University of Central Florida STARS

Retrospective Theses and Dissertations

Summer 1981

Opportunistic Species of Macrobenthos in a Sewage-Polluted Lagoon, and an Analysis of the Indicator Concept

Raymond E. Grizzle University of Central Florida

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STARS Citation Grizzle, Raymond E., "Opportunistic Species of Macrobenthos in a Sewage-Polluted Lagoon, and an Analysis of the Indicator Concept" (1981). Retrospective Theses and Dissertations. 561. https://stars.library.ucf.edu/rtd/561 OPPORTUNISTIC SPECIES OF MACROBENTHOS IN A SEWAGE-POLLUTED LAGOON, AND AN ANALYSIS OF THE INDICATOR CONCEPT

BY

RAYMOND EDWARD GRIZZLE B.S., Florida State University, 1972

THESIS

Submitted in partial fulfillment of the requirements for the degree of Master of Science: Biology in the Graduate Studies Program of the College of Natural Sciences at the University of Central Florida; Orlando, Florida

Summer Quarter 1981 ACKNOWLEDGEMENTS My graduate committee, Drs. Jack Stout, John Osborne, Haven Sweet and Robert Virnstein, provided a valuable re­ view of the manuscript. Drs. Virnstein and Stout gave guid­ ance throughout the study, and reviewed several early drafts of the manuscript, providing much valuable comment. Mr. Ka­ lani Cairns and Dr. Paul Mikkelsen identified voucher speci­ mens of most species of crustaceans and molluscs, and Ms. Teresa Toohey kindly provided her time and talent in drawing all figures. Personnel of the Brevard County Health Department !ended assistance in several respects; Mr. Bill Stegner was particularly helpful during the field work. My wife, Teri, typed the manuscript, and provided much needed support, especially during the latter stages of the study. The Brevard County Health Department funded t h e field and laboratory portions of the study.

iii TABLE OF CONTENTS

SECTION I. OPPORTUNISTIC SPECIES OF MACROBENTHOS IN A SEWAGE-POLLUTED LAGOON Page

Introduction ...... ~...... 1 Study Areas...... 5 Materials and Methods ...... · ...... 9 Results...... 14 Discussion ...... 25

SECTION II. ANALYSIS OF POLLUTION INDICATOR CONCEPT Overview of Indicator Concept ...... 29 Hypothesis 1: Superior Invasion Abilities ...... 32 Hypothesis 2: Superior Tolerance Abilities ...... 34 Hypothesis 3: Superior Competitors For Food ...... 38

APPENDICES A. Station A, Natural Substratum Data ...... 42 B. Station B, Natural Substratum Data ...... 46 C. Station A, Recolonization Data ...... 51 D. Station B, Recolonization Data ...... 56 E. Station A, Physicochemical Data ...... · 61

F. Station B~ Physicochemical Data ...... •. 63

REFERENCES Sec ti on I...... 6 4 Section II ...... 68

iv SECTION I. OPPORTUNISTIC SPECIES OF MACROBENTHOS IN A SEWAGE-POLLUTED LAGOON INTRODUCTION Many marine macroinvertebrate species have been described as "indicators" of organic pollutants, e.g., sewage effluents, which produce an enrichment effect (Pearson and Rosenberg 1978). A gradient of macrobenthic changes is often described along a gradient of organic input. The gradient may progress from an area nearest the pollution source that is lacking macrofauna, to a less­ impacted area where species numbers are depressed and densities are high, to an area where densities, biomass, and species numbers are high, to an area where pollution effects are minimal (Pearson and Rosenberg 1978, Dauer and Conner 1980). There are no definite criteria for identi- fying indicator species, but most indicators were reported as the numerical dominants in some portion of the polluted waters. Thus, most indicator species were probably de­ scribed form waters corresponding to the middle portion of the above gradient (see Pearson and Rosenberg 1978 for compilation of and criteria for reported indicator species). Those species that are numerically dominant in polluted waters are not always explicitly called indicator species (Pearson and Rosenberg 1978, Gray 1979, Dauer and Conner 1980, Santos and Simon 1980). Pearson and Rosenberg (1978, p. 256) refer to species that have been labled "pollution indicators" by other authors, as "dominant or prominent" species in organically polluted waters. Gray (1979, p. 555) uses "species that increase in abundance under slight pol­ lution" to mean the same thing. In this report, as in most of the literature, pollution indicators are defined as spe­ cies that have been reported as numerical dominants in pol­ luted waters, regardless of their persistence over time or 2 the presence of other species. Indicator species have been reported as density domi­ nants in areas where few other species ·were present (Reish 1959, 1960 and Stirn 1971), and in areas where many other species were present (Bagge 1969, Santos and Simon 1980, Grizzle 1979, present study). Such differences in community complexity suggest that different explanations may be re­ quired to account for the dominance of the indicator species in different areas. A common explanation for the dominance of indicators is that they are tolerant of pollution stress such as low dissolved oxygen, which is generally acknow­ ledged to be the major stress factor in enriched areas (Pear­ son and Rosenberg 1978, Pearson 1980). It has also been suggested that reductions in competition and predation may allow indicators to become dominant (McNulty 1970, Reish 1979). However, I suggest that actual cause-effect relation­ ships between pollution and indicator species are not ade­ quately understood. Grassle and Grassle (1974) showed that several indica­ tor species are opportunistic and quickly invade newly avail­ able habitat. Thus, the dominance of indicators in polluted waters may involve post-disturbance invasion capabilities. Furthermore, Gray (1979, 1980) suggested that tolerance to stress may not be important, and noted that little data ar e available on tolerance abilities of species (i.e., indica­ tors) that increase in abundance under slightly polluted conditions. There is a general lack of information useful to assess relative tolerance abilities, especially to low oxygen concentrations, of marine and estuarine macroinverte­ brates in general (Hart and Hart 1979, Reish 1979, Reish and Barnard 1979, Boesch and Rosenberg in press). Gray (1979) proposed three adaptive strategies to pollution based on a model by Grime (1977). These include: repro­ ductive (the opportunist strategy), competitive and toler- ance modes. Several indicators are known opportunists, but 3 relative tolerance and competitive abilities are generally unknown. I offer the following hypothesis to account for the opportunist strategy of indicator species. This hypothesis is based on work by Pearson and Rosenberg (1978), Gray 1979, 1980) and Santos and Simon (1980). The introduction of organic wastes results in conditions such as sporadic periods of hypoxia that disturb the benthos. These dis­ turbances are sufficient to kill all or most species pre­ sent, and thus vacant habitat becomes available for re- colonization. Initially recolonization is mainly by oppor- tunists. The disturbance-recolonization scenario may be­ come a frequent occurrence (Santos and Simon 1980), and leads to a continued dominance of opportunistic species. Explicitly, the hypothesis is that indicator species are opportunists capable of rapid recolonization of disturbed areas. Most areas that fit this description likely remain organically enriched (i.e., polluted) throughout an annual cycle. However, conditions sufficient to produce a sub­ stantial loss of organisms and subsequent macrobenthic re­ colonization are only manifested on a sporadic basis. Pollution indicator species may be present throughout the year, but numerical dominance is perhaps variable over time. The opportunist hypothesis emphasizes invasion ability as the most important characteristic of indicator species, and implies that tolerance abilities may not be important (Gray 1979). This deduction might be considered a secondary prediction of the hypothesis, but I treat it (in converse form, i.e., that indicators are more ~olerant than non-indi­ cators) as a separate hypothesis because superior tolerance abilities has long been the primary explanation for the indicator concept. A major purpose of the present study was to assess the role of opportunistic species in polluted Sykes Creek, and thereby provide a test of the above oppor­ tunist hypothesis. The tolerance hypothesis is also 4 partially tested by data from the present study, and will be discussed. Gray's (1979) third explanation, which hy­ pothesizes that indicators are relatively better competi­ tors (probably exploitative competitors for food), is not addressed in the present field study. It remains largely untested. In Grizzle (1979) I considered Sykes Creek an ''unpre­ dictable" environment (sensu Slobodkin and Sanders 1969) based on the occurrence of several fish kills associated with hypoxic conditions and algal blooms. The Creek was shown to be moderately enriched by sewage effluents and urban runoff, but only to manifest low oxygen concentrations sufficient to cause fish kills on a sporadic basis. Also, a few species numerically dominated the macrobenthos, most shared opportunistic characteristics. The macrobenthos showed large temporal variability. Thus, available data showed Sykes Creek to be similar to polluted areas likely to be dominated by indicator species that are opportunistic. The opportunist hypothesis predicts the dominant, and therefore "indicator," species in the polluted Creek to be opportunists. The tolerance hypothesis predicts the indi­ cator species will show superior tolerance to disturbances such as low oxygen concentrations when compared to non-indi­ cator species. In this paper I report data from a station in Sykes Creek and a control station in the Banana River, Florida, that test the opportunist and tolerance hypotheses. My objectives were: (1) define those species displaying the most opportunistic (sensu MacArthur 1960) and equilibrium ($ensu McCall 1977) characteristics using recolonization experiments, (2) assess natural substratum macrobenthic data based on abundance of these species, and (3) relate selected physicochemical data to macrobenthic differences between stations and macrobenthic dynamics. STUDY AREAS The study sites were located in coastal waters of Brevard County, Florida. These sites, Sykes Creek and the Banana River, may be classified as mixohaline-euhaline estuaries {Cowardin, et al. 1979), but are perhaps more aptly described as coastal lagoons. They are part of the east-central Florida, U.S.A., Indian River coastal lagoon system (Grizzle 1979, and Figure 1). Station A was located on the east side of Sykes Creek about 2 km north of SR 520 (Figure 1). In this area the lagoon is about 0.5 km wide and is bordered by finger­ fill canal residential developments on the west side, and impounded {for mosquito control purposes) mangrove marsh on the east. A filled causeway area and dense commercial and residential developments are immediately to the south. Station B, my control, was located near the east side of the Banana River just off the north shore of SR 401. The lagoon in this area is about 5.5 km wide, and is bordered by a government installation with low density development to the east and west, and access roads and filled causeway to the south. Over the 2-year study period salinity values ranged from 16 to 30% 4 at station A, and early morning water temperature values were from 8.0° to 29.5° C (Appendix E). Water depths at the study site were ,1.0 m. Sediment analyses were done by the methods in Holme and Mcintyre (1971). Samples taken in April 1977 and November 1978 showed the following mean values: 90.6% sand {particles >62 µm), 8.6% silt-clay (particles <62 µm), 0.8% shell (all particles >1 mm), and 1.3% volatile (loss after 1 hour at 500° C). Vegetation consisted primarily of the seagrasses Halodule wrightii as dominant, with some Figure 1. Locations of Station A in Sykes Creek and Station B in Banana River. 6

---- . : .. ·· 0 / / , / ... / / / / t / N / I BREVARD COUNTY

Bonano River 7 Syringodium filiforme and Ruppia maritima, the latter occurring mostly during the spring and early summer. Numerous epiphytic algal species were observed. Per- cent vegetative cover was visually estimated to range from 20 to 75% from winter to summer. Water depths and vegetation types and coverage at station B were very similar to station A. Over the study period salinities at B ranged from 20 to 33%. and water temp­ eratures ranged from 6.5 to 29.0° C (Appendix F). Sediment samples taken the same time as at station A were: 88.4% sand, 11.0% silt-clay, 0.6% shell and 2.0% volatile. About 5.5 million liters per day of secondarily treated sewage effluents and an undetermined, but substan­ tial, amount of urban stormwater runoff enters Sykes Creek in the general area of station A. The nearest residential areas and/or sewage effluent discharges to station B are approximately 2.5 km to the south and 8.0 km to th~ north. Chemical parameters related to enrichment were only occa- sionally measured during the study. However, data are available (Betz Engineers and Brevard County Health Dept., unpublished data) from near the study sites (Table 1). Presented values were measured from samples taken within Phosphorus (Total P0 l km of station A, and 5 km of B. 4 as P) and chlorophyll (Chl ) concentrations were higher a a (p <.001) at station A than at station B. Total Kjeldahl nitrogen (TKN) was higher at station B (p <.01). These findings might appear inconclusive with respect to relative enrichment. However, Chl concentrations show station A a to be much more enriched than station B (Table 1). Also, I have observed several fish kills in Sykes Creek previous to the · present study, and found these to be associated with hypoxic conditions and algal blooms. No fish kills were observed during the present study in either study area. Table 1. Selected water quality parameters collected near stations A anq B from 1976 through 1979. Total Kjeldahl nitrogen (TKN) values were higher at station B (p <.01, Mann-Whitney U test), but total phosphate as phosphorus (T-P0 as P) and chlorophyll (Chl ) were higher at station A 4 a a ( p < .O 0 1 , Mann-Whitney U t es t) .

Station A, Sykes Creek Station B, Banana River

TKN T-Po as P Chl TKN T-Po as P Chl 4 a3 4 a3 (mg/1) (mg/l) (mg/m ) (mg/l) (mg/l) (mg/m ) -- - Mean: 1. 02 0. 18 30.43 1. 30 0.04 4.59

Range: ~.01-1.40 0.09-0.26 6.26-59.46 0.70-1.85 <0. 0 1-0. 11 0.10-14.50 n: 15 17 21 19 24 30

co MATERIALS AND METHODS Field Collections Macrobenthic collections from the natural substratum were made at stations A and B (Figure 1) at monthly inter­ vals from July 1977 through June 1978, and at bi-monthly intervals from August 1978 through July 1979. Samples were taken with a hand-held PVC coring device 15 cm in diameter. Each sample was a composite of six cores except on three occasions (July, December 1977 and May 1978) when the cores were analyzed individually to estimate the adequacy of the composites. Cores were taken in a random-like (true random sampling using a numbered grid and random numbers was not accomplished, but rather samples were taken in a non-syste­ matic and arbitrary manner) fashion only in unvegetated areas. Each sampling station covered an area of approxi­ mately 10 x 100 m, and was in water depths ranging from 0.2 to 1.0 m. Only unvegetated bottoms were sampled so as to make the natural substratum data as comparable as pos­ sible to the recolonization data (methods below). Macro­ benthos of seagrassed areas proper generally differ in species composition and organism density from macrobenthos of immediately adjacent unvegetated bottoms (O'Gower and Wacasey 1967, Santos and Simon 1974, Orth 1977, Virnstein 1978). Each sample was sieved on a 0.5-mm sieve and the resi­ due fixed in 5% formalin with rose bengal stain added. Ani­ mals were sorted in the lab and preserved in 80% EtOH or IpOH. All specimens were identified, in most cases to spe- cies, and enumerated. In those cases where a taxon was extremely abundant, a 1/10 to 1/2 aliquot of the sample was taken of that particular taxon to facilitate counting. These aliquots were taken by evenly spreading the sample over the bpttom of a sorting pan, dividing the sample into equal 10 sections, and sorting one or more sections. Appropriate conversion factors were then applied to obtain density estimates on a per m2 basis for that taxon.

For the recolonization studies at both sites all sediments were taken from the natural substratum at sta­ tion A and were defaunated by one of two processes. The first process consisted of placing the sediment directly in­ to circular plastic dish pans B cm deep and 0.05 m2 in area at the top, and it was allowed to dry exposed to the air, then was re-wetted with tap water. This wet-dry process was continued for 5 weeks. As a check on effectiveness the con- tents of two pans were sieved; no living macroinvertebrates were found. The second process involved placing the sedi­ ments into black plastic bags, sealing them, and allowing them to remain exposed to the sun for about 15 weeks during the summer. Temperatures of 400 C were measured in the sedi­ ment in the bags. Parts of the contents of several bags were sieved and no living macroinvertebrates were found. After defaunation, the sediments were returned to the study sites in plastic pans which had been filled to just below the lip with sediment. The pans were individually covered with plastic sheeting and nestled about 5 cm into the natural substratum. After turbidity had settled the plastic sheeting was removed. Six to 20 pans of def aunated sediment were placed at each station on 1 December 1977, 20 March, 9 June and 21 September 1978, allowing recoloniza­ tion sequences initiated at four different times of the year to be monitored. Two pans were removed at each sampling period (see Appendices C and D for sampling dates) by indi­ vidually placing a fine mesh nylon cloth over the top of each pan, and slowly raising it to the surface. The contents were emptied into a 0.5 mm sieve and processed. The two pans were composited for a single sample which was treated exactly as the natural substratum samples. 11 Oxygen, salinity, temperature, and pH of the near­ bottom waters were measured in situ using a dissolved oxy- gen-temperature meter, refractometer, and pH meter. Each station was monitored at approximately weekly to bi-weekly intervals, but up to several times per week during the sum- mer. A total of 91 measurements were made at station A and 50 at station B during the 2-year study. Measurements were always within 2 hours a~ter sunrise when oxygen concentra­ tions would likely be minimal for any 24-hour period. Temp­ erature would be minimal for ihat day, but would still re­ flect the general date of maximum levels.

Data Analysis A species was considered "common" and subjected to further analyses if it met at least one of the following cri­ teria: (1) present in at least 80% of the natural substratum samples (15 of 19 at station A or 14 of 17 at B), (2) present in at least 80% of the natural substratum samples taken when the recolonization pans were in place (8 of 10 from both sta­ tions), and (3) present in any sample at a density of greater than 1,000 organisms/m2. These criteria would include all persistently present species so that adequate data would be available for analyses, and all species with at least transi­ ent numerical dominance and thus possible opportunistic cha- racteristics. The criteria were applied independently to data from each station. The term "opportunist" was used by MacArthur (1960) to contrast "equilibrium" species. He essentially considered opportunists to be species with populations that are vari­ able in space and time, dependent on environmental variabil­ ity. Several studies on marine benthos have also defined the term "opportunist." Grassle and Grassle (1974) charac­ terized opportunists as species that have an "initial re­ sponse to disturbed conditions, ability to increase rapidly, large population size, early maturation, and high mortality!' McCall (1977) considered his "Group 1 species" to be oppor- 12 tunists which are "early colonizers" that have "many repro- ductions per year, high recruitment, rapid development, and

high death rate." Rhoads, ~ al. (1978) referred to McCall's "Group 1 species" as "Group 1 colonizers", with no mention of the term "opportunist." The changing concepts (see Parry

1981) involved with ~- and K-selection are also relevant, further complicating the term. Obviously, the term "oppor­ tunist" entails a complex of criteria. However, the essen­ tial attributes of such species seem to be that they are capable of rapidly invading and dominating vacant habitat, but are temporary dominants. Species capable of rapid invasion but temporary domi­ nance do often show early maturation, high mortality, many reproductions per year, and high recrutiment. But some op- portunists may not possess all these characteristics. For example, some species may rapidly invade an area by immigra­ tion of large numbers of adult organisms, which after a short time may emigrate from the area. Are these species to be considered opportunists? Based on MacArthur (1960), I believe they would be termed opportunists. Therefore, in this report I use the term "opportunist" to mean a species showing large and rapid population density increases in va­ cant habitat (defaunated sediments), and large density de- creases. Maximum rates of observed density change, both increses and decreases, were calculated for each species for each re­ colonization sequence for each study· site. These absolute values were summed to get a maximum rate of density change (MRDC) expressed in organisms/m2/month. The MRDC was calcu­ lated for each species from each station independently (Table 2). A MRDC greater than 5,000 was chosen to qualify a spe­ cies .as an opportunist. Equilibrium species were defined (using criteria simi­ lar to McCall 1977) as those species showing relatively low MRDC values (Table 2), low densities (generally less than l,OOO/m2), and persistent presence in all samples. Their I 13 populations in the recolonization sequence invariably rose to a low peak density and remained relatively stable. These species were also relatively large in size. RESULTS Samples from station A yielded approximately 96 species; station B yielded 121 species. From both sta- tions a total of 131 species were collected, with 86 occur­ ring at both stations. Thus all but 10 of the species from station A occurred at station B, plus an additional 35 spe- cies (Appendices A, B, C and D). Using the above criteria to qualify as "common," 25 species from station A and 20 species from station B, for a total of 35 different species (Table 2), were selected for further analyses. Substantial numbers of oligochaetes and nematodes were occasionally encountered, but were not considered in this study. In a comparison of the effectiveness of 0.5 mm vs 0.25 mm-mesh sieves, I found that most of these two taxa were passing through the 0.5 mm sieve (which was the size used in the present study). Therefore, they were ignored because it seemed likely that their densities were being inaccurately estimated.

Objective (1): Define the Species Displaying Opportunistic and Equilibrium Characteristics Using Recolonization Data Eight species were defined as opportunistic and three were defined as equilibrium based on recolonization data from the present study. The following species listed in decreas­ ing order of relative degree of opportunism, were selected: Corophium ellisi, Anomalocardia auberiana, Grandidierella bonnieroides, Capitella capitata, Parastarte triquetra, unidentified podocopan ostracod, Parasterope pollex, and Haploscoloplos foliosus. The choice of these was somewhat subjective for several reasons. There was no apparent division point between MRDC values (5,000 was chosen as 15

Table 2. Ranking by maximum rate of density change (MRDC), which is a summation of the maximum rates of increase (In.) and decrease (De.) for each of the four recol­ onization sequen~es. All units are in number of organisms/m2/month.

Seq. fl l Seq. 112 Seq. /)3 Seq. 114 Rank Species In. De. In. De. In. De. In. De. MRDC

1 Corophium ellisi 13527 0 20000 9364 19476 4871 14249 0 81487 2 Anomalocardia auberiana 141 0 3110 1416 4268 1438 6667 2326 19366 3 Grandidierella bonnieroides 4468 797 64 18 2294 1457 575 0 9673 4 Capitella capitata 1199 0 3978 1642 813 456 214 0 8302 5 Parastarte triguetra 43 0 366 19 1 3316 2857 513 66 7352 6 podocopan ostracod 133 34 662 67 488 705 3846 1374 7309 ~ 7 Parasterope pollex 1271 0 3978 751 285 152 18 0 6455 Q) 8 Haploscoloplos f oliosus 15 60 0 2796 4 49 362 32 322 0 5521 ~ 9 Gammarus mucronatus 2198 0 108 35 557 0 842 0 3740 C,) 10 Streblospio benedicti 124 0 286 6 112 124 1025 418 2095 ct> 11 Gyptis brevipalpa 50 0 227 133 902 502 11 4 0 1928 ~ 12 Polydora l.!.&!!.! 575 309 204 25 89 24 308 95 1629 :; 13 Tellina tampaensis 21 9 451 18 295 119 487 40 1440 14 Hargeria rapax 459 0 516 168 1 81 64 0 0 1388 < 15 Clymenella mucosa 614 115 215 214 33 14 22 0 1227 c: 16 Cymadusa comp~ 483 0 11 6 157 0 275 0 932 0 1 7 Eteone heteropoda 34 0 62 76 228 1 11 172 0 683 :! 18 Utriculastra canaliculata 43 44 2 3 7 116 49 16 137 7 649 :: 19 Tagelus plebeius 64 1 8 119 95 18 0 179 33 526 tn 20 Prionospio heterobranchia 53 24 0 0 41 23 1 1 0 152 21 Nereis succinea 0 0 5 0 76 0 66 0 147 22 Nassarius vibex 43 18 19 6 16 16 17 0 135 23 Ophiophrag~ilograneus 0 0 65 23 8 5 l 7 0 118 24 Dorvillea rudolphi 0 0 43 0 19 0 7 0 69 25 Melinna maculata 10 0 0 0 0 0 0 0 10

1 Parasterope pollex 2600 0 3010 867 130 74 1 1 0 6692 2 Prionospio heterobranchia 644 45 266 0 684 0 1368 527 3534 3 Capitella capitata 364 72 11 0 429 348 385 154 1763 i... 4 Clymenella mucosa 700 0 387 0 53 0 342 120 1602 QI 5 diastylid cumacean 222 0 785 416 32 0 55 0 1510 ! 6 Scolelepis texana 78 0 40 0 48 0 812 344 1322 a:: 7 Cymodoce f axoni 82 33 66 46 16 5 786 249 1283 ~ 8 Haploscoloplos f oliosus 9 6 0 0 300 332 299 124 1070 cu 9 Phascolion cryptus 130 111 247 0 217 0 60 3 768 ; 10 Tellina tampaensis 39 0 75 23 207 241 9 4 598 i:Q 11 Caecum pulchellum 101 106 86 6 98 37 85 33 552 .. 12 Ophiophragmus filograneus 44 0 118 0 166 0 60 0 388 i:Q 13 Gyptis brevipalpa 22 0 29 0 150 0 85 0 286 c: 14 Melinna maculata 92 44 6 0 0 0 11 0 153 ~ 15 Utriculastra canaliculata 42 18 11 6 23 37 9 4 150 ~ 16 Amygdalum papyrium 6 0 11 6 65 23 0 0 1 1 1 .i 1 7 Tellina versicolor 39 22 22 0 27 0 0 0 11 0 tn 18 Glycinde solitaria 0 0 0 0 21 0 26 4 51 19 Glycera americana 1 7 0 12 0 5 0 11 0 45 20 Diopatra cuprea 5 6 0 0 11 0 18 0 40 16 minimum to qualify as opportunist) except at station B where only P. pollex was relatively high (Table 2). Also, most of the opportunists displayed very equilibrium-type recolonization patterns at least once. Most only had two or three (out of four) "typical" opportunistic-like sequences of rapid density change (Table 2, Figure 4). Several species, e.g., Streblospio benedicti and Polydora ligni, previously cited as opportunists (Table 3) did not behave as opportunists in the present study (Table 2). Therefore, even though there are clearcut differences between oppor­ tunistic and equilibrium patterns of recolonization, a species may not consistently display opportunistic characteristics. The equilibrium species were Ophiophragmus filograneus, Phascolion cryptus and Tellina tampaensis. Their re- colonization patterns were consistently similar in all recolonization sequences (Figure 3).

Objective (2): Assess Natural Substratum Data Based on Abundance of Opportunistic and Equilibrium Species Station A in polluted Sykes Creek was dominated by opportunistic species in the natural substratum. Station B, the Banana River control site, had less opportunists and a greater relative abundance of equilibrium species (Table 3). The 25 "common" species from station A included all eight herein-defined opportunists with the top ranking five being opportunists. The 20 "common" species at station B included only three opportunists. Even the one species defined as opportunistic based on station B data ranked only fourth in abundance in station B natural substratum. The percent composition of opportunists was 88.1% at station A and 24.0% at B. The three equilibrium species made up 25% of all specimens collected from station B, with the most abundant species being equilibrium, vs 2% of the specimens Table 3. Ranking of the "common" species based on total number of specimens collected over the 2 year study from natural substratum samples only. An apostrophe (') precedes each species defined in the present study as an opportunist, and a quotation mark (") precedes each equilibrium type species.

Station A, Sykes Creek Station B, Banana River Species Total Total Collected Collected 'Corophium ellisi 33,713 "Phascolion cryptus 937 'Haploscoloplos foliosus 3,803 Clymenella mucosa 762 'Capitella capitata 2,510 'Capitella capitata 669 'Anomalocardia auberiana 2,318 'Parasterope pollex 661 'podocopan ostracod 1,730 diastylid cumacean 652 Clymenella mucosa 1,565 "Ophiophragmus f ilograneus 309 Hargeria rapax 1, 11 8 "Tellina tampaensis 305 "Tellina tampaensis 1,080 Melinna maculata 295 'Parasterope pollex 814 Scolelepis texana 276 'Parastarte triquetra 712 Prionospio heterobranchia 258 'Grandidierella bonnieroides 615 Cymodoce f axoni 182 Gammarus mucronatus 510 'Haploscoloplos foliosus 160 Gyptis brevipalpa 485 Glycinde solitaria 130 Eteone heteropoda 325 Gyptis brevipalpa 114 Polydora ligni 256 Diopatra cuprea 113 Tagelus plebeius 237 Caecum pulchellum 106 Utriculastra canaliculata 205 Utriculastra canaliculata 101 Streblospio benedicti 131 Glycera americana 68 Prionospio heterobranchia 96 Tellina versicolor 54 Dorvillea rudolphi 73 Amygdalum papyrium 53 "Ophiophragmus filograneus 48 Cymadusa compta 30 Nereis succinea 28 Nassarius vibex 21 Melinna maculata 18 ...... -....,J 18 being equilibrium species at station A. One might argue that circular reasoning is involved in this assessment because seven of the eight opportunists were defined as such based only on station A data; only one species was defined as opportunistic using station B data (Table 2). However, only recolonization data were used in defining opportunistic and equilibrium species. Even though the recolonization patterns in the present study were apparently reflective of surrounding natural substratum populations (Figures 2, 3 and 4), at least two studies have indicated that surrounding natural substratum populations apparently did not determine the recolonization patterns at their study sites (Boesch and Rosenberg in press, Fredette 1980). Consequently, I believe the above data suggest a difference in relative importance of species of different life history strategies at the polluted vs less-polluted study sites. The opportunist hypothesis predicted that the Sykes Creek station A numerical dominants, i.e., indicator species, would be opportunistic. This prediction was fully supported in that the top five numerical dominants from the natural substratum samples, Corophium ellisi, Haploscoloplos foliosus, Capitella capitata, Anomalocardia auberiana and Parasterope pollex, were all defined as opportunistic. These five species made up 84% of the total specimens collected from station A (Table 3).

Objective 3: Relate Physicochemical Data to Macrobenthic Data Station A macrobenthos manifests the enrichment of the water column (Table 1) by greater densities of organisms than at station B (Figures 2a and ~a). This enrichment ef­ fect is well documented in many areas (McNulty 1970, Stirn

1971, Pearson and Rosenberg 1978, Soule, ~ al. 1978, Reish 1979, Dauer and Conner 1980), and will not be discussed. Other physicochemical data and macrobenthic dynamics re- Figure 2. Station A, Sykes Creek, (a) natural substratum community densities with early morning dissloved oxygen (DO) concentrations and temperature levels, (b) community densities for the four recolonization sequences. The bars on part (a) community density means show ± ls. 19

(a) 60 Natural Substratum, Station A -.-- COMMUNITY O> 'E OENSlTY () 0 45 75 30

~ ci. 30 5.0 20 E ~

-() () Q 15 2.5 10

...._.x (\J E ......

~E o+-~-'---'-~..J..----~_,___._~..___,___..______._~..J..--'-_._ c: Recolonization, Station A (b) ~ I () . I 45 I I I I 30 I I I I 15 I I I I o__ ~_._~.__-L-__. ______._ ____.__._.~~---~------~~ JS NJ MM JS NJ MM J 1977 1978 1979 SEQUENCE: I 2 3 4 I DEC 20MAR 9JUN 21SEP Figure 3. Part (a) station B, Banana River community den­ sities, natural substratum and recolonization; (b), (c) and (d) population densities of the three equilibrium species in the natural substratum and recolonization sequences. All natural substratum mean densities for July and December 1977 and May 1978 have bars showing + ls. 20

15 Station B Community Densities (a) I I I 10 I I -0 I 0 I 0 5 I I x I I r'

Phascol ion cry_Qtus, Station B (d)

JSNJMMJSNJMMJ JSN JMMJSN JMMJ 1977 1978 1979 1977 I 2 3 4 1979 I DEC I 9JUN I 20MAR 21SEP Natural Substratum ·(:!: Js) Recolonization Sequences 1-4 Figure 4. Population densities of the top three opportunis­ tic species showing natural substratum and recolonization data. All natural substratum means for July and December 1977 and May 1978 have bars showing ± ls. 21

60 ellisi, Station A ~Rhium (a)

45 I I I I I 30 I I I I I I I I I 5 ~ I I o I I o I I x I ) NE 0-t---r-r--T-r--r-r--r--r--.---r--r~-...:--+~~~,..._...,.~~~~~~~ ...... (b) Cl> E U> c 0 ~ 2.5 0

~ . 7,800 (c ) Anomalocardia auberiana, Stati~~2 ~0 ~ ~.. , 1' '\ 2. I \ I ~ I \

JSNJMMJSNJ.MMJ NJMMJSNJ 1977 1978 1979 1977 I 2 3 4 1979 I DEC I 9JUN 1 20MAR 21SEP Natura I Substratum (:!:Is) Recolon izotion Sequences I- 4 22 vealed no correlations, with the exception of oxygen and temperature at station A (Appendices A and E, Figure 2). If all monthly means for oxygen and temperature are shifted forward 2 months (e.g., correlate January oxygen and temp­ erature with March benthic data) they show Spearman's rank

) correlation coefficients (r 8 of +0.87 and -0.90, respec­ tively, when correlated with macrobenthic densities (Figure 2a). These data suggest a strong relationship involving a time lag between oxygen-temperature changes and macro­ benthos. Also, maximum temperatures in conjunction with minimum oxygen concentrations coincided (no 2-month lag) with macrobenthic density drops for three consecutive sum­ mers at station A (Figure 2a). If the above correlations represent a cause-effect re­ lationship, then the summer oxygen-temperature extremes may be considered to represent a disturbance to the macrobenthos because of the density decreases (Table 4). Also, oxygen concentrations were significantly lower at station A than at station B (Wilcoxon's signed rank test, p<.05), presum­ ably because of differences in pollution effects. In summer 1978 when the pattern of oxygen-temperature extremes and macrobenthic declines was first noticed, only two oxygen and temperature measurements had been made in June and July 1977 and only five from April to July 1978. However, between 1 May and 30 July 1979, 27 oxygen and temp­ erature measurements were made at station A. This was an attempt to more accurately determine the date of occurrence of extremes of the parameters, and to show any correlation with macrobenthic declines. From May through July oxygen concentrations were consistently near or below 2.5 mg/l. Maximum temperature for May was 26.5° C; June had a maxi­ mum of 28.SO; the summer maximum of 29.5° was first re­ corded on 5 July. On 11 June station A macrobenthic den­ sity was 34,000 organisms/m2; on 27 July it had dropped to below 2,000 organisms/m2. Thus, for 1979 the density 23

Table 4. Station A, Sykes Creek, natural substratum densities taken before and after 5 July 1979 oxygen-temperature extreme. An apostrophe (') precedes each opp or tun is t , and a- quot at ion mark (") precedes each equilibrium type species.

2 Organisms/m Species 11 June 27 July

'Corophium ellisi 20,240 10 'Haploscoloplos foliosus 5,980 460 'Capitella capitata 2,480 40 'Anomalocardia auberiana 640 60 'podocopan ostracod 600 320 Clymenella mucosa 550 200 Hargeria rapax 550 0 "Tellina tampaensis 620 130 'Parasterope pollex 50 0 'Parastarte triquetra 160 0 'Grandidierella bonnieroides 20 0 Gyptis brevipalpa 70 110 Eteone heteropoda 140 190 Polydora ligni 1,010 20 Utriculastra canaliculata 140 40 Streblospio benedicti 20 . 0 Prionospio heterobranchia 0 10 "Ophiophragmus f ilograneus 20 20 Nereis succinea 50 0 Nassarius vibex 0 20 Melinna maculata 10 0 24 decrease producing minimum densities was observed just af­ ter maximum temperatures were reached in conjunction with already minimum oxygen concentrations. Large density de­ creases were noted for most species at station A, including all five indicator species (Table 4). These results sug­ gest no special tolerance by the indicators to oxygen-temp­ erature extremes if the relationship is cause-effect. Therefore, the prediction of superior tolerance by the indi­ cator species is not supported. No extreme seasonal fluctuations in macrobenthos oc- curred at the less-polluted station B (Figure 3a). Temp- erature levels on any given date were usually within 1° of station A, but as mentioned, oxygen concentrations were significantly higher. However, some oxygen concentrations below 2.5 mg/l were recorded during 1977 and 1978 at station B (Appendix F). Only two oxygen and temperature measure­ ments were made at station B during summer 1979 so adequate comparison with the 27 measurements from station A cannot be made. These data could indicate a relationship between macrobenthic density and critical oxygen-temperature levels, since the macrobenthos at station A were apparently not com­ pletely eliminated each summer but rather decreased to a density similar to station B macrobenthos (Figures 2a and 3a). DISCUSSION As mentioned above, three major hypothetical explana­ tions have been put forward to account for the dominance of indicator species in organically polluted coastal waters. Of these, the opportunist hypothesis is the primary expla­ nation tested by the present field study. My data concerned with the tolerance hypothesis are tentative at best. The competition hypothesis is not tested by my field data. Therefore, while the total pollution indicator concept is addressed in Section II, only the opportunist and tolerance hypotheses will be briefly discussed below.

The dominant indicator species a~ station A in polluted Sykes Creek were shown to be opportunistic based on recolo­ nization data, as predicted by the opportunist hypothesis. Conversely, station B Banana River data showed a greater relative abundance of equilibrium-type species. These data suggest the pollution effects at station A are manifested by a shift in life history strategies from equilibrium to more opportunistic. Natural substratum recolonization after annual def aunations in organically enriched Hillsborough Bay, Florida clearly demonstrated the opportunistic chara­ cter of the dominant indicator species (Santos and Simon 1980). Pearson and Rosenberg (1978) and Gray (1979, 1980) discussed the opportunistic life history strategy of several pollution indicator species. Based on recoloni- zation of experimental and natural substrates, there are now at least 25 species defined as opportunists mainly because of excessive rates of density change. Seventeen of the 25 are also reported pollution indicators (Table 5). These data suggest that a general explanation for the indicator concept is emerging. However, a full investi- 26

Table 5. Species that have been defined in the listed references as an "opportunist," or can be inferred as such based on data presented in that report, because of extreme invasion and/or mortality rates. If reported as a density dominant, i.e. an "indicator," in waters polluted by organic wastes, the reference is given. Reference key: I-Grassle and Grassle (1974), 2-McCall (1977), 3-Pearson and Rosenberg (1978), 4-Grizzle (1979), 5-Santos and Simon (1980), 6-Fredette (1980), 7-Virnstein (1979), 8-present report.

Collected From Reported as an Reported as an Species Sykes Creek "Opportunist" "Indicator"

Polychaeta Capitella capita ta YES 1,2,8 3,8 Cistenides gouldii YES 6 Eteone heteropoda YES 6 3 Haploscoloplos f oliosus YES 8 8 Heteromastus f ilif ormis NO 6 3 Mediomastus calif orniensis NO 5 3,5 Microphthalmus aberrans NO I Nereis succinea YES 6 Polydora ligni YES 1. 6. 7 3 Streblospio benedicti YES 1,2,5,6,7 3,5 Syllides verrilli NO 1

Oligochaeta Paranais litoralis NO 6

Mollusca Anomalocardia auberiana YES 8 4,8 Haminoea solitaria NO 1 Ma coma tent a NO 1 Mulinia lateralis YES 1. 5. 7 5 Mysella planulata NO 5 5 Parastarte triguetra YES 8 4

Amphipoda AmEelisca abdita YES 2. 4' 5 4,5 CoroEhium ellisi YES 8 4,8 Grandidierella bonnieroides YES 4,5,8 4,5

Cumacea CyclaEsis sp. NO 5 5

Ostracoda unidentified podocopan YES 8 8 ParasteroEe pollex YES 8

Tanaidacea Bargeria raEax YES 4 4 27 gation of tolerance and competitive abilities of most indicator species has yet to be performed (see Section II). The indicator species in Sykes Creek are opportunistic. Possible annual disturbances that would produce vacant habi­ tat and allow invasions by opportunists are discussed below. But are these disturbances necessary to allow the opportu­ nists to dominate? Perhaps the opportunistic life history strategy is coincidental with superior competitive abilities for exploiting food. Carefully designed laboratory and/or field experiments will be required to fully unravel the rea­ sons for the dominance of the opportunistic indicator spe­ cies in Sykes Creek (see Section II for more details on pos­ sible investigative approaches). Each summer in my study there were sharp declines in densities of most species present, including indicator spe­ cies, at station A. These declines were associated with oxygen-temperature extremes. Watling (1975) reported simi­ lar declines for three consecutive summers associated with high water temperatures in a shallow Delaware estuary, but did not report oxygen data. Santos and Simon (1980) re­ ported three consecutive summer dieoffs affecting all species present in polluted Hillsborough Bay, Florida, associated with hypoxic periods. If the relationships in Santos and Simon (1980) and my study were cause-effect, then the pre­ diction that indicators are more tolerant of disturbance is not supported. A reasonable explanation for station A data is that oxygen-temperature levels resulted in environmental conditions insufficient to support the high macrobenthic densities. There were also strong correlations between station A oxygen (rs= +0.87) and temperature (rs= -0.90) and macro­ benthic densities when oxygen and temperature data were shifted forward 2 months. Why the lag for the macrobenthic densities to manifest the changes in oxygen and tempera­ ture? There are probably numerous factors contributing to 28 macrobenthic population dynamics in Sykes Creek. The pre­ sent study could by design do nothing more than suggest pos­ sible relationships suitable for further investigation. Oxy­ gen and temperature are major environmental parameters af­ fecting most aquatic organisms, and it seems reasonable to expect some relationship between them and population dynamics. Reish (1979) reviewed several reports showing significant impairment of reproductive abilities of two polychaete species at reduced oxygen concentrations. Reduced reproductive capacities could perhaps account for the 2- month lag time owing to normal population control factors, e.g.,predation, not being offset by possible continued recruitment. It may also be that some pollution-enriched areas with high densities of macrobenthos are good feeding grounds for predatory organisms seasonally entering the system (see Soule,~ al. 1978). Virnstein (1980) re- viewed several studies showing significant reductions in macrobenthic densities by predation. Virnstein (1979) showed that several previously reported indicators were very susceptible to predation (see further discussion below). Peterson (1980) suggested that the density crashes generally observed in populations of opportunists may be a result of naturally short life spans. This may also be true, but at station A populations of species not known to be opportunistic also declined (Table 4). These data suggest several possible avenues for further investigation. The tolerance hypothesis is not supported by my data for explaining the dominance of indicator species in Sykes Creek, yet it is not refuted. Better-designed studies are needed to provide adequate testing of this hypothesis in Sykes Creek. A combination of laboratory and field experiments that will allow an assessment of oxygen tolerance and sub le th al effects, possible impacts of predation, and long-term aspects of community succession in the absence of catastrophic disturbances, are needed. SECTION II. AN ANALYSIS OF THE INDICATOR CONCEPT OVERVIEW OF INDICATOR CONCEPT The use of indicator species data as a means to assess pollution impacts has generally been limited in marine studies. Other methods of data assessment have generally been more popular. The indicator concept is not basically flawed, but is nonetheless based on descriptive surveys (see Pearson and Rosenberg 1978). Researchers have not utilized working hypotheses (Platt 1964) that would provide testable predictions; thus explanations have tended to be based on speculation rather than experimental data. It is un­ deniable that certain indicator species flourish in some polluted areas, but some of the same species also dominate in unpolluted areas (Eagle and Rees 1973, Botton 1979). This is perhaps the main complaint with the indicator con- cept - conflicting observations. But this complaint is based on a restricted view of the concept, where species presence means pollution, and vice versa. While the present state of the art may have restricted it to this type of use, the potential use of species composition data in the indicator framework is b y no means that narrow. There are obviously reasons for such apparent discrepancies. By addressing these reasons using a systematic approach of hypothesis testing, I believe real progress can be made in the general use of macrobenthic data in pollution impact studies. The possible alternative life history strategies for macrobentic species with respect to response to organic pollution was proposed by Gray (1979) based on a model by Grime (1977). These strategies consisted of the r- and K-strategy concept with emphasis on reproduction and comp­ etition, respectively, plus tolerance abilities. In low 30 disturbance-low stress areas superior competitive (K-strategy) abilities are more successful, and in low disturbance-high stress areas tolerance abilities are more successful. In high disturbance-low stress areas reproductive superiority (~­ strategy) is more successful, and in high disturbance-high stress areas all species are excluded. To my knowledge no one has examined a polluted area using these hypothetical strategies, although Reish (1967) and Henriksson (1969) pro- vided a test of the tolerance strategy. Of the three hypotheses, the opportunist explanation has recently been shown to account for the dominance of several indicator species (Gray 1979, Santos and Simon 1980, section I in present report). But much more remains to be learned. I am in agreement with Gray that the above three strategies perhaps represent an oversimplified view. How- ever, when stated in hypothesis form with predictions they provide a sound basis for direct testing of the major proposed explanations for the dominance of indicators in polluted areas. Owing to the dif£erent meanings that have been as­ signed to "_£-strategy" and "!_-strategy" (see Parry 1981), I offer the following re-statement of Gray's (1979) strat­ egies in hypothesis form eliminating the~- and K- aspects. Each hypothesis is followed by some of the reports from which it was taken and by proposed predictions. These hypotheses are that indicator species dominate in organically enriched areas because: (1) They possess superior invasion abilities, i.e.,are more opportunistic, and thus better able to recolo­ nize vacant habitats produced by sporadic pollution­ produced dieoffs (Grassle and Grassle 1974, Pearson and Rosenberg 1978, Gray 1979, Santos and Simon 1980). This hypothesis predicts that experimental and natural recolonization studies in polluted areas will show the indicator species to be opportunistic. Life history studies will show that indicators possess reproductive 31

characteristics suited f6r the opportunistic trait of rapid invasion, e.g., frequent breeding and brood protection of young. (2) They possess superior abilities to tolerate low oxygen concentrations and/or other stressful conditions re­ sulting from pollution. This hypothesis is found in many reports (Filice 1959, Reish 1959, Pearson and Rosenberg 1978). It predicts that the indicators are more resistant to disturbances by hypoxia and perhaps other stresses than non-indicator species. (3) They possess superior abilities to utilize increased food supplies associated with organic enrichment. This hypothesis has apparently not been explicitly stated except in Gray (1979), although McNulty (1970), Stirn (1971) and Reish (1979) proposed the importance of supposed decreases in competition and predation to the

dominance of i~dicators. This hypothesis predicts that enrichment of a natural substratum or laboratory microcosm containing "normal" macrobenthic densities and species numbers, and including some known indicator species, will result in a numerical dominance of the indicator species. Investigations of long-term aspects of competitive abilities and the effects of predation would require long-term experimints and additional treatments. These hypotheses should not be viewed as exclusive al­ ternative hypotheses but rather as possibly complementary in some cases. Each should be tested against its respective null hypothesis (see Strong 1980). There are probably sit­ uations where any one or more (or perhaps none) of these three give an accurate explanation for observed population changes. I offer the following as a brief assessment of the validity of each hypothesis with possible general approaches to testing them. HYPOTHESIS 1: SUPERIOR INVASION ABILITIES (OPPORTUNISTS) Pearson and Rosenberg (1978) and Gray (1979, 1980) pro­ vide recent summary discussions of this hypothetical expla­ nation. Thus, discussion in the present report will be limited. The opportunist life history strategy would be advantageous in a polluted area that is frequently disturbed, resulting in available habitat for recolonization. Because many moderately enriched systems display highly variable ox­ ygen concentrations (see below}, then this hypothesis might be expected to account for the dominance of indicator species in such areas. The benthic community of these areas may be expected to be comprised of a large number of species, and to show high temporal variability. Because at least seventeen indicator species have been shown to be opportunistic (Table 5, Section I), it appears that this hypothesis is emerging as a general explanation for the dominance of indicator species in polluted areas. However, the remaining two hypotheses are largely untested. A life history strategy emphasizing superior invasion abili­ ties may be coincidental with other characteristics allowing the indicators to dominate in polluted areas. In any case, further studies will be needed to test this hypothesis with other indicator species. Experimental recolonization studies should continue to provide much useful data even though the methods are not without problems. For example, results may be affected by storms (McCall 1977), other organisms (Fredette 1980), timeof sequence initiation (present study), sediment types, con­ tainer size and placement, or other variables. Also, de­ termining the relative degree of opportunism of a particular species may not be straightforward. Nonetheless, results which showed clearcut interspecif ic differences in recolo- 33 nization patterns have been reported by several authors. Some species have been defined as opportunistic based on density changes in two or more studies (Table 5 in Section I). The utility of this method is established. Additional methods providing a better understanding of the opportunist ptrategy include general laboratory studies which concen­ trate on physiological, genetic, and reproductive aspects of life histories (see Gray 1979). For example, Grassle and Grassle (1977) demonstrated the cosmopolitan pollution indicator Capitella capitata actually is a complex of at least six sibling species. Rice and Simon (1980) demon­ strated substantial intraspecif ic variation in Polydora ligni, another pollution indicator. Also, Eckelbarger (1980) suggested that study of mechanisms of yolk snythesis in polychaetes of differing reproductive strategies could provide a better understanding of their adaptive signifi­ cance. In summary, future studies concerned with testing this hypothesis should include descriptive surveys which monitor natural substratum recolonization, experimental re­ colonization studies, and laboratory work on life history aspects. These studies should be performed in conjunction with testing the remaining hypotheses discussed below. HYPOTHESIS 2: SUPERIOR TOLERANCE ABILITIES Oxygen reduction is generally considered to be the primary stress sometimes leading to disturbance when die­ off s occur in organically enriched waters (Pearson and Ro­ senberg 1978, Pearson 1980). Multiple stresses are in­ volved in many areas due to the various pollutants asso­ ciated with sewage effluents and the presence of industrial or other toxic discharges. However, in this report pollu­ tion-associated oxygen reductions are emphasized. The tolerance hypothesis has been the major explana­ tion to account for the dominance of indicator species in moderately polluted areas, but adequate data have not been available to substantiate this explanation. The literature dealing with tolerance studies on marine macroinvertebrates is voluminous, and concerned mainly with laboratory work. However, extrapolation of laboratory results to field condi­ tions is seldom justified when attempting to explain field observations. The general problem is that in the labora­ tory the test organisms are under "artificial" controlled conditions; whereas in a natural system there are additional biological and physicochemical factors (e.g., with anoxia in natural systems there is generally a concomitant build­ up of toxic hydrogen sulfide) affecting the organisms (Li­ vingston 1979, Reish 1979, Sinderman 1979, Kinne 1980). Also, there are probably few areas where investigators have adequately described field conditions with respect to water quality, especially oxygen concentrations. For ex- ample, decreased oxygen has been correlated with some indi­ cator species, e.g., Reish (1959), Leppakoski (1968), His­ cock and Hoare (1975), Kocatas and Geldiay (1980), but oxy­ gen is often quite variable over time in enriched waters, sometimes changing several mg/l in a few hours (Odum 1960, 35 Barlow, ~ ~· 1963, Knudson and Belaire 1975, Sanders and Kuenzler 1979, personal observations in Sykes Creek). Be­ cause oxygen is such an important environmental parameter, it seems likely that decreased oxygen concentrations corre­ lated with indicator dominance results from a cause-effect relationship. However, do the reported correlations mean that indicators were more tolerant of hypoxia, or were they just the most successful recolonizers of the area after a temporary undetected anoxic period that killed all macro- fauna present? These questions cannot be answered with available data. It seems apparent that available field and laboratory data are not adequate to clearly show cause­ effect relationships between tolerance abilities and indi- cator species. Nevertheless, there are adequate data to perhaps reveal some trends in oxygen tolerances among macro­ invertebrates in general. Numerous factors are known to affect an organism's tol­ erance to low oxygen concentrations; these include temp­ erature, pollutants, body size, sex, parasitism, and molt­ ing stage (Vernberg and Vernberg 1972). Again the problem of extrapolating laboratory data to field conditions is raised. However, some trends among several taxonomic groups do appear. Hammen (1976) concluded, after comparing results from Theede (1973) and uncited references, that tolerance (involving LT50 and maximum survival times) to hypoxic con­ ditions varies from a few hours to 51 days. He reported: 1) bivalve molluscs are most tolerant, 2) a variety of ma­ rine invertebrates from at least six phyla, including an­ nelids, can tolerate hypoxia for 1 to 6 days, and 3) small crustaceans are intolerant of hypoxia. Results of oxygen tolerance tests by Henriksson (1969) on a group of pollution indicators including polychaetes and bivalves supported these generalizations. Also, Reish (1967) found Capitella capitata, a major pollution indicator and an indicator of the "polluted zone" in his study, to be less tolerant (28- day Lc ranging from 0.65 to 2.95 mg/1 of oxygen) than 50 36 two other polychaetes that were indicators of the "semi­ heal thy zone." Reish's data showed a considerable range of tolerance and the unexpected result of the supposedly tolerant indicator species being less tolerant than other species. Therefore, variability is evident among and within taxa for tolerances to decreased oxygen concentra­ tions, but trends among phyla are present . .Major phyla in decreasing order of importance based on number of indicator species contained are: annelids (mostly polychaetes), molluscs (mostly bivalves) and arthro- pods (all crustaceans) (Pearson and Rosenberg 1978, Table 5 in Section I). It appears then that indicator species may be expected to show quite variable tolerances to hypoxia. Tolerance abilities may be the major factor allowing some indicators such as molluscs to dominate in polluted areas. However, these data also support the contention that other hypotheses are needed to fully explain the indicator concept. Another possibility for investigation is that "oxygen poisoning" may occur in some enriched areas due to supersat- uration of the water with oxygen. Excessive oxygen concen- trations are reported in enriched waters, especially in late afternoon on sunny warm days, due to increased phytoplankton densities and photosynthetic oxygen production (Sanders and Kuenzler 1979, personal observations in Sykes Creek). Some invertebrates are known to be killed by excessive oxygen con­ centrations (Vernberg and Vernberg 1972, Weber 1978). Livingston (1979) pointed out various drawbacks in all experimental methods from straightforward laboratory work, to simulated ecosystems (=microcosms), and in situ enclosures. He stated that a combination of life history studies, long­ term field studies, and laboratory and field experiments will probably be needed to bridge the gap between bioassays and field conditions. Laboratory microcosms (Mcintyre 1977) and in situ enclosures (Zeitzschel 1978) seem to offer particular promise when considering the unique environmental conditions found in any given area and the difficulties involved with 37 experimentation in a reasonably natural setting. If field studies in natural systems are used it should be re-empha­ sized that oxygen and other physicochemical parameters in many estuarine areas are highly variable over time. Also, recolonization studies have shown that macrobenthic response to disturbance can be substantial within only a few days (McCall 1977, Fredette 1980). Therefore, near-continuous monitoring of oxygen concentrations and approximately weekly macrobenthic sampling would be required to adequately test this hypothesis in the field (Pearson 1980). HYPOTHESIS 3: SUPERIOR COMPETITORS FOR FOOD This hypothesis is a natural inference based on the fact that the indicators are the dominant species present, and because organic pollutants mean potentially more food, they are considered better competitors for the food. This hypothesis was not addressed in the present field study, and is apparently not explicitly stated except in Gray (1979). Although McNulty (1970), Stirn (1971) and Reish (1979) discussed supposed decreases in competition and predation in polluted areas because of the general decrease in species numbers sometimes reported. This decrease may be the case in some areas, but often there are communities with numerous other species present where indicators dominate. Thus, competition is probably not always reduced when indicators dominate. How predation reduction is related to the numerical dominance of indicator species is more difficult to address, but I commonly observed numer­ ous fish species and the blue crab (Callinectes sapidus), a known benthos predator (Virnstein 1979), during the study period at station A. It is possible that predation is generally reduced in moderately polluted areas at certain times, but it is probably not eliminated in many areas. In any case indicators must at least be better competitors under some conditions when compared to other species pre­ sent, but many questions remain. For example, what role does predation play? Is the possible competitive superi­ ority of indicators limited to a certain time frame; that is, are they only able to out-compete others for a few months after a disturbance, or can they dominate indef­ initely? Is a general species reduction required for the indicators to become abundant? 39 Virnstein (1979) showed that predation by crabs (Callinectes sapidus) and/or fish (Leiostomus xanthurus) reduced the populations of the following previously reported pollution indicator species: Heteromastus filiformis, Streblospio benedicti, Polydora ligni, Para­ prionospio pinnata, Nereis succinea, Mya arenaria, and

Mulinia lateralis. All but P. pinnata and~· arenaria are also reported opportunists (Table 5). These data suggest that reduced predation may be a factor allowing indicator species to dominate in some instances, but more work is needed. Also, based on field observations Santos and Simon (1980) suggested that the opportunist Ampelisca abdita may be an effective interference competitor, but long-term aspects of its competitive abilities are un­ known. Finally, it is generally believed that some dis­ turbance is required to allow an influx of opportunists (Grassle and Grassle 1974, McCall 1977), but this may not always be true. Young and Young (1978) showed that en­ riching 4 m2 study areas by adding organic fertilizer re­ sulted in significant increases in population numbers of several species over the controls. These species included: Streblospio benedicti and Capitella capitata, both indi­ cators and opportunists, Laeonereis culveri, a density dominant in Santos and Simon's (1980) enriched study area,

and Cymadusa compta. All but ~· compta also showed the highest of all observed mean densities in enriched treat­ ments caged to exclude predators. These data suggest that these species are superior exploitative competitors for food over at least some time frame (see also Peterson 1980). They further suggest that disturbance (see below) was not required for significant increases to occur in the populations of the opportunistic species and some known indicators, and (as in Virnstein 1979) that predation effectively limits densities of some indicator species. In summary, predation may play an important role in 40 controlling some indicator species (Young and Young 1978, Virnstein 1979); some indicators are apparently better exploitative competitors for food than other species (Young and Young 1978); and competitive abilit­ ies of indicator species over long time periods is poorly understood. It has been suggested that the introduction of organic wastes into an ecosystem is a "disturbance" (Young and Young 1978, Gray 1979). Young and Young apparently suggested this because the definition of "opportunist" generally includes a reference to response to "disturbance" (Grassle and Grassle 1974, McCall 1977), and their opportunistic species responded to enrichment itself with population increases. Gray noted that organic pollution can smother some benthos (while producing an altered sediment composition, see Pearson and Rosenberg 1978) and thereby produce dieoffs, and concluded that organic pollution can be considered a "disturbance." However, such obvious sediment alterations are not observ­ ed in all areas where opportunists and indicator species dominate (Dauer and Conner 1980, present study). The term "disturbance" has generally been held to mean an event directly producing mortality among some of the organisms in an area (Pearson and Rosenberg 1978, McCall 1977).

Because enrichment ~ se has not been shown to my know­ ledge to directly kill benthos, and because Gray's mention of sediment alterations is not always the case; I believe it is incorrect to generally consider organic pollution and enrichment~~ as a "disturbance." Another aspect pertinent to this hypothesis is the generalization that r-strategists are poor competitors com­ pared to K-strategists (Wilson and Bossert 1971, Pianka 1972), and opportunists generally are ~-strategists (Grassle and Grassle 1974 and McCall 1977). Because several of the indicators have been shown to be opportunistic and some 41 are at least superior short-term competitors for food, the testing of this hypothesis has additional importance (see Santos and Simon 1980). The relationship of various characteristics generally attributed to ~- and K-strate­ gists, and even the meanings of the terms themselves (Parry 1981), are certainly not straightforward and con- sistent. However, testing of this hypothesis could pro- vide more information. A complete evaluation of this hypothesis will be difficult. Peterson (1980) reviewed the major approaches to the study of competition in soft-bottom benthos, and suggested a combination of laboratory and field experiments as the best approach. To assess aspects of enrichment and competition, it might be possible to enclose benthos (or set up a laboratory microcosom) with high species diversity and low densities typical of "normal" unenriched areas, then slowly increase organic input to the system. By introduction of predators, disturbance by hypoxia, holding the system "as is," or other appropriate treatments, suf­ ficient data could be obtained to adequately assess this hypothesis. Kuenzler, ~ ~· (1973) obtained useful data on enrichment effects of secondary sewage effluents using a similar approach in artificial ponds, but they only reported cursory benthic data. 2 Appendix A. Station A, Sykes Creek natural substratum, raw data, densities in organisms/0.1 m

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May Jun Jul 14 15 14 19 17 14 17 24 20 17 12 9 22 25 19 19 25 11 27

Annelida: Polychaeta Ampharetidae Hobsonia f loridana ------1 3 2 -- - - 1 1 Melinna maculata - 1 - - - 1 1 2 2 2 1 2 2 2 - 1 - 1 Arenicolidae Arenicola cristata -- 1 - 1 - 5 - 1 - 1 1 - 1 - 4 Capitellidae Capitella capita ta 260 213 61 29 18 78 83 78 192 115 385 193 15 21 24 92 207 248 4 Dorvilleidae Dorvillea rudolphi -- 8 6 3 16 2 9 6 6 8 1 2 2 - 1 1 Eunicidae Mar~ sanguinea -- 2 1 - 1 - 1 1 3 1 ------2 Glyceridae Glycera americana ------1 Goniadidae Glycinde solitaria ------1 1 1 - -:- 5 1 --- 7 2 Hesionidae Giptis brevipalEa 20 12 35 13 11 47 32 41 46 52 38 6 32 13 14 13 7 7 11 Podarke obscura 1 - 1 1 3 1 1 - --- 1 7 -- - - - 3 Parahesione luteola - - 1 ------1 Maldanidae Asychis carolinae ? ------1 Branchioasichis americana - - - 1 1 - 5 - 1 2 1 2 -- - - 3 3 1 Clymenella mucosa 78 24 12 5 8 144 161 387 256 110 74 5 - - 3 3 41 SS 20 Nereididae Ne re is succinea -- 1 - 3 8 4 1 2 2 1 1 - - 1 - - 5 ---Onuphidae Diopatra cuprea - 2 - -- - - 2 - - - - 1 Orbiniidae Haploscoloplos f oliosus 534 338 28 13 28 138 221 223 291 179 175 51 21 28 37 87 432 598 46 H. robust us ------1 Scoloplos rubra ------1 Pectinariidae Cistenides gouldii - 1 5 1 1 - - - 1 -- - 10 2 2 Phyllodocidae Eteone heteropoda 31 18 41 5 7 14 16 41 17 8 6 7 12 - 6 29 10 14 19 Sabellidae Sabella microphthalma ------1 Serpulidae unident. sp. - - - - 1

~ N 2 Appendix A. Station A, Sykes Creek natural substratum, raw data, densities in organisms/0.1 m (cont.).

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May Jun Jul 14 15 14. 19 17 14 17 24 20 17 12 9 22 25 19 19 25 11 27

Annelida: Polychaeta (cont) Spionidae Polydora ligni 3 1 1 1 - 3 2 11 2 - 28 28 1 22 1 - 14 101 2 PrionosEio cirrif era 1 - - - - - 1 - - 1 p. heterobranchia - - 6 11 8 22 11 5 11 7 2 - 1 - 2 - 1 - 1 ScoleleEis texana ? ------2 9 - 2 1 ------1 Streblos.E...!.£ benedicti 3 - 5 3 1 13 10 28 14 2 4 8 - 29 - - - 2

Arthropoda: Crustacea Amphipoda CoroEhium ellisi 2053 32 2 189 258 368 882 18 77 1840 3312 4416 2080 690 64 4 216 1564 5796 2484 2024 1 Cimadusa comEta - - - - - 3 3 1 12 3 1 - -- 1 2 2 Gammarus mucronatus -- -- 1 1 47 55 92 138 24 - - - 50 60 Grandidierella bonnieroides 132 6 25 4 25 88 41 - 2 - 6 18 2 17 156 9 11 2 unident. BP· H ------28 ------1 Cumacea Oxiurostylis smith! -- - - - 2 3 6 6 3 1 -- - 1 8 - 2 1 unident. sp. B - - - -- 1 - 2 6 - - - - - 1 3 Isopoda Cymodoce faxoni - - - - - 1 -- 2 3 3 1 - -- - 4 Edotea sp. 1 - 1 Mysidacea unident. sp. A - 1 2 2 1 - 8 2 11 1 - 2 - - 6 10 Ostracoda ParasteroEe Eollex 23 6 2 6 4 13 17 129 138 83 287 6 - 1 4 23 4 5 unident. podocopan - 2 12 9 - 26 SS 110 23 110 90 46 6 115 230 497 166 60 32 unident. sp. D - - -- - 1 - - - - 1 unident. sp. J ------5 6 - - 1 - - - 5 Tanaidacea Hargeria raEax 51 - - 1 2 13 48 92 166 179 102 3 2 - 11 101 202 55

Chordata: Ascidiacea unident. sp. B ------1

Coelenterata: Anthozoa unident. a c t i n a r i an s p. A 3 ------12 3 - - - 3 -- - - 1

.i:-- VJ Appendix A. Station A, Sykes Creek natural substratum., raw data, densities in organisms/0.1 m2 (cont).

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May Jun Jul 14 15 14 19 17 14 17 24 20 17 12 9 22 25 19 19 25 11 27

Echinodermata: Holothuroidea unident. sp. A - - - - - 1 ------1 Echinodermata: Ophiuroidea Ophiophragmus filograneus 5 2 7 2 4 6 4 2 2 2 2 1 - - 1 2 1 2 2 Mollusca: Bi val via Amygdalum papyrium -- 6 1 4 2 1 - - - - - 6 1 2 - - 1 Anomalocardia auberiana 38 35 8 142 184 111 149 195 37 23 53 21 262 285 331 138 64 64 6 Brachidontes exustus -- - - - 1 -- - - 1 - 1 1 1 Laevicardium mortoni --- 2 Lyonsia hyalina floridana 10 4 1 2 13 45 13 18 48 9 28 - 1 -- 4 18 2 Mulinia lateralis -- - 2 3 1 ------14 1 1 1 Mytilopsis leucophaeata ------2 Parastarte triquetra 16 31 2 10 46 24 - 4 5 8 135 6 20 46 221 39 28 16 Tagelus plebeius 2 6 8 15 12 17 29 46 33 18 6 - 15 23 6 2 Tellina exerythra 7 - - - -- 1 - 2 !· tampaensis 6 51 24 46 37 63 66 101 70 71 83 23 36 60 57 75 51 62 13 unident. leptonid 1 - - - 1 unident. sp. A 3 - 1

Mollusca: Gastropoda Acteon punctostriatus - - - 1 1 - - 1 1 - - - 1 4 Crepidula convexa -- - - - 1 f· plana ------2 ------3 Haminoea succinea 1 - - 3 1 3 - 9 Melongena corona ------1 Nassarius vibex - - 1 1 2 3 2 1 3 1 -- 1 2 1 2 - - 2 Prunum apicinum - 2 - 4 2 1 - 2 ------1 4 - - 1 Sayella crosseana ------1 - 1 - - -- 2 Stellatoma stellata 1 ------1 Turbonilla sp. ------1 Utriculastra canaliculata 24 14 2 16 7 7 1 6 3 1 21 7 12 10 12 23 6 14 4 unident. sp. ------1

Phoronida Phoronis Sp· 2 ------1 - 2 Platyhelminthes Euplana gracilis ------2 1 1 2 7 - -- 2 1 - 1

~ ~ 2 Appendix A. Station A, Sykes C.reek natural substratum, raw data, densities in organisms/O.l m (cont).

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May Jun Jul 14 15 14 19 17 14 17 24 20 17 12 9 22 25 19 19 25 11 27

Platyhelminthes {cont) Stylochue oculiferous - - 5 1 - 3 4 -- 1 3 - - 1 16 1 - 4 unident. ep. C ------5 Rhynchocoela unident. spp. 4 1 3 3 4 3 4 6 3 3 6 4 4 - 2 1 1 2 1 Sipuncula Phaecolion crypt us - --- 1

~ Vl Appendix B. Station B, Banana River natural substratum, raw data, densities in organisms/0.1 m2.

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May 14 15 15 19 17 14 17 24 20 17 12 9 22 25 19 19 25

Annelida: Polychaeta Ampharetidae Melinna maculata 29 26 29 2 2 16 12 27 29 28 7 23 6 1 18 11 7 unident. sp. ------1 Arenicolidae Arenicola cristata - - 1 - 1 1 - - - 1 - -- 5 Capitellidae Caeitella capita ta 6 66 276 -- 12 9 8 20 9 13 7 6 161 10 5 11 Notomastus latericeus 1 ------1 - 1 Cirratulidae Thar}'.:X sp. ------2 Dorvilleidae Dorvil lea rudolphi -- 1 4 6 - 4 - 1 1 - 1 -- - - 2 Eunicidae Lysidice ninetta ninetta 1 Mar~ sanguinea ------2 - 2 1 Glyceridae Glycera americana 4 3 2 - 2 - 3 9 12 6 5 1 5 - 3 3 6 Goniadidae Glicinde solitaria 4 5 14 8 9 20 10 9 4 3 2 3 - 9 8 6 6 Hesionidae Gyetis breviealpa 14 6 14 5 6 11 2 7 6 6 2 7 6 3 3 1 6 Podarke obscura - 3 2 1 5 4 2 5 - 1 1 3 2 1 2 Parahesione luteola - - 1 Lumbrineridae Lumbrineris sp. ------2 Magelonidae Magelona sp. ------3 Maldanidae Asichis carolinae 1 ------2 - 1 1 - - 1 Branchioasychis americana - 1 1 1 1 3 - -- - - 2 -- 1 Climenella mucosa 6 19 51 18 24 35 32 31 78 51 58 83 20 31 60 4 101 Nereid idae Laeonereis culveri - - - 9 6 - - 1 - 1 - - - 3 1 1 Nereis succinea - - - 1 unident. sp. B - 17 18 - 4 7 - - - - 50 Onuphidae Diopatra cuprea - 4 7 4 13 14 4 15 2 16 1 4 - - 15 3 s Opheliidae Armandia maculata - - - -- 1

.p-. °' Appendix B. Station B, Banana River natural substratum, raw data, densities in organisms/O .1 m2 (cont).

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May 14 15 15 19 17 14 17 24 20 17 12 9 22 25 19 19 25

Annelida: Polychaeta (cont) Orbiniidae HaEloscoloElos f oliosus - 6 16 1 -- - - - 2 3 - 5 110 4 - 1 H. fragilis ------2 H. robustus --- - 2 - - -- - 1 ScoloElos rubra 4 6 5 - - 3 1 - 2 - 3 - 2 Paraonidae Arie idea sp ------5 23 28 37 - 18 12 32 32 9 4 Pectinariidae Cistenides gouldii -- - - 1 1 - 1 - 1 Phyllodcidae Eteone heteroEoda ------1 1 3 1 - 3 E. longa ? - 1 Phyllodoce castanea ------1 - 1 Polynoidae unident. sp.A ------5 Sabellidae Branchiomma nigromaculata 1 Sabella microEhthalrna - 1 - - - 1 2 1 5 2 1 -- - - 3 Serpulidae unident. sp. 3 -- - - - 1 Spionidae Polydora anoculata ------1 p. ligni 1 7 3 ------3 2 9 - - 9 Prionospio heterobranchia 7 19 16 9 5 3 4 12 29 41 16 11 3 41 6 6 9 S2i0Ehanes sp. ------1 ScoleleEis texana ? 5 9 9 4 11 17 12 11 3 7 9 6 6 129 13 9 3 Streblospio benedicti - 3 5 ------2 Terebellidae Pis ta eris ta ta ------6 - 7 R_. palrnata 6 1 6 3 2 4 2 - - 1 3 - - - - - 3

Arthropoda: Crustacea Amphipoda Ampelisca abdita 3 2 2 8 17 10 1 6 2 1 - - - - 11 2 2 Corophium spp. ? - 2 2 1 -- 1 - 2 - ---- 9 - 9 Cymadusa cornEta 1 2 3 6 4 5 - 7 1 9 4 - - 8 5 1 4 Gammarus mucronatus - - 1 - 1 1 - - 2 - 2 Grandidierella bonnieroides - - 2 - 7 6 ' - 1 - 1 - - - 1 3 - 1 ,t:... -....J Appendix B. Station B, . Banana River natural substratum, raw data, densities in organisms/0.1 m2 (cont). - T·a-xon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May 14 15 15 19 17 14 17 24 20 17 12 9 22 25 19 19 25

Amphipoda (cont) unident. sp. A ------1 1 unident. sp. B ------4 1 unident. sp .. D ------2 unident. sp. H ------1 unident. sp. J ------1 Cumacea Oxlurostilis smithi - 2 5 16 101 99 27 27 23 18 24 - - 10 85 161 3 Isopoda Clmodoce f axoni 1 -- 3 4 5 2 1 3 - 1 -- 130 11 9 8 Erichsonella attenuata --- - 6 5 2 2 1 - - - - - 1 - 1 Mysidacea unident. SP· A 1 s - 4 - - 1 -- 1 2 -- 8 1 1 Ostracoda ParasteroEe Eollex 70 2 6 2 16 64 69 so 74 19 94 106 - - 17 17 7 unident. podocopan - - -- - 5 - 2 5 2 50 6 - 7 15 2 unident. sp. D 1 unident. sp. J ------1 5 7 - - - - 2 Tanaidacea A12seudes sp - - - - 4 3 ------18 1 - 1 Hargeria ra12ax 1 - 2 1 1 1 - 2 1 1 - 1 -- 2 2

Chordata: Ascidiacea unident. sp. A ------1 2 Coelenterata: Anthozoa unident. actinarian sp A - - --- 1 - 2 Echinodermata: Holothuroidea unident. sp. A 2 -- - 1 - - 1 1 1 1 unident. sp. B ------9 s 1 - - - 1 1 1 Echinodermata: Ophiuroidea Ophiophragmus f ilograneus 4 5 12 2 11 43 30 16 23 29 18 15 17 16 37 5 3

Hemichordata unident. sp. A ------1

~ 00 2 Appendix B. Station B, Banana River natural substratum, raw data, densities in organisms/0.1 m {cont).

Taxon 19 77 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May 14 15 15 19 17 14 17 24 20 17 12 9 22 25 19 19 25

Mollusca: Bi val via Amygdalum papyrium - 6 2 1 7 2 3 5 2 5 - 9 - 3 1 5 8 Anomalocardia auberiana - 6 6 6 5 5 2 1 - - - 1 15 15 26 9 8 Brachidontes exustus 1 - 2 - 1 - - 2 - 3 12 2 1 - 1 1 4 Laevicardium mortoni - 2 2 7 9 11 3 2 2 - 1 - - - 2 - 1 Lyonsia hyalina f loridana 5 14 3 14 13 3 - - - - - 1 1 7 1 Mulinia lateralis ------1 -- -- 1 Parastarte triguetra ------1 2 Parvilucina multilineata 2 2 11 -- - 1 2 Tagelus plebeius - 2 1 1 - 2 1 ------1 Tellina versicolor 6 3 5 - - 6 1 1 6 1 9 7 1 - 1 - 3 T. tampaensis 7 12 17 2 3 28 11 5 9 18 27 18 18 41 39 15 11 unident. leptonid ------2 unident. sp. A 1

Mollusca: Gastropoda Acteon punctostriatus --- 1 Astyris lunata - - - - - 1 1 1 Caecum pulchellum 3 2 10 -- 18 5 9 11 8 7 7 6 - 2 2 7 Cerithium muscarum ------1 -- 1 - - - 1 Crepidula convexa 3 2 6 1 3 8 - - - - 1 1 - - - 1 3 Haminoea succinea 1 2 - 5 13 9 1 - 12 1 - - 2 9 - 2 Nassarius vibex ------1 Polinices duplicatus - - -- - 3 2 --- - 1 1 - 2 Prunum apicinum 1 4 - - - 4 2 3 6 2 4 - - - 1 - 4 Pyrgothara plicosa ------1 Pyramidella crenulata ------1 - - - 1 Sayella crosseana - 2 ------3 - - - - 2 Turbonilla sp. 1 - --- l Utriculastra canaliculata 22 20 7 4 3 17 7 5 1 1 6 - l 1 5 unident. nudibranch ------l unident. sp. ------1

Phoronida Phoronis sp 11 14 4 - - 4 1 1 - 2 - 2 6 - 37 20 8

Platyhelminthes Euplana gracilis ------1 - 2 Stylochus oculiferous - - - 4 4 8 6 6 13 3 2 1 2 4 2 - 2 unident. sp.A 1 1 - - - 1 unident. sp. B - - - - 3

.p.. \0 2 Appendix B. Station B, Banana River natural substratum, raw data, densities in organisms/0.1 m (cont).

Taxon 1977 1978 1979 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Aug Oct Dec Mar May 14 15 15 19 17 14 17 24 20 17 12 9 22 25 19 19 25

Rhynchocoela unident. spp. 11 - 5 18 22 42 13 23 12 20 20 9 8 13 37 30 9 Sipuncula Phascolion cryptus 27 24 29 32 39 57 101 92 97 106 54 31 26 17 52 52 29

V1 0 · 2 Appendix c. Station A, Sykes Creek recolonization data, organisms/0.1 m . Taxon Sequence If 1 Sequence fl 2 Sequence 113 Sequence 114 Year~ 1977-1978 1978 1978-1979 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar Apr Jun Aug Oct Jul Sep Nov Jan Oct Jan 14 17 20 17 9 22 25 17 21 16 18 25 18 Annelida: Polychaeta Ampharetidae Hobsonia f loridana - 4 5 ------6 - 3 Melinna maculata - - 2 Arenicolidae Arenicola cristata - 2 6 - - 1 1 - 1 3 42 - 19 Capitellidae CaEitella caEitata 1 13 260 370 86 13 10 100 1 9 49 25 61 Dorvilleidae Dorvillea rudolEhi - - - - 2 2 11 - - 2 6 - 2 Eunicidae Lysidice ninetta ninetta ------1 Maq~hysa sanguinea --- - - 1 15 - 3 17 7 Goniadidae Glycinde solitaria - - - - 1 3 1 1 4 2 1 Hesionidae GyEtis breviEalEa -- 1 6 9 72 40 111 2 30 53 12 43 Podarke obs cur a --- - 1 5 - 1 - - 3 Parahesione luteola ------1 Maldanidae Branchioasychis americana - - - - 1 - 1 - - - 7 - 9 Clymenella mucosa 36 23 150 20 40 48 3 3 - 1 8 - 6 Nereid idae Laeonereis culveri - - 1 Nereis succinea - - - - 2 2 3 3 4 5 21 1 19 Onuphidae DioEatra cuErea - - - - - 2 2 - 4 3 8 - 3 Opheliidae Armandia maculata - 1 ------Vl - - - f-1 Appendix C. Station A, Sykes Creek recolonization data, organisms/0.1 m2 (cont).

Taxon Sequence II 1 Sequence II 2 Sequence II 3 Sequence 114 Year: 1977-1978 1978 1978-1979 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar Apr Jun Aug Oct Jul Sep Nov Jan Oct Jan 14 17 20 17 9 22 25 17 21 16 18 25 18 Orbiniidae HaEloscoloElos f oliosus 8 127 450 260 230 16 1 17 20 14 90 37 125 H. f ragilis ------1 Paraonidae Aricidea sp, ------1 - -- - - 1 unident. sp. A ------1 Pectinariidae Cistenides gouldii - - - - - 27 4 1 5 7 3 4 2 Phyllodocidae Eteone heteroEoda - 4 11 4 - 17 1 28 4 25 40 3 50 Sabellidae Sabella microEhthalma - - 4 -- 2 - - - - 1 - 1 Spionidae Polydora ligni 15 80 16 2 7 - 43 11 19 26 21 36 10 PrionosEio cirrif era ------1 p • heterobranchia 1 7 2 - - - - 5 - 3 1 - 3 ScoleleEis texana ? - - - - 1 - 1 - - - 1 Streblospio benedicti 1 15 27 8 7 - 60 2 2 33 7 120 6

Arthropoda: Crustacea Amphipoda AmEelisca abdita ------1 CoroEhium ellisi 205 950 3750 1860 240 6 3 1300 243 610 4700 310 4200 Cymadusa comEta 37 125 225 1 - - - - 1 5 38 - 75 Gammarus mucronatus 21 25 480 10 4 - - - - 9 126 - 230 Grandidierella bonnieroides 210 180 15 2 13 8 18 205 31 460 154 68 225 unident. sp. A ------10 - 25 unident. sp. J - - - - 2 unident. caprellid ------3 V1 N 2 Appendix C. Station A, Sykes Creek recolonization data, organisms/0.1 m (cont).

Taxon Sequence #1 Sequence II 2 Sequence #3 Sequence #4 Year: 1977-1978 1978 1978-1979 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar Apr Jun Aug Oct Jul Sep Nov Jan Oct Jan 14 17 20 17 9 22 25 17 21 16 18 25 18 Cumacea Ox:yurostylis smithi 38 - 6 5 2 - - -- - 2 unident. sp. B 5 - 35 18 ------2 - 15 Decapoda unident. alpheid ------1 unident. galatheid ------2 Pagurus mclaughlini - 2 Rhithropanopeus harrisii - - - - 6 2 - - 2 1 2 - 1 Isopoda Cymodoce f axoni - 35 9 - 2 -- - - - 24 - 45 Edotea sp. ------1 - - 2 Erichsonella attenuata - - - - 1 Mysidacea unident. sp. A 1 - 3 21 30 ------2 12 Ostracoda Parasterope pollex 3 22 285 370 240 35 2 35 2 - 16 1 6 unident. podocopan 1 16 9 30 15 32 171 60 144 220 72 450 75 unident. sp. J - - 12 11 8 6 1 - 1 - 2 - 3 Tanaidacea Hargeria ~ax 3 10 105 48 19 8 - 5 12 -' 38 Arthropoda: Pycnogonida Callipallene brevirostris 1 1 2

Chordata: Ascidiacea unident. sp. B - 16 60 ------1 75 - 62 Coelenterata: Anthozoa unident.actinarian sp. A 1 2 - 2 3 - - - 3 - 3 1 - l/'I VJ 2 Appendix C. Station A, Sykes Creek recolonization data, organisms/0.1 m (cont).

Taxon Sequence II 1 Sequence If 2 Sequence fl 3 Sequence 114 Year: 1977-1978 1978 1978-1979 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar Apr Jun Aug Oct Jul Sep Nov Jan Oct Jan 14 17 20 17 9 22 25 17 21 16 18 25 18 Echinodermata: Holothuroidea unident. sp. B ------4 - 2 Echinodermata: Oph i uro idea Ophiophragmus f ilograneus - - - 6 2 8 9 1 2 1 5 2 6

Mollusca: Bi val via Amygdalum papyrium 1 - -- - - 1 1 3 3 5 2 4 Anomalocardia auberiana 4 20 20 265 20 67 720 525 213 300 116 780 145 Brachidontes exustus ------2 Laevicardium mortoni ------2 Lyonsia hyalina f loridana 47 78 45 50 - 4 Mercenaria campechiensis ? ------1 Mulinia lateralis ------1 - 24 10 - 6 Parastarte triguetra 2 - 3 34 1 - 6 2 40 660 60 60 42 Tagelus plebeius 3 1 1 2 - 33 13 1 5 7 9 21 12 Tellina tampaensis 1 - 2 42 48 43 48 11 75 82 57 57 46 Mollusca: Gastropoda Acteon punctostriatus -- - - - 4 - 2 15 1 Astyris lunata ------1 Cre_Eidula convexa - - - - 3 - - 1 c. plana ------1 - 4 - 1 Eupleura caudata - - - - 1 2 Haminoea antillarum - 14 2 H. succinea 2 4 -- - 2 - 43 5 9 Melongena corona - - - - 3 2 - 1 2 2 Nassarius vibex 2 - - 1 - - 4 2 3 - 1 2 3 Prunum apicinum 1 - 1 1 - -- 1 1 - 1 - 1 Sayella crosseana - - - - 1 1 - - 2 Utriculaetra canaliculata 6 1 10 22 2 4 5 6 10 7 15 16 14 l1' ~ 2 Appendix C. Station A, Sykes Creek recolonization data, organisms/0.1 m (cont).

Taxon Sequence Ill Sequence II 2 Sequence II 3 Sequence /14 Year: 1977-1978 1978 1978-1979 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar Apr Jun Aug Oct Jul Sep Nov Jan Oct Jan 14 17 20 17 9 22 25 17 21 16 18 25 18 Phoronida Phoronis sp. 1 - - - - 3 1 2 2 1 3

Platyhelminthes Euplana gracilis - - 1 5 - - - 1 - 1 18 - 7 Stylochus oculif erous - - - - 1 - - 8 - 7 3 1 2 Rhynchocoela unident. spp. - 14 10 10 1 3 - - 2 2 3 - 5

IJ1 IJ1 2 Appendix D. Station B, Banana River recolonization data, organisms/0.1 m .

Taxon Sequence If 1 Sequence II 2 Sequence II 3 Sequence fl 4 Year: 1977-1978 1978 1978 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar May Apr Jun Jul Sep Nov Oct Jan 14 16 20 12 17 9 17 21 16 25 18 Annelida: Polychaeta Ampharetidae Hobsonia f loridana ------5 Melinna maculata - - 19 11 - 1 - - - - 3 Arenicolidae Arenicola cristata - - - 2 - 6 - 2 - 6 5 Capitellidae Capitella caEitata - 40 25 18 1 1 7 100 35 45 3 Notomastus latericeus ------3 Dorvilleidae Dorvil lea rudolphi - - - 3 -- 1 2 9 6 2 Eunicidae Marphysa sanguinea ------1 Glyderidae Glycera americana - 1 1 4 - 2 - 1 1 - 3 Goniadidae Glycinde solitaria ------1 1 5 3 2 Hesionidae GyEtis brevipalEa - - 1 5 - 5 2 12 40 10 12 Podarke obscura - 2 - 5 - 6 21 7 7 2 2 Lumbrineridae Lumbrineris sp. --- -- 1 Magelonidae Magelona sp. -- - 31 - 28 6 Maldanidae Clymenella mucosa 2 10 19 145 - 67 7 10 20 40 7 Nereididae Laeonereis culveri - 3 1 2 Nereis succinea - 4 ------1 2 V1 0-- Appendix D. Station B, Banana River recolonization data, organisms/0.1 ~ 2 (cont).

Taxon Sequence #1 Sequence II 2 Sequence #3 Sequence I! 4 Year: 1977-1978 1978 1978 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar May Apr Jun Jul Sep Nov Oct Jan 14 16 20 12 17 9 17 21 16 25 18 Onuphidae DioEatra cuErea - - 1 - - - - - 2 1 6 Orbiniidae HaEloscoloElos f oliosus - 1 1 - - - 5 70 8 35 1 H. f ragilis - -- 7 Paraonidae Arie idea sp. - - - 15 - 9 1 1 50 35 30 Pectinariidae Cistenides gouldii ------1 Phyllodocidae Eteone heteroEoda - 2 - --- - 1 - - 2 Sabellidae Sabella microEhthalma - - 4 3 Sabella sp.. - - - 30 - 2 1 Spionidae ParaErionosEio Einnata ------1 Polydora ligni - 1 - 2 - 11 81 30 PrionosEio cirrif era ------2 p • heterobranchia 5 - 6 135 - 46 5 22 150 160 16 ScoleleEis texana ? -- 1 15 - 7 - 3 12 95 1 Streblos:eio benedicti - - 2 1 - 1 2 1 Terebellidae Pista :ealmata - - 3 20 - - - - 4

Arthropoda: Crustacea Amphipoda AmEelisca abdita 5 4 2 - 3 - - - 1 1 1 Corophium spp. ? 1 2 - 1 - - 5 - 1 - - \J1 -....J Appendix D. Station B, Banana River recolonization data, organisms/0.1 m2 (cont).

Taxon Sequence 11 l Sequence 112 Sequence 113 Sequence 114 Year: 1977-1978 1978 1978 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar May Apr Jun Jul Sep Nov Oct Jan 14 16 20 12 17 9 17 21 16 25 18 Amphipoda (cont) Cymadusa comp ta 6 5 5 25 25 4 - 8 1 35 10 Gammarus mucronatus 1 - 1 Grandidierella bonnieroides 18 17 - 22 10 1 6 - 3 2 unident. sp. A -- - 1 - - 1 - 1 unident. sp. B - - - 5 4 unident. caprellid - - - - 1 Cumacea Oxyurostylis smithi - 4 50 52 73 1 -- 6 2 17 Decapoda unident. caridean ------1 Isopoda Cymodoce f axoni 3 - 17 1 1 8 - 1 - 3 92 24 Erichsonella attenuata 5 -- 1 - - 1 - 1 4 Mysidacea unident. Sp· A 5 - 1 - 16 - - - 1 Ostracoda Parasterope pol lex 5 36 172 640 280 130 16 - 2 - 3 uni dent. podocopan 1 - 1 6 4 52 4 12 10 - 40 18 unident. sp. J - - 12 35 4 Tanaidacea Apseudes sp. - 1 1 - - - - 1 Hargeria ~ax 3 4 1 6 2 4 6

Arthropoda: Merostomata Limulus polyphemus ------1

Arthropoda: Pycnogonida \J1 Callipallene brevirostris ? -- - 2 ------00 Appendix D. Station B, Banana River recolonization data, organisms/0.1 m2 (cont).

Tax on Sequence If 1 Sequence If 2 Sequence If 3 Sequence If 4 Year: 1977-1978 1978 1978 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar May Apr Jun Jul Sep Nov Oct Jan 14 16 20 12 17 9 17 21 16 25 18 Chordata: Ascidiacea unident. sp.A - - - 1 unident. sp.B - 5

Coelenterata: Anthozoa unident. actinarian sp. A ------5 unident. actinarian sp. B ------1 Echinodermata: Holothuroidea unident. sp. A - - 1 unident. sp0 B 5 - 6 5

Echinodermata: Ophiuroidea Ophiophragmus f ilograneus 1 1 12 20 11 28 4 29 60 7 17

Mollusca: Bivalvia Amygdalum papyrium - - - 1 1 - 8 3 1 - 1 Anomalocardia auberiana -- - 8 -- - 25 11 - 5 Brachidontes exustus 1 3 - 1 1 - 7 4 2 Laevicardium mortoni - 3 6 1 - - - - 2 6 Lyonsia hyalina f loridana - - - - 1 - 2 3 Parastarte triguetra ------2 Tagelus Elebeius ------1 Tellina tamEaensis -- 8 9 7 3 - 45 - 1 T. versicolor - 1 9 5 2 4 - 1 6 unident. leptonid ------5 Mollusca: Gastropoda Acteon Eunctostriatus ------1 V1 Astyris lunata 2 2 ------1 - 1 "' Appendix D. Station B, Banana River recolonization data, organisms/0.1 m2 (cont). Taxon Sequence ti 1 Sequence II 2 Sequence /! 3 Sequence 114 Year: 1977-1978 1978 1978 1978-1979 Beginning Date: Begin 1 Dec Begin 20 Mar Begin 9 Jun Begin 21 Sep Sampling Date: Dec Jan Mar May Apr Jun Jul Sep Nov Oct Jan 14 16 20 12 17 9 17 21 16 25 18 Mollusca: Gastropoda (cont) Bulla stria ta -- - 1 - - - - 4 3 Caecum Eulchellum -- 21 3 8 7 12 7 - 10 1 Cerithium muscarum - 9 1 1 7 - 1 4 4 6 9 CreEidula convexa - - - 1 - 2 2 - - - 1 EEitonium ruEicola - - - 1 Haminoea antillarum ------1 - 5 H. succinea 4 3 3 - 1 - 16 13 Melongena corona ------1 Nassarius vibex - 1 - - 1 1 Prunum aEicinum - - 2 7 - 4 - 6 2 5 1 Sayella crosseana - - 1 - - - - 1 - 1 Stellatoma stellata - - - 1 Utriculastra canaliculata 2 - 1 5 1 - 2 7 - 1 unident. nudibranch ------1

Phoronida Phoronis sp. - - - - - 1 - 1 3

Platyhelminthes Eu.Elana gracilis - - - 1 - - - - - 3 Stylochus oculif erous - - - 3 - 1 2 4 4 - 5 unident. sp.A 1 17 unident. sp. B 1 ------3 Rhynchocoela unident. spp. - - 3 10 3 6 2 6 6 15 10

Sipuncula Phascolion crypt us - 2 29 9 23 33 20 67 72 7 3 °'0 Appendix E. Station A, Sykes Creek, early morning physicochemical measurements.

1977 Jun Jul Aug Sep Oct 1 11 4 5 9 12 15 24 31 9 16 23 3 22 Diss. Oz (mg/l) 2.0 2.0 1. 2 1. 4 1. 2 1. 3 3.4 2.0 3.9 2.6 3.0 2.0 1. 5 3.8 Temp. (OC) 27.0 29.5 29.0 29.5 29.0 29.0 29.0 26.S 28.0 28.5 29.0 27.5 27.5 22.5 Salinity (%.) 24 26 27 28 27 28 28 26 29 26 28 25 26 28 . pH 8.3 - 8.1 8.2 8.2 8.1 7.9 8.0 - 8.3 8.6 8.4 - 8.3 1977 (cont) 1978 Oct Nov Dec Jan Mar Apr Jun 29 5 2 7 13 23 30 16 25 13 3 24 30 Diss. o2 (mg I 1) 6.0 4.0 2.6 6.5 6.3 5.6 9. 2 8.8 7.2 6.8 3.0 1. 5 0.8 Temp. (OC) 21.5 24.0 23.0 13.0 17.5 12.0 14.0 8.0 18.0 18.5 22.0 22.5 29.0 Salinity (%0) 25 27 23 21 23 20 22 23 23 23 23 26 24 EH 8.2 8.0 7. 7 8.0 8.2 7.8 8.0 7. 7 8.1 8.3 8.4 8.2 8.1 1978 (cont) Jul Sep Oct Nov Dec 10 17 27 29 6 11 13 6 16 21 30 8 15 Diss. Oz (mg/l) 0.5 0.6 4.5 2.6 2.8 2.8 2.8 3.5 5.1 4.6 3.6 2. 3 5.0 Temp. (OC) 29.0 27.5 27.5 27.0 25.5 24.5 24.5 21.0 23.5 23.0 23.0 24.0 17.5 Salinity (%.) 24 24 18 18 16 19 18 23 23 23 23 22 23 EH ------7. 6 7.7 7.8 8.2 7.9 8.0 1979 Jan Feb Mar Apr 4 11 18 25 9 28 5 16 19 23 27 30 4 6 Diss. Oz (mg/l) 8.5 8.4 6.5 9.0 7.0 s. 2 3. 2 4.5 3.1 2.9 3.2 6. 3 3.4 1. 4 Temp. (oc) 9.5 14.5 16.5 10.5 12.5 15.0 21.0 18.5 18.0 21.5 16.0 22.5 22.5 21.S Salinity (%.) 18 22 18 18 20 19 20 20 19 19 18 20 20 20 PH - 8.2 8.1 - 8. 3 8.5 8.3 8.1 8.0 8.2 8.0 8.2 8. 2 7.9

°'I-' Appendix E. Station A, Sykes Creek, early morning physicochemical measurements (cont),.

1979 (cont) Apr (cont) May 9 12 13 16 18 20 25 26 27 30 1 2 4 9 Diss. Oz (mg/1) 3.3 1. 5 Ll 1. 5 2.0 2. 2 3.0 2.8 2. 5 2.0 3 .. 2 1.0 2.. 5 1.. 5 Temp. (oC) 21. 5 23.5 2 3 .. 5 21.0 22.0 22.5 21. 5 21..0 22.0 24.0 24 .. 0 23 .. 5 24.0 24.0 ) Salinity (,.. -:- - - - 22 - 25 - 24 -· - 24 - 23 H 1979 (cont) May (cont) Jun 11 14 16 18 23 25 29 30 1 6 7 11 13 29 Diss. Oz (mg/1) 2.6 1. 8 1. 4 2. 7 1. 2 1. 5 1. 8 0.6 2.5 1. 0 2 .. 8 2 .. 2 2.4 2.5 Temp. (OC) 25.5 26.5 25.5 24.0 25.0 23.5 25.o 26.0 27.0 28.0 28.5 27.0 27.0 28.0 Salinity ( r. • ) 23 - 22 23 ------23 H 1979 (cont) Jul 2 3 5 9 12 17 19 26 30 Diss. Oz (mg/1) 2.8 1. 2 2.0 1. 8 1. 8 1. 2 1. 8 2. 2 1. 6 Temp. {OC) 29.0 29.0 29.S 29.0 29.0 29.0 29.5 28.5 28.5 Salinity (,.. ) pH

0\ N Appendix F. Station B, Banana River, early morning physicochemical measurements.

1977 Jun Jul Aug Sep Oct 1 11 4 5 9 12 15 24 31 9 16 23 3 22 Diss. 02 (mg/l) 2.0 1. 2 3. 3 1. 5 3.0 2.7 1. 8 - 2.5 3.2 3.0 3.0 2.8 2.2 Temp. (OC) 26.0 28.5 28.0 28.5 29.0 28.0 28.5 - 27.5 28.0 27.5 27.5 27.0 20.5 Salinity (%.) 29 32 32 32 32 31 32 - 32 32 32 30 31 33 EH 8.2 - 8.2 8.2 8.2 8.1 8.1 - - 8.3 8.3 - - 8.5 1977 (cont) 1978 Oct Nov Dec Jan Mar Apr Jun 29 5 2 7 13 23 30 16 25 13 3 24 30 Diss. Oz (mg/l) 4.8 3. 7 5.6 6. 8 6.0 9.8 10.2 10.0 8.2 9. 2 6.4 5.5 1. 2 Temp. (°C) 21.5 23.5 22.5 12.5 18.0 10.0 11.5 6.5 17.0 17.5 22.0 19.5 28.5 Salinity (%.) 31 31 29 25 25 .23 26 25 27 25 26 29 28 EH 8.0 8.0 8.2 8.0 8.3 8.2 8.3 7.3 8.2 8.4 8.6 8.3 8.0 1978 (cont) Jul Sep Oct Nov Dec 10 17 27 29 6 11 13 6 16 21 30 8 15 Diss. Oz (mg/1) 1. 2 - 2.0 - 2.8 4.0 0.7 7. 2 6.5 5.8 5.0 2.6 5.0 Temp. (OC) 28.0 - 26.5 - 25.5 23.5 23.5 20.0 23.5 22.5 23.0 23.5 16.0 Salinity ( r.. ) 26 - 26 - 25 25 25 26 26 26 27 27 27 EH ------8.2 8.2 8.2 8. 2 8.0 8.1 1979 Jan Feb Mar Apr 4 11 18 25 . 9 28 5 16 19 23 27 30 4 6 Diss. Oz (mg/l) 10.0 7.0 9.0 9 . 8 8.0 7. 5 1. 6 7. 2 7.0 4.8 7. 2 - 4.8 5. 2 Temp. (OC) 8.0 14.0 16.0 9.0 11.0 13.0 20.0 16.0 17.5 21.0 15.0 - 22.5 20.0 Salinity ( r.. ) 20 24 22 21 22 23 24 23 24 25 24 - 25 25 pH - 8. 3 8.4 - 8.3 8.5 8.1 8.4 8.5 8.4 8.6 - 8.5 8.5

(j'\ w REFERENCES

Section I

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Section II

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Gray, J. S. 1980 Why do ecological monitoring? Marine Pol­ lution Bulletin 11, 62-65.

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