The current study examines salinity tolerance in naked amoebae. A biodiversity study was conducted in the Salton Sea, an inland lake in southern California, with an average salinity of 44 ‰. Amoebae were also collected from hypersaline ponds around the perimeter of the Sea where salinities averaged 160 ‰. A total of 45 species of amoebae were isolated, about one third of which were new to science. One Salton Sea species, Platyamoeba pseudovannellida n.sp. was found to survived over the range 0 - 150 ‰. A first estimate of abundances of amoebae in the Sea showed that densities could reach 237,120 cells L-1. Many of the isolates were observed to consume cyanobacteria and algae suggesting that amoebae are important regulators of blooms in the Sea, although this was not tested experimentally. Samples from the intertidal zone of a beach, a habitat also subject to salinity fluctuations, provided the first abundances of naked amoebae in sand. Densities ranged between 181 and 8473 amoebae cm-3, again suggesting that amoebae are important micrograzers in this challenging environment. From the aforementioned studies, 6 clones of amoebae were isolated for salinity tolerance experiments (2 marine beach isolates, 2 Salton Sea isolates, and 2 hypersaline pond isolates). A seventh clone, Acanthamoeba polyphaga, a common freshwater/soil amoeba was obtained from the Culture Collection of Algae and Protozoa (CCAP). The experiments compared the effects of gradual versus no acclimatization and used growth rate and culture yield as indices of effect. Generally, amoebae were tolerant over a wide range of salinity conditions and were not markedly influenced by pre-conditioning to salinity regimes. Acanthamoeba grew in 0 -12 ‰, marine clones 2 and 3 in 0 - 110 ‰, Salton Sea clones 4 and 5 in 0 - 150 ‰, and the hypersaline clones 6 and 7 in 0 - 270 ‰ salt. The results suggest that most amoebae are essentially unaffected in terms of growth and yield by moderate and severe salinity changes. The survival and activity of large populations of amoebae in sites subject to salinity challenges suggest that they should be considered in future studies designed to understand their as yet undefined ecological role.

This study addresses the fungi of two poorly studied subtropical coastal habitats: a mangrove site and recreational sandy beaches. Little is known regarding the occurrence and distribution of the higher filamentous fungi in mangroves of South Florida. Previous studies have demonstrated that marine fungi are an important degradative component and assume an important role in nutrient recycling systems in estuarine and near-shore ecosystems. In this study over 30 species of higher filamentous fungi were identified from driftwood collected in the mangroves in J.U. Lloyd State Park over a period of one year. The drift wood collected was mainly comprised of pieces of Rhizophora mangle and Conocarpus erectus. The predominant species, by frequency of occurrence, include the Ascomycetes Hypoxylon oceanicum (8.7%), Leptosphaeria australiensis (15.6%), Lulworthia grandispora (5.2%), and Nais glitra (11.6%) as well as the Fungi Imperfecti Humicola alopallonella (5%) and Cirrenalia species (6.4%). A new record for Florida is the Ascomycete Massarina velatospora, and a new host record for Phaeosphaeria gessneri occurring on R. mangle is reported. In addition, a description of two undescribed ascomycetous species is included. Overall, the marine mycota of South Florida appears to be very similar to that reported for other tropical and subtropical regions. Another site with important overlooked fungal components is the sand of bathing beaches. The second purpose of this study was to obtain mean counts of colony forming units (CFUs) of yeasts from the wet and dry sand of three bathing beaches in South Florida. The different yeast species were also isolated and identified, using molecular methods, in order to see whether there are any pathogenic species that grow in the sand. A total of 21 yeast species were identified including 4 Basidiomycetes and 17 Ascomycetes. Several species are known to be human pathogens. The most frequently occurring species included the Ascomycete Candida tropicalis and the Basidiomycete Rhodotorula mucilaginosa. Both species diversity and total mean counts of CFUs were found to be higher in the dry sand vs the wet sand, probably as the result of a more stable habitat. Mean counts were highest at the most crowded beach, suggesting that humans and warm-blooded animals may serve as a source of contamination of the sand.

Although there is a long history of artificial reef use, little statistically verifiable experimentation has been done examining questions about artificial reef functionality. In a series of four studies using small artificial reefs as models, I examined the effects of manipulation of: refuge size, resident fishes, complexity, attractants, and site selection on fish recruitment and fish assemblage formation. Each study was conducted over 18 to 24 months by divers on SCUBA doing visual censuses monthly with the exception of one study which was censused quarterly. During all censuses, fishes within 1m of the reef were identified to species, individuals were counted, and all fishes were assigned to one of five size classes (0-2, 2-5, 5-10, 10-20, and 20+ cm total length). Mean total lengths were used to calculate biomass using published length-weight relationships. Using Rinker reef modules, a multilevel reef design with high internal complexity, deployed on sand substrate at 21m depth, I examined the effects of resident fishes on fish recruitment and overall fish assemblage formation, and secondarily, compared the results of my study to those of a similar study done at a different depth (7m), nearby. There were significant differences in recruit abundance (fishes <5 cm TL), total fish abundance, and species richness between treatments at the deep site as well as differences between the deep and shallow sites. Results of my study indicate that reef fish recruitment in Broward County water is likely not resource limited but may be driven by larval limitation or post-settlement predation. This finding, however, may be site specific. Comparison with the other study indicates differences between sites in fish abundance, juvenile abundance, species richness, and species composition. Using Reef Ball™ artificial reef modules, hemisphere shaped reefs with a large central void space and 18 side holes, I examined differences in recruitment and fish assemblage formation on identical reefs at different depths (21m and 7m), approximately 1.5km apart. There were significant differences between sites for species richness, fish abundance (all species combined, >5 cm TL), juvenile abundance (fishes <5cm TL), and biomass. Results indicate greater juvenile (fishes <5cm TL) abundance at the shallow site but greater overall fish abundance and greater species richness deep. These results suggest important site dependent differences in both juvenile recruitment and overall fish assemblage formation. Swiss Cheese reefs, concrete cubes with 12 tunnels of varying sizes through them, were used to examine the effects of refuge size and complexity on recruitment and assemblage formation. Significant differences were found between treatments for large fish abundance (>20cm TL), total fish abundance, and species richness. Results of this study support the importance of refuge size in both recruitment and overall fish assemblage formation, with more fishes of all size classes on large refuge reefs than small. However, there was no statistical support for a role for complexity (two refuge sizes) versus single refuge size in fish assemblage formation. Using Reef Ball™ artificial reefs I examined the effect of floating a single, 10m, poly-propylene line suspended over the reef module. In this case, there was no significant effect of using this type of attractant. The second part of the study examined the effect of complexity versus void space on recruitment and assemblage formation by adding concrete blocks to the internal void space in the Reef Balls. In this study there was significantly greater fish abundance, juvenile abundance, and species richness on the modules with concrete blocks. These result support a clear-cut role for internal complexity in fish recruitment and overall assemblage formation. Overall, results of this multi-part study provide important new information about the effects of various design and functional attributes of artificial reefs. In particular, the importance of complexity in design, and site selection, on recruitment and assemblage formation was further clarified.

Two species of epigean crayfish, Procambarus alleni (the Everglades crayfish) and Procambarus fallax (slough crayfish), may be keystone species that inhabit wetlands in south Florida and the Everglades. Recent field studies showed that although these two species occur in sympatric and syntopic distribution, Everglades crayfish prefer shallow water and short hydroperiod conditions, whereas slough crayfish prefer areas that are more permanently flooded (Hendrix 2000). Slough crayfish have invaded some areas within the range occupied by Everglades crayfish, and may be the more successful competitor. Because of their critical role throughout the trophic structure of Everglades wetlands, shifts in relative abundance of these two species through water management decisions may have significant effects on wetland communities and the overall availability of crayfish as food for other organisms. To examine the biology and ecology of Everglades and slough crayfish, three experiments were conducted on juveniles, under laboratory conditions that simulated environmental conditions in wetlands of south Florida. Adult crayfish of both species were obtained mostly from natural areas in south Florida, including wetlands that were historically connected to the northern Everglades. Young crayfish were hatched from berried females captured in the field or bred in the laboratory. Experiment 1. Growth, survival, and development of Everglades and slough crayfish hatchlings were monitored to three months of age, under stable conditions (water depth and food availability). Weight, total length, survival, and development (presence and size of male gonopods) were recorded at nearly four week intervals. Slough crayfish had significantly higher survival rates than Everglades crayfish, however, statistical analysis indicated that Everglades crayfish grew significantly larger than slough crayfish, at a faster rate. Linear regression showed that juvenile slough crayfish were heavier at a given length, and combined with gonopod development, was used to predict that slough crayfish become mature at an earlier age than Everglades crayfish. Experiment 2. In this multifactorial experiment, the effects of abiotic (various conditions of food availability and water levels) and biotic (density and competition) factors were examined on the survival and growth of hatchlings of both species up to three months old. Assuming that slough crayfish was an invading species, emphasis was placed on competitive influences of slough crayfish on Everglades crayfish. In conditions simulating different water levels, Everglades crayfish survival was most impacted by low food availability, high density, all three water levels, and intraspecific competition, while highest survival took place in conditions of high food availability, and low density. Lowest survival of slough crayfish occurred in low food availability, high density, and low water levels. slough crayfish had higher survival in all conditions tested. Everglades crayfish grew significantly larger in size than slough crayfish in all conditions tested. Growth of Everglades crayfish was most impacted by low food availability, drying conditions, high density, and intraspecific competition in high and low densities. The best conditions for growth of Everglades crayfish included high food availability, low water levels, low density, and interspecific competition with slough crayfish. The growth of slough crayfish young was most impacted by low food availability, high density, and high density interspecific competition. Slough crayfish grew largest under conditions of high food availability, low density, and low density interspecific competition, but reached the same size in all three water levels tested. Experiment 3. Patterns of behavior and choice of substrate of juvenile Everglades and slough crayfish, in the presence of an arthropod predator were observed, both day and night, during a 48 hour time period. Juveniles were offered four choices of substrates commonly found in Everglades environments (Utricularia foliosa, Panicum hemitomon, Typha domingensis, and sand), and seven possible behavior choices (feeding, resting, moving, digging, retreating, avoiding, or approaching).With and without the presence of an arthropod predator, both species spent the greatest amount of time in U. foliosa and P. hemitomon, and the least amount of time in T. domingensis and on sand. At night, in the presence of the predator, slough crayfish spent significantly more time secluded in bladderwort than Everglades crayfish, but Everglades crayfish was twice as exposed on sand. In the absence of the predator, feeding was the primary activity of both species during the day, but at night Everglades crayfish foraged while slough crayfish rested. a greater percent of time Both species were more mobile during the day, whether the predator was present or not. In the presence of an arthropod predator, juveniles of both species fed more during the day, but at night spent more time resting. Because of its larger size, propensity for burrowing, and probably a more size-structured population, Everglades crayfish may have a competitive advantage in resource holding potential, ability to survive adverse drying conditions, and in reproduction, by producing larger numbers of eggs. Slough crayfish grow more slowly, tend to be heavier than Everglades crayfish at a given length, and reach maturity at a smaller size and younger age than Everglades crayfish. U. foliosa was the preferred substrate at all times by young crayfish, probably due to providing optimal shelter and food. In the presence of an arthropod predator, diurnal activity patterns were followed. If survival and growth strategies of slough crayfish are enhanced by long hydroperiods and appropriate depths in Everglades environments, then slough crayfish could have a considerable competitive advantage over Everglades crayfish in survival, reproduction, and development strategies. However, Everglades crayfish may have size-related advantages over slough crayfish.

Electronic pop-up satellite archival tag (PSAT) technology has been successfully used to monitor the at-large behavior of a suite of pelagic animals, especially regarding habitat utilization. Additionally, algorithms using ambient light-level data have allowed the derivation of geolocation estimates along the duration of the deployment. However, the diel behavior of swordfish moving below the photic zone during daylight hours precludes this methodology because of the lack of ambient light-level data. To produce deployment tracks for swordfish, a mathematical model was created to analyze hydrographic temperature and pressure data recorded by PSATs. This hydrographic-based model applies Principal Component Analysis (PCA) to vertical temperature profiles in order to estimate the movement between the initial location of release and the location of the first tag transmission. PSAT data from swordfish (n=4), blue marlin (n=13), white marlin (n=2), and black marlin (n=1) were used to generate daily coordinate estimates. The marlin data provided sufficient light information to derive geolocation estimates using two light-based state space models, while the hydrographic PCA model was used to derive comparison estimates. Comparisons of the two models show an average root mean square error of 174.3 km with a standard deviation of 119 km. These results demonstrate the ability of this PCA model to extract the movement of tagged fish with consistent reasonable accuracy, within 1-2 degrees of light-based estimations. This study shows the feasibility of using temperature and depth data instead of light levels to allow effective tracking of swordfish and any species that demonstrate crepuscular diving behavior.

An evaluation of the relative rates of sediment transport of an oolitic aragonite sand and a quartz quarry sand as possible beach renourishment materials has been conducted. When comparing equal volumes, the aragonite experienced less transport than the quartz in both the longshore and in the onshore-offshore directions. When comparing equal size fractions, in sizes 0.35mm and smaller, aragonite was less transportable. The quartz was less transportable in the sizes greater than 0.35mm. This trend was observed in two separate experiments and is attributed to the effective density ratio of aragonite to quartz, dissimilarities in roundness and sphericity, and to differential entrainment and transport of these materials in suspension and bed load within the confines of the inherent bed roughness. The effective density ratio of aragonite to quartz is highest in the smaller grain sizes and decreases with increasing grain size because the larger aragonitic grains possess fewer oolitic lamellae per grain and resemble their initial biogenic nucleus. In the smaller size fractions where suspension transport is thought to predominate, a larger quartz grain is hydraulically equivalent to a smaller aragonite grain due to the greater density of the aragonite. The aragonite has a higher settling velocity out of suspension and it is less entrainable, due to sheltering effects in the bed matrix allowing a lower position in the velocity profile and a larger reactive angle to the flow. As grain size increases above 0.35mm, the density of the aragonite approaches that of the quartz. The principle of hydraulic equivalence suggests that for two materials of similar density, there should be no difference in the entrainment and transportability between equal size fractions. The preferential transport of the aragonite relative to the quartz in the size fractions greater than 0.35mm is attributed to the difference in their shape, where the rounder aragonite is more easily rolled in traction as the size of both the aragonite and quartz exceed the background bed roughness. The physical characteristics of aragonite indicate that it has a hydraulic behavior similar to a quartz sand of a slightly larger size. If renourishment is undertaken on John U. Lloyd Beach with aragonite, the most probable source material would be a mining stockpile (mean size 0.52mm) from Ocean Cay in the Bahamas. Based on a theoretical (mean size only) method of the U.S. Army Corps of Engineers, utilization of this stockpile material would reduce the erosion rate on Lloyd Beach by 10%. The results of my study indicate that beach losses could be further reduced by using this aragonite due its higher density. Secondary characteristics such as density and shape of the renourishment material manifest themselves differently in the suspension and bed load modes of transport and should be considered when choosing a borrow source. Additional transport studies need to be done utilizing larger volumes of material and monitored over a longer time interval.

This study examines the effectiveness of the Florida Department of Environmental Regulation (FDER) in regulating, through mitigation, the wetlands of Broward County, Florida. Utilizing agency permit files, wetland impacts and required mitigation were analyzed for the years 1983 - 1991. Field evaluations were conducted to determine the actual area of wetland impacts and completion of required mitigation as permitted by FDER. Mitigation areas were evaluated based upon a set of criteria developed for this study. A total of 82 permits were reviewed, resulting in the evaluation of 30 completed mitigation areas. Results indicate that freshwater wetlands containing both forested and marsh areas were permitted for the largest impact and were impacted the most by project activities. However, mangroves comprised the largest area of required mitigation while freshwater forested areas composed the largest area of completed mitigation. The largest impact to the county's wetlands occurred in 1986 and the most mitigation was required in 1987. The study found no trend or consistency in mitigation ratios as analyzed on a yearly basis, although impacts or mitigation involving only trees commanded a higher mitigation ratio than impacts expressed as an area. The overall potential mitigation ratio for permits issued by FDER between 1983 and 1991 in Broward County was 2.3:1; however, by excluding preservation and easement areas, the ratio becomes 1.2:1. The actual mitigation ratio for areas with completed project impacts and mitigation was 2:1; by excluding preservation and easement areas, the ratio becomes 0.7:1, indicating a loss of wetland area through the FDER permitting process. Results of mitigation area evaluations found that permitted wetland impacts were incomplete at 24% of the sites, mitigation was not required in 5% of the permitted projects, mitigation was either incomplete or not attempted at 41% of the proposed mitigation areas, and permit requirements were met at 30% of the mitigation areas. The completed mitigation areas were ranked by using criteria developed for this study. On a scale of 1 to 3, with 3 being the highest, saltwater mitigation areas averaged a rank of 2.3 and freshwater mitigation areas averaged 2.0.

Relationships between the nutritional environment and copepod egg production were investigated in Acartia tonsa from the Port Everglades estuary (Ft. Lauderdale, Florida) and in Centropages velificatus, Temora stylifera, and Undinula vulgaris from the eastern Gulf of Mexico. Egg production was measured by incubation procedures. Female copepods were incubated either individually (in 250 mL containers) or in groups of 5-10 (in 2 liter containers) for 24 hours. The concentration of particulate protein, lipid, and water-soluble carbohydrate was determined in size-fractionated microplankton samples (1-8 um, 8-100 um). Correlations were identified between egg production (transformed to carbon-specific and protein-specific production), the nutritional environment and the physical environment (i.e. temperature) by least squares techniques. Significant species-specific correlations were detected between nutrient composition and egg production. The nutrients utilized by copepods for energy (carbohydrates and lipids) appear to be important to the egg production of A. tonsa and C. velificatus. During the spring, protein-specific production in C. velificatus varied inversely with the lipid concentrations of both particle size classes (1-100 um and 8-100 um) (correlation coefficient [r] = -0.62, significance level [P] < 0 .05, number of data points [n] = 12) and water temperature (r = -0.62, P < 0.05, n = 12) . Protein-specific production in Acartia tonsa was correlated with seston water-soluble carbohydrate concentrations in the seston (r = 0.88, P < 0.05, n = 10 ) except during a diatom bloom which occurred in June 1993. Multi-variate analysis revealed a strong relationship between protein- and carbon-specific production of A. tonsa and nutrients utilized for energy (carbohydrates and lipids) (r = 0.91, P < 0.001, n = 9). Centropages velificatus protein- and carbon-specific production was significantly correlated with the combination of water-soluble carbohydrate and protein concentrations in the seston (8-100 um) (r = 0.72, P < 0.05, n = 14). Estimated ingestion rates suggest copepod species feed at different rates in order to obtain the same percentage of body nutrients. This may be due, in part, to the relationship between the nutrient content of a particular species and the seston nutrient concentrations observed in their distinct environments.

While limestone quarry lakes have existed in South Florida for many years, only recently have they received serious scrutiny. A thorough understanding of the trophic dynamics of these lakes has yet to be achieved. Questions have arisen as to the value of these lakes for such purposes as water reclamation, conservation, and recreational use. The purpose of this study was twofold, 1) to investigate the trophic processes within these lakes with special regard to phosphorus limitation, and 2) to help provide a better understanding of the linmology of these lakes, specifically through the quantification and identification of the invertebrate life and water quality analysis. The pH in the four lakes in this study averaged above 8.0 over a two year period from January 1994 to December 1995. The surface dissolved oxygen averaged 7.1 mg/L during the same period. Chlorophyll-a averaged 1.1 mg/m3 during a six month period from April through September 1995. Surface total phosphorus levels averaged 0.012 mg/L (0.39 ug-at L·1) over the same six month period, which is not indicative of highly productive systems. While phytop1ankton were abundant during the two year period, the populations were dominated by very small forms of chlorophytes and cyanobacteria. The average alkalinity was high (150.4 mg CaCO3/L, 3.0 meq L-1), which is not surprising considering the geochemistry of these lakes. However, alkalinity was poorly correlated with the trophic measures (chlorophyll a, total phosphorus, alkaline phosphatase activity and orthophosphate). To investigate phosphorus limitation in these lakes, the specific activity of the enzyme alkaline phosphatase, secreted by the phytoplankton, was studied over the course of 6 months and during a 24 hour period. The assumption was that if these lakes were phosphorus limited, then alkaline phosphatase activity should vary inversely with orthophosphate. Furthermore, chlorophyll-a should be positively correlated with orthophosphate. In the six-month study the Jatter relationship was found to be significant (Spearman r= 0.69; p= 0.0002, n= 24). Alkaline phosphatase activity and orthophosphate showed a nearly significant, inverse relationship (Spearman r= -0.402, p= 0.051, n= 24). Regression analysis from the diel study also showed a significant inverse relationship between alkaline phosphatase activity and orthophosphate (r= 0-.548, p= 0.033, n= 12). Alkaline phosphatase activity appears to provide a simple means of assaying the degree of phosphate limitation and the trophic state of these lakes.

Critical to advancement of marine shrimp culture in the United States is the reduction of costs associated with feeding, aeration, and water exchange. Tracking the flow of chemical components is a quantitative means of comparing different levels of each of these items which will allow refinement of costs. Elucidation of the path of nitrogen through the pond system was a first step in understanding how components were affected by different combinations of feed, aeration, and water exchange (Hopkins, et al., in review). In the present research, total carbon is tracked to obtain another view of the movement of chemicals through the system which are affected by various combinations of water exchange, as it relates to water quality. The primary result of this work was the production of a carbon budget for marine shrimp ponds. The budget indicated that sludge was the largest carbon component in each pond, and that phytoplankton production, using CO2 from the atmosphere, was the main carbon production method. The water quality results also indicated that if water quality is maintained, then the rate of exchange does not necessarily have to be as high as previously thought to gain high yields. In addition, filtration of pond water for water quality control does not appear as effective at water quality maintenance as small amounts of water exchange.