A weighed aliquot of the homogenized sarn ple was placed in a
20 ml porcelain crucible and combusted in a muffle furnace at 500 C for four hours to
oxidize all of the organic matter (Isaac and Jones, 1972). The ash resick e was brought
into solution by the additi n of hydrochloric acid and evaporated to dryness on a
hotpl ate using mild heat (70 -80°C). The sample, after cooling, was brought back into
solution by the addition of 2 N nitric acid, filtered through a #42 Whatman filter paper
and diluted to a known volume with distilled water. The sample was then analyzed by
flame atomic absorption.
Total carbon, total hydrogen and total nitrogen were determined using a Perkin-
Elmer Model 240 Elemental Analyzer. The analyzer accurately determines the carbon,
hydrogen, and nitrogen contents of organic compounds by detecting and measuring
18

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their combustion products (C0 2 , H 2 0 and nitrogen). Combustion takes place in pure
oxygen under static conditions. The combustion products are then analyzed
automatically in a sell-integrating, steady-state, thermal conductivity analyzer.
Results are recorded in bar graph form on a strip chart recorder.
Synthetic Organic Compounds
Samples were homogenized using a mortar and pestle and extracted using the
continuous Soxhlet extraction unit. Samples were then evaporated and interfering
lipid-soli.ble materials were removed by successive deanup on aluminum oxide and
FlorisiJ, columns. Samples were then concentrated by evaporation and analyzed for the
selected organic compounds using gas chromatography. A more detailed description of
the above procedure can be obtained from Thompson (1977).
LITTER PRODUCTION
Litter collections were made at nine stations representing all of the six forest
types described by Snedaker and Lugo (1973). Table 2 is a listing of the forest type,
locations, site number, collecting period, and number of collections made at each site.
TABLE 2. FOREST TYPE, LOCATION AND NUMBER OF COLLECTIONS
AT EACH LITTER PRODUCTION SITE
Forest Type
Collecting
Period
(Years)
Location
and
Site Number
Number
of
Collections
Fringe
2.3
3.1
Turkey
10,000
Point, Florida (37)
Islands, Florida (5-11)
940
1,240
Dwarf
2.2
2.2
Turkey
Turkey
Point, Florida (23)
Point, Florida (30)
*
352k
352
Hammock
•
2.3
Turkey
Point, Florida (30)
940 x
Overwash
3.1
10,000
Islands, Florida (3-7)
620 X
Riverine
3.1
3.1
10,000
10,000
Islands, Florida (6-14)
Islands, Florida (6-1 .5)
620
620
Basin
4.5
Rookery Bay, Florida
1600 X
* Enclc ures (individual plant)
X Baskets (0.25 m 2 )
All litter collecting units were constructed to minimize lc ses of matter due to wind,
tic s and decomposition; and to prevent inundation and wetting between collection
periods. All units were constructed to meet the following criteria set forth by
Newbould (1970): (1) there should not be an aerodynamic effect preventing litter from
falling into the collection unit, (2) it should not ă op or blow ut again, (3) and
material from other sources (i.e., ground) should not get in.
19

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Litter oaskets were constructed of wooden frames 0.5 m x 0..5 m with 0.1 m-higri
This gave a 0.25 rn surf ace drea for the interception of litterfall. The bottom
u the ousket 000s!sted of 1 nm -mesh nylon screen secured with monel staples. Tne
Dask-ets were positioned above t;e ground using two methoas depenuing on prop root
neight. ‘ nen prop root height as moderate f 1 meter) baskets were piacec
appro.vinatelv one neter above the ground using tour 2.5 cm x . .5 on cypress stakes
driven into toe ground and securvo to each corner of the basket with nails. When prop
root he giit riluD tea this nethoc, baskets were suspended from limbs and secured
against wind aisturbance using ntcn cord.
1 he low canopy, low nsity and relatively high tidal levels precluded the use of
litter baskets to the dwarf mangrove lorest, thus an alternative method, endosures,
was used. A frame constructed of 2. cm x 2.5cm x 120cm cypress stakes was placed
over the naivtaual dwarf nangroves. A bottom of I mrn -mesh nylon screen was
secured above the prop roots a d fastened to the wooden frame. Then the entire
frame was wrapped with I mmL mesh nylon screen and secured to the stakes and
bottom screen, thus encioting the individual plant on afl sides. This entrapped all the
fali plant parts and prevented them from being washed or blown away.
Tne litter from enclasures and baskets was collected at 14 to 21 day intervals to
prevent any weight loss due to decompos ltlonb The litter was returned to the
laboratory and dried to a constant weight at 70 C. The litter was then sorted into
wood, miscellaneous ilowers, bracts and buds), and leaves, and seeds by species. The
material was weighed using a top—loading balance to the nearest 0.1 g. The data from
the oas iets are reported in d .ry weight per ground surface area per unit time. The
encic ure cata were originally e ressed as weight per individual plant per unit time
but were converted to a ground surface area by using the density Undivicuals per
ground surface area)at the difierent sites.
20

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Section 7
RESULTS AND DfSCUSSI3N
MANGROVE MODEL - OBJECTIVE I
Efforts to assemble computer models for the collation and organization of data,
arid eventual simulation, were applied to mangroves in early 1971. In this early work,
the models served a conceptual purpose (see Lugo et at. 1971) but as early as 1972
(Miller 1972) simuiatior6 were also being run for specific objectives. The state of the
art in the modeling of the mangrove ecosystem is now highly refined but is still
constrained by the lack of data particularly with regard to functioning of tie whole
system. For the purpose of this objective, a total of 18 mangrove computer models
(Browder et at. 1974, Burns 1976, Carter etal. 1973, Lugo 1976, Lugoetal. 1971, Lugo
etal. 1976, Miller 1972, Odum and Sell 1976a, b, c, Odurn 1976a, Odum etal. 1974, Sell
1976; Snedaker 1974, Stanford 1973, 1976, and Statler 1976) were analyzed and used as
the basis for the construction of a whole systems model applicable to this project. The.
resulting model (Fig. 4) is described in this section and parameterized for copper in
Appendix B. The model is based on the energetic notation of Odum (1971) which uses:
cirdes to identify any source ( c c sink) of mass cc energy external to the system of
interest; “tanl ” to identify storages which have finite boundaries within the system; a
“bullet-shaped’ symbol denoting a specific producer (plant) population and hexagon
denoting a specific consuner (animal) population, both of which have self-maintaining
properties; an “arrow-shaped’ symbol to aenote a precise two-factor interaction with
either un i-directional or reverse flow properties; and the conventional heat 5ink symbol
indicating the loss of heat as a function of work. The model (Fig. 4) is considered to be
preliminary as it would require refinement for the purpose of computer simulation.
General Mangrove Ecosystem Model
The model for the mangrove ecosystem is depicted in Figure 4 and described
relative to the general dass of heavy metals. The forcing functions are aesignated by
title and number, e.g. Weathering (2); storages by title and the letter Q followed by a
number si.bscript, e.g. Surface Water Q 1 ; and flows are indicated by letter, e.g. (A).
At the left side and upper-right of the figure are the primary forcing functions of
weathering (2), runoff (3), rainfall (4) and tide (12). Sources of heavy metals are shown
as terrestrial (I), which includes herbiddes, and munidpal and industrial wastes;
atmoslimeric (Q 0 ), which are derived from agrio 1ture and industry and includes
cropdust, coal and petroleum cons ui-i ption, and oceanic (13), which serves to dilute and
export toxic materials to offshore areas. In this regard, for example, the ocean can
also be considered an external source of diluted and/or chemically transformed
materials.
Chemical parameters such as Eh and pH (10 and 11) determine the form (oxidized
or reduced) of the metal in the aqueous media. Obviously these parameters can only
21

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so
F—-’
p ’J
/
Figure 4. General process model for I avy meidis.

-------
predict the direction of the specific reaction and its stability boundaries under
specified conditions, and do not account for reaction rates. However, until more data
are made vaiIdble concerning reaction rates under natural conditions, thermodynamic
and empirical reasoning would have to suffice.
Other chemical processes are represented as oxidation (8) and co-precipitation or
adsorption (9). Both categories are broad and are meant to contain implicit
mechanisms. For instance, oxidation ii 1udes a number of reactions driven by 02.
Bacterial oxidation, decomposition, dissolution of organic molec es and break-up into
particulate detritus are included in the forcing function. The M (9) modules serve to
illustrate the mechanism of removal by precipitation, adscrption, chelation, epitaxial
growth and any other type of metal-ligand complexation which might immobilize a
metal ion.
Heavy metals may be initially delivered to coastal areas from point sources and
runoff (3) from municipal-industrial areas and carried to the coast by pipes, streams,
canals or sheet flow (A) depending on specific source and the local hydrology.
Incorporated in the runoff waters are weathering products from soil leaching and
erosion (2). Rainfall (4) is depicted as having a mu!tipli& (or amplification) effect on
transport of terrestrially derived materials and is coupled with runoff and weathering
to produce the transport of heavy metals to the surface water (Q 1 ) in mangrove
ecosystems. In addition, rainfall also serves to “so-ub” the atmosphere (Q 0 ) of
particles produced from agriculture and industry (5) as shown in pathway (C).
Tidal incursion (12) brings estuarine waters (Q 14 ) into the mangrove region where
heavy metals may be introauced or diluted depending on their concentration and form.
The ti function is diagrammed as a two-way switch which exchanges surface estuary
waters (Q 14 ) with the ocean (13). Thus, the tide switch worl the pathway (D) as
either an Input or output and depicts a part of the removal mechanisms of heavy
metals in surface and estuarine waters.
The pathway (E) represents a feed back loop of materials oxidized (either
biologically or chemically) or broken down into particulate matter which may then be
re-introduced to the water column by stirring or dissolution. Some of the material
may be volitilized and re-enter the atmosphere (Q 0 ).
Interstitial water (Q 4 ) within the s ..bstrate exchanges material via pathways (I),
(U) and (V). Pathways (I) and (V) are primarily a function of evapotranspiranpn and
tidal characteristics. The exchange rate between interstitial water and surface water
(Q 1 ) is not known but, due to the rather impermeable nature of the mangrove
substrate, the exchange may be limited to turnover induced by evapotranspiration and
hydrostatic head dillerences imposed by flooding tides. Topographic slope may also be
considered as a major influence on the exchange.
Pathways (B), (G), and (F) relate to removal mechanisms of chemical species
from surface waters (Q 1 ). Besides tidal flushing (I)) and exchange with interstitial
water (Q, ), these are considered to be the major pathways by which metals may be
stored wiThin the mangrove realm. The pathways (B) and (ç are dependent on a whole
series of ion complexing processes (9), represented by M . This function includes
chelation, coprecipitation, adsorption and epitaxial growth. It is a complex
phenomenon involving organic and inorganic ligands and is s .bject to further research
concerning its importance as an effective removal mechanism in natural systems. As
23

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shown in the diagram, these comnolexes may combine with the surface peat (Q.) or
become bound to overwash sediment or marl (Q ) which may occur as part o the
swstrate within the forest Metals may be rethrned to the surface water (Q 1 ) by
oxithtion or dissolution (s ), (9), (10) and ( Ii ).
Direct uptake of metals occurs along pathways (F) and (H). These represent
uptake by prop roots from surface water 1Q 1 ) and uptake by subsurface roots from
interstitial water The sui (7) is illustrated as being the energy source for the
uptake pathways. The 1:miter (R) serves to point out that not all of the radiant energy
from the s .n is utilized for production but is also used to heat the air and water, etc.
Once the metals are trarsported and assimilated ifl the various plant tissues, such as
prop roots (Q 7 ) , wood (Q 8 ), leaves (Q 9 ), leaves (Q 9 ), fruit (Q 1 ) and subsurface peat
(Q 6 ), they are then subject to release via s h processes as lifterf all (M), mortality,
(L’, herbivore grazing (K) and peat turnover (S). When leaves fall from the mangrove
(M), they become litter (Q ) and are decomposed by mic oorganisms and mechanical
breakdown (E) and exportecV to the estuary via pathway (U)), tidal flushing. Standing
dead matter (Q 11 ) is consumed by various organisms which help to incorporate the
wood and root tissue (N) into the surface peat where oxidation and decomposition IE)
further break down and expose the metals once again to the surface water (Q 1 ).
Peat turnover (5) is a more complicated process due to the lack of information
concerning the specific mechanisms. The diagram indicates that root growth in the
stbsi .rf ace replaces a part of the peat mass by volume displacement. The displaced
peat causes the peat surface to become slightly elevated and subjected to oxidation (E)
and 1c5 5.
Herbivore (Q 1 ,) and carnivore (Q 13 ) interactions are illustrated in a very general
sense. The herbivo ës graze on various plant parts (K) as a food source and may return
metals to the surface peat (Q,) or inorganic sediment (Q 5 ) through I ecal material and
decomposition upon death (N) Pathway (P) is an e ort pathway and allows for a
transitory species to migrate into contiguous systems. The carnivore popilation, or
cornmu ity, (Q 1 ) consume herbivores along pathway (O)and contribute their waste (N)
to surf ace peat s and inorganic sediment in touch the same manner as herbivores.
Carnivores may also be transitory and export assimilated metals to other areas along
the pathway (P).
TI-us basic model was used as the basis for the sampling design and for a more
detailed version for pararneterizatiori with respect to the metals copper, mercury,
cadmium and arsenic. The parameterized model for copper is presented in Appendix B
as an example of an approach to understanding the role and cycling of an element in
the roangrove-estuarine ecosystem. In the absence of a large amount of data on
transfer rates di metals between and among compartments, it is not possible to
simulate s xh models with any realism because the assumptions and estimated data too
heavily influence the outcome. The primary insight gained from this effort was the
reinforcement of the need for rate data on elemental fluxes in the contect of the
dynamics of the mangrove ecosystem.
Parameterization efforts were also made for the synthetic organic pesticides,
DDT, dieldriri and toxaphene, but no example is given, mainly because of the almost
complete absence of data pertaining to mangroves. The accumulation of sufftci t
data on the synthetic organics is visualized to be an even more troublesome task than
would be experienced for the metals, largely because: (1) they are frequently present
24

-------
in low concentrations, (2) analyses are comparatively more eqensive, and (3) they
are nonconserv ve in the environment. In this latter regard, as a dass, they tend to
be rapidly metabolized or chemically altered in both oxidizing and reducing
environments, but in general, their chemistry is essentially unknown in the mangrove
environment. However, what has been learned through the course of this study
concerning both the metals and the synthetic crganics is discussed elsewhere in ti-us
report.
WATER QUALITY AND SALINITY - OB3ECTIVE 2
One of the more perplexing problems in the study of water quality and mangrove
eccsystem dynamics is the confounding influence of salinity. There is a tendency to
view salinity as a controlling factor in the behavior of the nearshore environment
when, in fact, salirUty may simply be an autocorrelate of many other factors which
also have predictable seasonal patterns. The reasonfor this is that the cyclical rise
and fall in salinity each year reflects the decrease and increase in freshwater runoff,
which is a I u ction of seasonal rainfall. This seasonal pattern also correlates well with
seasonal changes in water temperature. Of particular interest, however, is the fact
that entrained in terrestrial runoff water are the products of terrestrial weathering
and leaching as well as materials from a variety of other sources. These materials
most certainly influence the quality of the receiving waters and, depending on the kind
ana concentration of material, has biological influences as well. Thus, in any effort to
assign importance to components of water quality, or tz statistically partition
variances, salinity must be viewed separately in order to determine whether it should
be included as a dominantfactor in water quality. In this research, an effort has been
made to identify the role of salinity with respect to mangrove structure and
productivity to reduce its impact as a possible confounding variable.
The importance of soil water salinity as an ecoingical f tor governing the
distribution, abundance and vitality of mangroves is not completely known. Chapman
(1975) stated that little work has been done to determine the extent to which the
mangrove species are obligate halophytes. He condudeci however that salt is not
required for mangrove development. Other authors also concur that salinity is not a
required factor (Bowman 1917; Warming and Vahi 1925; Rosevear 1947; Egier 1948;
Daiber 1960; and Walsh 1974). Although there is some contradictory evidence (see
below), it is generally conduded that mangroves are facultative halophytes. In other
words, mangroves simply tolerate salinity and each of the species varies in its
tolerance limit. Table 3 presents some Literature references pertaining to mangroves
growing in freshwater. -
Mangroves, being facultative halopl ytes, have a competitive advantage over
other tree species with lower salinity tolerances. Egier (1948) demonstrated that
Rhizoç*iora mangle grew well in freshwater when alone, but was inable to compete
with other macrophytes in non-saline environments. Mangroves thus dominate the
s .btropical and tropical coastal zone, not because they require salinity, but because
their potential competitors are less tolerant to salt (West 1956; Chapman 1976). In
relation to metabolic energy, it has been argued that the salt control mechanism
requires a higher expenditure of energy as salinity increases (Waisel 1972; Queen 1974;
Lugo and Snedaker 1974; Gale 1975). This increased energy expenditure does not
reduce the competitive advantage of the mangrove relative to non-halopliyte
competitors, but instead is the basis for their competitive advantage.
25

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TABLE 3. REFERENCES IN THE LITERATURE TO MANGROVES BEING MAINT/INED!N FRESHWATER
Genus Location Remarks Reference
Rhizophora sp. Washington, D.C. Grown in greenhouses using Egler t1948)
USA freshwater
Biuguiera sp. and Indonesia Flowering, fruiting and re- Steenis t1958)
Sonneratia sp, generating in an artiLcial
- freshwater swamp
Sonneratia sp. Inoonesia Natural stand at an eleva- Steenis (1963)
of 175 m in freshwater
Bruguiera sp. Calcutta Growing in a freshwater pcnd Chapman (1975)
in the Botanical Gardens
Br guiera sp., Florida, USA Introduced from Australia, Gill (1969)
Xylocarpus sp. and maintained at Fairchild
Aegriceras sp. Tropical Gardens in fresh-
water
Avicennia spp. and unknown Grown in greenhouses using Chapman (1952)
bruguiera sp. freshwater
Avicennia spp. and Germany Grown in greenhouses using Winkler U931)
Bruguiera sp. freshwater
Avicennia sp. Florida, USA Maintained in a greenhouse Lugo personaI
with distilled water communication)
Rhizophora sp. Florida, USA Natural stand growing in Snedaker
freshwater swamp (ms. in prep.)
Rhizophora sp. Jamaica Natural stand growing in Chapman (1944)
freshwater swamp
Ueritiera sp. Bangladesh Natural stand thriving Hooker (1878)
several kilometers
from coast

-------
Maximum salinity tolerances have not:béen, fully documented for mangrove
species. Data scattered throughout the literature suggest that the maximum tolerance
varies among species and age classes (McMillart 1971 and 1974; Connor 1969;.Clarke
and Hannon 1970; and Kylin and Gee 1970). Tie upper salinity limit for mangroves for
any extended time period seems to• be 90 ppt. •. This upper limit (90 ppt) appears
reasonable in Iig t of the conclusion of Sdiolander etal. (1965) that high sap pressures
in mangroves enable them to extract freshwater from concentrated seawater of about
2.5 times rKrmal salinity (Table 4), although this upper tolerance limit may be.
e eeded by a factor of two in Avicennia germinans for short periods of time with no
apparent long term damage (McMzllan .1974)
Conrior (1969), working with A. marina in nutrient culture demonstrated that the
twes of salts present are also important to the vitality of this mangrove. A. marina .
showed a positive growth response to sodium chloride whereas all concentrations of
potassium chloride and calcium chlcx-ide tested suppressed growth. The greatest
positive response for sodium chloride occurred at approximately half the concentration
of awater. The normal habitat of this species reflects its tolerance to high
concentrations of sodium rather than an optimum adaption to. it. Tie detrimental
effect of the other salts showed rio simple unifying effect referable to osmotically
mediated stress,thus tie response is probably dominated by specific ion effects on tie
physiolc y of the plant. Chapman (1966), in commenting on ecoingical classification of
plants growing in saline habitats, noted the possibility that individual ions are more.
important than total salinity
In a mangrove community, one which contains multiple species of mangroves,
salinity has been shown (Lugo et a!. 1975) to. be the controlling factor in their
distribution. Termed the “metabolic basis of zonation,” the concept implies an optima!
salinity range for each species and a corresponding segregation resulting in “zo ies. t ’
Hicks and Burns (197)) further support Lugds conclusions with their work relating
surface and ground water chloride concentration and primary production in different
species of mature mangroves. Their data show a negative correlation. between gross
primary productivity (total carbon fixation) and increasing chloride concentrations for
R. mangle and a positive correlation for A. germinans and Laguncularia racemosa .
The optimum salinity for mangroves could vary under different conditions, for
instance, nutrient availability, tidal flushing, upland runoff and the range of
competitors present, but research evidence for this is lacking. Water quality, alone,
cannot account f cr all of the observed variations in mangrove structure and
functioning, due to the mitigating influences of other factors, including salinity.
POLLUTANTS MANGROVE ENVIRONMENT - OBJECTIVE 3
Synthetic Organic Compounds
During the course of this work, 180 samples of water, sediments, and bioL i 1
materials (i.e., mangrove tissues) were analyzed for ten synthetic organic compounds
reported as common in the environment (aidrin, dielthn, DDT, DDE, DDD, lindane,
hyptachior, mirex, parathion, and PCB’s). The samples were obtained from southern
Florida and Puerto Rico. None of the compounds were detected. The gas
chromatographic records c id, however, show the presence of an unidentified organic
compound in a few of the samples which was later identified to be one of the active
ingredients in a commercial insect repellent. It was concluded that splte
27

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TABLE 4 IN Sif U SOIL WATER SALINITIES
Genus Location Salinity References
Bruguiera
C eriops
Lurnnitzera
Rhizophora
Avicenrila
Australia
East Africa
U.S.A.
West Africa
Puerto Rico
Puertu Rico
Australia
Australia
East Africa
98
90
80
58
67
60
25
60
90
ppt
ppt
ppt
ppt
ppt
ppt
ppt
ppt
ppt
•


MacNae (i966)
Chapman (1975)
Davis (1940)
Giglioli and King
Lugo and Cintron
Lugo and Cintron
MacNae (1966)
MacNae (1966)
Chapman (1975)
(1967
(1975)
(1975J
Laguncularia
U.S.A.
F-laiti
Australia
U.S.A.
Puerto Rico
Puerto Rico
90
48
55
55
60
37
ppt
ppt
ppt
ppt
ppt
ppt
Snedaker (unpub.
Lugo and Cintron
MacNae (1966)
Davis (i940)
Lugo ano Cintron
Lugo and Cintron
ms.)
(197))
(1975)
(1975)
28

-------
precautions against contamination, the field crew’s use of this repel1 t did, in fact,
contaminate the samples
Trez results became the sthject of attention, largely because earlier work
(Carter et al. 1973) demonstrated the presence of several of the compounds of interest
(DDT, DDE, DD’D, PCB’s, dieldrin and rnirex) in sediment and biological samples from
the same general area and DDT, DDE, DDD and the PCl ’s were detected frequently.
The most significant of their results was the presenceof the lipid-soluble chlorinated
hydrocarbons in the top carnivores such as the Fkri gar and the Bonito; consumer
animals were not analyzed in our study. The sampling for this work took place during
the 1972 calendar year, and Carter et al. (1973) concluded. . . “The consistent absence
of detectable pesticides in the water and the low concentrationsfound in the sediment
and most of the biological samples suggest. a lack of significant pesticide
contamination at the present time.”
The sampling for our project took place during the 1975 calendar year, or three
years following the above cited work. It is conceivable that the pesticide loading for
this area had decreased and that the materials present in the earlier study were no
longer detectable. The same reasoning might also apply to the Puerto Rican results
but we have little basis to argue any type of explanation.
It is believed significant that none of the bio1 ical materials contained any of
the synthetic organic compoun and that only the sed ents had consistently
detectable traces (Carter et a!. 1973). The literature on incorporated organic
pollutants in mangrove, albeit sparse, is consistent with these.survey results. Although
mangroves are affected by: certain synthetic organics which behave like plant
hormones (see Walsh et al. 1973 and citations therein), it seems reasonable to state
that macgroves are probably not active accumulators cr. biological magnifiers of, at
least, this group of synthetic organic compounds.
Metals and Nutrients
Metal and nutrient analyses were made to determine: (1) general concentrations
in mangrove tissues, (2) changes in concentrations airing leaf maturation,
(3) concentrations in macgrove litterf all, and (4) general stock levels in the mangrove
ecosystem.
In contrast to analyses for the ten synthetic organic compounds, metals were
detected in varying concentrations in nearly all of the samples collected in the field, in
both southern Floride and Puerto Rico. In no instance, however, were concentrations
considered detrimental to the health of macgroves. Furthermore, evidence did not
suggest that macgroves accumulate metals at what would be considered toxic
concentrations. -
Fŕllowing the initial sampling survey to identify areas st bjected to heavy
loadings of metals, the carbonate environment in southeastern Dade County (Turkey
Point), Florith, was selected for intensive study. Higher concentrations of metals
appeared in the Puerto Rican mangroves, due in large part to the nature of the geolc y
1 the island, but l istics dictated that the sL.bsequent work be done closer to our
ome institution. The Turkey Point area is close to sources of heavy metals (the
l xith Power & Lig it Company’s two fossil fuel electric plants, and, urban runoff
Erom metropolitan Dade County), and previous work (Gerchakov et a!. 1973, Therhaug
29

-------
at aL 1973) had established the presence of many of the metals in the environment.
Furthermore, this carbonate environment, depauperate in both clay and organic matter
(with regard to the cation exchange capacity,) s gested no permanent sink for metais
(Segar and Peilenberg 1973) and thus tneir probable retention in biologically-mediated
cycles. Although a large number of me metals had been reported as occurring in tt:e
sediments of soutnwestern Florida (Ten Thousand Islands, Carter et iii. 1973), there
was no comparable nearby source and levels were notably low.
Table 5 is a comparison of the composition of selected elements in red mangrove
tissue and peat collected in Puerto Rico and southeastern Florida at the same perod m
time tJunelJuiy). Values represent 9 sampling stations in Puerto Rico and 12 sampling
stations in southeastern Florida (Turkey Point area). Regional variations in the
elemental compositions reflect differences in the s .bstrates of the upstream
watersheds. Table 6 represents tt composition of additional elements of interest for
red mangrove icxated in southeastern Florida. Tables 7 and S are the eiemental
composition by compartment for black and white mangroves in the southeastern
Florida area. These data snggest that significant differences exist amcx g the
mangrove species but it is not possible to assi i these differences to either nabitat
characteristics or different species-specific uptake rates. This identifies a problem to
be pursued insofar as the zonation of the species may reflect differing exposures to the
metals based simply on frequency of inundation and flushing by freshwater.
Because of the recognized importance of detritai food webs generated by leaf
litter, specific attention was given to the fate of metals and nutrients incorporated in
mangrove leaves. For this purpose, leaf classes were categorized into a seq ’ !ence of
size—age classes and representative samples collected from mangroves at the Turkey
Point site. The basic question of interest was whether or not metals are biolcgically
concentrated in the leaves prior to senescence. Conversely, it would also be of
interest to o-iow whether, like phosphorus, they are translocated back into the woody
portions of the plant prior to abscission. The leaf age classes for the red mangrove are
defined as follows: the unfolded terminal bud was considered the first stage of leaf
development and those further down the whorl represented sequentially older leaves.
Red mangrove leaves appear to be opposite, but under dose examination they are
really whor led and the ontogeny of appearance and development is readiiy discernible.
The maxim isn number of leaves present on a single shoot of the red mangrove is six for
the Turkey Point site, although in other areas the total number may range as high as
nine. Based on leaf turnover rates calculated from data on I oliar l ornass and rate of
leaf litter production, it is possible to estimate the maximum age of the oldest
senescent leaves. For the Turkey Point site, this is approximately 9.6 months (Pool et
a!. 1975). Thus, the data shown in Table 9 reveal the changes in concentration during
the 9.6 month maturation period for Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, Sr, and
Zn. These data show both expected and unexpected results. First, the suite of rations,
Ca, Sr, and Mg, show a tendency to increase in concentration with age which is an
understood phenomenon; calcium is irreversibly bound in cell wall material as is Sr.
Magnesium also tends to maintain a specific 3:1 ratio relative to Ca and this too is
apparent in the results. In contrast, two of the more relatively molile elements, K and
P, show, contrary to expectations, a reversal in patterns. Potassium tends to be most
highly concentrated in’the primordial growth tissues, such as the cambium and the bud,
and to decrease in concentration with the aging of the leaf as a result of leaching and
retranslocation. However, these data s gest that in the latter stages of leaf
maturation, K increases steadily through senescence. in contrast, P is us s1ly lower in
the earliest stages maturation and increases to a concentration which remains stable
30

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TABLE 5. ELEMENTAL COMPOSITiON OF RED MANGROVE TISSUES AND PEAT
[ N PUERTO RICO AND SOUTHEASTERN FLORIDA
---
PUERTO
RICO
SOUTHEASTERN FLORiDA
Element (ppm)
Element
(ppm)
Compartment
P Cu Fe
Mn Zn
Cr P
Cu Fe Mn Zn Cr
Leaves
1,120
7
145
497
32
7
531
2
52 146 10
Nfl
Twigs
749
2
69
300
33
6
170
10
90 30 45
40
Branches
480
2
47
373
14
5
•
260
ND
134 142 6
ND*
Wood
229
2
31
112
23
4
213
ND
244 90 7
ND
Prop Roots
483
4
35
69
27
8
148
ND
70 41 16
ND
Fruit
858
ND
100
106
13
5
409
10
75 20 56
20
Litter
496
18
2,870
379
8
14
115
2
711 70 28
2
Peat (0—s cm depth)
Peat (at 25 cm depth)
507

40 20,600 333 60
NOT SAMPLED
#6
145
98
1!
14
1,376 70 29
3,325 61 7
11
18
ND None detected

-------
TABLE
b. ADDiTIONAL
IN
ELEMENTS OF
SOUTHEASTERN
INTEREST FOR
FLORIDA
THE
RED
MANGROVE
T A M-r
L
PPM
Compartment
%
C
H
N K
Ca
Mg
Sr
Al
Ni Pb
*
Leaves
43.1
5.4
1.3
1.6
1.7
0.7
184
50
ND
3
Branches
41.1
4.8
0.6
0.4
3.0
0.3
400
12
ND
2
Wood
39.7
4.6
0.5
0.4
2.7
03
337
88
ND
ND
Prop Roots
37.1
4.6
0.4
0.4
11
0.2
216
25
ND
ND
Standing Dead
33.9
4.0
0.6
0.3
2.6
1.3
294
138
ND
2
Seed1ing _____
40.7
4.9
0.6
0.6
1.2
0.3
146
83
3
ND
*
ND = None detected
32

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TABLE 7. ELEMENTAL COMPOSITION BY COMPARTMENT FOR BLACK MANGROVE
IN SOUTHEASTERN FLORIDA
ELEMENTS
%
Compartment
Sr
Cu
Fe
Mn
Zn
A1
Cr Ni
Pb
C
H
N
P
K
Ca M
Leaves
43.0
5.3
2.2
0.03
0.9
0.507
58
6
56
63
66
175
18. 80
ND
Erancbes
43.7
5.3
0.6
0.01
0.4
0.5 0.1
44
10
40
5
10
100
10 ND
*
ND
Wood
41.5
5.1
0.8
0.01
0.6
0.4 0.2
•56
10
55
5
6
100
10 ND
ND
Pneumato hores
41.5
4.4
0.8
0.01
1.0
1.1 0.3
134
8
68
18
8
150
5 ND ND
*
ND None detected

-------
TABLE 3. ELEMENTAL COMPOSITION BY COMPARTMENT FOR WHITE MANGROVE
IN SOUTHEASTERN FLORIDA
ELEMENTS
Compartment
%
PPM
Sr
Cu
Fe
Mn
Zn
Al
Cr Ni
Pb
C
H
N
P
K
Ca
Mg
Leaves
41.6
4.4
0,6
0.03
0.4
1.2
0.5
89
6
60
27
63
90
4 24
ND
Branches
41.1
4.6
0.6
0,01
0.4
1.6
0.5
115
2
255
30
15
120
NDND
ND
\ iood
39 .1
4.3
0.6
0.02
0.5
2.1
0..5
135
3
256
44
i
120
0 10
ND
Standing Dead
40.6
4.1
0.8
0.01
0.1
1.6
0.7
150
ND
120
5
U
150
ND ND
10
*
ND None detected

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TABLE 9. ELEMENTAL COMPOSITiON OF MATURING RED MANGROVE LEAVES
FROM THE BUD THROUGH SENESCENCE
Leaf Size/Age Class
%
.
Sr
ELEMENTS

PPM
Cu Fe
Mn
Zn
Al
Cr Ni
Pb
P
K
Ca
Mg
Bud
0.08
0.8
.
1.1 0.5
88
5 35
60
11
*
ND
10 ND
10
1st leaf
2nd leaf
.
0.09
0.07
0.9
0.7
0.8
1.1
0.5
0.5
63
88
5 25
5 70
45
70
16
18
ND
ND
10 ND
20 10
10
10
3rd leaf
0.06
0.6
1.3
0.6
100
5 50
90
10
ND
10 ND
10
4th leaf
5th leaf
0.04
0.04
0.8
1.1
1.3
1.4
0.6
0.6
113
113
ND 45
ND 90
90
100
8
17
ND
50
10 ND
20 10
10
10
6th leaf
0.03
1.2 1.3
0.6
113
5 65
95
12
ND
20 10
10
*ND = None detected

-------
tiirorh senescence, or drops just prior to senescence. The data on P show the higriest
concenxrauon in the bud arid a steaay decrease during maturation. This rather unusual
phenomenon is ntarpreted as rsoresenting retranslocation.
In contrast to the above nutrients (and Sr) only two of the metals, Fe arid Mn
show a change in concentration with uge The others, Cr, Cu, Ni, Pb and Zn reveal no
particular Dattern. It is interesting to note, however, their relatively low concentra-
tious. despite toe fact that the nearby estuarine environment has been cited for its
sit!v iugin concentrations of metals from a nearby f ossil4uel electric plant
ri2ug at a! 19 ’ oec ice I , Fe Cu, and n a-c Ii 4 r er (Cerchakov et a.
L r i eciL e ox he do ins cc m caroo ’a ar no f’ne s ice in the suostrates (Segar and
- eiienberg i”f. ) there is no permanent sink for these metals and ostensibly they
remain in circulation via ohysical and biol iczl processes.
1NOLX OF MANGROVE DYNAMICS - OBSECTIVE 4
One of the primary objectives of this study was to identify a specific parameter
associated with margroves which would: (1) serve as a calibrated index of produc vity,
(2) reflect at least i.he broad characteristics of the hysical environment, and (3) be
asUy measured in a highiy reproducible manner. Many ciifferent integrating
measurements were considered and three were finally selected for evaluation: the
complexity inde, Hcliiuci e 1967, Holdri e at al. 1971), the length:width ratio of
mature msngrove sun leaves, and biweekly rates of leaf litter production. Each of
these ree parameters proved to be highly useful for different pJrposes. First, the
cornp exity index quantitatively categorizes differences in the structural complexity of
man ro.’e forest bjt is difficult to relate to specific aspects of water cuality other
than salinity. During the course of the field work, 25 sites in Florida, Puerto Rico,
Mecico, and Corta Rica were visited and data taken for calculation of the complexity
index and a survey of the general environment. The res its were published (Pool etal.
1977) arid documented for the first time the large quantitative differences in mangrove
forest structure in thc low latitude tro ce of the western hemisphere. As part of this
and associated wcch, whele leaf samples were taken at each of these sit , plus a site
in Haiti, from wtuich measurements were made of each leaf’s length and width and, on
selected samples, leaf surface area. These data show a possible correlation with
irrigitude (leaves show a general decrease in size from west to east), but it was not
possi ie to develop any correlatior with other parameters measured. A summary of
ti’e results is ircluded in this report as part of Appendix (A).
Rate of Leaf litter production proved to be the most useful sir le index reflecting
tno ciesireci information. The final selection of this parameter was based on a
prt:Limirmry artalysis of ( tterf all records maintained sirce 1971; this preliminary
analysis was reported by Pool at al. (1975). As a result of recognizing the value of
continuous litterf all records, additional sites were established in southern Florida to
develop a data base for each of the mangrove forest types described by Lugo and
Snedaker (1974) and representing different types of southern Florida er vironments;
high salinity carbonate and low salinity ciastic/peat. These sites were visited regularly
during the project period but funds were only available to work up the data through
March 1976. (The stations are still maintained and visited on a voluntary basis sirce
that date bat no provisions are available for the workup and interpretation of the
data.) The data on litter production provide the primary basis for the interpretations
and conclusions developed in this report, largely because leaf litter production met the
iritial requirements br a general index of mangrove vitality and the physicul
36

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environment.
Litter Production
The litter production record was analyzed initially from the hypothesis that the
highest rates of IItterf all would be associated with the ‘better’ quality surface waters.
Thet is, the highest rates would occur i the sites in southwestern Florida and the
lowest rates in southeastern Florida. This premise also argues that local variations
would be related to the mean salinity of the interstitial soil water.
The litter production records for the southeastern Florida sites are presented in
Figures 5 through 8, and those for the southwestern Florida sites in Figures 9 through
13. The data did not s port the initial hypothesis, that is, with the exception of the
dwarf forest, there was no apparent difference between the two study areas. The data
from which Figures 5 through 13 were derived, are sunmarized as annual means in
Table 10. Notably in this regard, the fringe forest exposed to the relatively
oligotroçtiic water of southeastern Florida exhibit higher litter production rates than
the fringe forest site in southwestern Florida.
The first general statement that can be made is that the annnual litter
production cycle in southeastern Florida is similar to that in southwestern Florida:
litter is produced year-round with a peak in the fall of each year. This pattern is now
believed to be typical of mangrove forests in southern Fic”da irrespective of the
absolute production rates. The second general statement is that there is consistently
lower litter production rates for the dwarf forest as compared to each of the other
types. With regard to the dwarf forest-type replications, which are 700 m apart along
a transect perpendicular to the land-sea interface, there is no significant difference
between the two production patterns. As in the other examples, the high peaks,
particularly in the fall represent storm-induced shedding. However, because of the
dwarfed and stunted stature of the dwarf forest, storm-induced breakage of limbs
seldom occurs. In general, the dwarf forest type appears to be relatively resistent to
the types of storm damage which distort litter production patterns for all of the other
types.
Rates of mangrove litter production do not differ significantly between forests
on tre southwestern coast of Florida and those on the southeastern coast, despite
broad differences in water quality. In southeastern Florida, the mangrove forests Oo
not receive any terrestrial runoff except that which results from local rainfall. The
area is influenced by the relativley oligotro xc waters of Card Sound which exhibit a
constant year-round salinity only slightly lower than that of sea water. In comparison
to southwestern Florida, Card Sound waters are remarkably dear. The sthstrate is a
dacareous marl over a limestone bedrock several meters below the surface. During
the spring and early summer, water levels are at their lowest and only the highest of
the highest tides inundate significant portions of tie mangrove study area. In contrast,
the waters of southwestern Florida experience a seasonal change in salinity due to
abundant terrestrial runoff, primarily in later summer and early fall when water levels
tend to be at their highest. The mangrove forests there are thus either perpetually
inundated by all high tides, or experience the flushing effect of freshwater runoff. The
waters are darkly stained with organic matter and tend to be eutropic in terms of their
nutrient content. With this background, it is apparent that the mangroves of both
coasts of the state do not reflect the difference in water quality, with the exception of
the dwarf forest and to a lesser extent, the hammock forest. It is believed that the
37

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6.0
T°TAL SEED FA .LL
1 .4
A
TOTAL WOOD LL
1.0.1
0.5
—
TOTAL MISC. FALL
A. ..
\A
TOTAL UTTER FALL
2.0 ________
0 r I
S J M S J M S J M S J M S J
912 1913 974 375 1q76
Figure 5. Litter production by compartments for fringe forest 1137 located in
southeast Florida.
38
6.0 TOTAL LEAF L1
4.0 -
2.0-
1.5 -j
0.5
0
8.0 -
60-
4.0-

-------
6.0 1
4.0
2.0
0
6.0 -
4.0
2.0
0
TOTAL LEAF FALL
4 4 4
TOTAL SEED FALL
; 4 4 4 T - -
TOTAL WOOD FALL
TOTAL MISC. FALL
4 I 4
1.5-
1.0-
0.5-
04
8.0
60
4.0
2.0
0
TOTAL LITTER FALL
j M
1 r’ ,,’,I —1T— -, V .; ,,? 1 ’.rlIIrT r rI 4 —i I
S .1 M S J M S J M S i M S J
19fl 2972 1973 1974 97S 1916
Figure 6. Litter production by compartments for hammock forest #30 located in
southeast Florida.
N
E
I ..
C
39

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TOTAL LEAF FALL
4 OH
C)
4.0 -
2.0-
‘.5 1
i.c) 1
0.5
C)
TOTAL WOOD FALL
TOTAL MISc. FALL
H
8.0-
50-
TOTAL UTTER FALL
A)’
i \‘
,-rr-r rc
5 J M
S J M
S J M S
J M S
J
t 71 1 12
I
74
— -
197
i\
-—
TOTAL SEED FALL

—r r T’ T 1 - ___ _ _f_ 1
---- __ _j
4-0 -
2.0 -
0
Figure 7. Litter production by compartments for dwarf
southeast Florida.
forest #30 located in

-------
row. LEAF FALL
4.0
TOTAL SEED FALL
4 .0
2.0

TOTAL woo FALL
1.0
0.5. -

1$] TOTAL MISC. FALL
°i
0.5-i
0
S J
191t
Figure 8. Litter production by compartment for dwarf forest //23 located in
southeast Florida.
0
—-
TOTAL LITTER FALL
4.0
2.0
M S J M S J
1972 t973 1974 191 1976
S
41

-------
6.0 TOTAL LEAF FALL
A
ii\

2.01 . \ j N ,/ \T J
y
I’
0 r r r -i——
6.0 TOTAL SEED FALL
4.04
2 .0
o Lr__yr _ .
TOTAL WOOD FAIL
I
> .S 1 TOTAL MISC. FALL
TOTAL LITTER FALL
i
4.04 /
2.0
S 4 M
S .1 M 5
4 T’ S
4 M S
4
97 i 72 1 73
3 *
I 1
Figure 9. Litter production by compartment for fringe forest #5-11 located in
southwest Florida.
42

-------
6 0
4.0
2.0
0
N
I-
C,
U.’
C
8.0 TOTAL LITTER FALL
S J M
S .3 M S
.3 M S
.3
M S
.3
1971 1972 1973
I —1
1974
1
1971
1976

Figure 10. Litter production by compartments for overwash forest #3-7 located in
southwest Florida.
43
TOTAL LEAF FALL
6.0 TOTAL SEED FALL
4.0
2.0.
0
1.5
I l I
1.5 TOTAL MIS LL
1.0•
0.5
0 -r I
6 0
4.0
2.0
0

-------
6.0
2.0 -
6.0 -.
4.0 -
2.0 -
0
> .
‘.4
E
— 0.: ,- ,
—
1.0J
0.5 -
o
8.0
601
2.0—
0
IOTAL LEI F FALL
I ‘ r /
t
;
TOTAL SEED FALL
It
t.’ . 1_• \. -t
5.3

TOTAL WOOD FALL
TUTAL MtSC. FALL 1 . .
a
TOTAL LITTER FALL
S J
M
S
J
M S J
M
S .1 S
) ‘ 1
72
1973
1934
Figure 11. Litter production by compartments for riverine forest 116-14 located in
southwest Florida.
4L
95

-------
6.0 1
4.0
2.0
6.0 TOTAL
4 ,0
2.0
0
t .5
1 0
0. 5
0
1.5-
1.0-
0.5-
0
60
4.0
2.0-
0
TOTAL LEAF FALL
.. - ..:.‘ \ j .
20
1 TOTAL MISC. FALL
TOTAL
TOTAL LITTEH FALL
S J M S J M S .3 M S .3 M S .3
197L 1972 1973 1 97 I97 1976
Figui -é 12. Litter production by compartments for riverine forest f6-15 located in
southwest Florida.
SEED FALL
WOOD FALL
45

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TOTAL LEAF FALL
2.0
o
6.0 1 TOTAL SEED FALL
::: 1
0 - - 1 u r T
1.S- TOTAL WOOD FALL
1.01
0.5
— I •
C
w
13- TOTAL MISC. FAL l.
= 10-
8.01 TOTAL UTTER FALL
601
4.0 -
A
2.0
o
S 3 M S 3 M S 3 M S 3 M 3
2q77 1973 1974 97S
1—--
Figure 13. Litter production by compartn ents for basin forest iocated in southwest
Florida.
46

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TABLE 10. SUMMARY OF MANGROVE FOREST COMMUNITY LITTER PRODUCTION
IN SOUTHERN FLORIDA
Mangrovea
Forest
Type
coiiectionb
Period
(years)
NumberC
of Data
Points
Locationd
and
Site .
Sitee
h
aracter
Litter
Production
( m 2 . year)
Fringe Forest 2.3 940 S.E. Fia. (37) A 1082
3.1 1240 S.W. Fia. (5-11) B 981
Riverine 3.1 620 S.W. FIa. (6-14) 1066
3.1 620 S.W. FIa. (6-15) 1173
O ’erwasji 3. 1 620 S.W. Fla. (3-7) B 1024
Basin ‘ 4.5 1600 SW. Fla. B 741
FI mmod< 2.3 940 S.E. Ha. (30) A 750
Dwarf 2.2 352 SE. Fla. (23) C 168
2.2 352 S.E. Ha. (30) C 271
a Based on the classification reported by Lugo and Snedaker (19Th).
b Through March 1975; data collected to present date remain unanalyzed.
C Number of collection dates x number of within -site replicate .
d Southeastern and southwestern Florida.
C A - high salinity, low nutrient, carbonate environment with subsurface peat deposits.
B - tow salinity, high nutrient, organic-rich environment with subsurface peat deposits.
C - high salinity, low nutrient, carbonate environment without subsi.a-face peat deposits.

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maintenance of high rates of litter production in the fringe forest and hammock forest
in southeastern Florida are iiue to the presence of organic soils and peat beneath them.
In this regard, the organic soils serve as a nutrient reservoir which is reflected in the
better structure and higher productivity as compared to the contiguous dwarf forests
which grow on pure calcite marl.
During the litterf all production studies, the biweekly litter samples were pooled
by moritn and analyzed for selected elemental constituents (Table 11 and 12) for the
southeastern Florida study site. They are sunrnarized nere for documentary purposes
as tte early termination of the grant precludea statistical analysis and interpretation.
The compositional data for the fresh-fallen leaves do not reveal a seasonal trend, but
do show differences among species as was demonstrated in the preceding data.
Cornoarisons with the ocmpcs!tional data for fresh leaf material (Tables 6-8) si gest
that large losses of certain elements occur just prior to leaf abcission and/or during
tne first two weeks of decomposition following senescence, e.g., phos iorus and
potassium. Phosphorus is probably retranslocated within the plant during senescence
whereas potassium is probably leached following the death of the leaf. The increase in
potassium just prior to abcission s likely related to internal salt-balancing mechanisms
within the plant (Waisel 1972). The relatively uniform elemental composition in litter
throughout the year indicates that if there is a tran er of an entrained pollutant to
detrital food webs, it probably occurs as a pulse during the fall season of maximum
litter production.
WATER QUALiT AND t NGROVE ECOSYSTEM DYNAMI - OBJECTIVE 5
Water qJaiity and marigroves interact in a logi liy defined reciprocal
relationship insofar as each is presinied to influence the other. In general, the
mangrove-dom ated environment acts as an uptake zone removing fr n the
circulating waters a variety of r itrients requisite to normal mangrove fuoctioning as
well as other chemical elements present in those waters. Conversely, the mangrove-
dominated environment also acts as a source of materials res og from metabolic
activity and through the continual production of organic detritus. Specific attention in
this project has been given to water quality constituents, both pollutant and natural,
which could influence mangroves in a detrimental manner, cr be biologically
concentrated and shunted in the detrital-based estuarine feodwths.
The research en water-borne pollutants consisting of the synthetic organic
compounds turned out io be inconclusive in that neither excessive pollutant loadings
nor symptomatic stress effects on marigroves were observed. These synthetic organic
compounds were not found to be present in significant concentrations in the local
environments, nor were si iificant levels detected in mangrove tissues. Thus, no
evidence was obtained which could be interpreted to suggest that such compounds have
a deleterious effect on mangroves or that they might tend to be concentrated in
mangrove tissues. The work of Walsh et a!. (1973) remains as the only significant
statement on what might happen to mangroves as a result of synthetic organic
exposure, but even that work (seedlings, herbicides) cannot be extrapolated with
reference to this project.
The metals of interest were genecaliy fo.ind to be present either in normal
concentrations consistent with the mineralo of the catchment area or in slightly
elevated concentrations due to local emission sources. In general all of the metals
appear to be freely taken up by mangroves and concentrated one to five qrders of
48

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TABLE 11. ELEMENTAL COMPOSiTION OF RED MANGROVE LEAF LITTER,
FOR 1974 BY MONTH FOR THE DWARF FOREST, SOUTHEASTERN FLORiDA
ELE MENTS
%
Month C N P K Ca
PPM
Mg Sr Fe Mn Zn
gd anrov Leaves
January 42.8 0.5 0.008 0.7 1.3 0.5 125 30 82 17
February 41.9 0.5 0.011 0.9 1.7 0.6 150 50 85 14
March 42.2 0.5 0.009 1.0 1.6 0.6 150 270 100 11
April 40.0 0.5 0.009 1.2 1.6 0.7 150 60 100 40
May 41.1 0.5 0.001 1,2 1.6 0.6 i38 65 95 44
Ju’ie Łi.0 9 0 5 0 006 0 9 1 2 0 5 106 35 65 47
uty 42 6 0 6 0 005 0 8 1 4 0 6 131 25 60 50
August 43.1 0.6 0.006 1.0 1.3 0.6 125 20 70 11
September 43.4 0.6 0006 0.8 1.2 0.1 113 30 70 54
Octobe NA NA NA NA. NA NA NA NA NA NA
November 43,3 0.6 0.008 0.9 1.3 0.6 125 40 70 5
December 41.0 0.4 0.008 0.7 1.4 0.5 125 40 95 8
*
NA = Not analyzed
49

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TABLE 12. ELEMENTAL COMPOSITION ON MANGROVE LITTER, FOR 1974
BY MONTH FOR THE HAMMOCK FOREST, SOUTHEASTERN FLORIDA
ELE
MEN
TS
Month C N P
%
PPM
K Ca Mg
Sr Fe Mn Zn
rov L eaves
January 41.7 0.5 0.018 0.6 1.5 0.6 138 60 60 22
February 41.5 0.4 0.013 0.7 1,8 0.8 150 445 70 18
March 41.2 0.4 0.018 0.7 1.7 0.8 163 50 65 12
April 39.8 0.4 0.013 0.7 1.6 0.7 150 245 60 ii
May 40.0 0.4 0.012 0.7 1.6 0.7 138 50 55 30
Ju e 43.8 0.4 0.010 0.4 1.4 0.6 125 35 45 40
July 43.0 0.4 0.015 0.7 2.2 1.0 194 60 75 10
August 41.2 0.4 0.010 0.5 1.4 0.7 138 35 50 37
September 38.8 0.4 0.015 0.8 2.3 1.1 213 55 75 11
October 41.5 0.5 0.013 0.5 1.8 0 ,8 169 45 50 4
November 39.6 0.4 0.012 0.5 1.6 0.8 144 35 55 7
December 41.1 0.3 0.013 0.6 1.6 0.7 150 125 60 18
Black Mar g ove Leaves
January 45.4 0.9 0.017 0.8 0.6 1,1 75 270 115 32
February 41.2 0.7 0.019 0.8 0.8 1.1 63 210 130 28
March 38.8 0.7 0.019 0.8 0.7 1.2 63 115 125 41
April 43.3 0.8 0.022 0.8 0.7 1.1 50 60 130 54
May 41.2 0.7 0.014 0.7 0.6 1.0 50 80 115 38
Ju e 46.9 0.8 0.017 0.3 0.8 0.9 69 85 120 65
July 44.8 0.9 0.015 0.6 0.7 0.8 69 65 105 64
August 33.6 0.6 0.017 0.4 0.6 0.8 63 65 120 23
September 44.8 0.9 0.015 0.7 0.7 1.0 81 75 135 44
October 43.3 0.9 0.027 0.8 0.6 1.0 88 60 85 35
November 43.9 0.9 0.021 0.6 0.5 0.9 63 60 95 20
December 46.5 1.0 0.017 0.6 0.7 1.1 75 85 125 33
50

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TABLE 12. CONTINUED
ELEMENTS
PPM
Month C N P K Ca Mg Sr Fe MnZn
White Mangrove Leaves
3anuary 39.5 0.3 0.020 0.3 1.8 0.6 125 110 20 35
February 39.7 0.3 0.011 0.2 1.7 0.6 113 50 20 30
March 40.5 0.3 0.015 0.2 1.6 05 113 150 20 60
April 41.6 0.4 0.016 0.2 1.7 0.5 113 50 20 32
May 38.7 0.3 0.012 0.3 1.5 0.6 100 80 15 46
3ix e 43.2 0.4 0.018 0.2 2.0 0.5 125 100 20 66
Suiy 42.2 0.3 0.013 0.3 1.7 0.5 125 50 15 33
August 43.0 0.3 0.014 0.2 1.8 0.4 125 45 15 20
September 40.6 0.3 0.011 0.3 1.9 0.5 125 45 20 23
October 40. 6 0.4 0.017 0.2 1.7 0.5 119 65 10 21
November 38.6 0.3 0.011 0.3 2.0 0.6 138 50 15 23
December 40.3 0.2 0.010 0.1 1.7 0.5 113 50 15 32
51

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REFERENCES
Atkinson, M.R., G.P. Findlay, A.B. Bope, M.G. Pitman, H.D.W. Saddl and K.R. West.
1967. Salt regulation n the mangroves Rhizo ora mucronata Lam. ann
Aeg:alttis annul ata R.Br. Austral. 3. Biol. Sci. 20: 589-599.
Baltze , F. t9t9. Les formations vegetales asssociees au delta de Ia Durnbea
(Nouveile Cale onie) Cah. ORSTOM, Ser. Geol. 1W: 59-84.
Bowman, H.H.M. 1917. Ecoingy and physiol y of the red mangrove. Proc. Amer.
P L1. Soc. .6: .519—672.
Browder, 3. T. Ahistrom and M. Sell. i974. Nutrient models and perspectives on
mangrove recover in Rt..ng Sat. In: H.T. Odum, M. Sell, Mark Brown,
3. 2.uccrietto, C. Swallows, 3. Browder, 1. Ahistrom and L. Peterson, Models of
herbicide, inangroves, and war in Vietnam. The effects of herI cides in South
Vietnam. Part B: Working Papers. Nat. Academy of Sci. Washington, D.C.
burns, L.A. 197b. A model of mangrove ecosystems, rationale, data analysis, and
model fonmlation, pp. 53-84. In: H.T. Odum (Ed.) Guidelines for management
of mangroves in soutfl Floriaa. Contract No. 14-i t0004-426. Final Report to
U.S. Dept. of interior. Center for Wetlands, Univ. Fla. Gainesville.
Carter, M.R., LA. Burns, T.R. Cavinder, K.R. Dugger, P.L. Fore, D.B. Hids,
H.L. Revells and 1.W. Schmidt. 1973. Ecosystems analysis of Big Cypress
Swamp and estuaries. EPA 904/9 . -74--O0, U.S. Environmental Protection
Agency, Region JV, Atlanta. 478 pp.
Chapman, V.]. i944. The 1939 Cambri e University e edition to Jamai . L A
study of the botanical processes concerned in the development of the Jamaican
shore-line. 3. Linnean Soc. .Landon) Bot. 52: 407-447.
Chapman, V.]. 952. Problems in ecoingical terminolc y. Proc. ANZAAS Sect. M.
Bot., pp. 259-279.
Chapman, V.3. . 966. Vegetation and salinity, pp. i3—42. In: H. Boyko (Ed.) Saline
irrigation for agriculture and forestry. 3unk Pubi., The Hague.
Chapman, V.3. i975. Mangrove biogeography, pp. 3-22. In: G. Walsh, S. Snedaker arid
hi. Teas Eds. Proc. International symposium on biology and management of
inangroves, ‘o1s. I & IL Held 8-11 Oct. 1974 in Honolulu. inst. Food Agric. Sci.,
Urui. Florida, Gainesville. 846 p.
Chapman, V.]. 1976. Mangrove vegetation. Strauss & Cramer, Germany. 447 pp.
54

-------
Chapman, V.3. and 3.W. Ronaldson. 1958. The mangrove and salt-grass flats of
Auckland Isthmus. N.Z. Dept. Sd. Ihe. Res. Bull. No. 125. 79 pp.
Cnristian, G.D. 969. Medicine, trace elements and atomic dbsorption spectroscopy.
Anal. Chern. 41(1): 24A-40A.
Cintron, G., A.E. Logo, 0.3. Pool and G. Morris. 1978. Mangroves of arid
environments in Puerto Rico and adjacent islands. Biotropica 10(2): 110-121.
Clarke, L.D. and N.J. Hannon. 1969. The mangrove swamp and salt marsh
communities of the Sydney District. IL The holocoenonc complex with
particilar reference to ysiography. 3. Ecol. 57: 213-234.
Clarke, L .D. and N.J. Hannon. 1970. The mangrove swamp and salt marsh
communities of the Sydney District. ill. Plant growth in relation to salinity and
waterlcgging. 3. Ecol. 58: 351 -3&9.
Connor, 0.3. i969. Growth of grey mangrove ( Avicenriia marina ) in nutrient culture.
Biotropica1(2): 36-40.
Curray, J.R., F.J. Emmel and P.3.S. Crampton. 969. Holocene history of a strand
plain, lagoonal coast, Nayarit, Mexico, pp. 3-i00. In: A. Ayala Castanares arid
F.B. Phieger (Edsj Lagunas Costeras, un Sirnposio UNAM-UNESCO 28-
30 November, 1967.
Daiber, F.C. 1960. Mangroves: the tidal marshes of the tropics. Univ. Delaware
Estuarine Bull. 5: 10-15.
Davis, 3.H., Jr. 1940. The ecology and geologic role of mangroves in Florida.
Carnegie Inst. Washington Pub. 517: 303-412. Papers from the Tortugas Lab,
Vol. 2.
Day, 3.H., N.A.H. Millard and G.J. broekhuysen. i953. The ecology of Sooth African
estuaries. Part LV. The St. Lucia system. Trans. R. Soc. South Africa 34: 129.
Dost, H. (Ed.). i973. Acid sulphate SOIlS, Proc. kit. Symp. 13-20 August, 1972
Wagerungen. Vol. 1 & 11. Pub!. [ 8. International Institute for Land Reclamation
and Improvement, Wageningen, The Netherlands.
Duursma, E.K. 1976. Radioactive traces in estuarine chemical studies. In:
3.0. Burton and P.S. Liss i Ecls.). Estuarine Chemistry, pp. 159-i.83. Academic
Press, New York,
Eg1e , F.E. i948. The dispersal and establishment of red mangrove, Rhizoc4 ora , in
Florida. Carib. Forest. 9: 299-3 10.
Environmental Protection Agency. i971. Manual of methods for chemical analysis of
water and wastes. U.S. Environmental Protection Agency. Cincinnati, Ohio.
298 pp.
Gale, 3. i975. Water balance and gas exchange of plants onder saline conditions, pp.
168-185. In: A. Poijakoft-Mayber and 3. Gale tEds.) k 1ants in saline
55

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envir onments. Springer -Veri ag, New Y ark.
Gerchakov, S.M. D.A. Segar and R.D. Steans. 973. Chemical and hydroic ical
rnvestigations in an area of thermal discharge to a tropical marine estuary,
pp. 603-618. in: D.J. Nelson (Ed.) Radionuclides in ecosystems, Vol. 1. Proc.
Third Nat. Symp. Ractoecology, 10 -12 May, i971. USAEC CONF 710501-PL.
Oak Ric e, Term.
Gigiio1 , M.E.C. and D.F. King. i966. The mangrove swamps of Keneba, Lower
Gambia River basin. 111 . Seasonal variations in the chloride and water content of
swamp soils with observations on the water levels and chloride concentration of
free soil water under a uarren mud flat during the cry season. 3. AppI. Ecol. 3:
1-19.
Gill, A.M. i969. Tidal trees: orient and occident. Fairchild Trap. Garden Bull. 24(3):
7-10.
l-laan, 1D. de. 1931. Her een en auder over de Tjilatjapsdie vloedbosschen. Tectona
24: 39 -7&. Un: V.3. Chapman. i976. Mangrove vegetation. Su-auss & Cramer,
Germany. 4 4 7 p.)
Head, P.C. i976 . Organic processes in estuaries. In: 3D. Bur n and P.S. Liss (Eds.).
Estuarine Chernistry,pp. 53-91. Academic Press, New Yxk.
Keald, E. 1971. The production of organic detritus in a south Florida estuary. Sea
Grant Tech. Bull. No. 6, Univ. Miami. 110 pp.
Kicks, D.B. and L.A. Burns. 1975. Mangrove metabolic response to alterations of
natural freshwater &ainage to southwestern Florida estuaries, pp. 238-255. In:
G. Walsh, S. Sneclaker and H. Teas (Eds.) Proc. international symposium on
biolc y and management of mangroves, Vols. I & II. Held 8-11 Oct. 1974 in
Honolulu. inst. Food Agric. Sci., Univ. Florida, Gainesville. 846 p.
Ho1&ic e, L.R. 1967. Life zone ecoic y. Trop ca1 Science Center, San Jose, Costa
Rica. i06 pp.
HoJc i e, LR. W.C. Grenke, W.H. 1-latheway, 1. Liang and J.A Tasi, Jr. 1971.
Forest environments in tro ca1 life zones. Pergarnori Press, New York. 747 pp.
Hooker, EL). 1878. Flora of British India. Vol. 11. Reeve, London. 435 pp. (In:
V.3.Chapman. 1976. Mangrove vegetation. Strauss & Cramer, Germany.
447 p.)
l-iowarth, R.W. 1979. Pyrite: Its rapid formation in a salt marsh and its importance in
ecosystem metabolism. Science 203: 49-51.
1saac, R.A. and J.B. Jones. i972. Effects of various dry ashing temperatures on the
determinations of 13 nutrient elements in five plant tiss s. Comm. in Soil
Science & Plant Anal. 3: 261.
Kylin, A. and R. Gee. 1970. Adenosine triphos atase activities in l ves of the
mangrove Avi nnia nitida Jacq. Plant Physiol. 45: 169-172.

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Lugo, ACE . &97i . r re ’e wetlands, pp. i90- 240 In: C.H. Wharton, -LT. Odurn,
1(. Ewei, 1. Lue ’er, A. Logo, R. boyt, 3. Bartholomew, . DeBeilvue, S. Brown,
M. Brown and L. Duever, Forested we lar ds of Florida their management and
uee. Final rc-pnrt to Div. of Sc Planning. Center for Wetlands, Univ. Flonda,
Gainesville.
Logo, A.E. and C. Cintron. i975. The :; ‘igrore forests of Puerto Rico and their
management, pp. 825-846. In: G. Walsh, S. Snedaker and H. Teas (Eds.) Proc.
international symposium on biology anJ management of rnangroves, Vols. I & IL
Held 8-11 Oct. 1974 in Honolulu. Inst. Food Agric. Sd ,, Univ. Florida,
Gainesville. 846 p.
Lugo, A.E. G. Evink, M.M. Brinson, A. Broce and SC. Sriedaker. i975. Diurnal rates
of photosynthesis, respiration and transpiration in mangrove forests of south
Florida, pp. 335-350. in: F,B. Galley and E. Medina (Eds.) Tro cal ecol icel
systems. Springer-Verlag, New York.
Logo, A.E.,M. Sell and S C. Snedaker. 976. Mangrove ecosystem analysis, pp. 113-
.145. In: B.C. Patcen (Ed.) Systems analysis and simulation in ecol y, Vol. IV.
Academic Press, New York,
Lugo, A.E. and S.C. Snedaker. :974, The ecolugy of mangroves. Ann. Rev. Ecol y &
System atics 5: 39 64.
Lugo, A.E ., S.C. Snedaker, S. Bayley e nd H.T. Odum. 1971. Models lot - ç anning and
research for the south Florida environmental study, p. 37-42. Final report on
Contract No. l4—10 - -900 —363, National Park Service, U.S. Dept. of Interior.
Center for Aquatic Sd., Univ. Fla. Gaines i1le.
McMillan , C, 971. Environmental factors affecting seedling establishment of the
black mangrove on the central Texas coast . Ecology 52; 927 ’93Q .
McMiUan, C. 1974. Salt eolsrance of mangroves and sobrnerged aquatic plants,
pp. 379-390. in: R. Reimoid and W. Queen (Eds.) Ecoingy of ha1o iytes .
Academic Press, New York. 605 pp.
MacNae 7 W. 1966. Mangroves in eastern and southern Australia. Austral. 3. Bot. i4:
67 104.
MacNae, W. 1968. A genocal account of’ the fauna and flora of mangrove swamps and
forests in the lndo -West-- Pacific region. Advances Marine Biol. 6: 73-270.
Miller, P.C. 1972. Bioclimate, leaf temperature, and primary production in red
mangrove canopies on south Florida. Ecolc€y 53: 22-45.
Mom-man, F.R. and L .3 . Pens. 1975. Characteristics of mangrove soils in relation to
their agricultural land use and potential, p. 529-547. Tn: G.E. Walsh,
S.C. Snedaker and Ff3. Teas (Eds.) Proc. International symposium on biol y and
management of mangroves. Vols. I & IL Held 8-11 Oct. 1974 in Honolulu. Ir t.
Food Agric. 3d ., Univ. Florida, Gainesville. 846 p.
Newbould, P.3. 1970. Methods for estimating the primary production of forests. P
57

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Handbook No. 2. Blackwell Sd. Pubi. Oxford, England. 62 pp.
Odum, H.T. i976a. Use of energy diagrams for environmental impact statements,
pp. 107-213. in: Tools for coastal zone management. Marine Tech. Soc.,
Washington, D.C.
Odurn, H.T. (Ed.) 1976b. Guidelines for management of mangroves in south Florida.
Contract No. 14—1610004--426. Final Report to U.S. Dept. of Interior. Center
for Wetlands. Univ. Fla. Gainesville.
Odum, ftT. and M. Sell. 1976a. Models for organizing and presenting data, pp. 92-94.
In: H.T. Odum (Ed.) Guidelines for management of mangroves in south Florida.
Contract No. 14-1610004-426. Final Report to U.S. Dept, of Interior. Center for
Wetlands, Univ. Fla., Gainesville.
Odum, H.T. and M. Sell. 1976b. Simulation models, pp. 95-102. In: H.T. Odurn (Ed.)
Guidelines for management of mangroves in south Florida. Contract No. 14-
1610004-426. Final Report to U.S. Dept. of Interior. Center for Wetlands, Univ.
Fla., Gainesville.
Odum, H.T. and M. Sell. 1976c. A model of mangroves and water management,
pp. 107-116. In: H.T. Odum (Ed.) Guidelines for managemenZ of mangroves in
south Florida. Contract No. 14-1610004-426. Final Report to U.S. Dept.
Interior. Center for Wetlands, Univ. Fla., Gainesville.
Odum, l-LT., Mark Brown, 3. Zucchetto, C. Swallows, 3. Browder, 1. Ahlstrom and
L. Pete -son. 1974. Models of herbicide, mangroves, and war in Vietnam. The
effects of herbiddes in South Vietnam. Part B: Working Papers. Nat. Academy
of Sci.Washington,D.C.
Odum, W.E. 1971. Pathways of energy flow in a south Florida estuary. Sea Grant
Tech. Bull. No. 7, Univ. Miami. 162 pp.
Parker, C.R. 1972. Water analysis by atomic absorption spectroscDpy. Varian
Techtron Pty. Ltd. Sprinvale, Vic., Australia. 78 pp.
Piper, C.S. 1950. Soil and plant analysis. Univ. of Adelaide, Australia.
Pool, D.3., A.E. Lugo and S.C. Snedaker. i975. Litter production in mangrove forests
of southern Florida and Puerto Rico, pp. 213-237. In: G.E. Walsh, S. Snedaker
and H. Teas (Eds.) Proc. international symposium on biology and management of
mangroves, Vols. I & IL Held 8-11 Oct. 1974 in Honolulu. Inst. Food t gric. Sci.,
Univ. Florida, Gainesville. 846 p.
Pool, 0.3. S.C. Snedaker and A.E. Lugo. 1977. Structure of mangrove forests in
Florida, Puerto Rico, Mexico and Costa Rica. Biotroj ca 9(3): 195-212.
Queen, W.El. 1974. Physiolc y of coastal haloj ytes, pp. 345-353. in: R.3. Reimold
and W.H. Queen (Eds.) Eco1c y of halophytes. Academic Press, New York.
Rollet, B. 1974. Introduction a l’etude des mangroves du Mexique. Bois Fcrets Trop.
156:3-74.
58

-------
Rosevear, D.R. 1947. Mangrove swamps. Farm & Forest 8: 23-30.
Scholander, P.F., H.T. Hammel, E.D. Bradstreet and E.A. Hemrningsen. 1965. Sap
pressu e in vascular p’ants. Science 148: 339-346.
Segat-, D.A. and R.E. Pellenberg. 1973. So.ne aspects of the biogeochemical cycles of
trace metals in a subtropical estw.rv including ecosystem compartment model.
Presented at Symposium on Environmental Biogeochemistry, Logan, Utah.
Sell, M. 1976. Nutrients, herbicide and circulation, pp. 272.316. In: H.T. Odum (Ed.)
Guidelines for management of mangroves in south. Florida. Contract No. 14-
1610004-426. Final Report to U.S. Dept. of Interior. Center for Wetlands, Univ.
Fla., Gainesville.
Snedaker, S.C. i972. Ecolc€ical Studies on a Subtropical Terrestrial Biome. Proposal
to the Florida Power and Light Compeny. Xerox.
Snedaker, S.C. and A.E. Lugo .. 1973. The role of mangrove ecosystems in the
rnantenance of environmental quality and a high productivity of desirable
fisheries. Final Report submitted to the Bureau of Sport Fisheries and Wildlife.
Contract No. 14-16-008-606. 404 pp.
Stanford, R.L. 1973. Computer simulation of a nitrogen mass balance model. In:
S.C. Snedaker. 1972. Ecological studies on a subtropical terrestrial biome.
Proposal to the Florida Power and Light Company.. Xerox.
Stanford, R .L. 1976. Nutrient cycling in a south Florida mangrove ecosystem. M.S.
Thesis, Univ. Fla., Gainesville. 166 pp.
Steenis, C.G.G.3. van. 1963. Miscellaneous notes on New Guinea plants. VIL Nova
(Bot.) Guinea: 189. No. 12.
Steller, D.L. 1976. An energy evaluation of residential development alternatives in
criangroves. In: H.T. Odum (Ed.) Guidelines for management of mangroves in
south Florida. Contract No. 14-161004-426. Final Report to U.S. Dept. Interior.
Center for Wetlands, UnIv. Fla., Gainesville.
Taras, MJ., A.E. Greenberg, RD. Hook and M.C. Rand (Edsi. 1971. Standard
methods for the examination of water and wastewater. American Public Health
Association, Washington, D.C. 847 pp.
Thom, B.G. 1967. Mangrove ecology and deltaic geomor ology; Tabasco Mexico. 3.
Ecol. 55: 30 1-343.
Thom, B.G., L.D. Wri t and 1M. Coleman. 1975. Mangrove ecology and deltaic-
estuarine geomorphology: Cambridge Guif-Ord River, Western Australia. 3.
Ecol. 63: 202-232.
Thompson, 3.E. (Ed.). 1977. Analysis of pesticide residues in human and
environmental samples. U.S. Environmental Protection Agency. Health Effects
Research Laboratory, Environmental Toxicology Division. Research Triangle
Park, North Carolina.
59

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Thorhaug, A., D. Segar and M.A. Roessler. 1973. Impact of a power plant on a
s itropica1 estuarine erwironinent. Marine Pollution Bull. 4(11): 166-169.
Tine, M. van and S.C. Snedaker. 1974. A bibliography of the mangrove literature.
Prepared for the Inwrna onai Symposiun on Biology nd Management of
Mangroves held 8-11 October, 1974 in Honolulu. Inst. Food Agric. Sd., Univ.
Florida? Gainesville.
Troll, W. and 0. Dragendorfi. 1931. Uder kie L wurzel von Sonneratia Linn. und H’re
biolc ische Bedentuag. Planta 13: 311-473. (In: V.3. Chapman. 1976. Mangrove
vegetation. Süauss & Cramer, Germany. 447 p.)
Waisel,Y. 1972. Bio1 y of halophytes. Academic Press, New York. 395 pp.
Walsh, G.E. 1974. Mangroves: a review, pp. 51-174. In: FL Reimold and W. Queen
(Eds.) Eco1c y of halophytes. Academic Press, New York. 605 pp.
Walsh, G.E., R. Barrett, G.H. Cook and l.A. Hoilister. 1973. Effects of herbicides on
seedlir s of the red mangrove, Rhizophora mangle L. Bioscience 23(6): 361-364.
Walsh, G.E., S.C. Snedaker and H.J. Teas (Eds.) 1975. Proc. International Symposiun
on Biology and Management of Mangroves, Vol. 1 & IL Held 8-11 October, 1974
in Honolulu. Inst. Food Agric. Sci., Univ. Florida, Gaine’wille. 846 pp.
Walsh, G.E., K.A. Ainsworth and R. Rigby. 1979. Resistence of red mangrove
( Rhizophora mangle L.) to lead, cadmi rn, and mercury. Biotro ca 11(1): 22-27.
Walter, H. and M. Steiner. 1936. Die Okok ie der Ost-Afrikanischen Mangroven. Z.
Bot. 30: 65-193.
Warming, E. and M. Vahl. 1925. EcoIc y of plants, revised ed. O,cford Univ. Press,
Lcndori. 422 pp. (In: V.3. Chapman. 1976. Mangrove vegetation. Strauss &
Cramer, Germany. 447 p.)
Watson, 3.G. 1928. Mangrove forests of the Malay Peninsula. (Malayan Forest. Rec.
No. 6) Fraser & Neave, Ltd., Singapore. 275 pp.
West, R.C. 1956. Mangrove swamps of the Pacific cxast of Colai bia. Ann. Ass.
Amer. Geogr. 46: 98-121.
Whelan, 1. 1974. Methane, carbon dio,dde, and dissolved sulfate from interstitial
water of aastal marsh sediments. Estuarine Coast. Marine Science 2: 407-415.
Winkler, H. 1931. Einige Bemerkungen uber Mangrove-Pfianzen u d den
Amorjtto * aIlus titanum in Hamburger Botanischer Garten. Ber. Dtsth. Bot.
Ges. 49; 87-102.
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PPF L IX A
oo a gle L LEAF LENGTHS, WIDTHS AND RATIOS
by
Daniel 3. Cottrell
Rosenstiel School of Marine and Atmospheric Science
University of Miami
Miami, Florida 33149
The length-width data for 34 sites in Puerto Rico, western Mexico, Haiti,
southwestern Florida, and southern Dade County, indude some 4,742 measurements of
indivickial leaves. Leaf material used for size analysis consisted of sin leaves
coIlec ed from R. The leaves were placed instandard plant presses and dried
at 70 C to constant weight. The cried leaf material was weighed on an analytieal
balance and leaf area, length, and width measured. Leaf area was determined on a
I-f ayashi Denko Automatic Area Meter Model AAM -5, which can measure the area of
irregular flat surfaces having a maximum thickness of 4mm, width of 150 mm, and an
infinite length with an accuracy of ÷ 1% or better. The device incorporates a
photoelectronic apparatus to measure total area and an internal integrator providing a
direct readout of the area measured in square millimeters. Dimensions of the leaves
were measured with a millimeter rule. The length of the leaf was measured from the
base of the petiole, where it attached to the leaf, to the leaf tip. The width of the
leaf was measured at its broadest part. These data are summarized in Table A-I.
The dwarf mangroves of southern Dade County have leaf lengths comparable to
other R. nie in southern Florida, but leaf widths are smaller than those from other
areas of southern Florida. Fringe mangroves in southeastern Florida appear be very
similar in leaf dimensions to those found in the Ten Thousand Islands area of
southwestern Florida.
A linear regression of the mean data in Figure A-I was performed and yielded
the following regression equation:
Width = (0.47) + (Length x 0.42)
Standard Error (SE) = 0.43
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TABLE A—i. MEAN LENGTHS AND WIDTHS OF RED MANGROVE LEAVES
FOR 34 LOCATIONS FROM PUERTO RICO, WEST MEXICO, HAITI,
SOUTH WESTERN AND SOUTHEASTERN FLORIDA
Location Length (cm) Width (cm) n
Eastern Island, Mexico 14.7 6.8 64
El Calon, MExico 14.5 6.0 99
Coconut Point, Mexico 13.5 5.5 85
Las Paimas (Exterior), Mexico 13.4 6.5 80
Las Pairnas (interior), Mexico 12.8 5.5 132
Barra de Teacapan, Mexico 12.5 5.4 119
Cain Tidal Creek, Mexico 11.8 5.3 108
Pana1 (South), Mexico 11.8 5.3 91
Teacapan Point, Mexico 11.5 6.9 73
Pana1 (North), mexico 11.4 5.6 77
Ceiba #1, Puerto Rico 11.3 5.2 183
Panal (Medio), Mexico 11.1 5.9 89
Ceiba /12, Puerto Rico (LAI) 10.3 4.3 100
Port—o--Prince, Haiti -. 10.1 4.6 117
Pinones 1/2, Puerto Rico 10.0 4.4 384
Pinones 111, Puerto Rico 9.7 4.7 266
Punta Gorda #2, Puerto Rico 9.4 4.5 204
Punta Gocda 1/2, Puerto Rico 9.2 4.6 206
Jobos Bay, Puerto Rico 9.2 4.2 77
Southeastern Florida-fringe forest 9.1 4.0 295
Ceiba 112, Puerto Rico 9.0 4.1 258
Ceiba //1, Puerto Rico (LAI) 8.9 4.7 100
Site 5-11, 10,000 Islands, Florida 8.9 4.0 96
Punta Gorda, Puerto Rico (LA!) 8.6 4.2 100
Site 3-7, 10,000 Islands, Florida 8.6 4.0 100
Site 6-14, 10,000 Islands, Florida 8.4 3.8 100
Aquirre #1, Puerto Rico (LA!) 8.3 4.0 100
Rookery Bay, Florida 8.2 3.9 99
Southeastern Florida-scrib mangrove 8.2 3.1 345
Aquirre #2, Puerto Rico (LA!) 8.1 3.7 100
Aquirre //2, Puerto Rico 7.9 3.9 177
Aquirre 1/1, Puerto Rico 7.8 4.1 196
Guayanilla (Control), Puerto Rico 6.8 3.6 89
Guayanilla, Puerto Rico 6.4 3.0 33
62

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LEAF WIDTH (cM)
A
0
*
0
SOUTHEAST FLORJD,4
HAITI
SOUTHWEST FLORIDA
Figure A-I. ReIation.s -üp between the length and width of red mangrove leaves shown
superimposed over the linear regression (solid line) of the two variables
bounded by + I standard error (dotted lines).
15
14
13
1 1
z
w
-J
8
7
6
5
9
I ’
-J
0
S
WEST MEXICO
PUERTO RICO
3 4 5 6 7
63

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Correlation coefficient (r) 0.90
The regression line has been plotted on Figure A-I. Points lying outside the standard
error may be interpreted as having a mean tendency be longer or wider than the
majority of the sampled population.
Selected sites were also used for leaf area measurements. 1-lowever, leaf areas
from southeastern Florida were obtained from leaf traces rather than from pressed
leaves and constituted a small sample size in comparison to other sites. For this
reason, the average leaf area was obtained by performing a multiple regression
analysis on the leaf lengths, widths, and leaf-tracing areas from the fringe and dwarf
mangroves in order to estimate the mean leaf area for each type. The regressions
yielded the following eqjations:
Dwarf mangrove leaf area -
Width (7.79) + Length (1.56) - 16.82
Leafarea= .98
Fringe mangrove leaf area -
Width (6.36) + Length (2.87) - 24.53
Leaf area =
These ecpations gi the estimated mean leaf area for dwarf and fringe mangroves as
20.54 and 27.12 cm , respectively.
For selected sites, the rectangular area (RA) of the leaves was determined by
multiplication of the length and width data, and compared to the empirically-
determined leaf area (LA). The percentage difference between the two measures of
area constitutes an index of deviation from a perfect rectangle. Leaves which are
characteristically more oblate would tend to have higher LA/RA percentages than
those which are more lanceolate. Table A-2 lists the results of these comparisons and
demonstrates that red mangrove leaves from the western coast of Florida have
stronger tendencies for lanceof ate shapes than their southeastern Florida and Puerto
Rican counterparts. The strongest lanceolate tendency occurs at the overwash forest
(site 3-7) in southwestern Florida and the strongest oblate tendency occurs at the
dwarf mangrove site in southeastern Florida.
Variations in leaf dimension and shape may be due to genetic, climatic, physical,
and biochemical factors. Within the southern Dade County study area however the
e hange of genetic material is assun ed to be random and mogeneous and possibly
inconsec jential to observed differences in leaf morphology.
The most confounding aspect of the interpretation of the leaf size data is the
strong tendency of a longitudinal gradient; largest leaves in western Mexico decreasing
in size eastward to Puerto Rico. This suggests that the same species was not collected
from all sites; for example the western Mexico Rhizophora could be R. stylcsa and not
mangle . However, no taxonornic verification of species (or presence of a hybrid) has
been made. The duster of similar sizes for Florida and Puerto Rico suggests that R.
mangle was collected in all instances and that the variation could in fact be associated
64

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TABLE A-2. COMPARISON OF LEAF AREA (LA) AND RECTANGULAR AREA
(RA) FOR TENDENCIES TOWARD
O LATE OR LANCEOLATE LEAF SHAPE
Lccation Length Width
Rectangular Leaf
Area (RA) Area (LA) LA A
(cm) (cm)
-
Puerto Ri
(cm2)
—
(cm 2 ) (%)
Aquirre #1, P.R. 8.3 4.0
Aquirre #2, P.R. 8.1 3.7
PntaGorda, P.R. 8.6 4.2
33.20
29.97
36.12
24.88 74.9
22.01 73 . 4
28.28 78,3
Ceiba 1/1, P.R. 8.9 4.7
Ceiba //2, P.R. 10.3 4.3
41.83
44.29
31.46 75.2
33.11 74.8
SoutheasternFlorith
Dwarf mangrove 8.2 3.1
Fringe mangrove 9.1 4.0
25.49
36.40
20.54 80.8
27.12 74.5
Southwestern Florida
Site 5—11 -
(Fringe mangrove) 8.9 4.0
35.60
21.24 59.6
Site 6-14
(Riverine mangrove) 8 4 3.8
31.92
18.65 58.4
Site 3-7
(Overwash mangrove) 8.6 4.0
Rookery Bay, Napie .5 8.2 3.9
34.40
31.98
18.92 55.0
19.12 59.8
Totals
381.13
265.33
Average Percent Davi tion from a rectangle
(Total LA/Total RA) -
69.6
65

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with environmental differences. However, at the time of this report that association
had not been made.
Lugo and Snedaker (1974) reported a decrease in leaf dimension coincident with
increase in water temperature due to them-al loading in Guayanilla Bay, Puerto Rico.
However, Davis (1940) observed changes in leaf size which he attributed to the
influence of salinity. Analysis of leaf dimension and shape may detect environmental
stress, but more detailed studi need to be performed to test the techni que.
66

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REFEREN .S
Davis, 3. 11., 3r. 1940. The eco1c y and geoic ic role of mangroves in Florida.
Carnegie Inst. Washington P . 517: 303-412. Papers from the Tortugas Lab,
Vol.32.
Lugo, A.E. and S.C. Snedaker. 1974. The ecok y of mangroves. Annu. Rev. Ecol. &
Systematics 5: 39-64.
67

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APPENDiX B
CONCEPTUAL MODEL PARAMETERIZED FOR COPPER
by
Richard D. Drew
Department of Environmental Regulation
Tallahassee, Florida 32304
The pathways and storages of copper in a mangrove forest ecosystem are
schematically represented in Figure B - I. The forcing functions and storages are
desa ibed in Table B-i, with predicted values based on the literature and/or calculated
from assunptions stated under “remarks” in the table.
Terrestrial source inputs into the mangrove su-f e waters are regulated by
weathering, runoff and rainfall. Rock weathering of silicates, sulfides and oxdes
results in a release of copper and s sequent transport in solution to surface waters
(Q,). The degree of transport is regulated by adsorption and by the solubitity of
sultides, ph phates, carbonates and hydroxides. The effects of chemical weathering
result in low concentrations of copper (approximately 3 ppb) as ol erved in unpolluted
streams and rivers (I ). Concentrations of copper in rainfall (1 ) represent rain arid
snow v ues or iginating mainly from pollution (Wedepohl 1974). Pollution ffecting
surface waters via runoff, rainfall and dust fall originate from the 4.1 x 10 lbs. of
copper cor umed annually in the U.S.A.; in alloys, electrical equipment, pipes and
roofing, textile processes, pigmentation tanning, photography, electropiating and t ’e
agricultural industry (Harrison 1973). Agricultural sources of copper indude insecti- .
ddes, fungicides, and copper sulfate which is used extensively as an aquatic weed and
algal toxin (McGehee 1973).
Once in the surface waters (Q 1 ), the copper metal exists in three states dissolved
ionic, dissolved organic com exes, and suspended particulate matter. Dissolved ionic
forms exist primarily as Cu , CuCO and Cu(OH),, depending on pH of the water. At
the average sea water pH of 8.1, 90percent of the ionic species is Cu (OH) 2 and 8
percent is CuCO 3 (Zirino and Yamamoto 1972). Dissolved organic complexes represent
metal interactions with dissolved amino acids, humic and fulvic adds and other
naturally occurring dissolved organic chelators (Siegel 1971). Suspended particulate
matter associated with copper results from active or passive uptake of the metal by
miaoorganisms, and by adsorption and absorption to suspended days, sediments and
detritus.
Biogeochemically, copper is a required miaonutrient or a toxin dependent on the
68

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Figure B-I. Conceptual model for copper.
4’
0\

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TAbLE 13 -i. VALUES ObTAINED FROM THE Lfl RAI URL TO PARAML1ERJZE COPPLR CYCLING
IN A MANGROVt ECOSYSTEM bASED ON THE CONCr PTUAL MODEL !‘RLSLNTED
IN FIGURE 13-1
Diagram
Notation Concentration 1)escrtption Remarks Ref cr i ices
20 ppm—2.5 ppm Terrestrial based on veiage concentration found Shacklette ct al. 971
n ) soil samples rneasurcd in the
fjSh——25 ppm , ann troin a wor’d vic
study , U ppm
L ? Weathering “There is only a l aI and uiiiior Wedepohl l97
riiobilization of copper to be expected
at places of chemical rock weatnering
except where large bodies of copper
soindes are exposeo.’
1.4 u /1—15 pg/I Runof.t Based on groundwater anti surface Wencpokii 1979
water in USA and USSR, 4 gIi—i3
pg/i, ano from rivers, 1.4 j ig/i—I5
ugh. Values rep:esenttrig pollution
influences or particulate siistarices
containing copper are greater than
mgJl, whereas ulcoutaminated
continental waters Contain an
average 3 i g!l.
14 0.4 pgil-43.7 pg/i Rainfall based on precipitation from sites Harrison 1973,
across Japan, 0.4 ugh to 1.1 pg/i, Wedepohl 1974,
southern Ciuic go, Gary (Indiana), Susawara 1%?
aid Lai-’crte (lndianai , 10.9 ugh
T
ContInued)

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TABLE B-i. CONTiNUhD
based on tribasic copper sulfate used
in Dade County, Florida, during 19b2
in griculture and Iawr , 7.b
10 kg. 4 rea of Dade County =
5.32 x 10 rn.
Required as energy source for
photosynthesis.
Ocean Based on average of open see values
from the Gull of Mexicu, anu the
tropical northeast Atlantic.
lV can concentration for unçontamina-
ted air in Hawaii, ng/rn ; soutji
shore o 4 ake Micnigan 69 rig/rn -
166 ng/m ; and seveçal Canad4an
provinces, 0.9 ng/m’-IS ng/m .
based on Concentrations from Fahka-
Union Bay, less trian 20 pg/I to
36 pg/I and Fahkahatchee Bay,
30 pg/I to 60 pg/I in southern
Flonda; range for the Florida
Straits, )-25 pg/I; a man-influenced
mangrove estuary, 3.0-7.1 pg/I
and; “clean” mangrove estuaries,
Lostrnan’s Five Bay, 2.6-3.6 gII
and Broad and Shark River estuaries
1.7-2.5 jig/I. Surf e Water repre-
sented sum of dissolved orgariics and
Inorganics.
MacDonald and Deictirnanr
1970, Leignty . i96L
Siowey and Hood I
Riley and Iayior 1972
Hoffman et si. 197i
Harrison 19
Carter et al, 19 ,
Dept. of f erior 1969,
Alexander and Corcoran
1967, Harriss 1973
Diagram
Notation Concentrdtion DescTiption Re rk Ref erence
14.2 mg/rnL Agriculture
inaustry
17 6 x 1(J 1 °kcaI/cm Sunl gnt
1.0 pg/I
3
0. ng/rr ,-
166 ng/m
Odurn 1970
Atmos tiere
1.7 pgfi-bO pg/I Surface Water
i,Continued)

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10.13 mg/’ 2
0.15 mg/ni
Detriti vores
and Herbivores
(resident and
transient
populations)
Based on concentrations in L.
racemosa and R. mangle , 12 pg/g
to 2 I) ngig .1y weight. Grains per
m for tne fruit structur of
mangrove forest 11 g/m
Approximation based on coricen-
tratoons in overstory and understory
sterns from A. Rerrninaris , L.
racemosa of 9 pg/g to 2 10 pglg dry
weight. Grams per m for tne
stanuing aead str ture of mangrove
forest = 4.1 kg/rn
Based on concentrations observed in
resident and transient populations
associated with the mangrove forest,
1.4 jig/g to 8 g/g cry weight.
Grams per in for the resident
herbivore strucutre 2 of mangrove
forest 6.34 pg/rn . The transient
herbivore struct ’re of mangrove
forest is assu-neo to be 50% of the
estuary t’ rbivore biomass 50%
(20 pg/rn ) = 10 pg/rn 4 . Total
detritivore and herbivore biornass
= resident + transient = 16.34 pg/rn 4 .
Walsh 1974, Lugo and
Snedaker 1974
Walsh 19/4, Lugo ana
Snedaker 1974
Eustace 1974,
Bryan 1971, Windom and
Smith 1972, Segar et a!.
1971, Clarke 194?,
Mountain 1972, Golfey
et a(. i962
TABLE
B-I. (CONTINUED)
Diagram
Notation Concentration Description R eznarks References
Q 10
QI’
Mangrove
Fruit
Mangrove
Standing Dead
I
37 mg/rn 2 -
41 mgJm
I
22.9 pg/rn 2
1421.6 pg/in
(Continued)

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TABLE B -I. (CONTINUED)
Based on concentrations observed in
resident and transient carnivores
associated with mangrove forests,
1.5 pglg to 2 .6 iig/g ory weight.
Grains ,er in for the resident 2
carnivore structure 0.037 glm
and br transient population, 50%
of the estuari carnivor structure
of 50% (2 g/m I I g/m . Total
carnivore biomass = r sident +
trdnsient = I .037 g/m
Estuarine Water value represents the
sum of dissolved organics and inor-
ganics ana particulate matter dnd
suspended detritus cumpartrnents.
Dissolved organics and Jncrganics are
based on concentrations from a man-
influenced mangrove estuary, 3.0 tigfl
to 7.1 pg/I and a “dean” mangrove
estuary, Lostman’s Five Bay, 2.6 pg /I
to 3.9 pg/I, ann Broad and Shark River
estuaries, 1.7 ugh to 2.7 pg/I, all
located in Southern Florida; also
Florida Straits with 5-25 ugh.
Par ti cut ate in at ter compartment based
on levels from Shark River estuary,
17.4 pg/g.
Riley and Segar 1970,
Martin and Kanuer 1973,
Golley et al. 1962
Dept. of lrnerior 1969,
Flarriss 1973,
Alexander and Corcoran
1967
Diagram
.
Notation Concentration Description Remarks References
Q 13 l.6g/m 2 2
23.4 gim
Q 14 2.6 pg/I-
2) pg/I
Carnivore
(resident and
transient
populations)
Estuarine
Water
Continue ij)

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a.’
TABLE B-I. (CONTINUED)
Diagram
Notation
Concentration
Description
R cmnarks
References
Q 15
17.4
iig/g
Particulate
Suspended
Matter
or
Based on concentratLons in combined
particulate matter and suspended
detritus, from Shark River,
Southern Florida.
Harriss
1973

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concentration. Copper compounds have been isolated from plant enzymes, chloro-
phyll-a, redoxenzymes, tyresinase and ascorbic acid oxidase, and from animals;
enzyme activator, flavoproteiri, respiratory pigments (haemocyanin), uricase, and
butryryl CoA dehydrogenase (Martin and Knauer 1973, Wedepohl 1974). Due to
copper’s ysiol i l importance and potential toxicity, the metal occurs only in
moderate concentrations in most organisms. Uptake and turnover rates of copper in
biotic and abiotic compartments has received little attention in the literature, with
much of the research concentrating on toxicity to plants and animals or accumulation
of the metal at various tropiuic levels.
The present state of knowledge and information of copper is inadequate to allow
management of copper in local environments. Hazardous concentrations pose a
potential health problem and must be dealt with on the ecosystem level before rational
management can be instituted. Pathways and chemical states must be identified and
modelled in order to control the potential problem of copper pollution.
77

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REFERENC $
Alexander, LE. and E.F. Corcoran. 1967. The distribution of copper in troj cal sea
water. Lirnnol. & Oceanogr. 12: 236-242.
Bryan, G.W. 1971. The effects of heavy metals (other than mercury) on marine and
estuarine organisms. Proc. Roy. Soc. Lond. B. 177: 389-410.
Carter, M.R., L.A. Burns, T.R. Cavinder, K.R. Dugger, P.L Fore, D.B. Hicks, H.L
Revells, and T.VI. Schmidt. 1973. Ecnsystems analysis of the Big Cypress Swamp
and estuaries. EPA 904/9-74-002, U.S. Environmental Protection Agency, Region
IV, Atlanta. 478 p.
Clarke, G.L. 1947. Poisoning and recovery of barnacles and mussels. Biol. Bull. 92:
73-91.
Eustace, 1.1 1974. Zinc, Cadmitrn, Copper and Manganese i - species of fin! ish and
shellfish caught in the Derwent Estuary, Tasmania, Aust. 1 Mar. Freshwat. Res.
25: 209-220.
Golley, F., H.T. Odum and R.F. Wilson. 1962. The structure and metabolism f a
Puerto Rican red mangrove forest in May. Ecol. 43: 9-19.
Harriss, R.C. 1973. South Florida eco1 ical study: heavy metals and pesticides in
estuarine systems. Summary Report, Nat. Park Serv. (Manuscript)
Harrison, P.R. 1973. Air pollution by lead and other trace metals. In: S.K. Dhar (Ed.)
Metal ions in biological systems—studies of some biochemical and environmental.
problems, Vol. 40. Advances in Experimental Medicine and Bio1 y. Plenum
Press, N.Y.
Hoffman, G.L., R.A. Duce, and E.J. Hoffman. 1972. Trace metals in the Hawaiian
marine atmosphere. 1 Geophys. Res. 77: 5322.
Leighty, R.G., M.H. Gallatin, 1L. Malcolm and F.B. Smith. 1965. Soil associations of
Dade County, Florida. U.S.D.A., Circular S-77A.
Lugo, A.E. and S.C. Sriedaker. 1974. The ecolcgy of mangroves. Ann. Rev. Ecol y &
Systematics 5: 39-64.
Lytle, T.F., LS. Lytle and P.L. Parker. 1973. A geochemical study of a marsh
environment. Gulf Res. Reports 4: 2 14-232.
MacDonald, W.E. and W.B. Deichmann. 1970. Pesticides used in Dade County, Florida,
during 1962. In: W.B. Deichmann (Ed.) Pesticides Symposia. HaIcG and Assoc.
78

-------
Inc., Miami.
Martin, LU. and G.A. Knauer. 1973. The elemental composition of ‘plankton.
Geochem. Cosmochim. Acta. 37(7): 1639-1653.
McGehee, 3.T. 1973. Chemical control methods. In: R.L. Lyerly (Ed.) An evaluation
of aquatic weed control methods for power plant cooling reservoirs. Florida
Power & Light Report L-6.
Mountain, 1A. 1972. Ftxther thermal addition studies at Crystal River, Fla., with an
annotated checklist of marine fishes collected 1969-1971. Dept. of Fla. Nat.
Res. Prof. Papers, Series 20.
Odum, H.T. 1971. Environment, power, and society. 3thn Wiley & Sons, inc., New
York. 331 p.
Riley, LP. and D.A. Segar. 1970. The distribution of the major and minor elements in
marine animals. H. Molluscs. 1 Marine Biol. Ass. U.K. 51: 131-36.
Riley, 3.P. and D. Taylor. 1972. The concentrations of cadmium, copper, iron,
manganese, molybdenum, nickel, vanadium, and zinc in part of the tropical
north-east Atlantic Ocean. Deep-Sea Res. 19: 307-317.
Segar, D.A, R. Chester and 1P. Riley. 1971. The distribution of the major and minor
elements in marine animals. II. Molluscs. 3. Marine Biol. Ass. U.K. 51: 131-
136.
Segar, D.A., and R.E. Pellenberg. 1973. Trace metals in carbonate and organic rich
sediments. Mar. Poll. Bull. 4(9): 138-142.
Shacklette, H.T., 3. C. Hamilton, 3.G. Boernen and 3.M. Bowles. 1971. Elemental
composition of surfidal materials in the coriterminous United States. U.S. Geol.
Surv. Prof. Papers 5740: 1.
Siegel, A. 1971. Metal-organic interactions in the marine environment. In: 5.3. Faust
and Hu ter (Eds.) Organic compounds in the ac atic environm t.
Slowey, 3.F. and D.W. Hood. 1971. Copper, manganese and zinc concentrations in
Gulf of Mexico waters. Geochem. Cosmochim. Acta, 35: 121-138.
Snedaker, S.C. and A.E. Lugo. 1973. The role of mangrove ecosystems in the
maintenance of environmental quality and a high productivity of desirable
fisheries. Final Report Submitted to the Bureau of Sport Fisheries and Wildlife.
Contract No. 14-16-008-606. 404 pp.
Sugawara, K. 1967. Migration of elements through phases of the hydrosphere and
atmosphere, p. 501-521. In: A.P. Vinogradov (Ed.) Chemistry of the earth’s
aust, Vol. IL S. Manson, 3erusalem.
U.S. Department of Interior. 1969. Disposal of the effluents from salination plants
into estuarine waters. U.S. Dept. of Interior. R and D Progress Report. #415.
79

-------
Viriogradov, A.P. 1959. The geochemistry of rare and dispersed chemical elements in
soils. (2nd ed.) Consultants Bureau Enterprises, New Yock.
Walsh. G.E. 1974. Mangroves: a review, 51-174. R. . Reimold and W.ft Qt en (Eds.)
Eco1 y of halo ytes. Academic Press, New Yock. 605 p.
W epthi, K.i-i. 1974. Copper, p. 29-B-1-20-0-1. In: K.H. Wedepohi (Ed.) Handbook
of Geochemistry. Vol. 11/4. Springer-Verlag, Berlin.
Windom, H.R. and R. Smith. 1972. Distribution of Fe, Mg, Cu, Zn and Ag in oysters
along the Georgia coast. 1 Fish. Res. Bd. Canada 29(4): 450-452.
Zirino, H. and S. Yamamoto. 1972. A pH dependent model for the chemical speciation
of pper, zinc, cadmium, and lead in seawater. Limnol. & Oceanogr. 17(5):
661-671.
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