WATER POLLUTION CONTROL RESEARCH SERIES • 18050 DAI 02/70
BIOLOGICAL EFFECTS OF EFFLUENT
FROM A DESALINATION PLANT
AT KEY WEST, FLORIDA
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U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER QUALITY ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
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On Cover:
Snowy egret Leucophoyx thula
American shad Alosa sapidissima
Brown shrimp Penaeus aztecus
American oyster Crassostrea virginica
Drawings By:
Alston Badger
Bears Bluff Field Station
National Marine Water Quality Laboratory
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BIOLOGICAL EFFECTS OF EFFLUENT FROM A DESALINATION PLANT
AT KEY WEST, FLORIDA
W.D. Clarke, J.W. Joy
and R.J. Rosenthal
Westinghouse Ocean Research Laboratory
San Diego, California
for the
FEDERAL WATER QUALITY ADMINISTRATION
DEPARTMENT OF THE INTERIOR
Project #18050 DAI
Contract #lU-12-li?0
February 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price $1
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CONTENTS
Page
1. INTRODUCTION l
1.1 Reasons for Study 1
1.2 Location and Environment 1
1.3 Background and Purpose 1
2. DESCRIPTION OF STUDY AREA 4
2.1 Geographical Location 4
2.2 Geography and Geology 4
3. PLANT CHARACTERISTICS 9
4. METHODS AND PROCEDURES 14
4.1 Physical Measurements ^
4.2 Chemical Measurements *•*
4.3 Procedures for Collecting Physical and Chemical Data 16
4.4 Biological Measurements ^°
4.4.1 Quadrat Counts 18
4.4.2 Plankton Tows 18
4.4.3 Biological Settlement Racks 18
4.4.4 Gorgonian Colony Transplants 19
4.4.5 Seawall Invertebrate Counts 21
4.4.6 Fish Occurrences in Discharge and Control Areas 21
4.4.7 Transect Counts of Lobsters and Stone Crabs in
Discharge and Control Areas 22
4.4.8 Marine Algae Occurrences in Discharge and
Control Areas 22
4.4.9 Bottom Samples 22
4.5 Procedures for Collecting Biological Data 23
5. RESULTS 24
5.1 Physical 24
5.2 Chemical 26
5.3 Biological 34
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5.3.1 Quadrat Counts 36
5.3.2 Plankton Tows 36
5.3.3 Biological Settlement Racks 44
5.3.4 Gorgonian Colony Transplants 45
5.3.5 Seawall Invertebrate Counts 53
5.3.6 Fish Occurrences in Discharge and Control Areas 53
5.3.7 Transect Counts of Lobsters and Stone Crabs in
Discharge and Control Areas 60
5.3.8 Marine Algae Occurrences in Discharge and
Control Areas 60
5.3.9 Bottom Samples 65
6. DISCUSSION OF RESULTS 69
7. CONCLUSIONS AND RECOMMENDATIONS 72
8. REFERENCES
9. APPENDICES
A Dow Chemical Defearning Agent, Polyglycol 15-200, Al-2
Physical Properties and Toxicological Data
B Quadrat Log Sheets Bl-4
C Data Sheets for Settlement Disks Cl
D Species Composition of Plankton Sample Aliquots Dl-6
E Mann-Whitney U-Test Calculations El-3
ii
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LIST OF FIGURES
Figure Title Page
1 Location of Key West. 2
2 Locations of Key West, Stock Island, Safe Harbor and
desalting plant. 5
3 General bottom topography and surface features in
the vicinity of Safe Harbor, including locations of
stations used during the study. 6
4 Aerial view, looking west, of Safe Harbor and desalting
plant and Key West. 7
5 Aerial view of entrance to Safe Harbor and desalting
plant. 7
6 General view of desalting plant, showing flash-
distillation units that produce fresh water. 10
7 View of flash-distillation units. 10
8 Schematic of desalting plant. 11
9 Open sump that receives blow-down water and cooling
water discharges. 12
10 Effluent discharging from subsurface pipe into Safe
Harbor's entrance channel. 12
11 Gorgonian colony transplant attached to cement
hemisphere. 20
12 Histograms of current direction at Stations 4-10. 25
13 Monthly mean and extreme bottom temperatures for
Stations 1-10. 27-28
14 Monthly mean and extreme surface salinities for
Stations 1-5. 29
15 Temperature profiles for stations in entrance channel
and harbor showing thermal inversions produced by
effluent plume. 31
16 Surface temperature and salinity at Stations 2, 3,
and 4. 32
17 Bottom temperature and salinity at Stations 2, 3,
and 4. 33
18 Monthly mean bottom dissolved oxygen values for
Stations 1-4. 35
19 Upper right corner of quadrat at Station 4A, Dark
objects are the black tunicate, Ascidia nigra. 37
iii
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20 Lower right quarter of quadrat at Station 1 showing
a lobster, Panulirus argus, occupying hole under
rock ledge. 37
21 Plankton volumes for the six sets of tows made
during the biological field trips to Key West. 42
22 Mean growth attained by cheilostomatid bryozoans on
the upper surfaces of settlement disks in the dis-
charge and control areas. 46
23 Locations of gorgonian colony transplants relative
to the end of the discharge pipe. 47
24 Floral and faunal zoning in the immediate vicinity
of the discharge pipe. 50
25 Detail of gorgonian colony transplant showing
damaged condition resulting from exposure to effluent. 52
26 Occurrence of the black tunicate, Ascidia nigra, per
vertical section of seawall as a function of distance
from the discharge. 54
27 Occurrence of the buccinid gastropod, Cantharus
tinctus, per vertical section of seawall as a function
of distance from the discharge. 55
28 Discharge and control areas used for marine fish
occurrences. 57
29 Locations of transect lines for lobster and stone
crab counts in discharge and control areas. 61
iv
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LIST OF TABLES
Table Title Page
1 Characteristics of source well water. 9
2 Observations and collections made at each station
during study. 17
3 Numbers of the black tunicate, Ascidia nigra, per
square meter in the five bottom quadrats studied in
Safe Harbor. 38
4 Numbers of the spiny lobster, Panulirus argus, per
square meter in the five bottom quadrats studied in
Safe Harbor. 39
5 Numbers of the stone crab, Menippe mercenaria, per
square meter in the five bottom quadrats studied in
6
7
8
9
10
Safe Harbor.
Number of different kinds of plankters occurring in
plankton tow aliquots by month and tow.
Occurrence and absence of plankters in the discharge
area.
Gorgonian colony transplant experiments .
Fish occurrences in discharge and control areas.
Transect counts of the spiny lobster, Panulirus argus,
40
43
43
48
58-59
in discharge and control areas. 62
11 Transect counts of the stone crab, Menippe mercenaria,
in discharge and control areas. 63
12 Occurrences of marine algae in discharge and control
areas. 64
13 Organisms found in benthic samples. 66-68
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1. INTRODUCTION
1.1 REASONS FOR STUDY
The Key West study was undertaken to determine the impact of the
discharge from a large desalting plant on the surrounding environment.
There is little information on the effects of elevated temperatures and
high salinity on tropical organisms and so the geographical location of
the desalting plant was an important factor for proposing the study. The
current population growth and economic development in the low latitudes
of the world will create a greater demand for desalting plants to meet
the fresh water requirements of growing communities, particularly in
the more arid regions. This projected development is creating a greater
need to gather more information on the environmental and biological effects
of discharges from existing desalting plants. The Key West desalting plant
affords a good site for modeling studies and controlled experiments which
can be carried out in the follow-up studies to the present one.
1.2 LOCATION AND ENVIRONMENT
Key West lies at the western end of a long chain of low-lying islands
and keys that extend southwestward from the tip of Florida (Figure 1). These
islands are called the Florida Keys and lie just outside the tropical zone.
For heuristic purposes, they can be considered a tropical environment.
The northern edge of the Gulf Stream bathes these islands and coral patch
reefs are quite extensive throughout the area. The flora and fauna of the
keys are made up of typically warm-water tropical forms but the total
numbers of species are somewhat impoverished when compared with regions
to the south. Part of this impoverishment is probably related to the
local climate. During the winter months, the area is somewhat atypical
for a tropical area being subject to extremely low air temperatures (51°F.
or 10.5°C.). These low temperatures occur when the cold continental air
mass moves south off the mainland. The shallow inshore waters are
drastically chilled at these times and this is reflected in the biota.
Species of fish and invertebrates found in the Greater Antilles and
Caribbean are absent from or occur only seasonally in the shallow-water
habitats around the Florida Keys.
1.3 BACKGROUND AND PURPOSE
The Key West desalting plant is the largest one currently operating
in the United States (2.62 MG/D, 9.92 million liters/day). Westinghouse,
having an interest in environmental problems, believed that a study of the
environmental effects of the effluent would be a valuable investigation.
The study was originally proposed to FWPCA as an exploratory investigation
to determine the magnitude of the impact of the desalting plant effluent
on the surrounding environment. The main purpose of the study was to
establish the approximate extent of the effluent plume by physical measure-
ments and to see if the effluent was producing any changes in the local
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SO NAUTICAL MILES
Figure 1. Location of Key West.
2
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biological communities. It was desirous to ascertain whether or not the
discharge was deleterious, had minimal effect on the surrounding environment,
or might even have a beneficial effect. The work carried out under the
present study was also intended to lay the ground work for a follow-on
study to look in greater detail at the environmental and biological
implications of a heated, hypersaline discharge.
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2. DESCRIPTION OF STUDY AREA
2.1 GEOGRAPHICAL LOCATION
The Key West desalting plant is located on Stock Island, the first
major island to the east of Key West (Figure 2). The plant is built on
the eastern jetty of the entrance channel to Safe Harbor, a man-made harbor
on the south side of Stock Island (Figures 3, 4 and 5). The study area dur-
ing this project was confined to the harbor proper, the entrance channel,
approach channel, and the shallow flats to the east and west of the harbor
out to a distance of about one-half kilometer from the harbor entrance.
2.2 GEOGRAPHY AND GEOLOGY
The near shore area off Stock Island is typical of that found through-
out much of the Florida Keys. It is primarily a shallow-water shelf,
representing a submerged platform of Pleistocene limestone on which, the
present day islands stand. The only deep areas on this shelf are man-made
channels and harbors. The major features of Safe Harbor are all man-made.
The main axis of the harbor.entrance channel and approach, channel runs
in a north-south direction. The harbor and channels were dredged originally
to a depth of 9 meters (m), but the approach channel in places has filled
with sediment to nearly one-half its original depth, thus there is a sill
between the deep basin of the harbor proper and waters of equivalent depth.
off shore. The head of the harbor is expanded on its eastern and western
sides into a series of anchorages and marinas. Most of these extensions
communicate with the main harbor through unrestricted openings. The marina
at the very head of the harbor is an exception in that its basin is cut off
from the main harbor by a shallow sill only 2.7m deep.
The entrance channel because of its manner of construction is deeper by
about 1.5 m along the edges near the jetties than it is in the middle. The
walls of the channel consist of nearly vertical limestone rock exposures
and steeply sloping deposits of coarse sands and fine gravels that are,
in many instances, at the angle of repose. The channel is carpeted with very
fine sands and soft muds. The fine sands are limited to the edges of the
channel bottom. The approach channel is similar in form, having the same
distribution of rock outcroppings and sediments. The main differences are;
thicker accumulation of fine mud sediments on the bottom of this channel and
the lack of jetties along its edges.
Right at the entrance to Safe Harbor, there is a large basin of deep
water which shoals gradually to the east and deepens to entrance channel
depths on its west side. The bottom of this basin is covered with fine mud
sediments. The walls of the basin are similar to those of the channels
and were formed by dredging.
The shallow flats on either side of the harbor and channels are carpeted
with fine sand sediments. Exposures of the underlying limestone platform
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contour intervals
in feet
Figure 2. Locations of Key West, Stock Island. Safe Harbor and desalting plant.
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,~6 ft
12ft
=o
1300m
Figure 3. General bottom topography and surface features in the
vicinity of Safe Harbor, including locations of stations
used during the study.
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Figure 4. Aerial view, looking west, of Safe Harbor
and desalting plant (left foreground) and
Key West (background).
Figure 5. Aerial view of entrance to Safe Harbor and
desalting plant (left).
7
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occur on parts of the shallow flats. Large areas of the sand are consolidated
by extensive beds of marine grasses and algae. The rock outcroppings on
deeper portions of the island shelf are covered in places with coral patch
reefs and isolated coral heads.
There is no permanent fresh water drainage in the Stock Island area and
runoff is limited to periods of heavy rainfall. In restricted bodies of water
such as the marina at the head of Safe Harbor or the very shallow waters near
the island, runoff rain water can greatly lower the salinity of the sea water.
- 8 -
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3. PLANT CHARACTERISTICS
An oil-fueled boiler supplies heat for the plant's fifty flash-
distillation units. These units make up the major part of the physical
plant (Figures 6 and 7). Electrically powered pumps draw salt water from
three deep wells into the plant and circulate the fresh water and brine
produced by the flash-distillation units through the plant as well as the
cooling water required for plant operation. The source water for distilla-
tion comes from 180-foot-deep wells (55 m) drilled down through the
jetty at Safe Harbor. At peak operation the three wells can supply 6,600
gallons (25,000 liters) per minute. Characteristics of the source water
are given in Table 1. The limestone walls of the wells provide a natural
filter which prevents intake clogging problems common to the alternative
of drawing the salt water supply directly from the ocean.
Table 1
CHARACTERISTICS OF SOURCE WELL WATER
Temperature 25.6°C(78.0°F) Throughout year
Salinity 40°/00 average Range 39°/00 to 42°/oo
Calcium Carbonate 197 ppm
Hydrogen Sulphide 6 ppm
The well water is preheated to 100°F (38°C) and treated with sufficient
sulfuric acid to convert the C0~ ion to CO,, gas. Increasing the acidity of
the well water also drives off the unwanted H^S gas in solution in the well
water. Caustic soda is then added to neutralize the excess acid and to
bring the pH of the well water to a suitable level to reduce scaling problems
in the flash-distillation units. An anti-foaming agent POLYGLYCOL 15-200
(see Appendix A) is also added to the water prior to its entering the flash-
distillation units. The treated well water is then heated to 250°F (121°C)
and enters the first flash-distillation unit. It passes through a total of
fifty units,fresh water is produced at each stage and the heated brine loses
3°F (1.6°C) per unit. A final temperature of 100°F (38°C) is attained in the
last unit. The cooling is accomplished by circulating the 78°F (25.6°C) un-
treated well water through the units. A schematic of the desalting plant
is given in Figure 8. Piping used in the flash-distillation units is a
cupro-nickel alloy similar to monel; it is approximately 70% Ni and 30% Cu.
At peak operation, production is 1,800 gallons (6,800 liters) of fresh
water per minute resulting in 3,600 gallons (13,600 liters) of briny "blow-
down" water per minute with a salinity of about 60°/00- The blow-down water
is mixed with the cooling water in an open sump (Figure 9) before discharge
into the entrance channel of Safe Harbor. Cooling water discharges into the
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Figure 6. General view of desalting plant, showing flash-
distillation units that produce fresh water.
Figure 7. View of flash-distillation units.
10
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Well
Well
Well
Cooling water
CC>2 and
H2S driven off
Well water 78°F.
Preheated to
100° Rand
acidified
Buffered
and
Heated to
250° F.
50 flash distillation units
Cooling
water
Fresh water
Brine
Sump
Discharge pipe
Safe Harbor Channel
Figure 8. Schematic of desalting plant.
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Figure 9. Open sump that receives blow-down water (left)
and cooling water (right) discharges.
Figure 10. Effluent discharging from subsurface pipe
into Safe Harbor's entrance channel.
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sump at a rate of 1,200 gallons (4,500 liters) per minute along with the
blow-down water which discharges into the sump at a rate of 3,600 gallons
(13,600 liters) per minute. Thus, at peak operation, the total discharge
from the 61 centimeter (cm) diameter pipe that drains the sump is 4,800
gallons (18,200 liters) per minute into the entrance channel of Safe Harbor
(Figure 10). The effluent consists of a mixture of one part coolant water
to three parts of blow-down. Both components have a maximum temperature of
about 98°F (37°C) when they enter the sump. The coolant water, however,
has a salinity of about 40°/00 in contrast to approximately 60°/00 for the
blow-down water.
The characteristics of the effluent vary with time since they are de-
pendent on the level of fresh water production at which the desalting plant
is operating. The reason for this is that the amount of well water being
desalted varies depending on how much fresh water is being produced, while
the cooling water cycle runs at a constant rate and volume. Thus the amount
of effluent and its salinity become less as fresh water production drops.
The demand for fresh water from the desalting plant depends on the
status of the water supply at Key West. The fresh water product of the de-
salting plant supplements the water supply piped from the mainland. The
plant, in general, has operated below full capacity during most of the study
period. The average output per day in 1968 was 1.8 million gallons (6.8
million liters) or 70% of peak production. During this period the plant
operated 90% of the time. The average rate of effluent discharge was about
3,700 gallons (14,000 liters) per minute with a salinity of about 55% during
1968. Figures to date for 1969 look as though fresh water production by
the plant will be slightly higher.
A unique feature of the Key West desalting plant is that it draws its
salt water from deep wells. The water level in these wells follows the
tidal fluctuations quite closely. The vertical excursion of the water level
in the wells differs from the tidal excursion by not more than 5 to 10% and
its phase lags by about ten minutes. Despite this strong coupling with the
tides, the well water maintains its temperature and chemical properties within
narrow limits throughout the year (see Table 1). Therefore, the transients
in the properties of the desalting plant's effluent reflect fluctuations in
the plant's operation rather than in the source water. By way of compari-
son, the effluent of a desalting plant that drew its intake water directly
from the sea would not only vary due to changes in plant operation, but
would change in response to seasonal and daily variations in the source
water's physical properties. Under these circumstances, it would be very
difficult to identify changes in the effluent caused by changes in plant
operation.
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4. METHODS AND PROCEDURES
4.1 PHYSICAL MEASUREMENTS
Temperature, current direction and velocity were the physical measure-
ments taken at ten of the stations established in the study area. During the
initial seven months of the study, these measurements were taken in the
morning and afternoon, Mondays, Wednesdays and Fridays weather permitting.
Measurements were taken twice weekly, in the afternoons only, during the
summer continuation of the study. Temperature profiles were made by taking
measurements at intervals from surface to bottom at each of the physical
stations using a rapid response electric underwater thermometer manufactured
by Oceanics Enterprises, Inc. A second surface temperature reading was taken
with a standard bucket thermometer manufactured by Kahl Scientific (Model
No. 297 WA 105). These two instruments were checked against an accurate
laboratory thermometer and were found to be mutually consistent within
0.1°C. Field measurements of temperature were made to the nearest 0.1°C.
Near-surface current direction was routinely measured at six of the
stations outside the harbor by the following method. About one-quarter pound
(113 grams) of powdered fluoroscein dye was placed in a small canvas bag.
The bag was buoyed about a half meter below the water surface at each station
during the morning survey and generally there was enough dye for both the
morning and afternoon measurement. The visibility of the dye streaks and
the distance over which they could be seen varied, depending on light condi-
tions. The dye paths were recorded on field sheets and the current direction
was derived by measuring the angle of the dye path drift relative to true
north.
Bottom current speeds were also measured at these same stations using
a small tripod supported Savonius-rotor current meter. The rotor was held
about 35 cm above the bottom. Unfortunately, at the shallower stations, its
true measurement of current velocity was obscured by surface wave induced
water movements. Current information was not collected during the summer
extension of the study.
In addition to the above measurements, a Hydro Products recording,
Savonius-rotor current meter and temperature sensor system (Model No. 501B)
was used to measure bottom currents and temperature in the basin at the en-
trance to Safe Harbor (Station 4). The rotor of this instrument was placed
approximately one meter above the bottom for all periods of current
measurement.
The temperature sensing portion of this instrument is not extremely sen-
sitive or accurate, having a slow response time and an accuracy of + 3% of the
reading within its 0° to 40°C (32° to 104°F) range. This instrument recorded
several five-day periods of continuous current and temperature data, on a self-
contained strip chart recorder, but for most of the study it did not function
due to mechanical and electrical difficulties.
14
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A tide staff was placed on the seawall near the discharge pipe of the
desalting plant and the water level was recorded by the field team during
both the morning and afternoon surveys.
4.2 CHEMICAL MEASUREMENTS
Three properties of the seawater samples collected at the ten physical
stations were measured; salinity, oxygen and alkalinity. Salinity deter-
minations were made in the laboratory with a Hytech Salinometer (Model No.
62220), the reliable operation and accuracies of which are well documented
(Brown and Hamon, 1961; Cox, 1965). Salinities determined by the conduc-
tivity method may be related to the older chlorinity determinations by
S (°/0o) = 1.80655 (Cl °/00) ,
where S, the total dissolved solids in seawater, is defined empirically as:
S (°/0o) = 0.08996 + 28.29720 R = 12.80832 R2 - 10.67869 R3
+ 5.98624 R4 - 1.32311 R5 ,
and where R is the ratio of the conductivity of the unknown seawater sample
to one having a salinity of exactly 35°/00 when both are at 15°C. (Wooster,
Lee and Dietrich, 1969).
A Hach Chemical Company oxygen determination kit was used for this
study to measure the amount of dissolved oxygen in water samples. The deter-
mination is based on the so-called "dry Winkler method". The powdered re-
agents for this determination are packaged in individual, sealed polyethylene
capsules. Each capsule contains the correct quantities of manganous sulfate,
alkaline iodideazide and sulfamic acid for determining the oxygen content
of an individual water sample. A new reagent, phenylarsene oxide, that is
completely stable was used in the titrations rather than sodium thiosulfate,
the usual reagent for the Winkler method (Thompson and Robinson, 1939).
A Hach Chemical Company alkalinity determination kit was used to measure
the alkalinity of water samples collected during this study. Alkalinity is
obtained directly as equivalent CaCOo, in grains per gallon from buret read-
ings at the end of titration (1.0 grain/gallon = 17.118 mg/liter = 17.118
ppm = 0.34205 milli-eqtaivalents H per liter.)
Alkalinity, which is a measure of the buffering capacity of the sea
water, can be defined as the sum of the equivalent concentrations of weak
acid anions minus the sum of the weak base cations. It was determined by
titrating a sample with a standard solution of a strong acid to the recom-
mended end point of about pH = 4.8 (Standard Methods 12th Edition). An
indicator mixture of Brom-Cresol Green and Methyl Red changes, but not
abruptly, from blue-green to pink in this range. The recommended end point
occurs as the green color disappears; i.e., the solution turns a light pink-
grey with a bluish cast.
The water samples from which the above chemical determinations were made,
were collected with a two-liter plexiglass Van Dorn bottle manufactured by
15
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Hydroproducts (Model No. 120). Sub-samples used for salinity and alkalinity
determinations were decanted into polyethylene bottles having poly-seal
stoppers. Sub-samples for dissolved oxygen measurements were placed in
standard 300 milliliter BOD bottles with ground glass stoppers. The water
samples for oxygen determinations were immediately "fixed" by adding man-
ganous sulphate, alkaline iodideazide and sulphamic acid after being de-
canted from the main sample.
4.3 PROCEDURES FOR COLLECTING PHYSICAL AND CHEMICAL DATA
During the Phase-I study, a field team was maintained at the Key West
site to collect the physical and chemical data. On Mondays, Wednesdays and
Fridays of each week, weather permitting, field team investigators made
physical measurements and collected water samples at Stations 1 through 10*
(Figure 10). For the observations and measurements made at all of the sta-
tions see Table 2. A small (16 ft) outboard powered boat was used and the
stations were occupied in the numerical order indicated in Figure 10. Tem-
perature profiles were recorded on field sheets while they were being made
at each station. Measurements were made at 0.3 m increments except at
Stations 5, 6, and 7 where they were made at 0.6 m increments.
Current direction was determined from dye drift at the stations outside
the harbor (Stations 4 through 10). Bottom current measurements were taken
at these same stations. This information was also noted on field sheets.
Water samples were collected 0.5 m below the surface of the water and
0.5 m above the bottom except at Stations 8, 9, and 10 where the water was so
shallow that the two samples would occur at nearly the same point in the
water column. At Stations 1 through 4 a third water sample was collected
at about mid-depth, 5.5 m below the surface. Subsamples for salinity, oxygen
and alkalinity determinations were decanted from the 2.0 liter water sample
immediately after its collection. The subsamples were then temporarily
stored in compartmented cases for transport back to the laboratory. The
chemical properties of these subsamples were analyzed the following day in a
laboratory rented at the Florida Keys Junior College.
The Phase-I study, involving morning and afternoon surveys three times
a week, ran from 11 November 1968 to 15 May 1969. During the summer ex-
tension of the program which ran from 26 May to 27 August 1969 surveys were
run twice weekly only in the afternoons at Stations 1 through 4 in the
harbor and Stations 8 and 9 on the shallow flats on either side of the en-
trance to Safe Harbor.
4.4 BIOLOGICAL MEASUREMENTS
A wide variety of biological measurements were made during the Phase-I
investigation. These included quadrat counts, plankton tows, settlement
racks, gorgonian colony transplants, seawall invertebrate counts, fish
occurrences in discharge and control areas, transect counts of lobsters and
stone crabs in discharge and control areas, marine algae occurrences, in
discharge and control areas, and bottom samples.
Stations with letters after them are biological stations,
16
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Table 2
OBSERVATIONS AND COLLECTIONS MADE AT EACH STATION DURING STUDY.
Station
Number
Physical
Measurements
(temperature,
salinity, dis-
solved oxygen,
alkalinity)
Current
Measurements
Quadrat
Monitoring
Plankton Tow
(between sta-
tions)
Bottom
Sample
1
X
X
X
1A
2
X
Tow 1
1A-2
X
2A
X
3
X
X
Tow 2
2-3
X
3A
3B
X
4
X
X
Tow 3
3-4
X
4A
X
5
X
5A
Tow 4
5-5A
X
X
6
X
X
X
7
X
X
8
X
X
X
8A
X
Tow 5
8- 8 A
X
X
9
X
X
X
9A
X
Tow 6
9-9A
X
X
10
X
X
X
10A
X
Tow 7
10-10A
X
X
-------
4.4.1 Quadrat Counts
Quadrats 4m in area were located on the bottom at 12 of the biological
Stations (1, 2A, 3, 3B, 4A, 6, 8, 8A, 9, 9A, 10, 10A) between 11 and 16
December 1968 (see Figure 10). A quadrat consisted of a polypropylene line
arranged in a square, 2 m per side, and held in place at each corner by a
large nail driven into the substrate. This marking technique provided the
diving biologists a way of returning to the same areas on the bottom during
each field visit. They selected the 4 m^ quadrat size for two reasons:
(1) they had been using this size quadrat along the southern California
coast and staying with a common size permitted comparing the effectiveness
of the method in two very different environmental areas; (2) the 4 m2 quadrat
is large enough to include significant numbers of attached organisms for
studying changes in the density and composition of these organisms. To in-
crease the accuracy of the counts, the divers placed a subdivided 1.0 m
reference frame over each quarter of the 4 m^ quadrat when counting organisms.
During each visit to a quadrat, the field team counted the numbers of
major organisms, where they could, and determined the percentage of plant
cover when present. They kept records on plastic slates, plotting the posi-
tions of organisms on these slates while underwater. This information was
transfered later to log sheets. Examples of log sheets, showing divers'
observations during one field inspection of the quadrats are given in
Appendix B.
4.4.2 Plankton Tows
Plankton tows were taken between Stations 1A and 2, 2 and 3, 3 and 4,
5 and 5A, 8 and 8A, 9 and 9A, and 10 and 10A. The locations of these tows
are seen in Figure 10. The biologists used a 30-cm diameter net (125 meshes
per inch, or 50 meshes per cm) for collecting plankton. The small diameter
of the net was necessary to allow for towing over the shallow flats. Each
tow was approximately 275 m long and lasted about 10 minutes. All of the
tows were made near the surface during daylight hours. The plankton samples
were preserved with four percent formalin immediately after collection.
The total volume of each plankton sample was measured in the laboratory
by placing the sample in a 100-ml cylindrical graduate and allowing the
plankton to settle within the fluid fraction for 15 hours.
The investigators took two aliquots of each sample for species analysis
by the following method. They adjusted the whole plankton sample to a total
volume of 100 ml, mixed it thoroughly and removed the aliquots. Each aliquot
represented 1/100 of the total plankton sample. These samples, which were
dominated by copepods, have been analyzed by Dr. A. Fleminger, a copepod
specialist at the Scripps Institution of Oceanography.
4.4.3 Biological Settlement Racks
Settlement racks with eight disks attached (four of cement and four of
rubber) were used during this program to study the effluent's effects on
settlement and growth of attached organisms on new clean uncolonized sub-
strates. On 3 October 1968, divers placed the first rack on the slope at
18
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the edge of the channel in 7 m of water, about 11 m below the discharge
pipe and near the southern edge of the plume (near Station 3).
On 12 December 1968, the investigators put the second rack into posi-
tion on the west side of Safe Harbor, opposite the desalting plant but
closer to the harbor entrance, at a depth of 6 m. This location, near
Station 3B, was selected as a control area because it was similar to the
depth at Station 3 as well as the type of substrate and species of organisms
inhabiting the area. Also the location was sufficiently removed from the
effluent discharge point so as to not be visibly affected by the effluent.
Since 40 days elapsed between the placement of the first rack and the
second, the investigators put new settlement disks on the rack near the dis-
charge to make it comparable with the control for the rest of the study.
The settling organisms had a choice of upper or lower surfaces as well as
a choice of substrate — rubber or cement.
A number of investigators have used artificial substrates to attract
plants and animals in their settlement stages. Pearce (1968) attached
disks of various materials — cement, rubber and wood — to a weighted rack
that stood slightly off the bottom. The disks were approximately 0.25 m
in diameter with a surface area of 0.05 m?. He placed the racks in the
environment and collected the disks at regular intervals for examination. The
settlement disks are used to study species' substrate preference, the time
and amount of settlement, growth, succession and competition for space.
Disks, similar to Pearce's, were used in the present study and samples
were collected from settlement racks on 27 January, 31 March and 2 June
1969. Each disk was brought to the surface in a plastic bag, placed into a
solution of 7.5% MgC^ for about 2 hours and then stored in 10% formalin
for subsequent examination.
During analysis of the settlement disk, the unattached epifauna were wash-
ed off and size sorted by using U.S. Bureau of Standards 1.0- and 0.5-mm screens.
The attached sessile organisms on each surface of the disk were counted using
a method developed by Pearce (1968). A circular piece of plastic the same size
as the settlement disk from which a wedge 1/10 of the surface area (0.005 m ) had
been cut, was randomly placed on the settlement disk. All of the organisms ly-
ing within the wedge were counted. Two counts were made on the upper and on the
lower surfaces of the disk, giving a total of four counts per disk. Sample work
sheets used for these counts are given in Appendix C.
4.4.4 Gorgonian Colony Transplants
On 14 December 1968, 18 gorgonian colonies were selected near Station 8A
(see Figure 10) at a depth of about 2 m. Eleven transplants were Pseudo-
pterogorgia bipinnata, two were Plexaurella dichotoma and five were
Pterogorgia anceps. Three of the Pseudopterogorgia bipinnata colonies were
transplanted at the original site (Station 8A) to serve as controls for the
transplant method. The remaining 15 colonies were towed slowly behind the
boat to near the desalting plant and placed around the discharge area at
varying distances and depths.
19
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The method used to hold the colonies in place at both the control and
outfall sites was the following. A cement hemisphere 31 cm across the
base was used as an anchor for each colony. The basal attachment of the
colony was inserted into a hole passing through the cement hemisphere. The
remaining space in the hole was filled with a non-toxic epoxy putty (Rosenthal,
1969) to fix the colony permanently in place (Figure 11).
The selection of gorgonian colonies for transplant experiments in the
outfall region was based upon several factors: (1) the gorgonians are one
of the more common sessile organisms in the Florida Keys; (2) colonies are
easily transplanted (Gary 1914 and Grigg 1970); and (3) they are sensitive
to changes in the environment (Grigg 1970).
The distribution of gorgonians is controlled by their physiological
requirements and the availability of suitable substrates (Bayer, 1961).
Some limiting factors are temperature, salinity, illumination, depth and
substrate. Gary (1918) determined the upper temperature tolerances for
twelve species of gorgonians growing on the reefs off the Dry Tortugas,
Florida. He found that most species died when exposed to temperatures be-
tween 34.5°C to 38.2°C. Gorgonians are for the most part stenohaline and
require salinities similar to those required for nearshore coral reefs.
Where coral reefs are best developed, the surface salinity averages about
36°/00 (Bayer, 1961). Gohar (1940, 1948) found that some species of gor-
gonians die if they are deprived of illumination. Grigg (1970), however,
working with California gorgonians belonging to the genus Muricea, found
that illumination was not a limiting factor. Depth distribution is depend-
ent on the individual species (Bayer, 1961). The reef species used during
this study generally occurred at depths between 2 and 10 m.
Figure 11. Gorgonian colony transplant attached to
cement hemisphere.
20
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Availability of suitable substrate within the depth range of the species
is one major factor controlling gorgonian distributions in the Florida Keys
(Bayer, 1961). The larvae of gorgonians require a rough and solid sub-
strate for settlement (Carey, 1914).
None of the study team has yet found gorgonian colonies within Safe
Harbor, although they have observed small, newly settled colonies on the
rocky rim of the basin near the entrance of the harbor. The substrate within
the harbor seems suitable for larval settlement in several areas, but other
ecological factors such as pollution, turbidity, sediment deposition or
space competition with other sessile organisms may have prevented the larvae
from colonizing these regions. Since the larvae have not been successful
in settling the area, the biologists wondered if adult colonies would sur-
vive in the harbor, particularly in the region of the discharge.
4.4.5 Seawall Invertebrate Counts
The desalting plant's concrete seawall, which runs along the east side
of the entrance channel to Safe Harbor, provides a uniform substrate to
study the distributions of organisms relative to the effluent field. The
seawall extends 72 m north and 53 m south of the discharge pipe. Its con-
struction forms rectangular sections below the surface of the water, 1.8 m
long by approximately 0.8 m high, along the entire length of the seawall.
Thus, it offered a series of sampling areas equal in size for contiguous.
density counts either side of the discharge pipe.
The subsurface portion of the seawall is densely colonized with organisms,
Some of the more abundant forms are: the ascidians, Ascidia nigra and
Botrylloides nigrum; the hydroid, Plumularia sp.; mollusks, Ostrea frons,
Ostrea equestris, Cantharus tinctus and Thais haemastoma; a cheilostomatid
bryozoan; a grapsoid crab, Grapsus grapsus; barnacles, Balanus amphitrite and
Tetraclita squamosa stalactifera; the fishes, Gobiosoma sp. and clinids; as
well as the green algae, Cladophoropsis membranacea.
The solitary black ascidian Ascidia nigra and the gastropod Cantharus
tinctus were selected for density counts along the seawall. These two
organisms were chosen because of their common occurrence throughout Safe
Harbor and their different living habits — filter feeding versus carnivorous
feeding and sessile versus motile.
4.4.6 Fish Occurrences in Discharge and Control Areas
Two areas along the east side of the entrance channel to Safe Harbor
were selected for studying the species inhabiting them. Both areas had simi-
lar types of substrate and equivalent depths of water. They also had rows
of mooring dolphins placed at the break in slope at the edge of the channel.
Each of these dolphins consists of 5 or 6 pilings surrounding a central
piling, bound together at the top with cables. The biologists suspect that
these dolphins provide a strong attraction for fishes. Sessile organisms,
such as barnacles, oysters and serpulid worms, which have accumulated on the
pilings may serve as food for some fishes. The arrangement of the pilings
also provides shelter and hiding places in which reef fishes are often ob-
served. Randall (1963) has demonstrated that tropical reef fishes require
rough, irregular surfaces as part of their habitat.
21
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The discharge area was situated/along the seawall at the desalting
plant while the control area was located about 170 m farther in the entrance
channel to Safe Harbor at the sit/ for the new Key West City Electric power
plant. The dolphins at the latter site were emplaced in December 1968
whereas the dolphins at the desalting plant had been in place prior to the
start of the study-
Dives were made in the two areas to determine if there were any signif-
icant differences In the fish populations inhabiting them. Species were
noted first on a presence or absence basis. Secondarily, the species
sighted were categorized as to whether they were common or uncommon. Nota-
tions were made on underwater slates by the biologist divers while swimming
in the discharge and control areas. Some observations were also made re-
garding the behavior of different species of fish in the currents created
by the discharge.
4.4.7 Transect Counts of Lobsters and Stone Crabs in Discharge and Control
Areas
Two species of crustaceans, the Florida spiny lobster, Panulirus argus,
and the stone crab, Menippe mercenaria, are common in Safe Harbor and at
times occur in the discharge area. Panulirus argus ranges throughout the
study area. They aggregate where the bottom is rocky and irregular or where
man-made rubble litters the bottom. Menippe mercenaria also ranges through-
out the study area, but in most cases tended to be less numerous than the
lobsters.
A 50-m transect line in about 5 m of water was set up in the discharge
area of the desalting plant and a similar one in the control area off the
site of the new Key West City Electric power plant. The counts of lobsters
and stone crabs were limited to a band 2 m wide along the line's total
length. The discharge area transect was placed approximately 8 m from the
end of the discharge pipe and extended 25 m either side of the pipe along the
edge of the entrance channel. The other transect was located in the control
area approximately 170 m up the entrance channel from the discharge pipe.
4.4.8 Marine Algae Occurrences in Discharge and Control Areas
The occurrence or absence of benthic algae was investigated in the
discharge and control areas since it was noted that algae were lacking or
very sparce in an irregularly shaped zone immediately around the discharge
pipe. Two similar areas were selected in the discharge and control areas
and the species of algae present were noted.
4.4.9 Bottom Samples
Bottom samples were taken at Stations 1, 2, 2A, 3A, 5, 5A, 8, 8A 9
9A, 10 and 10A (see Figure 10 and Table 2) on 29 June, July, and'12 through
14 October 1968. These samples were obtained with a scoop that takes a
sample approximately 500 mi. in volume. These samples were placed" in labeled
jars and preserved immediately with a solution of formaldehyde.
22
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At a later date the sediments were sifted through 1-mm and 0.5-mm
sieves and the organisms removed. These organisms were subsequently
identified to major group or sometimes down to genus and species.
4.5 PROCEDURES FOR COLLECTING BIOLOGICAL DATA
Unlike the field team for the physical program, the biological field
team was not stationed in Key West and only payed periodic visits to the
study area to collect data. Several of these trips were made prior to
the actual contract. Biological investigations were conducted at Key
West during the following time periods: 27 June to 2 July, 10 to 14
October, 8 to 17 December 1968, 22 to 28 January, 24 to 28 February,
29 March to 4 April, 28 May to 3 June, and 28 to 29 June 1969. During
the field trip periods, the bottom quadrats were checked by divers,
plankton tows were made using the 16 ft. outboard powered boat, and
various other collections and measurements were made relating to the
settlement racks, gorgonian colony transplants and transect counts.
The field work generally took four to. seven days to complete. Time of
completion depended on weather and the types of experiments that were
conducted. A certain amount of time on each trip was spent in explora-
tory diving to learn more about the shape and behavior of the effluent
plume, the underwater topography in the study area, and to make
representative study collections of the organisms occurring in the area.
23
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5. RESULTS
5.1 PHYSICAL
Surface currents, which were measured routinely at the outside stations
(Numbers 4, 6, 7, 8, 9, and 10), showed a strong dependence on wind direc-
tion. They generally flowed in the same direction that the wind was blowing.
The relationship between wind and currents over the shallow flats is reflected
in the histo'grams of current direction derived from the dye drift observa-
tions (Figure 12). The prevailing winds are predominently out of the east
and the most common drift direction is to the west at all of these stations.
Station 8 which is just to the east of the harbor entrance shows the least
pronounced westerly trend as far as current direction and this is probably
related to the presence of the eastern jetty of Safe Harbor which is a barrier
to the westward flow of water across the shallow flats. Water flows out
around the end of this obstruction in various patterns depending on wind
conditions.
The observation of dispersed dye confirmed the conclusion that the cur-
rents over the shallow flats are primarily wind induced and that the tidal
component is very weak at most of these stations. Station 7, located in the
Boca Chica Channel, is an exception and currents observed there show a strong
tidal influence. The greatest frequency of occurrences in current direction
is along the axis of the channel. This channel cuts completely across the
keys which makes it quite different from Safe Harbor where one end is closed
off entirely.
Tidal currents are weak by comparison with wind-driven currents,
and on the whole, the latter predominate in the study area. Under pre-
vailing wind conditions, water enters the study area from the east and
flows across the approach channel of Safe Harbor along the south side of
Cow Key and then towards Key West. The movement of water in and out of the
harbor is a combination of tidal exchange, wind-driven surface drift, and
discharge from the desalting plant. There are differences, depending on
the depth, in the paths of communication between the harbor waters and outer
waters. Water in the upper 1.5 to 2.0 m communicates freely with that on
the shallow flats. This has been demonstrated with dye releases and the
drift of powdered aluminum on the surface waters. Water below these depths,
because of its greater density, appears to communicate with the outer waters
through the approach channel that cuts across the shallow flats at right
angles to the prevailing surface flow. Thus, any surface flow of effluent
would tend to drift west across the shallow flats under the prevailing wind
conditions. The more dense and deeper portions of the effluent plume, however,
can travel only in a north-south direction along the axis of the entrance
and approach channels.
In the case of surface currents, the almost continuous island barrier
north of the stations greatly reduces the probability of north driftine cur-
rents and this is reflected in the current histograms (Figure 12) The direr
tions of the observed currents indicate that under normal weather conditions
24
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40-
30-
20-
0-
40-
30-
20-
10-
n
30-
20-
10-
NO OF OCCURRENCE,
— . N) W ^
3 0 O O O C
till
50-
40-
30-
20-
10-
0_
60-
50-
40-
30-
20-
n
IM NE E SE S SW W NW |\
^—
N NE E SE S SW W NW |s
N N
|
1 1
f
— i—
E E SE S SW W NW IV
IM NE E SE S SW W NW IV
1 1 1
:
N NE E SE S SW W NW |(
1
V N NE E SE S SW W NW T
COMPASS DIRECTION
STATION 4
STATION 6
STATION 7
STATION 8
STATION 9
STATION 10
Figure 12. Histograms of current direction at Stations 4-10,
25
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Station 6 off Boca Chica Island is the least likely to be affected by the
effluent discharged from the desalting plant. This is because Station
6 is farthest geographically from the plant and under most conditions upcur-
rent from the point of discharge. Physical conditions at Station 6 there-
fore should represent normal conditions for the area.
Temperature data collected during the course of the study indicate that
there is a strong correlation between all stations both for mean and extreme
values. Surface and bottom temperatures (Figure 13) show the same seasonal
trends and there is no marked skewing of values at stations nearest the dis-
charge point. However, the mean bottom temperature at the station closest
to the discharge point averaged about 0.5°C higher than bottom temperatures
measured at equivalent depths at other stations, a very small difference
when compared with the natural environmental fluctuation of temperatures.
The extremes in temperature values at all stations are less during
the winter months of January and/or February; in the spring period the ex-
tremes are greater and temperature fluctuations are more variable. Towards
the end of spring and entering into the summer months the temperatures again
become more uniform and extreme values less divergent.
Humidity remains uniformly high the year around, impeding the evapora-
tive cooling of the surface waters. Thus, air temperature and -conduction
from the atmosphere, radiative balance, and wind speed are the major fac-
tors controlling the temperature of the surface waters. Since the winter
sunshine and wind conditions are fairly uniform, cold fronts advancing from
the north make air temperature the most important factor contributing to
rapid changes in surface water temperatures. Sudden abnormally low water
temperatures in the Florida Keys have caused fish kills (Galloway, 1951).
R. J. Rosenthal, one of the biological team members, observed a fish kill
along Key West's Tower Beach during December 1968. No fish mortalities were
observed in Safe Harbor during the same period. The deeper water of the
harbor probably was the main factor, since fish kills are usually limited
to shallow flats.
5.2 CHEMICAL
Salinity, like temperature, shows a strong correlation between sta-
tions. The harbor stations which are representative for all the stations
are plotted in Figure 14. The mean salinity for all stations reached its
lowest values during the month of January. This low corresponded with the
heaviest period of winter rains. From January on, the mean salinity at all
stations gradually increased through the spring months reaching its peak values
in the month of May. In June, the mean salinity values dropped again corres-
ponding with a period of increased rainfall. This drop is not quite as pro-
nounced in the bottom values but can be detected at most of the stations.
The salinity values for the next two months gradually increased and reached
their highest values for the study in the month of August.
The greatest extremes in salinity values occurred in June during the
summer period of increased rainfall. This can be seen at all of the stations
monitored during the summer period. A second less pronounced divergence
of the extreme values is seen during the winter rains.
26
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30
TEMPERATURE ° C
30-
NOV.
DEC
JAN.
FEB.
MAR.
APR.
MAY
JUN.
JUL.
AUG.
Figure 13. Monthly mean and extreme bottom temperatures for Stations 1-10.
27
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TEMPERATURE
30-
NOV.
DEC.
JAN.
FEB.
MAR.
APR.
MAY
JUN.
JUL.
AUG.
Figure,13. (continued)
28
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38.0-
36.0- -
34.0-
32.0-
30.0-
38.0-
36.0
34.0-
32.0-
30.0-
38.0
36.0
30.0
38.0-
36.0-
34.0-
32.0-
30.0.
38.0-r
36.0-
34.0-
32.0-
30.0-
-t-
1 T
T T
1 T
-I 1 1_
-I 1 1 1 1 1 1 1-
h
SALINITY %0
(-38.0-
36.0-
34.0-
32.0-
4-30.0'
STATION
I
-38.0-
32.0-
+-30.0-
STATION
2
38.0-
-38.0-
36.0-
34.0-
32.0-
(-30.0-
STATION
4
1-38.0-
36.0'
34.0'
32.0"
NOV. DEC. JAN. FEB. MAR. APR. MAY JUN, JUL. AU8.
. o-
STATION
5
Figure 14. Monthly mean and extreme surface salinities for Stations 1-5.
29
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Both surface temperature and salinity values were higher at Station 3
than neighboring stations during the winter months. The highest surface
salinity value for the entire study was recorded at this station during
the winter. Conversely, during the summer months, Station 3 values showed
much less divergence from other station values for salinity and tempera-
ture, approaching more closely the environmental conditions found through-
out the study area.
High salinity seems to be the controlling density property of the
effluent since the greater portion of the plume sinks after it leaves the
discharge pipe and seeks some intermediate depth in the water column. The
dominance of salinity is indicated by the presence of thermal inversions at
all of the harbor and entrance channel stations. Temperature profiles shown in
Figure 15 were all made within an hour of one another and so are comparable
with one another. The core of the effluent plume can be traced from station
to station by its elevated temperature. As it moves away from the discharge
point it becomes more dense through loss of heat and gradually sinks. It
does not sink as deeply in the upper end of the channel (Stations 2 and 2A)
because in general salinities are higher there as well as temperatures
(Figure 15). On the other hand, the effluent plume sinks to the bottom on
the seaward side of the discharge point because of the intrusion of less
saline water from outside the harbor during tidal exchange. The sinking of
the plume has been observed by watching the movement of fine suspended material
and dye injected into the effluent at its source. Only a very small fraction
of the effluent plume reaches the surface of the channel and this is buoyed
to the surface by the rising bubbles of air entrained in the effluent
when the blowdown and cooling waters are discharged into the sump (see
Section 3 PLANT CHARACTERISTICS).
The effluent plume of the desalting plant differs significantly from
the heated plumes discharged by power generation plants in that it sinks
below the surface and there is little loss of heat directly to the atmosphere.
Because the desalting plant effluent plume sinks and often comes in contact
with the bottom, it is the benthic organisms that are most drastically
affected. This has been confirmed by the biological investigations (see
Section 5.3 BIOLOGICAL RESULTS).
The temperature and salinity data also indicate that the tidal exchange
for Safe Harbor is not large. Looking at the values for Stations 2, 3, and
4 shows that some of the residual heat and salinity from the effluent re-
mains in the harbor throughout the tidal cycle. Station 3, which is closest
to the discharge point, generally has the highest temperature and salinity
values, both surface (Figure 16) and bottom (Figure 17) of any of the
stations located along the entrance channel or in the harbor proper. Sta-
tion 2, closer to the head of the harbor, has the next highest values.
Station 4, at the entrance to Safe Harbor, generally has values below those
found at Station 2. The relative values at these stations indicate an
asymmetry to the dispersion of the effluent in the harbor. The values of
salinity and temperature are observed to be greater on the inner harbor
side of the discharge point than on the outer. This asymmetry was also
observed during dye injection experiments and in the distributions of
organisms relative to the discharge point (see Section 5.3 BIOLOGICAL
RESULTS).
30
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APPROXIMATE
EXTENT OF CORE OF
EFFLUENT PLUME
28
Figure 15.
TEMPERATURE UC.
Temperature profiles for stations in entrance channel and harbor showing thermal inversions
produced by effluent plume. The station 3 profile is in an area of turbulent mixing and the
two lines show the highest and lowest temperatures recorded at each depth while the temperature
profile was being made.
291
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FEB. MAR. APR. MAY
O
o
LU
CC
3
NOV. DEC.
JUN. JUL. AUG.
Figure 16. Surface temperature and Salinity at
Stations 2, 3, and 4.
32
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TEMPERATURE '
19*
NOV. DEC. JAN. FEB. MAR. APR. MAY JUN. JUL. AUG.
Figure 17. Bottom temperature and salinity at
Stations 2, 3, and 4.
33
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Oxygen determinations for the stations in the study area indicate that
there is an overall correlation between stations. The average values for
all stations follow fairly closely the same seasonal trends as temperature
and salinity. However, unlike temperature and salinity, the pattern of
distribution for the values does not relate to the effluent field. The
most atypical values for dissolved oxygen were found at the head of Safe
Harbor at Station 1. The extremely low bottom oxygen levels found at
Station 1 are not typical of the harbor as a whole. The basin of the harbor
marina, within which Station 1 is located, is isolated from the main harbor
by a shallow sill only 2.75 m deep. The water exchange below sill depth
is very limited. This was reflected in the low variance in bottom tem-
peratures throughout the study, the build up of ^S in the deeper waters
of the basin, and the exclusion of organisms from this body of water once
it became anoxic. Observations made by the biological team while diving
at Station 1 also confirmed that there was minimal exchange. The pool of
bottom water was observed by them to become discolored and charged with ^S
during the summers of 1968 and 1969. Benthic organisms as well as fishes
were not found in the deeper parts of the basin during these times.
The highest oxygen values are found at stations on the shallow flats
to the west of Safe Harbor. These high values are related to the abundant
plant growth on the bottom. The divers on the biological team have ob-
served tiny bubbles (presumably oxygen) rising from the underwater vegeta-
tion on warm sunny days. By way of contrast, the stations in the harbor
do not have a well developed benthic vegetation even in the shallow areas
along the edge of the entrance channel. The important point concerning
the overall dissolved oxygen distribution in the study area is that the
effluent from the desalting plant does not appear to either raise or lower
the amount of oxygen in the area of discharge (Figure 18).
Alkalinity values like oxygen values showed little relationship to the
effluent field. The mean values show that there is correlation between
stations throughout the study period. The most anomalous extreme values
were found at Stations 1 and 8. The extreme fluctuations at Station 1 are
found in the bottom water which is to be expected based on the isolation
of that basin from the rest of the harbor and the anoxic conditions that
develop there. The extreme values at Station 8, which is on the shallow flats
just east of the harbor entrance, are not readily explained. A similarly high
extreme value was recorded at Station 10 during the same time period. The
range in extreme alkalinity values was greatest in the winter months
becoming less in the spring and summer months.
5.3 BIOLOGICAL
The biological measurements and observations used in this study showed
that the effects of the effluent on organisms were not evident at distances
as great as the effluent could be detected by the physical measurements emp-
loyed in the study. This finding indicates that the amount of dilution of the
effluent necessary to insure minimal impact on the local environment can be
determined in future studies.
34
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7.00
JAN. FEB. MAR. APR. MAY
NOV. DEC.
JUL. AUG.
Figure 18. Monthly mean bottom dissolved oxygen values for Stations 1-4.
35
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5.3.1 Quadrat Counts
The quadrats fell into two groups distinguished by the organisms
inhabiting them, the harbor quadrats (Stations 1, 2A, 3, 3B and 4A) and
the quadrats on the shallow flats (Stations 8, 8A, 9, 9A, 10 and 10A).
The harbor quadrats were populated by the black tunicate Ascidia nigra,
which attaches to hard substrates (Figure 19). This tunicate was found
throughout the harbor area and occurred at all of the harbor quadrats
except Station 3. This quadrat was continuously bathed by the plant dis-
charge and was very different in appearance from the other harbor quad-
rats. There were no visible growths of red, green or brown algae on the
rock surfaces. Bryozoans occurred sparingly. The most abundant organisms
were barnacles and filter feeding tube worms.
The tunicate counts for the harbor quadrats remained exceptionally
constant throughout the study (Table 3). The generally smaller numbers of
tunicates in the upper portions of the quadrats are due to the placement
of the quadrats near the top of the steep underwater banks that form the
edge of the harbor and channel. Often these upper portions were partially
covered with sand which prevented the settlement of the tunicates.
The spiny lobster, Panulirus argus, (Figure 20 and Table 4) and the stone
crab, Menippe mercenaria (Table 5), were also regular occupants of these
quadrats. The plants found in the harbor quadrats were typically small red,
brown, and green algae which formed a thin carpeting over the rock surfaces.
A species of sea lettuce, Ulva lactuca, was the only large plant occurring
on these quadrats (see Section 5.3.8 Marine Algae Occurrences in Discharge and
Control Areas).
The bottom quadrats on the shallow flats east and west of Safe Harbor
(Station 8, 8A, 9, 9A, 10 and 10A) form another group of stations that are
intercomparable. They are a mosaic of marine grasses and large green
algae interspersed with areas of sand and rock outcroppings. The rocky
areas are often colonized by gorgonians and small corals. Turtle grass,
Thalassia testudinum, occurs in most of the quadrats on the flats. A num-
ber of attached large green algae, identified as Penicillus capitatus,
Caulerpa sp., Udotea conglutinati, Halimeda opuntia, H. tuna, and
Sargassum pteropleuron, also occur in the quadrats. ^The solitary coral,
Manicina areolata, was found in the quadrats on the flats to the west but
not in the quadrats on the flats to the east of Safe Harbor. Other common
invertebrates were several species of sea urchins; Diadema antillarum,
Tripneustes ventricosus, and Lytechinus variegatus; a small gastropod7
Astraea tuber; pen shell clams, Pinna carnea and Atrina rigida; sponges
and several species of sea cucumbers; Stichopus badionotus, Holothuria
floridana and Actinopyga agassizi.
5.3.2 Plankton Tows
The results of the analyses of the plankton samples were rather in-
conclusive relative to the effects of the desalting plant effluent on spe-
cies composition or collection volumes. The inconclusiveness of the results
was probably due to the small number of samples taken during the study (35
plankton collections) and the fact that they were all daytime tows. The
locations of the plankton tows were distributed so as to sample the harbor
and entrance channel as well as the shallow flats either side of the harbor
36
-------
Figure 19. Upper right corner of quadrat at Station 4A.
Dark objects are the black tunicate, Ascidia
nigra.
Figure 20. Lower right quarter of quadrat at Station 1
showing a lobster, Panulirus argus, occupying
hole under rock ledge.
37
-------
Table 3
NUMBERS OF THE BLACK TUNICATE, Ascidia nigra. PER SQUARE
METER IN THE FIVE BOTTOM QUADRATS STUDIED IN SAFE HARBOR.
StatiDn 1 Station 2A Station 3 Station 3B Station 4A
1
6
0
6
10 Dec. 1968
1
7
0
7
22 Jan. 1969
1
10
0
15
26 Feb. 1969
*
/
/
/
13
4 April 1969
1
6
0
13
0
3
10 Dec
4
9
8
1
. 1968
7
8
22 Jan. 1969
3
26
28 Feb
6
/
5
24
. 1969
/
/
*
3 April 1969
3
19
6
10
0
0
10 Dec
0
0
0
0
. 1968
0
0
22 Jan. 1969
0
0
0
0
26 Feb. 1969
0
0
0
0
0
4
4
12
15 Dec. 1968
0
4
4
12
28 Jan. 1969
/
/
/
/
Feb. 1969
8
21
16
17
A
29 March 1969 1 April 1969
0
0
0
0
, 10
21
14
19
3
12
11
13
12 Dec. 1968
11
11
8
17
24 Jan. 1969
7
24
9
11
27 Feb. 1969
. 4
19
11
9
1 April 1969
5
16
11
15
3 June 1969 28 May 1969 31 May 1969 3 June 1969 3 June 1969
* Not counted where / due to adverse weather conditions and underwater visibility.
- 38 -
-------
Table 4
NUMBERS OF THE SPINY LOBSTER, Panulirus argus, PER SQUARE
METER IN THE FIVE BOTTOM QUADRATS STUDIES IN SAFE HARBOR.
Station 1 Station 2A Station 3 Station 3B Station
0
0
0
0
10 Dec. 1968
0
0
0
0
22 Jan. 1969
0
0
0
0
26 Feb. 1969
X
X
X
1
4 April 1969
0
0
0
0
*
0
0
0
0
10 Dec. 1968
0
0
0
0
22 Jan. 1969
0
0
0
0
28 Feb. 1969
0
X
X
X
3 April 1969
0
0
0
0
*
0
1
2
0
10 Dec. 1968
0
1
1
1
22 Jan. 1969
0
1
1
1
26 Feb. 1969
2
1
0
0
0
1
0
0
15 Dec. 1968
0
1
0
0
28 Jan. 1969
X
V
x
X
Feb. 1969
0
0
ft
0
0
0
0
4A
0
0
12 Dec.
0
0
1968
I
0
24 Jan.
0
0
1969
0
0
27 Feb.
0
0
1969
1
0
29 March 1969 1 April 1969 1 April 1969
0
0
0
0
0
0
0
0
0
0
1
0
I
3 June 1969 28 May 1969 31 May 1969 3 June" 1969 " 3 June 1969
* Not counted where / due to adverse weather conditions and underwater visibility.
- 39 -
-------
Table 5
NUMBERS OF THE STONE CRAB, Menippe mercenaria. PER SQUARE
METER IN THE FIVE BOTTOM QUADRATS STUDIED IN SAFE HARBOR.
Station 1 Station 2A Station 3 Station 3B Station 4A
0
0
0
0
10 Dec. 1968
0
0
0
0
22 Jan. 1969
0
: o
0 .
1
26 Feb. 1969
/
/
/
0
*
4 April 1969
0
0
0
1
0
0
0
0
10 Dec. 1968
0
0
0
0
22 Jan. 1969
0
0
0
0
28 Feb. 1969
0
/
/
/
*
3 April 1969
0
0
0
0
0
0
10 Dec
0
0
0
0
. 1968
0
0
22 Jan.. 1969
0
0
26 Feb
0
0
0
0
. 1969
0
0
29 March 1969
0
0
0
0
0
0
15 Dec.
0
0
0
0
1968
0
0
28 Jan. 1969
/
/
/
/
J
*
Feb. 1969
0
0
0
0
1 April 1969
0
0
0
0
0
0
.2 Dec.
0
0
24 Jan
0
0
0
0
1968
0
0
1969
0
0
27 Feb. 1969
0
0
0
i
0
1 April 1969
0
0
0
0
3 June 1969 28 May 1969 31 May 1969 3 June 1969 3 June 1969
* Not counted where / due to adverse weather conditions and underwater visibility
- 40 -
-------
entrance. Tows 2 and 3 were located in the entrance channel (see Figure
3 and Table 2). Tow 1 was at the head of Safe Harbor, while tows 5, 6 and 7
were located on the shallow flats either side of the harbor entrance.
The plankton sample volumes varied considerably both in respect to
time and location. The largest volume occurred in the inner harbor during
the month of March (Figure 21). This may be a reflection of the organic
loading at the head of Safe Harbor from the shrimp processing industry and
sewage along with a general spring boom of plankton throughout the study
area. Tows 2 and 3 which were closest to the discharge point showed no
consistent relationship, as far as volume, to the effluent field. Perhaps
with a more rigorous sampling program, a relationship might be found.
The species composition of the plankton sample aliquots did not show
any appreciable differences whether collected near the effluent field of the
desalting plant or far away. Table 6 shows the number of different types of
plankters occurring in aliquots by plankton tow and by month. Summing these
numbers horizontally gives a total number for each plankton tow (last
column in Table 6) which is indicative of the diversity level for the tow
for the total study period. Tows 2 and 3 which are closest to the discharge
point have on this basis the next to the lowest and highest diversity levels
respectively. These results may be a reflection of sample variation in-
herent in the small number of plankton samples taken during the course
of the study. Summing of the columns in Table 6 gives a total indicative
of the diversity level for each month that plankton sampling was conducted.
It may be significant that the highest diversity level occurred in March
of 1969 which coincides with the largest plankton volumes taken during the
course of the study.
A second set of comparisons were made of the plankton sample aliquots
in respect to the abundance of organisms in the discharge area and outside
the discharge area. It was assumed that the effluent would either eliminate
or enhance the numbers of some of the planktonic organisms similar to what
was found to be the case with benthic organisms. (See 5.3.3 Biological
Settlement Racks). Table 7 presents comparisons of plankton sample aliquots
on a monthly basis relative to abundance or absence in the discharge area.
The organisms appearing in the left column were selected on the basis of
being abundant (over 150 individuals per aliquot) in the discharge area
(plankton tows 2 or 3) and nowhere else in the study area during that month.
The organisms appearing in the right column were selected on the basis that
they were absent from the discharge area (plankton tows 2 and 3) but pre-
sent elsewhere in the study area during that month. All of the organisms
that were abundant only in the discharge area (left-hand column of Table 7)
for the month indicated did occur abundantly elsewhere in the study area
at other times (see Appendix D). The variability of occurrence of a parti-
cular organism in the plankton sample aliquots is exemplified in the case
of the copepod, Paracalanus crassirostris. In December, it did not occur
in the discharge area but was present elsewhere in the study area (right-hand
column Table 7). By contrast, in April, it was abundant in the discharge area
but was not abundant elsewhere (left-hand column Table 7).
41
-------
12,13 & 14 OCT. 68
E20|
LU
510
O
^ n
567
TOW NO.
I20
uu
510
_i
O
> 0
17&20 DEC.68
356
TOW NO.
40-
LU
510-
D
_l
O
^ n
30-
26 JAN. 69 -
J
LU
510-
l 1 D
.,,. ,_, „,,_. —_ . 1
• o
1 _ > n
14 M>
EVR.69
356
TOW NO.
TOW NO.
4 APR. 69
|20-
LU
510
O
> o
t
3 5
TOW NO.
2 JUN.69
|20-
LU
510-
_j
0
>f\
\J*
1 L
1235 67
TOW NO.
Figure 21. Plankton volumes for the six sets of tows made during the biological
field trips to Key West. Tows 2 and 3 are closest to the discharge
point. Tow 1 is at the head of Safe Harbor and Tows 5, 6 and 7 are
over the shallow flats either side of the harbor entrance (See Figure
3 and Table 2 for additional information).
42
-------
Table 6
NUMBER OF DIFFERENT KINDS OF PLANKTERS OCCURRING IN PLANKTON
TOW ALIQUOTS BY MONTH AND TOW. (See text for explanation).
Plankton
Tow No.
1
2
3
5
6
7
Monthly
Totals
Dec.
7
10
11
9
8
11
56
Jan.
11
8
10
16
11
12
68
Mar.
13
14
12
16
14
16
85
Apr.
11
14
18
9
15
12
79
June
9
8
14
8
14
6
59
Tow
Totals
51
54
65
58
62
57
Table 7
OCCURRENCE AND ABSENCE OF PLANKTERS IN THE DISCHARGE AREA.
(See text for explanation).
Month
Abundant in discharge area (tows
2 or 3) but not abundant elsewhere
Absent in discharge area
(tows 2 and 3) but present
elsewhere
Dec.
Calanoid nauplii
Acartia spinata
Clausocalanus spp. juveniles
Paracalanus crassirostris
Oncaea sp.
Microsetella rosea
Tanaids
Jan.
Acartia spinata
Labidocera spp. juveniles
Calanopia americana
Corycaeus spp.
Crab larvae
Shrimp larvae
Polychaete larvae
Clausocalanus spp. juveniles
Mar.
Acartia spp. juveniles
Oncaea sp
Microsetella sp.
Euterpina sp.
Barnacle cyprids
Apr.
Paracalanus crasslrostris
Barnacle nauplii
Labidocera mirabilis
Clausocalanus furcatus
Crab larvae
Amphipods
June
Paracalanus
Temora turbinata
Oncaea sp.
Crab larvae
- 43 -
-------
The plankters excluded from the discharge area for a particular month
(right-hand column Table 7) with the exception of four types of organisms (the
copepods; Labidocera mirabilis, Oncaea sp., tanaids and amphipods) occurred
in the discharge area at other times. The four exceptions were organisms
that occurred only in the waters over the shallow flats and generally were
rare in the plankton sample aliquots. For the complete analysis of the
plankton sample aliquots see Appendix D.
5.3.3 Biological Settlement Racks
The settlement disk studies were undertaken to establish whether a real
difference existed between the environment in the effluent plume area at
the desalting plant and a control environment located across the entrance
channel of Safe Harbor. Any differences seen in the numbers or condition
of organisms settling on the disks in the two areas should be relatable to
differences in the two environments. The settlement rack in the discharge
area is continually bathed by the effluent. This can be verified by follow-
ing the movements of suspended or dissolve material (such as fine sediments
or dye) in the discharged water. The presence of the effluent can also be
detected by the warmer temperatures recorded at the settlement rack. The
analyses of the organisms on the settlement disks from the discharge and
control racks showed significant differences in the numbers and condition of
the organisms in the two areas.
Two attached organisms were selected for comparison in the discharge
and control areas, balanoid barnacles and a cheilostomatid bryozoans. Both
of these organisms showed differences in their numbers in the two areas.
The balanoid barnacles were more abundant on disks collected from the dis-
charge area, averaging 50 individuals per 0.005 m^ of disk surface with a
range of 6 to 135 as opposed to 7 individuals per 0.005 m^ of disk surface
with a range of 0 to 17 in the control area. Thus, barnacles were on the
average 7 times more abundant on disks bathed by the effluent than on disks
in the control area. Their greater success in the discharge area would
indicate an enhancement of the environment for barnacles in the near effluent
field.
This same sort of enhancement is observed in the case of two species
of snappers, Lutjanus griseus and L. apodus (see 5.3.6 Fish Occurrences
in Discharge and Control Areas). as well as the stone crab, Menippe
mercenaria (see 5.3.7 Transect Counts of Lobsters and Stone Crabs in Dis-
charge and Control Areas). These fishes and the crab were observed to be
more numerous in the near field of the effluent discharge than elsewhere.
A nonparametric statistical test, the Mann-Whitney U-Test, was run on
the barnacle occurrence data. This test is a nonparametric ranking type
analysis which is coming into greater use by ecolegists. The results of
this test showed that there was a significant difference at the 0.05 level
in the barnacle populations of the discharge and control area. The formula
and calculations for the Mann-Whitney U-Test are given in Appendix E.
44
-------
The cheilostomatid bryozoan occurrences on the disks also showed
significant differences between the discharge area and the control area.
They were less abundant on disks collected from the discharge area, averaging
11 individuals per 0.005 m2 of disk surface with a range of 0 to 34 as
opposed to 34 individuals per 0.005 m^ of disk surface with a range of 1
to 104 in the control area. Thus, cheilostomatid bryozoans were on the
average 3 times more abundant on disks in the control area than on those
bathed by the effluent. This finding alone would indicate that the effluent
in the near field of discharge has a deleterious effect on the success of
cheilostomatid bryozoan colonies. However, in addition, measurements of
colony size in the two areas also substantiates the conclusion that the
effluent has a deleterious effect. Colonies collected and measured on 27
January 1969 averaged only 3 mm high on disks from the discharge area as op-
posed to 34 mm high on disks from the control area. Two months later the
respective mean heights of the colonies were 4 mm and 39 mm (Figure 22). The
colonies in the control area during the same time period, therefore, grew ten
times larger than those in the discharge area, strongly suggesting that the
effluent was adversely affecting both the success and growth rate of the
cheilostomatid bryozoan colonies. The Mann-Whitney U-Test was run on the
bryozoan occurrences in the two areas and it indicated that the differences
were significant at the 0.05 level (Appendix E) .
Adverse or exclusion effects of the effluent were also detected in
the near field discharge in some of the other biological investigations.
The quadrat at Station 3 (nearest quadrat to the discharge point) was found
to be different from the others in the Safe Harbor area in that it lacked
the black tunicate, Ascidia nigra, and had no visible growths of red, green
or brown algae. Bryozoans occurred only sparingly in this area and were
small in size (see 5.3.1 Quadrat Counts). The gorgonian colonies trans-
planted into the discharge area (see following section) showed deleterious
effects, particularly in the near field of the discharge. Some species
of animals were also excluded from sections of the seawall immediately ad-
jacent to the discharge point (see 5.3.5 Seawall Invertebrate Counts).
Thus in some instances, the presence of the effluent appears to attract or
favor the growth of organisms, whereas for others it excludes them or is
deleterious to their growth and development.
5.3.4 Gorgonian Colony Transplants
The gorgonian colony transplants yielded considerable information on
the effects of the effluent, particularly in the near field of the discharge.
The methods used for transplanting were discussed earlier (see 4.4.4
Gorgonian Colony Transplants). Of the 18 colonies transplanted on 14
December 1968, three were left at the site of collection (Station 8A) to
serve as controls and 15 were placed in the vicinity of the discharge pipe.
Figure 23 and Table 8 give the locations of the transplants with respect to
the discharge pipe and seawall.
On 27 January 1969, the transplanted colonies in the control area
(Station 8A) appeared healthy. No visible differences in their condition
from the naturally occurring colonies could be detected. The gorgonian
colonies transplanted to the vicinity of the desalting plant varied con-
siderably in condition depending on their location relative to the discharge.
45
-------
31 Mar. '69 39mm
27 Jan.'69 34mm
Discharge
Control
Figure 22. Mean growth attained by cheilostomatid bryozoans on the upper
surfaces of settlement disks in the discharge and control areas.
Disks were placed in the water 12 December 1968.
46
-------
1
N
5 METERS
dolphin (cluster of piles)
1
I
I
Toward inner harbor
/ «!'
ft :
10ft / :' /;/
• 9ft: :::
• :' -7ft\
: : '. :6ft
: : : '• -.5ft
''
CO
(0
w
o>
Q
(0
(0
discharge pipe
fuel dock
Toward entrance
••:; :•' / s
7 :; :: ; 8.*
= : .!/J ; 9*
indicates Gorgonian colony
Figure 23. Locations of gorgonian colony transplants relative
to the end of the discharge pipe. Detail insert shows
method anchoring colonies.
47
-------
-p-
00
Discharge area
Table 8
GORGONIAN COLONY TRANSPLANT EXPERIMENTS.
Location
Species Depth
Pseudopterogoria bipinnata
P. bipinnata
P. bipinnata
P. bipinnata
JP. bipinnata
P. bipinnata
P. bipinnata
P. bipinnata
Plexaurella dichotoma
P. dichotoma
Pterogorgia anceps
P. anceps
P. anceps
Control area
1. Pseudopterogorgia
bipinnata
2. P. bipinnata
3. P. bipinnata
8'0"
8'0"
6'4"
9 '10"
6'6"
10'8"
5'0"
9'0"
5'0"
8'0"
5'6"
5'0"
8'0"
8'0"
8'0"
Distance from
Discharge Pipe
11 '6" north
12 '8" north
15 '0" south
42 '11" south
45 '10" south
57'1" south
54 '3" south
35 '6" north
56 '0" south
58'6" north
21 "5" south
46 '4" north
Three colonies
Station 8a; 45
Station 8a; 45
Station 8a; 45
Distance from
Seawall
15-0"
15'0"
16'7"
27'5"
18'4"
28'2"
15 Tl"
24'2"
10'2"
18'5"
19'4"
No. in
Fig. 23
1
2
3
5
6
7
8
11
9
- 12
4
18'2" 10
lost before locations were
' east of station
' east of station
' east of station
Condition
Dead
Dead
Dead
Alive
Alive
Dead
Alive
Dead
Alive
(Lost)
Dead
Dead
plotted.
Alive
Alive
Alive
-------
The colony placed nearest the discharge pipe was severely damaged. The
coenenchymal tissue was soft and sloughing off and no polyps were visible.
Other colonies at distances out to about 10 m showed some signs of damage.
Beyond 10 m all colonies appeared to be alive and healthy.
On 26 February 1969, the transplanted gorgonian colonies in the
vicinity of the desalting plant were checked again. Colonies closer to
the discharge pipe than 12 m were dead or damaged, those beyond 12 m
appeared to be alive and healthy.
On 30 May 1969, the three control transplants near Station 8A were
examined and photographed. These transplants appeared healthy, unaffected
by the method of transplanting. The polyps were extended and the condition
of the coenenchymal tissue was similar to that of other Pseudopterogorgia
bipinnata colonies occurring naturally around Station 8A. The condition
of most of the transplants at the discharge location was in marked contrast
to the control situation. Only 4 out of the original 15 transplants were
alive as of 30 May 1969, and these were all farther than 12 m from the dis-
charge point.
The pattern of colony destruction relative to the discharge point showed
a certain amount of asymmetry. The effects of the discharging effluent seems
to extend farther to one side of the discharge pipe than the other. For
colonies the same distance from the discharge pipe, those on the inner harbor
side showed signs of damage or were killed before those on the entrance
side of the harbor. Thus, the asymmetry of the effluent field is also indi-
cated by the physical and chemical data (see 5.2 CHEMICAL RESULTS), as well
as some of the biological investigations (see 5.3.5) Seawall Invertebrate
Counts). Dye releases from the discharge pipe made by the biological field
team confirmed the asymmetry of the effluent field. The resulting dye dis-
tribution over the shallow shelf along the seawall matched very closely the
area from which ascidians and algae were excluded (Figure 24).
To account for the deaths of transplants, the following factors were
considered:
1. Method of transplant: not a factor; control transplants are
thriving.
2. Illumination: not a factor; all of the transplants were placed
at depths similar to their original sites.
3. Salinity: probably not a factor; the salinity measurements taken
around the discharge area showed only very small differences from
those measured at other stations. ,
4. Temperature: probably not a factor during normal plant operation.
The temperature of the effluent a short distance (3 m) from the
discharge point was below the thermal death point of the species.
Thermal shock might have been a problem during winter months when
the ambient water temperatures were low. If the desalting plant
shuts down and starts up again during these periods, the gorgonian
49
-------
red and green algae
cheilostomatid bryozoan
black ascidians
green algae
broken rocks and
numerous filter-feeding worms
gravel
rocks covered with barnacles and worms
discharge pipe
fuel dock
green algae
I
Toward inner harbor
black ascidians
red and green algae
cheilostomatid bryozoans.
Toward entrance
Figure 24. Floral and faunal zoning in the immediate vicinity
of the discharge pipe.
50
-------
colonies nearest the pipe may experience temperature changes
greater than 10°C within a matter of minutes. Thermal shock
would not be a problem during the summer months when ambient
temperatures approach 30°C.
5. Availability of food: probably not a factor. This area is
densely populated by other filter feeding organisms.
6. Scouring: possibly a major factor for the colonies transplanted
directly in front of the discharge pipe. Scouring by sand and
sediment entrained in the discharge plume can harm the polyps
and prevent them from feeding.
7. pH factors: the release of extremely acid water (pH 2.0) from
the discharge pipe during descaling operations could be the most
harmful factor to the transplanted colonies. Unfortunately,
the day-to-day condition of colonies could not be followed since
the biological team was not stationed at Key West.
8. Fouling: a few of the transplanted colonies were covered
moderately to heavily by serpulid worms, barnacles and algae.
However, this does not appear to be a factor because the trans-
plants that had the heaviest settlement of epizoans and epiphytes
were still alive on 29 June 1969.
9. Trace metals: copper, iron, etc. contained in the effluent may
be a factor, although the lethal limits for gorgonians are un-
known at this time and measurements were not made of these effluent
properties.
The transplants that died in the discharge area usually went through
the following stages prior to complete loss of the colony:
1. Polyp retraction
2. Sloughing and necrosis of coenenchymal tissue
3. Death of individual polyps
4. Axial rod exposure
5. Complete polyp mortality
Many of these symptoms can be seen in Figure 25. This photograph was
taken of a gorgonian colony transplant (Colony No. 3) placed about 5 m
from the discharge pipe.
The value of the gorgonian colony transplants was that they provided
a method of observing the biological effects of the effluent. These environ-
mentally sensitive organisms placed at different points in the effluent
field served as integrators of the long-term environmental conditions.
51
-------
Figure 25. Detail of gorgonian colony transplant showing
damaged condition resulting from exposure to
effluent.
- 52 -
-------
5.3.5 Seawall Invertebrate Counts
The two organisms selected for counting along the concrete seawall of
the desalting plant were the black tunicate, Ascidia nigra, and the carniv-
orous gastropod, Cantharus tinctus. On 29 and 30 May 1969, counts were made
within each contiguous rectangular area (1.8 m long by approximately 0.8
m-high, separated by 0.6 m-wide concrete buttresses). The water depth
ranged between 0.5 m and 1 m (averaging about 0.8 m), depending upon the
stage of the tide. Both the tunicate and the gastropod occurred abundantly
along most of the seawall, but the effluent appeared to exclude them from
those portions of the seawall nearest the discharge point. The exclusion
of these organisms was not symmetrical about the discharge point. The tuni-
cate was absent 43.2 m north (toward the inner harbor) of the discharge pipe
and 19.2 m south (toward the harbor entrance) of the pipe (Figure 26). The
gastropod was absent 36.0 m north of the outfall and 4.8 m south (Figure 27).
The gastropod, Cantharus tinctus. through its motility, is capable of respond-
ing to changes in the effluent field; the tunicate, Ascidia nigra, cannot,
because it is sessile. The occurrences of the gastropod closer to the dis-
charge may reflect its ability to respond more quickly to effluent field
changes.
The noticeably different north and south limits of exclusion for both
organisms relative to the discharge point are seen in the distributions of
other organisms such as the attached algae and in the pattern of gorgorian
colony mortalities discussed in the previous section. The algae range
closer to the discharge pipe on the south, or harbor entrance side, of the
pipe than they do on the north or inner harbor side (see Figure 24). The
reason for this difference was discovered by injecting fluoroscein dye into
the effluent. A portion of the effluent was deflected by the nearest mooring
dolphin so that it swung to the north over the shallow shelf along the edge
of the seawall. There was no corresponding deflection of the effluent plume
onto the shallow shelf on the opposite side, and the balance of the dis-
charged water flowed directly out into the entrance channel.
5.3.6 Fish Occurrences in Discharge and Control Areas.
Observations made in the discharge area during the early phases of the
study suggested that the effluent was attracting many reef fishes. Closer
investigation of this phenomenon, however, indicated that the situation
was far more complicated than first suspected. The investigators realized
that any of the following factors could be attracting the fish: the heat of
the effluent, the currents and turbulence that the effluent created, the
constant source of plankton brought into the area by the entrained water,
or a combination of these factors. Still another environmental factor,
completely independent of the effluent discharge, is the presence of a series
of mooring dolphins that parallel the desalting plant seawall. Each of
these dolphins consists of 5 or 6 pilings surrounding a central piling,
bound together at the top with cables.
A second series of dolphins identical in construction with those at
the desalting plant, was placed along the east side of the Safe -Harbor
entrance channel in December 1968 at the site for the new Key West City
Electric Power Plant. Sessile organisms encrusted the pilings of the
53
-------
01 o
CD O
o n
ft e
Hi rt
c c
P 3
NUMBERS OF
INDIVIDUALS
50-
40-
I I I I
12.0
I I I I I I
2.4 0 2.4 12.0
I I I I I I I I I I
24.0 36.0
Distance from Discharge (meters)
-------
NUMBERS OF
INDIVIDUALS
5Q_ _
~I 1 1 I I 1 I I I I T
48.0 36.0 24.0 12.0
I I
2.4 0 2.4
12.0 '
Distance from Discharge (meters)
-------
new dolphins in a very short time and within a few months they looked the
same as the desalting plant dolphins. The new dolphins lie approximately
170 m north of the discharge (Figure 28) and served as a control area for
comparing fish occurrences. They are in similar depths of water and far
enough from the desalting plant that no biological effects of the effluent
could be detected there (see 5.3.8 Marine Algae Occurrences in Discharge
and Control Areas).
The control dolphins began to attract fishes immediately after em-
placement. By 29 June 1969, divers had identified 46 species of fishes
in the control area, compared to 48 species identified around the desalting
plant discharge area (Table 9). Many more hours were spent observing fish
in the discharge area than in the control area. Since divers spent tens
of hours in the discharge area as against a maximum of 4 to 5 hours in
the control area, the chances of observing more species of fish in the
discharge area was better.
The similarity of the species lists for the two areas suggests that
the dolphins are a strong attractant to fish. It therefore seems likely
that the dolphins may be, for most fishes, a more important environmental
factor than the effluent.
A few species of fish do appear to be attracted to the effluent.
Snappers (Lutjanidae) at times swim directly into the effluent and right
up to the mouth of the discharge pipe where the temperature is close to
37°C. This behavior has been observed even during the winter when there is a
temperature difference of as much as 20°C between the effluent at the in-
jection point and the surrounding water. These excursions into the hottest
part of the effluent are short in duration (< 10 sec.), yet the fishes do
it repeatedly.
Two species of snappers, Lutjanus griseus and L. apodus, are more com-
mon in the discharge area than the control area. Schools of these fish
often remain stationary relative to the bottom, swimming just hard enough
to counter the current created by the discharge. At other times, they swim
rapidly through the effluent plume, around the nearest dolphin and then back
through the plume again. The numbers of these snappers diminish around the
outfall when the plant is shut down and no effluent is being discharged.
Juvenile chaetodonts, (Chaetodon capistratus, C_. ocellatus, Pornocanthus
arcuatus and Holacanthus ciliarus) and the porkfish, Anisotremus virginicus,
are more common along the irregular slope below the discharge pipe and around
the bases of the nearest dolphins than elsewhere in Safe Harbor. In support
of the greater availability of these fishes is the observation that tropical
fish collectors use the discharge area regularly to collect small speci-
mens of butterfly and angel fishes.
The juveniles of the porkfish, Anisotremus virginicus, along with many
of the chaetodonts are known "cleaners". The investigators have observed
56
-------
\
0\
170m
r
Control
\
\
/ i
/ V.
\
7
Toward inner harbor /
City Electric
DOLPHIN (side and top views)
Desalting Plant
L
^
q
'Discharge
\
\
Toward (entrance
* V C
/V
Figure 28. Discharge and control areas used for marine fish occurrences,
57
-------
Table 9
FISH OCCURRENCES IN DISCHARGE AND CONTROL AREAS.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Species
Spadefish. Chaetodipterus faber
Sergeant major, Abudef duf saxatilis
Beau gregorv. Eupomacentrus leucostictus
Cocoa damselfish, Eupomacentrus variabilis
Dusky damselfish, Eupomacentrus fuscus
Foureye butterflyf ish, Chaetodon capistratus
Reef butterflyf ish,, Chaetodon sedentarius
Spotfin butterflyf ish, Chaetodon ocellatus
Gray angel fish, Pomacanthus arcuatus
Queen angelfish, Holacanthus ciliarus
Blue angelfish, Holacanthus isabelita-
bermudensis
Slippery dick, Halichoeres bivittatus
Bucktooth parrot fish, Sparisoma radians
Striped parrotfish, Scarus croisensis
Blue parrotfish, Scarus coeruleus
Rainbow parrotfish, Scarus suacamaia
Doctor fish, Acanthurus chirurgus
Blue tang, Acanthurus coeruleus
Ocean surgeonfish, Acanthurus bahianus
Bar jack, Caranx ruber
Crevalle jack, Caranx hippos
Unid, jack, Caranx sp.,
Sheepshead, Archosargus probatocephalus
Black grunt, Haemulon bonariense
Tomtate, Haemulon autolineatum
French grunt, Haemulon flavolineatum
White grunt, Haemulon plumieri
Bluestriped grunt, Haeraulon sciurus
Porkfish, Anisotremus virginicus
Roundspot porgy, Diplodus caudimacula
Discharge
C
C
C
U
u
C
u
C
C
C
C
C
u
C
C
u
C
C
C
C
u
C
C
u
C
u
Control
C
C
C
U
U
C
u
C
C
C
C
C
u
u
u
C
C
u
C
C
u
C
u
u
C
C
u
C
u
C = Common U = Uncommon - = Absence
58
-------
Table 9 (continued)
FISH OCCURRENCES IN DISCHARGE AND CONTROL AREAS.
Species Discharge Control
31. Mojarra, unid., f: Gerreidae C C
32. Bermuda chub, Kyphosus sectatrix C C
33. Barred cardinal fish, Apo^on binotatus U
34. Flamefish, Apogon maculatus - u
35. Great barracuda, Sphyraena barracude C C
36. Needlefish, unid., f: Belonidae C C
37. Halfbeak, Hemiramphys sp. C C
38. Snook, Centropomus undecimalis U
39. Nassau grouper, Epinephelus striatus U U
40. Grouper, Mycteroperca sp. U U
41. Grouper, Epinephelus sp. - U
42. Seabass, unid., f: Serranidae U U
43. Tarpon, Megalops atlantica U
44. Schoolmaster, Lut janus apodus C U
45. Grey snapper, Lutjanus griseus C U
46. Yellowtail snapper, Ocyurus chrysurus U U
47. Mahogany snapper, Lutjanus mahogoni U
48. Neon goby, Elacatinus pceanops U U
49. Goby, Gobiosoma sp. C C
50. Crested goby, Lophogobius cyprinoides U
51. Goby, unid., f: Gobiidae C C
52. Blenny, unid., f: Blennidae C C
53. Spotted eagle ray, Aetobatus narinari U U
54. Green moray, Gymnothorax funebris U U
55. Spotted moray, Gymnothorax moringa U
C = Common U = Uncommon - = Absence
59
-------
juvenile porkfish cleaning parasites from the spadefish, Chaetodopterus_
faber. These cleaners may also draw fishes to the discharge area that
would not otherwise be attracted.
5.3.7 Transect Counts of Lobsters and Stone Crabs in Discharge and Control
Areas
The Florida spiny lobster, Panulirus argus, and the stone crab,
Menippe mercenaria, were found to be quite abundant in the study area. Both
of these species form the basis of valuable fisheries in the Florida Keys.
Initially, the biologists thought that the warm effluent was attracting
lobsters, but after having compared fish occurrences in the discharge area
with those in the control area farther up the channel, they decided to make
transect counts of the numbers of lobsters in the two regions. Counts of this
organism made during quadrat observations revealed that the lobster is quite
active and frequently moves from one area to another. Lobsters have been
present in a quadrat one time and absent the next. Most of these observa-
tions were made during periods when the lobster fishery was closed, so human
disturbance was a minimal influence on the presence or absence of the species
in Safe Harbor.
Divers ran a 50-m transect line in about 5 m of water along the bottom
in the discharge and control areas making counts of lobsters (Figure 29).
On 3 June 1969, there were only 5 lobsters along the discharge transect,
while there were 26 along the control transect. Repeating the same transect
counts on 28 June 1969, the divers again found 5 lobsters along the discharge
transect but 32 lobsters along the control transect (Table 10). On these
two particular occasions, there seemed to be fewer lobsters in the effluent
plume area than there had been during the biologists' earlier field trips.
This difference could reflect a seasonal effect, since the effluent may
attract lobsters in the colder months of the year.
The stone crab was far more common in the discharge area during the
entire study period (Table 11). Both juvenile and adult crabs were found
there, and gravid females were observed near the discharge pipe on 28 June
1969. Counts were made on 3 June 1969 and 28 June 1969 along the same two
transect lines used for the lobster counts. The first count yielded 42
stone crabs in the discharge area as opposed to 3 in the control area, and
the second count yielded 46 stone crabs in the discharge area as opposed to
15 in the control area. Stone crabs in the discharge area were found under
practically every available rock and in every hole. One juvenile crab
was living under the rim of the discharge pipe itself.
5.3.8 Marine Algae Occurrences in Discharge and Control Areas
There is a marked absence of attached marine algae in the immediate
vicinity of the discharge pipe (see Figure 24). This area corresponds
approximately with that from which the black tunicate, Ascidia nigra, is
excluded. The bottom examined for algae in this barren area ranged be-
tween 1 and 9 m in depth. Only two species occurred sparingly, a red algae,
Ceramium sp., and a green, Cladophoropsis membranacea. The latter was more
common (Table 12).
60
-------
I
\
City Electric
Toward inner harbor
Toward entrance —
\
Figure 29- Locations of transect lines for lobster and stone crab
counts in discharge and control areas.
61
-------
Table 10
TRANSECT COUNTS OF THE SPINY LOBSTER, Panulirus argus,
IN DISCHARGE AND CONTROL AREAS.
Discharge area
North
I 0 I
Om 5m
South
25m
30m
North
Om 5m
South
I 0 I
25m
30m
3 June 1969
1 I
10m
15m
I
35m 40m
28 June 1969
I 0 I
10m
15m
35m
40m
20m
45m
20m
45m
0 I
25m
Total 5
50m
25m
Total 5
50m
Control area
North
3 June 1969
Om 5m
South
I 0
25m
30m
North
Om
5m
South
25m
30m
10m
15m
35m 40m
28 June 1969
10m
15m
35m
40m
20m
45m
20m
45m
25m
Total 26
50m
4
16 |
0
0 1 2
25m
0
0 | 0 |
10 j
0
I Total 32
50m
- 62 -
-------
Table 11
TRANSECT COUNTS OF THE STONE CRAB, Menippe mercenaria,
IN DISCHARGE AND CONTROL AREAS.
Discharge area
North
5 I
Om
5m
South
25m
30m
Om
5m
South
9
25m
30m
3 June 1969
10m
15m
20m
35m 40m
28 June 1969
45m
10m
15m
20m
35m
40m
45m
25m
Total 42
50m
North
L 4 I
4 1
6
0 9
25m
Total 46
50m
Control area
North
1 I
25m 30m
North
L 3 I
Om 5m
South
25m 30m
0
3 June 1969
Om 5m
South
ill 0
10m
15m
20m
25m
0
Total 3
35m 40m
28 June 1969
45m
50m
10m
15m
35m
40m
20m
45m
25m
Total 15
50m
- 63 -
-------
Table 12
OCCURRENCES OF MARINE ALGAE IN DISCHARGE AND CONTROL AREAS.
Species Depth
Discharge area
1. Ceramium sp. 1m
2. Cladophoropsis membranacea .05-3 m
Control area
•*•• Caulerpa floridana .05-1 m
2. Caulerpa verticillata 1-2 m
3. Halimeda tuna 1-2 m
4. Cladophoropsis membranacea .05-3 m
5. Penicillus capitatus 1 m
6. Ceramium sp. 1m
7. Herposiphonia sp. 2m
- 64 -
-------
In the control area off the proposed Key West City Electric power
plant the biologists examined similar substrates at the same depths for
attached algae. Within an equivalent area extending along the channel
edge, they found seven species of algae (Table 12). The greater number of
species in the control region suggests that algal colonization in the immed-
iate vicinity of the discharge is being limited by factors related to the
effluent.
5.3.9 lottom Samples
The numbers of organisms contained in the bottom samples turned out
to be exceedingly small, particularly for samples taken in the harbor and
entrance channel. Diving observations also confirmed that there was
little in the way of benthic or infaunal life in the fine mud sediments that
covered the bottom of the harbor and channel. These sediments often
smelled of H2S and the presence of this poisonous gas may account for the
scarcity of life in the collected samples. The only organisms observed
on the harbor bottom were the jellyfish, Cassiopeia frondosa, an aplysiid,
Bursatella sp., and the horseshoe crab, Xiphosura polyphemus. The jelly
fish were very abundant during the winter and spring sometimes reaching
densities of 3 to 4 individuals per m . These organisms were found from
the head of Safe Harbor to the mouth of the entrance channel. The aplysiid
was only seen abundantly during a winter field trip made in December 1968.
At that time, it congregated in great numbers in the warm effluent on the
channel bottom down slope from the discharge pipe. Many of the individuals
were in tight clusters and copulating pairs were found in these aggrega-
tions. This aplysiid was seen on the bottom in other parts of the harbor
and entrance channel. However, it was not as numerous, nor was the mating
behavior as prevalent as that observed in the discharge area. It would
appear from these observations that the effluent was acting as a stimulus
for the reproductive behavior of this organism. The aggregation of gravid
female and juvenile stone crabs in the discharge area fits into this same
sort of behavior and may indicate that the effluent has a beneficial effect
on some species by creating a more suitable breeding habitat.
Horseshoe crabs were only sighted a few times in the harbor. The dis-
tribution of these sightings did not show any relationship to the location
of the effluent discharge.
The bottom samples from the stations on the shallow flats contained
more organisms in them than the harbor ones. The sediments were coarser
at these stations and H2S was never detected in the samples. The bottom
samples did not prove very useful to the study of the effects of the
desalting plant effluent since they contained few organisms. Like the
quadrats (see 5.3.1 Quadrat Counts) the harbor bottom samples formed one
comparable group and the shallow flats samples another. The size of the
sediments and the dissolved gases contained in these two sets of samples
played a stronger environmental role as far as the species present than
the effluent from the desalting plant. The organisms found in these samples
are listed in Table 13.
65
-------
Table 13
ORGANISMS FOUND IN THE BENTHIC SAMPLES.
Organisms
Nemertea
Rhynchocoela
Rhynchocoela
Annelida
Cirratulidae
Cirratulidae
Flabelligeridae
Maldanidae
Nereldae
Nereidae
Nereidae
Opheliidae
Orbiniidae
Orbiniidae
Orbiniidae
Phyllodocidae
Polynoidea
Serpulidae
Serpulidae
Syllidae
unid. polychaete
unid. polychaete
unid. polychaete
unid. polychaete
unid. polychaete
unid. polychaete
unid. polychaete frag.
Mollusca
Gastropoda
Astraea longlspina
Astraea phoebia
Number Station
Date
1
1
1
1
1
1
1
1
1
1
1
2
2
1
1
1
1
2
1
1
1
1
1
3
1
2
2
4
10
9
5
9A
9A
2
8A
9
8A
9A
9A
9
8A
9A
1
9A
9A
10
4
9A
5
8
5
9A
9
9
29
12
29
14
12
12
12
13
12
13
12
29
12
13
12
12
29
12
29
29
12
14
14
14
29
12
29
June 1968
Oct. 1968
June 1968
Oct. 1969
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
June 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
June 1968
Oct. 1968
June 1968
June 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
June 1968
Oct. 1968
June 1968
- 66 -
-------
Table 13 (continued)
ORGANISMS FOUND IN THE BENTHIC SAMPLES.
Organisms
Tegula lividomaculata
Triphora melanura
Atys sp.
Epitoniuiu sp.
Epitonium sp.
Natica sp.
Oliva sp.
Prunum sp.
Retusa sp.
Vermicularia sp.
Atyidae
Naticidae
Lamellibranchia
Area zebra
Divaricella quadrisulcata
Divaricella quadrisulcata
Laeyicardium laevigatum
Macoma constricta
Macoma constricta
Anadara sp.
Anadara sp.
Chione sp.
Tellina sp.
Tellina sp.
Cariidae
Lucinidae
Lucinidae
Lucinidae
Lucinidae
Tellinidae
Number Station
Date
1
1
6
1
1
1
2
1
5
1
1
1
10
10
5
9
10
10
5
5
8A
10A
10 A
4
29
29
14
12
12
29
14
14
13
12
12
29
June 1968
June 1968
Oct. 1968
Oct. 1968
Oct. 1968
June 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
Oct. 1968
June 1968
1
1
1
1
4
5
1
1
1
3
2
1
1
1
1
3
1
8A
9
10A
10A
4
5
2
10A
9A
5
8A
5
5
5
10
10A
2
29 June 1968
29 June 1968
29 June 1968
29 June 1968
29 June 1968
1 July 1968
12 Oct. 1968
29 June 1968
12 Oct. 1968
14 Oct. 1968
13 Oct. 1968
14 Oct. 1968
14 Oct. 1968
1 July 1968
29 June 1968
12 Oct. 1968
29 June 1968
67
-------
Table 13 (continued)
ORGANISMS FOUND IN THE BENTHIC SAMPLES.
Organisms
Number Station
Date
Scaphopoda
unid. scaphopod
Echinodermata
Holothuroidea
unid. holothuroid
unid. holothuroid
Ophiuroidea
unid. ophiuroid
unid. ophiuroid
Crustacea
Ostracoda
unid. ostracods
unid. ostracods
unid. ostracods
Decapoda
Pinnotheridae
unid. brachyuran megalopa
1
1
1
1
5
9A
9A
10
2
6
1
1
1
5
5
9A
5
8
14 Oct. 1968
1 July 1968
12 Oct. 1968
12 Oct. 1968
29 June 1968
14 Oct. 1968
14 Oct. 1968
12 Oct. 1968
14 Oct. 1968
14 Oct. 1968
68
-------
6. DISCUSSION OF RESULTS
The results of the physical, and chemical, studies have shown that
several of the properties (temperature and salinity) of the effluent can
be detected at greater distances from the discharge point than can gross
changes in the biological communities. This means that the levels of
effluent dilution necessary to produce minimal environmental modification
can be determined in a subsequent study.
Of the physical and chemical parameters measured (temperature, salinity,
oxygen, and alkalinity) only the distributions of temperature and salinity
could be related to the effluent discharge. Values for these two para-
meters at harbor and channel stations increased as one approached the
discharge point, and throughout the study temperature and salinity values
averaged higher at Station 3 (immediately off the desalting plant) than
at other stations. There is an asymmetry to the distribution of the
effluent plume in that it conserves some of its properties farther up the
entrance channel into the harbor than it does towards the entrance.
Comparing values for temperature and salinity at Station 2, 3, and 4,
which extend from the inner harbor to the entrance, the values are highest
at Station 3, next highest at Station 2, and lowest at Station 4 (see Figures
16 and 17) . This same asymmetry was observed in some of the biological
investigations and during the dye injection experiments. Attached algae
and several invertebrates were found to be excluded at greater distances
towards the inner harbor side of the discharge point than towards the
entrance side (see Sections 5.3.5 and 5.3.8). The gorgonian colony trans-
plants also showed a mortality pattern of the colonies that related to
the asymmetry of the effluent field (see Section 5.3.4). Finally, dye
releases in the effluent of the desalting plant confirmed that a portion
of the effluent plume swings in toward the inner harbor (see Section 5.3.5).
The averaged values for all the physical and chemical parameters
showed that the stations in the study area were correlated and followed
the same seasonal trends throughout the study period. Even the increasing
or decreasing ranges of extreme values paralleled one another from station
to station on a monthly basis. The plots of these extreme values indicated
that summer seemed to be the most stable season as far as the environment,
the only parameter showing exception to this was salinity, which became
more variable than the other parameters during the early summer rains.
The effects of the desalting plant effluent on the general study area
environment as measured by the methods employed in this study were small com-
pared to the observed seasonal changes. However, the short duration of this
preliminary study does not allow a definitive answer on the long-term effects
of the desalting plant effluent on the environment or biota. The temperature
and salinity differences caused by the effluent are greatest at the surface
during the winter months. Plots for Stations 2, 3, and 4 show that these
differences from the general environmental values diminish during spring and
summer (see Figure 16). Near the bottom, the differences, however, are
sufficient at Station 3 to exclude or limit the growth of some organisms.
69
-------
The biological investigations have shown that the effects of the
effluent in the near field can be either beneficial or detrimental,
depending on the organism. Stone crabs were attracted to the area and
were more numerous there than any other place investigated in Safe
Harbor during the course of the study (see Section 5.3.7). Barnacles
were found to be more successful and numerous on the settlement disks in
the discharge area than on those outside the area (see Section 5.3.3).
The juveniles of several species of fish were also observed to be more
numerous in the discharge area (see Section 5.3.6). On the other hand,
some organisms were adversely affected or excluded from the discharge
area. A black tunicate widely distributed in Safe Harbor was excluded
from the rocky surfaces and seawall near the discharge point (see
Sections 5.3.1 and 5.3.5). A common carnivorous gastropod was also
excluded from portions of the seawall (see Section 5.3.5). Bryozoan
colonies did very poorly on settlement disks in the discharge area.
Not only were there fewer of them, but they only grew to one-tenth the
size of those on the control settlement disks (see Section 5.3.3).
Gorgonian colony transplants did not survive when placed closer than
12 m to the discharge point (see Section 5.3.4). Finally, marine algae
were sparse or absent from an area immediately around the discharge
point (see Section 5.3.8).
The exclusion, mortality, or stunting of organisms near the discharge
point would appear relatable to properties of the effluent. Whether or
not they are specifically temperature and/or salinity cannot be determined
from the present study. Other factors, such as metal ions or chemical
discharges during descaling operations, may be critical to the organisms
living in the area and those factors should be investigated in the next
study. It can be seen from the small area of exclusion that the amount
of dilution necessary to minimize biological effects is not great and
could be determined by measuring some conservative property of the
effluent.
Why some organisms are attracted or do better in the discharge area
is harder to explain. In some cases, such as the stone crabs and juvenile
cleaner fishes, it would appear that the warmer temperatures are respon-
sible, particularly in winter when these organisms are not found'elsewhere
in Safe Harbor or on the shallow flats outside the harbor. Temperature
also seemed to be responsible for attracting the aplysiid sea slug and
inducing it to mate.
The presence of the many species of fish in the discharge area did
not seem to be related to the effluent field and in this case the physical
presence of the mooring dolphins seemed to be a more important environmental
factor (see Section 5.3.6). The success of barnacles and filter feeding
worms in the discharge area would seem to be related to several factors,
first their tolerance to the higher temperatures and salinities and
secondly, the large supply of planktonic food entrained and brought to
them in the currents generated by the discharge of the effluent. Barnacles
in this area feed simply by extending their cirri and do not rake the
water with typical feeding motions as they do in other parts of Safe Harbor.
70
-------
Thus, the problems of attraction or of growth enhancement of organisms in
the discharge area must be studied more carefully to determine the environ-
mental factors that are responsible. In summary, the gross biological
effects from the effluent discharge are limited to a small area and may be
detrimental or beneficial depending on the organism.
71
-------
7. CONCLUSIONS AND RECOMMENDATIONS
The Phase-I work has shown that some of the properties of the effluent
can be detected by physical and chemical measurements well beyond the area
that visible effects can be detected in the bottom communities. While the
effluent produces some beneficial effects such as attracting certain species
of fish and the stone crab, Menippe mercenaria, it has also been shown to
have deleterious effects for other organisms. Algae, tunicates, and gastropods
were excluded from the near-field of the effluent discharge and bryozoan
colonies were not as numerous in the discharge area nor did they grow as well
as they did outside of the area. Quantitative investigations of the physiolog-
ical and ecological effects of the desalting plant effluent in future studies
could lead to predictive capabilities as far as the amount of environmental
stress that can be tolerated at a given locality. The Key West municipal
government is considering locating a power plant and additional desalination
facilities at the Safe Harbor site. The additional discharges can be used to
test the predictive models developed during the Phase-II study.
For the Phase-II study, it is recommended that the main emphasis of the
study be to investigate biological alterations resulting from the effluent
of the desalting plant and to develop quantitative criteria for predicting
and assessing the impact of a heated, hypersaline effluent on the biota of the
receiving waters. Probably even more important to the Phase-II study is
determining the effects of descaling operations on the environment and biota.
All of the physical data for Phase-I work have been placed on magnetic
tape and punched cards. It is recommended that these data be analyzed more
completely.
-------
8. REFERENCES
Bayer, F. M. 1961. The shallow-water Octocorallia of the West Indian
region. Martinus Nijhoff, Hague: 373 pp.
Brown, N. L. and B. V. Hamon 1961. An inductive salinometer.
Deep-Sea Research. J3(l) : 65-75.
Cary, L. R. 1914. Observations upon the growth-rate and ecology of
gorgonians. Carnegie Inst. Wash. Pub. 182: 79-90.
Cary, L. R. 1918. The Gorgonaceae as a factor in the formation of coral
reefs. Carnegie Inst. Wash. Pub. 213: 341-362.
Cox, R. A. 1965. The physical properties of sea water. In Chemical Ocean-
ography. Edited by J. P. Riley and G. Skirrow, Academic Press, N. Y. Vol. 1,
pp. 73-120.
Gohar, H. A. F. 1940. Studies on the Xeniidae of the Red Sea. Pub. Marine
Biol. Sta. Ghardaqa (Red Sea) 2_: 25-118.
Gohar, H. A. F. 1948. A description and some biological studies of a new
alcyonarian species Clavularia hamra Gohar. Pub. Marine Biol. Sta. Ghardaqa
(Red Sea) 6j 3-33.
Grigg, Richard 1970. Doctoral thesis - University of California at San Diego,
Scripps Inst. of Oceanography.
Pearce, Jack 1968. Saucers in the sea.
Bull. Amer. Littoral Soc. 5^ (1): 14-19.
Randall, J. E. 1963. An analysis of the fish populations of artificial and
natural reefs in the Virgin Islands.
Carib. J. Sci. _3 (1): 1-16.
Rosenthal, R. J. 1969. A method of tagging mollusks underwater.
Veliger 11: 288-289.
Wooster, Warren S., Arthur J. Lee and Gunther Dietrich 1969. Redefinition of
salinity. Limnology and Oceanography. 14 (3): 437-438.
- 73 -
-------
APPENDIX A
DOW CHEMICAL DEFOAMING AGENT, POLYGLYCOL 15-200,
PHYSICAL PROPERTIES AND TOXICOLOGICAL DATA
-------
PHYSICAL PROPERTIES OF DEFOAMING AGENT
POLYGLYCOL 15-200 DISCHARGED IN
DESALTING PLANT EFFLUENT*
Average Molecular Weight 2600
Specific Gravity at 25/25°C. 1.063
at 75/25°C. 1.026
Pounds per Gallon at 25°C. 8.85
Refractive Index at 25°C. 1.460
Viscosity at 100°F., Centistokes 206
at 210°F., Centistokes 32.3
at 32°F., Centistokes 2056
Viscosity Index 138
Flash Point, °F. 470
Fire Point, °F. 550
Pour Point, °F. -40
Specific Heat at 25°C., cal/g/°C. 0.47
Surface Tension
at 25°C, dynes/cm. 34.3
at 75°C. dynes/cm. 32.4
* Information obtained from Dow Chemical Company
A-l
-------
TOXICOLOGICAL DATA FOR DEFOAMING
AGENT, POLYGLYCOL 15-200*
Polyglycol 15-200 has a low acute oral toxlcity. The LD is approx-
imately 20 g/kg. of body weight for rats, rabbits, and guinea pigs.
Direct eye contact results in only traces of any irritating effect.
Undiluted material is only very slightly irritating to the rabbit skin
on prolonged and repeated contact. Polyglycol 15-200 is not absorbed
through the skin in toxic amounts. Rabbits survive single massive doses
of 30 g/kg. of body weight, and repeated application of several grams
per day over a three month period was without evidence of adverse effect.
The material has also been tested extensively on human subjects;
skin patch tests with the undiluted material gave completely negative
results by both continuous and repeated insult technique. Polyglycol
15-200 is neither a primary irritant nor a skin sensitizer.
These data are sufficient to suggest that Polyglycol 15-200 is a
safe, suitable material for use in cosmetic applications where intimate
contact with the skin can be expected.
Information obtained from Dow Chemical Company
A-2
-------
APPENDIX B
QUADRAT LOG SHEETS
-------
JCEY WEST STUDY
F.W.P.C.A.
Station No.:
Location:
Date: /QfeCfM&Eft/
-------
KEY WEST STUDY
F.W.P.C.A.
foO 0
0 o 0
f/'ve
Station No.:
Location: 5/{F£. fa #60 /?-
Date:
Depth:
Quadrat Size:
SYMBOLS:
NOTES:
Ascidia nigra
Diadema antillarum
Ha lime da discoidea
Manicina areolata
Penicillus sp.
Pterogorgia sp.
Short spined urchin
I Thalassia testudinum
sp.
B-2
-------
_KEY WEST STUDY_
F.W.P.C.A.
>tM*£«i£i_ y&tyw*y.
1 X -,
-^^salii^i^L
fejItpttlftU^B
il48^i
W»*
^'
S*»J<
fif*
Station No.:
Location:ft,"f
Date:
Depth: ^-g'
Quadrat Size:
N4-
W
SYMBOLS:
Ascidia nigra
Diadema antillarum
Ha lime da discoidea
Manicina areolata
fpenicillus sp .
--- :"~ - " -----
Y Pterogorgia sp.
^c Short spined urchin
I Thalassia testudinum
sp.
B-3
NOTES:
-------
KEY WEST STUDY
F.W.P.C.A.
Station No. : £_
Location:
D a t e II
Depth:
Quadrat Size:
SYMBOLS:
Ascidia nigra
Diadema antillarum
Halimeda discoidea
Manicina areolata
Penicillus sp.
' '" -
Pterogorgia sp.
t Short spined urchin
I Thalassia testudinum
Udotea sp.
NOTES:
B-4
PS/IE. J ;
kg* A* cud A
-------
APPENDIX C
DATA SHEETS FOR SETTLEMENT DISKS
-------
Settlement Rack Data Sheet
STUDY:
F W P C A
Rack No. i
Disc Rubber
Days in water
Aliquot No. 1 (wedge 0.05m2)
Organism Number
barnacle 15
serpulid worm 38
Ostrea sp. 0
bryozoan present
STUDY: F W P C A
Rack No. 1
Disc Concrete
Days in water
2
Aliquot No. 1 (wedge 0.05m )
Organism Number
barnacle 12
serpulid worm ~-63
Ostrea sp. -~17
colonial tunicate (clear) 1
polychaete 1
eggs 2 sets
Location Discharge ,Safe
Surface Upper
Depth 24 ft.
Aliquot No. 2 (wedge 0.
Organism
barnacle
serpulid worm
Ostrea sp .
Harbor
05m2)
Number
-12
46
0
bryozoan 0
Settlement Rack Data Sheet
Date: 4 December 1968
LocationDischar8e » Sa£e Harbor
Surface Lower
Depth 24 ft.
Aliquot No. 2 (wedge 0.
Organism
barnacle
serpulid worm
Ostrea sp .
05m2)
Number
6
-59
-24
aeolid nudibranch
C-l
-------
APPENDIX D
SPECIES COMPOSITION OF
PLANKTON SAMPLE ALIQUOTS
-------
Date
Plankton Tow
Aliquot
Calanoids
Acartia spinata
A_._ tonsa
Acartia spp. juveniles
Labidocera scotti
L^ mirabilis
Labidocera spp. juveniles
Glausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crassirostris
P. parvus
Paracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
Cyclopoids
Qithona spp.
Corycaeus spp.
Oncaea sp.
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
o
(U
n
00
vO
r^.
iH
^
H
1
1
2
C
rt
>-> 150 per aliquot
C = common 20-150 per aliquot
R = rare <20 per aliquot
0 = absent from aliquot
D-l
-------
Date
Plankton Tow
Aliquot
Calanoids
Acartia spinata
A. tonsa
Acartia spp. juveniles
Labidocera scotti
L^ mirabl.lis.
Labidocera spp. juveniles
Glausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crassirostris
P. parvus
Faracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
Cyclopoids
Oithona spp.
Corycaeus spp.
Oncaea sp.
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
•M
O
O CO
vo
CM CT\
rH i~H
2
1 2
o
Ci)
P 00
\o
r-- c
t-H r
r>
H
2
1
2
6
to
VD
v*O C
CM r
^
-{
2
1
2
•
crt
S o\
^j- ^,
iH iH
2
J- 2
•H
(-1
O, ON
0s!
<± iH
2
1 ?
CU
3 CJ\
o\
CM iH
2
1 2
0
A
0
0
0
0
0
0
A
C
0
0
0
0
0
A
0
0
0
0
0
0
0
0
C
R
0
0
R
R.
3
R
0
A
0
0
0
0
0
0
A
C
0
0
0
0
0
A
0
0
0
0
0
0
0
0
C
R
0
0
R
R
0
R
0
C
0
0
0
0
0
0
0
0
0
R
0
0
A
A
0
0
0
0
0
A
0
R
C
0
0
0
R
0
0
0
0
C
0
0
0
0
0
0
0
0
0
R
0
0
A
A
0
0
0
R
0
A
0
R
C
0
0
0
R
0
0
0
0
C
0
0
0
0
0
0
C
0
0
0
0
0
C
A
0
0
0
0
0
0
0
0
0
0
0
0
C
0
0
0
0
C
0
0
0
0
0
0
C
0
0
0
0
0
C
A
0
0
0
R
0
R
0
0
R
0
0
0
C
0
0
0
R
A
A
0
0
0
0
0
C
R
0
0
0
0
A
A
0
0
0
0
0
C
0
R
C
0
0
0
R
R
0
R
R
A
A
0
0
0
0
0
C
R
0
0
0
0
A
A
0
0
0
0
0
C
R
R
C
0
0
0
R
R
0
R
0
A
0
0
0
0
0
0
C
C
0
0
R
0
R
A
R
0
0
R
0
A
0
0
A
0
0
0
C
R
0
R
R
A
0
0
0
0
0
0
C
C
0
0
R
0
R
A
R
0
0
R
0
A
0
0
A
0
0
0
C
R
0
R
0
0
0
0
0
0
0
0
0
0
R
0
0
0
C
C
0
0
0
0
a
C
0
0
C
0
0
0
R
R
0
0
0
0
0
0
0
0
0
0
R
0
R
0
0
0
C
C
0
0
0
0
0
C
0
0
C
0
0
0
R
R
0
0
A = abundant > 150 per aliquot
C = common 20-150 per aliquot
R - rare <20 per aliquot
0 = absent from aliquot
D-2
-------
Date
Plankton Tow
Aliquot
Calanoids
Acartia spinata
A. tonsa
Acartia spp. juveniles
Labidocera scotti
L. mirabilis
Labidocera spp. juveniles
Clausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crassirostriss
P. parvus
Paracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
Cyclopoids
Oithona spp.
Corycaeus spp.
Oncaea sp.
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
A = abundant > 150 per aliquot
C = common 20-150 per aliquot
R = rare <20 per aliquot
0 = absent from aliquot
o
CU
Q
l^*
1-1
oo
vO
CT*
H
3
1
2
C
n)
V
T\
O
v£> Cs
C^J r
H
3
1
2
^
CO
S <=
V
^
3
-* O\
H H
3
1
tj
n.
^3
OA
^Q ^
^
<3" iH
3
2 1
2
-------
Date
Plankton Tow
Aliquot
Calanoids
Acartia spinata
A. tonsa
Acartia spp. juveniles
Labidocera sco.tti
L. mirabilis
Labidocera spp. juveniles
Clausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crassirostris
P. parvus
Paracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
Cyclopoids
Oithona spp.
Corycaeus spp.
Oncaea sp.
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
A = abundant > 150 per aliquot
C = common 20-150 per aliquot
R = rare <20 per aliquot
0 = absent from aliquot
•
4-1
a
O 00
vO
m a>
rH rH
5
1(2
o
a)
Q 00
v£>
l-~ CT\
rH rH
5
1 | 2
3
>-3 O1
vD
\£> ai
C^ rH
5
1 I 2
•
M
^ <^
VD
-
< \o
a\
-3- r-\
5
1 |2
0)
G
3
I-) vD
-------
Date
Plankton Tow
Aliquot
Calanoids
Acartia spinata
A. tonsa
Acartia spp. -juveniles
Labidocera scotti
L. mirabilis
Labidocera spp. iuveniles
Clausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crassirostris
P. parvus
Paracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
Cyclopoids
Oithona spp.
Corycaeus spp.
Oncaea sp.
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
t-H i
f.
1
fl
r
o
P
o
n
o
A
p
n
n
n
0
0
A
0
0
A
0
n
R
'C
0
R
0
0
0
R
R
0
R
H
2
n
P
o
0
n
A
p
n
n
0
0
0
A
0
R
n
0
0
R
C
0
R
0
0
0
R
R
0
R
1-4 r
6
1
n
o
o
o
o
n
r
0
n
n
n
0
c
'n
0
n
o
R
n
c
0
0
0
0
0
0
0
0
0
R
H
2
o
o
o
o
o
n
r
o
n
n
n
0
c
r,
0
R
n
0
o
c
R
0
0
0
0
0
0
0
0
R
CM i-
6
1
n
r
f)
o
n
n
n
n
r,
p
n
n
R
0
C
A
0
0
n
R
n
0
0
0
R
0
0
0
R
0
0
R
H
2
o
r
Ct
o
o
n
n
n
r
p
n
n
p
0
c
A
R
0
0
R
n
0
0
0
R
0
0
0
R
0
0
R
iH i-
F
1
n
r
o
n
n
0
R
A
p
n
n
n
0
c
A
0
C
n
R
n
A
R '
0
C
0
0
0
0
R
0
R
H
?.
n
r
o
0
n
n
R
A
p
n
o
o
0
c
A
0
C
0
R
O
A
R
0
C
0
0
0
0
R
0
R
•vf r
6
1
o
r
n
o
0
n
n
r
P
n
n
0
0
c
r
0
0
0
c
n
c
R
0
c
0
0
0
R
R
0
R
H
?.
n
f
o
p
0
p
n
r
PL
n
n
n
0
c
r.
R
0
0
c
n
C
R
0
C
0
0
0
R
R
0
R
CVJ
6
1
0
R
R
c
A
Q
A
c
0
n
o
0
n
A
R
0
0
0
0
0
R
R
0
R
rH
2
0
R
p
n
0
A
r
0
0
o
0
o
A
0
0
0
0
0
0
R
R
0
R
A = abundant > 150 per aliquot
C = common 20-150 per aliquot
R = rare <20 per aliquot
0 = absent from aliquot
D-5
-------
Date
Plankton Tow
Aliquot
4J
O
0
!-H
1
30
<^Q
Q\
H
7
2
o
0)
P oo
\
o
CN i
7
1
£)
T\
H
2
3
vd
CSI iH
M
5-1 O^
vo
-* CT\
H iH
7 | 7
a 2
1 2
^
Pu CT\
150 per aliquot
C = common 20-150 per aliquot
R = rare <20 per aliquot
0 = absent from aliquot
* Aliquot lost
VU-L U.LAW -i-Uhp
Acartia spinata
A. tonsa
Acartia spp. juveniles
Labidocera scotti
L. mirabilis
Labidocera spp. juveniles
Clausocalanus furcatus
Clausocalanus spp. juveniles
Paracalanus crass irostris
P. parvus
Paracalanus spp. juveniles
Temora turbinata
Calanopia americana
Pseudodiaptomus sp.
calanoid nauplii
0
C
C
0
R
0
0
0
A
C
0
R
0
0
R
0
C
C
0
R
0
0
0
A
C
0
R
0
0
R
0
0
R
0
0
0
0
C
R
0
R
0
0
0
C
0
0
R
0
0
0
0
C
R
0
R
0
0
0
C
0
C
0
0
0
0
0
0
A
R
0
0
R
0
C
0
R
R
0
0
0
0
R
A
R
0
0
0
0
C
0
R
R
0
0
0
0
R
A
R
0
0
0
0
C
0
C
0
0
0
0
0
0
C
R
0
0
R
0
0
R
C
0
0
0
0
0
0
C
R
0
0
R
0
0
0
0
R
0
0
0
0
0
0
0
0
0
0
0
C
0
0
R
0
0
0
0
0
0
0
0
0
0
0
C
Cyclopoids
Oithona spp.
Corycaeus spp.
Oncaea sp.
A
0
0
A
0
0
C
R
C
C
R
C
A
R
0
A
R
0
A
R
0
C
0
0
C
0
0
C
0
R
C
0
R
Harpacticoids
Microsetella rosea
Euterpina sp.
Macrosetella sp.
harpacticoid nauplii
0
0
0
R
0
0
0
R
0.
0
R
C
0
0
R
C
0
R
0
A
0
R
0
A
0
R
0
A
0
R
0
C
0
R
0
C
0
0
o-
c
0
0
0
C
Crustacean larvae
crab larvae
shrimp larvae
barnacle nauplii
barnacle cyprids
Amphipods
Tanaids
Larvaceans
Chaetognaths
Echinoplutei
Polychaete larvae
-R
0
R
0
0
0
0
R
0
0
R
0
R
0
0
0
0
R
0
0
0
0
0
0
0
0
C
0
0
0
0
0
0
0
0
0
C
0
0
0
0
0
R
0
0
0
R
R
0
0
R
0
A
0
0
0
R
R
0
0
R
0
A
R
0
0
R
R
0
R
0
0
C
0
R
0
R
0
0
0
0
0
C
0
0
0
R
R
0
0
0
0
0
0
0
0
0
0
0
R
0
0
0
0
0
0
0
0
0
R
D-6
-------
APPENDIX E
MANN-WHITNEY U-TEST CALCULATIONS
-------
Formula for the Mann-Whitney U-Test
The formula for the Mann-Whitney U-Test is:
n-[_= The number of samples in the effluent plume environment
n2= The number of samples in the control environment.
R = The sum of the ranked counts.
z = U - ^u
a
u
^u= The mean value of U.
au= The standard deviation of the values of U.
The counts from the 24 sampled aliquots of the disks were combined
into 2 independent series of random samples, one for the discharge and
the other for the control. The counts for two sessile organisms (a barnacle
and bryozoan) , were used in this test. The data from each location were
combined into a single ordered series and tested (see following two pages).
The performed tests indicated that there was a significant difference
between the two areas as far as these organisms were concerned. Barnacles
were more common in the discharge area, and bryozoans were more common in
the control area.
E-l
-------
Mann-Whitney U-Test for Balanoid Barnacles on Settlement Disks
NJ
Date ] 27 January 1969 j 31 March 1969 2 June 1969 ,
i * [
J Material ' Concrete I Rubber Concrete
1 Discharge Counts I 21,21,3,14 10,6,25,10 135,122,106,132 j
' Control Counts j 8,8,0,3 j 0,0,6,16 3,4,16,17 i
Ranked Counts 0 0 0 3 3 3 4 6 6 88 10 10 14 16; 16 17T21~21 25 106 122 132' 135 !
Area ! Co Co Co Co Di Co Co Di Co Co Co Di DilDi Co Co CoiDi Di Di Di Di Di Di
Di=Discharge Co=Control
Rank in Discharge 5 8 12 13 14 18 19 20 21 22 23 24 ! Sum of Ranks=199
_,___. __._ _._. ,, ! .
Rank in Control 1 2 3 5 5 7 9 10 11 15 16 < 17 ! Sum of Ranks=101
U=(12)(12)
- 144 + 78 - R1
U,. , =144 + 78 - 199=23
discharge
=144 + 78 - 101=121
U
control
r =23-72 = _ 49
Jdischarge 17.3 17.3
7 =121-72 = 49
^control 17.3 17.3
= -2.89
= 2.89
Value of 2.89 refutes the Null Hypothesis
that there is no significant (0.05 level
of significance) difference between the
discharge and the control.
-------
Mann-Whitney U-Test for Cheilostomatid Bryozoans on Settlement Disks
Date
Material
Discharge Counts
Control Counts
27 January 1969
Concrete
4,10,23,26
6,2,75,72
31 March 1969
Rubber
3,3,34,28
38,44,104,48
2 June 1969
Concrete
0,0,0,0
7,4,1,4
Ranked Counts 0! 0 0 0 123 3 4 4 4 6 7 10 23 26 28 34 38 44 72 75 104 118
Area Di Di Di Di Col Co Di Di Di Co Co Co Co Di Di Di Di Di Co Co Co Co Co Co
_ _._ _.. . _ |
Di=Discharge Co=Control
Rank in Discharge 1 2 34 7 8 10 14 15 16 17 18 Sum of Ranks = 115
Rank in Control 5 6 10 10 12 13 19 20 21 j 22 23 24 Sum of Ranks = 185
U=(12)(12)
=144 + 78 - Rj^
U =144 + 78 - 115 = 107
discharge
U =144 + 78 - 185 = 37
control
107-72 35
discharge 17.3
7 _37-72 =
"control 17.3
17.3
35
17.3 =
= 2.09
-2.09
Value of 2.09 refutes the Null Hypothesis
that there is no significant (0.05 level
of significance) difference between the
discharge and the control.
------- |