West Coast Of Florida Research Articles

Seasonal variability and seagrass traits affect methane fluxes in a subtropical meadow

Abstract Plant traits which vary both within and between species often drive biogeochemical cycling. Understanding the relative role of within‐ and between‐species trait variability in driving carbon cycling is essential to scaling site measurements to global carbon budgets. In seagrass meadows, carbon and nitrogen mineralization rates and associated greenhouse gas emissions are highly variable, impeding our ability to reliably predict whether meadows are net carbon sinks. Evaluating the influence of within‐ and between‐species trait variability on greenhouse gas fluxes will improve our understanding of local‐scale drivers of greenhouse gas production and consumption in seagrass meadows. To test the effects of plant traits on dissolved greenhouse gas fluxes, we performed mesocosm incubations with live, intact seagrass plants. We compared methane (CH4) and nitrous oxide (N2O) fluxes under dark and light conditions from sediments dominated by Halodule wrightii and Thalassia testudinum across dormant, early and peak growing seasons in a subtropical meadow along the west coast of peninsular Florida. We also measured oxygen (O2) fluxes to interpret greenhouse gas fluxes within the context of community metabolism. We measured several seagrass traits, such as above‐ and below‐ground biomass and leaf and root area and assessed their impact as well as the impact of species identity on dissolved gas fluxes. We found that abiotic factors linked to metabolism (i.e. light and temperature) influenced greenhouse gas fluxes across seasons. In addition to light conditions and sampling month, plant size (a composite trait variable) was a significant predictor of O2 consumption and CH4 production under dark conditions, and better predicted fluxes than individual plant traits. CH4 production was slightly higher in H. wrightii‐dominated sediments, but species identity was less important than plant size in driving CH4 production. N2O fluxes were low and not influenced by plant traits or species identity. Synthesis: Our results indicate that within‐species more so than between‐species trait variability drives the direction and magnitude of CH4 fluxes in seagrass meadows. We identified a trade‐off where seagrass biomass is often associated with enhanced sediment carbon storage, but in our study, plant size promoted CH4 production, potentially offsetting the benefits of long‐term storage.

Coastal CUBEnet: an integrated observation and modeling system for sustainable Northern Gulf of Mexico coastal areas

The University of Southern Mississippi has developed the coastal CUBEnet environment. Coastal CUBEnet is a high-resolution, coastal ocean sensor, modeling, and data sharing web-based network that provides the environmental intelligence needed to support the complex modeling of the interlinked processes in the northern Gulf of Mexico. With near-real time data delivery via a common infrastructure, CUBEnet uses state of the art sensors to provide a set of networked measurements systems, visualization tools, and model developments to gain an understanding of the Gulf of Mexico’s marine environments. CUBEnet is also a mechanism for improved human engagement with Gulf of Mexico resources and provides stake holders with the data needed to make informed coastal, environmental, and economic decisions. The Coastal CUBEnet’s data environment utilizes both stationary and uncrewed mobile systems and high-resolution distributed sensors to create a networked platform across the northern coastal Gulf of Mexico. CUBEnet’s modeling environment has developed an implementation of The Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) Model for the Mississippi Bight region that has been applied to investigate shore to shelf advective exchange processes, and their influence on coastal water quality conditions that support the region’s prolific marine ecosystem. CUBEnet’s modeling environment provides prototype modeling applications that are supported by real-time observations of key coastal environmental variables. CUBEnet’s Web accessible visualization tools provide parameter fields and vertical profiles from hydrodynamic models and field observations. Nowcasts and forecast results are available for the Eastern LA coastline, MS coastline, Mobile Bay, and the West coast of Florida.

Fusing remote sensing data with spatiotemporal in situ samples for red tide (Karenia brevis) detection.

We present a novel method for detecting red tide (Karenia brevis) blooms off the west coast of Florida, driven by a neural network classifier that combines remote sensing data with spatiotemporally distributed in situ sample data. The network detects blooms over a 1-km grid, using seven ocean color features from the MODIS-Aqua satellite platform (2002-2021) and in situ sample data collected by the Florida Fish and Wildlife Conservation Commission and its partners. Model performance was demonstrably enhanced by two key innovations: depth normalization of satellite features and encoding of an in situ feature. The satellite features were normalized to adjust for depth-dependent bottom reflection effects in shallow coastal waters. The in situ data were used to engineer a feature that contextualizes recent nearby ground truth of K. brevis concentrations through a K-nearest neighbor spatiotemporal proximity weighting scheme. A rigorous experimental comparison revealed that our model outperforms existing remote detection methods presented in the literature and applied in practice. This classifier has strong potential to be operationalized to support more efficient monitoring and mitigation of future blooms, more accurate communication about their spatial extent and distribution, and a deeper scientific understanding of bloom dynamics, transport, drivers, and impacts in the region. This approach also has the potential to be adapted for the detection of other algal blooms in coastal waters. Integr Environ Assess Manag 2024;20:1432-1446. © 2024 SETAC.

Phytoplankton communities of the west coast of Florida – multiyear and seasonal responses to nutrient enrichment

Blooms of the harmful algae species Karenia brevis are frequent off the southwest coast of Florida despite having relatively slow growth rates. The regional frequency of these harmful algal blooms led to the examination of the dominant estuarine outflows for effects on both K. brevis and the phytoplankton community in general. There is comparatively little information on the growth rates of non-Karenia taxonomic groups other than diatoms. A seasonally based series (Fall, Winter, and Spring) of bioassay experiments were conducted to determine the nutrient response of the coastal phytoplankton community. Treatments included estuarine waters (Tampa Bay, Charlotte Harbor, and the Caloosahatchee River) applied in a 1:25 dilution added to coastal water to mimic the influence of estuarine water in a coastal environment. Other treatments were 5–15 μM additions of nitrogen (N), phosphorus (P), and silica (Si) species, amino acids, and N (urea) + P added to coastal water. Incubations were conducted under ambient conditions with shading for 48 h. Analyses of dissolved and particulate nutrients were coupled with HPLC analysis of characteristic photopigments and taxonomic assignments of biomass via CHEMTAX. The coastal phytoplankton community, dominated by diatoms, cyanophytes and prasinophytes, was significantly different both by bioassay and by season, indicating little seasonal fidelity in composition. Specific growth rates of chlorophyll a indicated no significant difference between any controls, any estuarine treatment, P, or Si treatments. Conditions were uniformly N-limited with the highest growth rates in diatom biomass. Despite differing initial communities, however, there were seasonally reproducible changes in community due to the persistent growth or decline of the various taxa, including haptophytes, cyanophytes, and cryptophytes. For the one bioassay in which K. brevis was present, the slow growth of K. brevis relative to diatoms in a mixed community was evident, indicating that identifying the seasonally based behavior of other taxa in response to nutrients is critical for the simulation of phytoplankton competition and the successful prediction of the region's harmful algal blooms.

Symbiotic survey of the bay scallop (Argopecten irradians) from the Gulf coast of Florida, USA

The bay scallop Argopecten irradians supported a commercial fishery in Florida but their population declined and the fishery closed in 1994. A recreational fishery remains open along the west coast of Florida despite continued threats from overfishing and a changing environment. Disease is among those threats, as it is for bivalve fisheries globally. We examined the relationship between bay scallop population density, its symbiotic microbiome, and geographic location. We focused on three sites within the range of Florida’s recreational scallop fishery: St. Joseph Bay (northern extent), offshore of the Steinhatchee River (central), and offshore of Hernando County (southern extent). The study was conducted prior to the seasonal opening of the fishery to minimize the impact of fishing on our results. We also sampled caged scallops that are used for restocking in St. Joseph Bay to assess the effect of artificially high density and confinement on the scallop pathobiome. Using a combination of traditional histological methods, molecular diagnostics, and metagenomics, a suite of 15 symbionts were identified. Among them, RNA-seq data revealed four novel + ssRNA viral genomes: three picorna-like viruses and one hepe-like virus. The DNA-seq library revealed a novel Mycoplasma species. Histological evaluation revealed that protozoan, helminth and crustacean infections were common in A. irradians. These potential pathogens add to those already known for A. irradians and underscores the risk they pose to the fishery.

Short-term forecast of Karenia brevis trajectory on the West Florida Shelf

Blooms of the toxic dinoflagellate Karenia brevis, also known as harmful algal blooms (HABs) or red tides, occur almost annually on the west coast of Florida, killing fish and other marine life, threatening public health and adversely impacting local economies. Mitigating such effects requires improved red tide forecast capabilities on the West Florida Shelf. A short-term Lagrangian trajectory forecast tool is developed to help federal, state, and local end users monitor and manage red tides on the west coast of Florida. The forecast products are based on the West Florida Coastal Ocean Model (WFCOM) and the Tampa Bay Coastal Ocean Model (TBCOM) nowcast/forecast systems. Observed K. brevis cell count data are uploaded daily into the models to generate 3.5-day forecasts of the bloom trajectories both on the shelf and in the estuaries. The tracking tool displays modeled bloom trajectories at the surface and near-bottom with five categories of cell concentrations (each approximately representing an order of magnitude difference in concentration). More general and user-friendly maps are also produced to provide red tide advisories along the coast, including those integrated with satellite imagery.

First Open-Coast HF Radar Observations of a 2-Phase Volcanic Tsunami, Tonga 2022

We describe results from coastal radar systems that observed anomalous current flows generated by the volcanic eruption in the Tongan archipelago on 15 January 2022 UTC, reporting the first radar detection of a volcanic tsunami. The eruption caused small tsunamis along the western U.S. Coast, generating some damage in a few harbors. The highest tsunami signal in U.S. tide gauge data from the California coast occurred at Arena Cove, with significant heights detected at Port San Luis and Crescent City. We analyze correlated wave orbital velocity detections by High Frequency (HF) radars along the coast between Gerstle Cove and Santa Barbara. Signals observed by the radars indicate that the event had two phases, each with its own distinct genesis: an initial weak surface disturbance, most likely generated by the wave of atmospheric pressure that moved outward from the blast source at just below the speed of sound, followed by a stronger disturbance that arrived approximately 3.5 h later, matching the arrival time for a wave moving entirely through the water from the volcano to the U.S. West Coast. We conclude that this phase consists of a conventional water wave tsunami and weaker waves generated by the pulse. We also report the detection of a small pulse-generated event off the west coast of Florida. Radar observations are compared with water level measurements at nearby tide gauges and a DART buoy, and with observations of barometric pressure. We point out that a Proudman near-resonance at the Tonga Trench is unlikely to explain the second phase observations. Comparison with tide gauge signals at San Francisco, generated by the Krakatoa eruption in 1883, support our conclusions.

Application of Multiobjective Optimization to Provide Operational Guidance for Allocating Supply among Multiple Sources

This study is motivated by multipleobjective optimization in short-term water management for a regional water utility. Although an increasing application of multi-objective evolutionary algorithm (MOEA) has been reported in the literature, we are not aware of its use for short-term water management by water utilities with diverse supply sources. This study presents an innovative practice for determining monthly resource allocation from multiple water supply sources that consider multiple objectives, including deviation from budgeted production, under or overutilization of a given portfolio of resources, and total cost of water production. This method is comprised of a simulation model, namely a production allocation model (PAM) and a MOEA. The decision variables of the MOEA optimization problem are monthly groundwater production from two groundwater wellfields. TheMOEA is used to search for Pareto optimal solutions across different objectives and the PAM uses MOEA output and considers operational constraints to determine water production from the other four supply sources in the decision horizon. Stochastic demand and supply realizations were generated to capture a wide range of uncertainties which were then sampled by a Latin Hyper Cube to make the computation tractable. A parallel computing environment was used to implement this near real-time decision support tool, providing timely guidance for water resources managers. One major difference between this study and many reported in the literature is that the MOEA was used to find Pareto solutions for each demand-supply realization rather than the entire ensemble. This setup allows water resources managers to explicitly explore Pareto solutions based on different supply and demand outlooks. The application of the innovative practice is demonstrated for a regional wholesale water supply utility, Tampa Bay Water, on the west coast of Florida in the United States. One additional advantage of MOEA-assisted planning is that it allows water managers to combine expert judgments and institutional knowledge in identifying solutions. A comparison between MOEA-assisted monthly production planning and heuristic planning reveals that the potential impact of short-term operations, e.g., deviation from budgeted production, is fully considered in a systematic approach. The proposed method can be applied to other regions with similar challenges in water resources management.

First successful nest for the Vulnerable American crocodileCrocodylus acutuspopulation on the west coast of Florida, USA

AbstractThe American crocodileCrocodylus acutusoccurs across the Americas, with its northernmost distribution being in South Florida, USA. This species has undergone severe declines across its range and is categorized globally as Vulnerable on the IUCN Red List and as Threatened on the U.S. Federal Endangered Species List. Long-term monitoring studies in the USA have documented a shift in American crocodile nesting activity and an expansion of its range throughout the southern and eastern coasts of South Florida. However, no successful American crocodile nests have been recorded until now on the west coast of South Florida. Here we document the American crocodile nest monitoring conducted during 1997–2021 at Rookery Bay National Estuarine Research Reserve and the first successful nest from the west coast of South Florida forC. acutus. Marco Airport and McIlvane Marsh are the two main American crocodile nesting areas identified at the Reserve, with 92 nests and 3,586 eggs recorded during 1997–2021. We found most nests at Marco Airport (95.7%) and only four nests (4.3%) at McIlvane Marsh. To date, none of the nests found at Marco Airport have produced successful hatchlings. In contrast, hatchlings have been produced at McIlvane Marsh since nests were first documented there in 2020. We discuss the implications of our findings in terms of the future conservation of the species.

The Effect of Changes in Trip Costs and Gag Regulations on Recreational Fishing Demand in the Gulf of Mexico

AbstractThe Gag Mycteroperca microlepis is one of the most popular reef fish targeted by anglers fishing in the Gulf of Mexico. Around 7% of all trips by private boat anglers fishing from the west coast of Florida in 2019 targeted Gag during the open season. We conducted a survey of private boat anglers in Florida and estimated a statistical model to predict changes in the number of fishing trips anticipated with changes in trip costs and Gag bag limits. We found that for the average angler, the economic value of each private boat trip is around US$200 and that a $10 increase in trip costs would decrease private boat fishing trips by 5%. We also found that, on average, private boat anglers targeting Gag would take 12% more trips if the bag limit was increased by one fish from the current bag limit of two fish. The results of our study will help to anticipate the extent to which recreational fishing effort and value could change when trip costs and Gag regulations change.

A Risk-Based Framework to Evaluate Infrastructure Investment Options for a Water Supply System

Increasing water demand due to socio-economic development often requires structure-level interventions, e.g., infrastructure expansion of water supply systems to bridge the gap between demand and water supply. Evaluating different expansion options is critical to making informed decisions. This study focuses on evaluating infrastructure investment options from the reliability perspectives of a water supply system. The evaluation framework is comprised of probabilistic demand projections, stochastic streamflow generation, a mixed-integer programming, and system performance evaluation. Different “industry understood” performance metrics, e.g., annual reliability, maximum delivery capacity, the probability of unsuccessful status, and the magnitude of potential water shortage, can be employed to evaluate the performance of water supply systems. This framework has been applied to Tampa Bay Water, a regional supply agency on the west coast of Florida, United States. The probabilistic demand projections for the future (2021–2040) consider socio-economic projections and climate conditions based on the statistics of historical observations. The Latin Hypercube Sampling algorithm is used to capture the bivariate distribution of supply and demand. This mixed-integer programming is a daily system optimization that minimizes operational cost and considers operational constraints and preferences, e.g., water withdrawal permits, facility production capacity, and water production preferences. Current infrastructure capacity and operational conditions are defined as the baseline scenario. Two additional planning scenarios of expanding the treatment capacity of a surface water treatment plant by 75,708 m3/day [20 million gallons per day (mgd)] and 113,562 m3/day (30 mgd) in the year 2028 are investigated. Results reveal that annual reliability would increase with the expansion of surface water treatment plant capacity. The spatio-temporal supply and demand variability determines that the firm yield from the surface water treatment is less than its expanded production capacity. Except for low demand realizations in the future, the duration and magnitude of potential water shortage could be reduced in both scenarios with engineering intervention. Although this framework is demonstrated for a regional water utility in Florida, it can be applied to other water supply systems around the world.

Use of fishermen’s local ecological knowledge to understand historic red tide severity patterns

In the past decade, the Florida Gulf Coast has experienced a number of severe outbreaks of Karenia brevis, a marine alga that produces harmful algal bloom (HAB) events commonly called “red tides.” These recurring red tide events have produced severe ecological and economic impacts. Although satellite and water sampling information can be used to identify and track the movement of more recent red tide events, the historic patterns of red tide occurrence and severity are less known. In addition, relatively little information is available about the impact of different red tide events on fish populations, marine habitats and the fishing industry over time. This presents a challenge to fisheries managers in accounting for the impacts of red tides in fisheries stock assessments and formulating policies that anticipate and mitigate the impact of red tide events on fishing dependent businesses. This paper describes the application of fishermen’s local ecological knowledge (LEK) data to improve the historic record on red tides on the west coast of Florida, and develop a red tide severity scale. In addition, this paper sheds light on the ecosystem-level insights that fishermen bring to the study of red tides. Eight years were consistently identified by interviewees, with some of the most severe red tide occurrences having increased in frequency in the last fifteen years. The paper concludes with a discussion on existing and possible future applications of the LEK data on red tides for fisheries assessment and management.

Spatial distribution of per- and polyfluoroalkyl substances (PFAS) in waters from Central and South Florida.

Per- and polyfluoroalkyl substances (PFAS) are notoriously persistent pollutants that are found ubiquitously present in aquatic environments. They pose a big threat to aquatic life and human health given the bioaccumulation feature and significant adverse health effects associated. In our previous study, PFAS were found in surface waters from Biscayne Bay and tap waters from the East coast of South Florida, at levels that arouse human health and ecological concerns. Considering that Florida supports millions population as well as treasured, sensitive coastal and wetland ecosystems, we have expanded the PFAS monitoring study on the occurrence, composition, spatial distribution, and potential sources encompassing tap waters from counties on the West coast of South Florida and Central Florida, and surface waters from Tampa Bay, Everglades National Park adjacent canals, Key West, including Biscayne Bay area. A total of 30 PFAS were analyzed based on solid-phase extraction (SPE) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS). PFAS were detected in all tap water (N = 10) and surface water samples (N = 38) with total concentrations up to 169ng L-1. Higher PFAS concentrations (> 60ng L-1) are mostly observed from polluted rivers or coastal estuaries in Biscayne Bay, and sites nearby potential points sources (military airbases, wastewater facilities, airports, etc.). Our findings on current PFAS contamination levels from diverse aquatic environments provide additional information for the development of more stringent screening levels that are protective of human health and the environmental resources of Florida, which is ultimately anticipated as scientific understanding of PFAS israpidly growing.

Termination of the 2018 Florida red tide event: A tracer model perspective

The 2018 Karenia brevis harmful algal bloom experienced along the west coast of Florida was the worst red tide occurrence there since 2005. Cell concentrations peaked in early fall of 2018, lessened in winter, and disappeared early in 2019. Here we examine the termination of this red tide event by using hindcast simulations of the West Florida Coastal Ocean Model, a numerical ocean circulation model that downscales from the deep Gulf of Mexico, across the continental shelf and into the estuaries. The underlying hypothesis is that without an offshore source of K. brevis cells, a nearshore bloom may quickly dissipate under the influence of a persistent upwelling circulation. To test this hypothesis, we used a passive tracer (without consideration of biological growth or decay) in the model to virtually indicate K. brevis cells. The tracer, inputted along the central West Florida coast where highest bloom concentrations were observed, was subsequently transported southward along the coast and offshore, significantly reducing the tracer concentrations over the three-month-long experimental duration, as was observed for the actual K. brevis cell concentrations. Whereas modeled tracer concentrations decreased over most of the West Florida coast, relatively higher concentrations remained just south of Sanibel Island, trapped there by the sharp bend in the coastline. Longer residence time for this area has important K. brevis implications. Lake Okeechobee nutrient flux through the Caloosahatchee River was thought to contribute to red tide in this region, and while these inputs may be a factor, a persistent upwelling circulation may also play a contributing role.

The influence of Lake Okeechobee discharges on Karenia brevis blooms and the effects on wildlife along the central west coast of Florida

Blooms of the dinoflagellate Karenia brevis (K. brevis) are a common occurrence in the Gulf of Mexico, especially along Florida's coast. The blooms produce brevetoxins, potent neurotoxins that are associated with mortalities of marine wildlife. In recent years, K. brevis blooms seem to have become more frequent and intense. The cause of these suspected increases is highly debated, with one suggested explanation being anthropogenic eutrophication. Patient records from the Clinic for the Rehabilitation of Wildlife (CROW) on Sanibel Island, Florida, USA, and K. brevis cell count samples from the west coast of Florida were used to assess trends in red tides and affected wildlife. Flow data from the Okeechobee waterway was used to investigate if discharges from Lake Okeechobee and the Caloosahatchee Estuary, where eutrophication is present, influence red tides along Florida's central west coast. Overall, K. brevis blooms show trends of increasing intensity and duration along Florida's coast between 1954 and 2020 (latest data available). This means the amount of wildlife affected will likely increase in the future, as a linear relationship was found between the number of admissions to CROW and K. brevis densities. Furthermore, water discharges from the Okeechobee waterway (including Lake Okeechobee and the Caloosahatchee Estuary) into the Gulf of Mexico were significantly correlated with K. brevis densities, which suggests that anthropogenic pollution might play a role in the observed increases. Clear correlations were found between K. brevis densities and brevetoxicosis patient numbers admitted, and this was strongest with overall admissions lagging 23 days behind cell counts. This further confirms brevetoxins as the likely cause of their morbidity and supports previous research on brevetoxin retention in the environment. Different species groups had significant correlations with K. brevis cell counts, double-crested cormorants showing the strongest link, and there were significant differences between these groups in lag times. The differences are likely due to their distinct foraging behaviours or susceptibilities to brevetoxins. These findings can help predict future trends in red tides and can guide further research on the effects of discharges on K. brevis blooms.

Status and Management of the Blue Crab Fishery in the Gulf of Mexico

AbstractManagement of the blue crab Callinectes sapidus fishery in the Gulf of Mexico is the responsibility of the individual states under the purview of a regional management plan. States generally follow the “2‐S” system of management, placing emphasis on size and sex. Despite management policies, harvest and juvenile abundances remain in decline. A significant trend toward decreasing harvest began in the early 2000s, with landings below average in 13 of the 20 years from 2000 to 2019. Since 2010, the fishery has maintained a lower but relatively stable harvest. There have been significant decreases in numbers of late‐stage juveniles in fishery‐independent trawl surveys, while numbers of megalopae and early juveniles have not exhibited declines. Postsettlement mortality is potentially driven by climate‐related hydrological processes that structure the biotic community (predator guild) and nearshore habitats. Diversity of predators, few predation‐free refuges, and a lack of seasonality in predation likely contribute to high regional mortality. Factors that influence quality and quantity of available refuge may ultimately control abundance. Although genetics data describe the population as panmictic, geographic differences in coastal climate and hydrological processes may act to structure populations. Separation of stocks according to ecozones may provide a more suitable approach to population delineation. The 2011 stock assessment divided the population into eastern and western regions based on confounding information on genetics, physiographic features that limit larval transport, variations in climate, and migration of female crabs along the west coast of Florida. There is concern that the population is undergoing Gulf of Mexico‐wide changes in biomass associated with regional climate regime shifts that may alter the resiliency of the stock. Whether the shift to a more favorable climate phase would reverse the declining trends is unknown. Changes in population levels could be rapid given the high juvenile mortality and short generation time as well as the importance of climate in structuring habitat.

Predictors of Osprey Nest Success in a Highly Urbanized Environment

ABSTRACT Ospreys (Pandion haliaetus) are adaptable fish-eating raptors that readily nest on artificial structures in heavily human-dominated areas. Although the Osprey is a well-studied species, few researchers have investigated the factors that influence nest success and productivity in an urban environment. We monitored Osprey nests from 2013 to 2017 in highly urbanized Pinellas County, located on the west coast of central Florida, USA. We used logistic exposure models to assess the effects of timing of nesting, nest attributes (nest substrate, height), and landscape-level variables (inter-nest distance, distance to water, and surrounding habitat type) on daily survival rate (DSR) of Osprey nests. The number of active nests (i.e., nests with eggs) in the study area ranged from 53 in 2013 to 79 in 2016, with an overall total of 329 during the 5-yr study. Although most nests produced at least one young near fledging age, 131 of the nests failed. We attributed 45% of nest failures to storm events and 50% to unknown causes. The best logistic exposure model specification included only two variables: the discrete variable representing the date incubation started and the nominal variable indicating the year 2015. Osprey nests initiated earlier in the season were more likely to survive, and later nests (initiated after 22 April) averaged only one fledgling each. Osprey nests in 2015 had the highest DSR and relatively few failed due to storms. Our results supported previous research indicating that early nesters were more successful than late nesters. Our results also indicate that storms may play a role in nest success of Ospreys in Florida. Other variables, such as the amount of urbanized land surrounding Osprey nests did not appear to influence nest survival, indicating that Ospreys can be productive even in highly urban environments.

Machine Learning Classification Algorithms for Predicting Karenia brevis Blooms on the West Florida Shelf

Harmful algal blooms (HABs), events that kill fish, impact human health in multiple ways, and contaminate water supplies, have increased in frequency, magnitude, and impacts in numerous marine and freshwaters around the world. Blooms of the toxic dinoflagellate Karenia brevis have resulted in thousands of tons of dead fish, deaths to many other marine organisms, numerous respiratory-related hospitalizations, and tens to hundreds of millions of dollars in economic damage along the West Florida coast in recent years. Four types of machine learning algorithms, Support Vector Machine (SVM), Relevance Vector Machine (RVM), Naïve Bayes classifier (NB), and Artificial Neural Network (ANN), were developed and compared in their ability to predict these blooms. Comparing the 21 year monitoring dataset of K. brevis abundance, RVM and NB were found to have better skills in bloom prediction than the other two approaches. The importance of upwelling-favorable northerly winds in increasing K. brevis probability, and of onshore westerly winds in preventing blooms from dispersing offshore, were quantified using RVM, and all models were used to explore the importance of large river flows and the nutrients they supply in regulating blooms. These models provide new tools for management of these devastating algal blooms.

The role of emergent physical and chemical properties of Florida spring complexes in predicting fish assemblage structure

Florida spring complexes (springs and their associated runs) represent patches of clear, cool freshwater habitat in a landscape of tannin-stained wetlands, streams, and rivers. These spring complexes differ in morphology, water quantity and quality, and biotic characteristics as well as in their connections to other water bodies. The purpose of this study was to determine whether watershed effects or emergent physical, chemical, and biologic properties of Florida spring complexes would predict fish assemblage structure. Spring complex morphology and water quality metrics were collected from water managers or from the literature, with the exception of dissolved oxygen, which was measured in situ. Fish data were collected by video surveys using GoPro® cameras on stationary tripods at 2 to 5 locations on the banks of each spring complex. Videos were analyzed for the total number of individuals of each species/video, species richness, and diversity. The environmental characteristics of spring complexes differed between watersheds, as the St Johns River spring complexes, which are near the east coast, differed from watersheds closer to the west coast of Florida. However, specific characteristics that discriminated between springs, like low dissolved oxygen concentration or abundant macrophytes, crossed watershed boundaries. Fish assemblages also differed between the St Johns River and western watersheds, but the differences were more subtle than the differences in environmental characteristics, and the characteristics of individual spring complexes also predicted fish assemblage structure. Conductivity, dissolved oxygen concentration, and macrophyte coverage best explained the variation in the fish assemblage structure among spring complexes. The overlap in spring complex fish assemblages across watersheds may be the result of the geologic youth of the freshwater fish assemblages, the high degree of hydrologic connectivity between water bodies, and possible impairment of spring complexes in Florida.

Microbial Respiration and Enzyme Activity Downstream from a Phosphorus Source in the Everglades, Florida, USA

Northeast Shark River Slough (NESS), lying at the northeastern perimeter of Everglades National Park (ENP), Florida, USA, has been subjected to years of hydrologic modifications. Construction of the Tamiami Trail (US 41) in 1928 connected the east and west coasts of SE Florida and essentially created a hydrological barrier to southern sheet flow into ENP. Recently, a series of bridges were constructed to elevate a portion of Tamiami Trail, allow more water to flow under the bridges, and attempt to restore the ecological balance in the NESS and ENP. This project was conducted to determine aspects of soil physiochemistry and microbial dynamics in the NESS. We evaluated microbial respiration and enzyme assays as indicators of nutrient dynamics in NESS soils. Soil cores were collected from sites at certain distances from the inflow (near canal, NC (0–150 m); midway, M (150–600 m); and far from canal, FC (600–1200 m)). Soil slurries were incubated and assayed for CO2 emission and β-glucoside (MUFC) or phosphatase (MUFP) activity in concert with physicochemical analysis. Significantly higher TP contents at NC (2.45 times) and M (1.52 times) sites than FC sites indicated an uneven P distribution downstream from the source canal. The highest soil organic matter content (84%) contents were observed at M sites, which was due to higher vegetation biomass observed at those sites. Consequently, CO2 efflux was greater at M sites (average 2.72 µmoles g dw−1 h−1) than the other two sites. We also found that amendments of glucose increased CO2 efflux from all soils, whereas the addition of phosphorus did not. The results indicate that microbial respiration downstream of inflows in the NESS is not limited by P, but more so by the availability of labile C.