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"Red tide" is the popular name for a harmful algal bloom that occurs frequently in Florida waters and has significant impacts on the environment, the economy, and human and animal health. This paper addresses the limited understanding of public attitudes surrounding red tide and the potential for message framing to increase support for mitigation action. A sample of Florida residents (n = 498) was randomly shown a digital article framed around different red tide impacts (economic loss, human health risks, ecosystem damage, or harm to charismatic species) or a control article not framed around a specific red tide impact. Participants were then queried about their emotional responses, support for red tide mitigation policies, and intentions to change their behavior to mitigate impacts. Participants reported higher levels of negative emotions after viewing the harm to charismatic megafauna framing, indicating that messaging may play a significant role in eliciting environmental emotions. Message frames did not significantly impact other policy attitudes. Results demonstrate barriers to shifting support for mitigation where public support for action is already high. [ABSTRACT FROM AUTHOR]

An assessment framework for Tampa Bay Water's Hydrobiological Monitoring Program (HBMP) has been established based on the relationship between freshwater flow and primary environmental indicators monitored under the HBMP. The underlying paradigm is based on the understanding that reduced flows can result in water quality conditions adverse to biological populations if these conditions exceed a specific magnitude and/or are beyond a certain duration. HBMP water quality parameters identified as primary indicators include salinity (due to osmotic pressure controlling distribution of fish, benthos, and vegetation among other ecological effects), dissolved oxygen (due to the aerobic stress to fish and benthos that can occur due to depressed dissolved oxygen concentrations), and chlorophyll-a (due to excessive phytoplankton blooms that may increase biological oxygen demand and can result in depressed dissolved oxygen concentrations). These primary indicators were identified because they specifically relate to linkages in the HBMP conceptual model as well as State of Florida water quality standards and a great deal of effort has been allocated to understanding these relationships. To this end, special studies have been implemented to further scientific information related to the effects of flows and withdrawals on the magnitude, duration, and distribution of phytoplankton as one aspect of the larger HBMP assessment framework. In this paper, we provide a summary of recent special studies completed in the lower Alafia River, focused on in situ fluorometer chlorophyll-a measurement, interpretation, and predictive capability. We share lessons learned and our steps for moving forward in efforts to relate flow (and withdrawal-related effects) on phytoplankton in the lower Alafia River. [ABSTRACT FROM AUTHOR]

We present AquaNutriOpt, a user-friendly Python package designed to tackle a complex combinatorial optimization problem aimed at optimizing nutrient management for the control of harmful algal blooms. This optimization process involves the identification of optimal Best Management Practices (BMPs) and Treatment Technologies (TTs). AquaNutriOpt is constructed based on a novel integer programming model, which we present in this paper. The package can accommodate various user inputs, automatically transforming them into an optimization model, and then solving it using a free solver. To demonstrate AquaNutriOpt's efficacy, we conduct a series of experiments on two watersheds around Lake Okeechobee in Florida, USA. These experiments illustrate that the optimal BMPs/TTs obtained by AquaNutriOpt can significantly reduce Phosphorus loads into the lake across various budget scenarios. We validate the results by running simulations with the process-based Watershed Assessment Model (WAM), confirming that the estimated percentage reductions closely align with the reports from WAM. • We study controlling harmful algal blooms (HABs) through nutrient optimization. • We develop a novel mathematical optimization model for nutrient optimization. • We develop a software package in Python based on the proposed model. • We show the efficacy of the package in a case study in Lake Okeechobee in Florida. [ABSTRACT FROM AUTHOR]

Water pollution threatens public health, especially in Florida, where excess nutrients cause reoccurring algal blooms. The law itself has become the problem. Florida serves as a case study in micro-deregulation because its system of environmental regulation has been incrementally dismantled through a combination of legally mandated "drops." Some deregulation occurred openly through exemptions, presumptions, preemptions, and deadline-driven procrastination. Other efforts are less transparent. Exercises of agency discretion, often based on vague standards, may be known to the government but hidden from public view. Furthermore, justice is willfully blind because the judiciary refuses to listen to citizen advocates, invoking doctrines of judicial restraint, standing, and fee-shifting to undermine access to courts in environmental affairs. Finally, some of the deregulatory efforts will never be truly understood due to the unknown impacts of appropriations and other structural deregulatory efforts. But as water quality continues to decline, Florida's citizens endure the consequences of deregulation, one drop at a time. [ABSTRACT FROM AUTHOR]

Introduction: Successful management and mitigation of harmful algal blooms (HABs) requires an in-depth understanding of the physiology and nutrient utilization of the organisms responsible. We explored the preference of various nitrogen (N) and phosphorus (P) substrates by two novel groups of HAB-forming phytoplankton originating from the Indian River Lagoon (IRL), Florida: 1) a consortium of picocyanobacteria (Crocosphaera sp. and 'Synechococcus' sp.) and 2) ananochlorophyte (Picochlorum sp.). Methods: Short-term kinetic uptake experiments tested algal use and affinity for inorganic and organic N substrates (ammonium (NH4 +), nitrate (NO3 -), urea, and an amino acid (AA) mixture) through 15N and 13C isotope tracing into biomass. Results: Picocyanobacteria exhibited Michaelis-Menten type uptake for the AA mixture only, while nanochlorophytes reached saturation for NH4 +, the AA mixture, and urea at or below 25 µM-N. Both picocyanobacteria and nanochlorophyte cultures had highest affinity (Vmax/Ks) for NH4 + followed by the AA mixture and urea. Neither culture showed significant uptake of isotopically-labeled nitrate. Disappearance of glucose-6-phosphate (G6P) added to culture medium suggesting use of organic P by both cultures was confirmed by detection of alkaline phosphatase activity and the tracing of 13CG6P into biomass. Discussion: Together, our results suggest that these HAB-forming phytoplankton groups are able to use a variety of N and P sources including organic forms, and prefer reduced forms of N. These traits are likely favorable under conditions found in the IRL during periods of significant competition for low concentrations of inorganic nutrients. Bloom-forming phytoplankton are therefore able to subsist on organic or recycled forms of N and P that typically dominate the IRL nutrient pools. [ABSTRACT FROM AUTHOR]

Despite years of efforts to improve water quality, harmful algal blooms remain a chronic phenomenon, with devastating environmental, economic, and social impacts in many regions worldwide. In this study, we assessed the complexity of nutrient pollution attributed to harmful algal blooms in South Florida (USA) by analyzing 20 years of flow and nutrient data within two headwater basins in the Lake Okeechobee (LO) watershed. The study used an established advanced regression method, the Weighted Regression on Time, Discharge, and Season (WRTDS) method, as an analysis framework to examine the impact of nutrient management practices on water quality trends. The WRTDS method produced total phosphorus (TP) and total nitrogen (TN) concentration and flux trends, which were then compared with existing and historic nutrient management records within the basin. Results from this study highlight divergences in progress to improve water quality. Nutrient management practices only had a weak impact on TP and TN flux trends in one of the two basins, where TP flux decreased 2% per year, and TN flux decreased 0.1% per year. TP and TN flux increased in the second basin. Variances of improvement between the two basins are likely attributable to differences in contemporary point source loading and legacy nutrient pools from non-point source inputs 20 years or more before the analysis period. The long-lasting impacts of legacy nutrients also emphasize a need for investments in technologies and practices that can withdraw nutrients from enriched soil and water. [ABSTRACT FROM AUTHOR]

Flow-regulated discharges of water from control structures into estuaries result in hydrologic and water chemistry conditions that impact spatial and temporal variability in the structure and biomass of phytoplankton communities, including the potential for harmful algal blooms (HABs). The relationships between regulated Caloosahatchee River (i.e., C-43 Canal) discharges and phytoplankton communities in the Caloosahatchee Estuary and adjacent nearshore regions on the southwest coast of Florida were investigated during two study periods, 2009–2010 and 2018–2019. During periods of low to moderate discharge rates, when mesohaline conditions predominated in the estuary, and water residence times were comparatively long, major blooms of the HAB dinoflagellate species Akashiwo sanguinea were observed in the estuary. Periods of high discharge were characterized by comparatively low phytoplankton biomass in the estuary and greater influence of a wide range of freshwater taxa in the upper reaches. By contrast, intense blooms of the toxic dinoflagellate Karenia brevis in the nearshore region outside of the estuary were observed during high discharge periods in 2018–2019. The latter events were significantly associated with elevated levels of nitrogen in the estuary compared to lower average concentrations in the 2009–2010 study period. The relationships observed in this study provide insights into the importance of managing regulated discharge regimes to minimize adverse impacts of HABs on the health of the estuary and related coastal environments. [ABSTRACT FROM AUTHOR]

The Indian River Lagoon (IRL), a 156-mile-long estuary located on the eastern coast of Florida, experiences phytoplankton bloom events due to increased seasonal temperatures coupled with anthropogenic impacts. This study aimed to gather data on the toxicity to human cells and to identify secondary metabolites found in water samples collected in the IRL. Water samples from 20 sites of the IRL were collected during the wet and dry seasons over a three-year period. A panel of cell lines was used to test cytotoxicity. Hemagglutination, hemolysis, and inhibition of protein phosphatase 2A (PP2A) were also measured. Cytotoxic blooms were seen both in the south (Microcystis) and the north (Pyrodinium) of the IRL. Each toxin induced a consistent pattern of cytotoxicity in the panel of human cell lines assayed. During blooms, cytotoxicity due to a single type of toxin is obvious from this pattern. In the absence of blooms, the cytotoxicity seen reflected either a mixture of toxins or it was caused by an unidentified toxin. These observations suggest that other toxins with the potential to be harmful to human health may be present in the IRL. Moreover, the presence of toxins in the IRL is not always associated with blooms of known toxin-producing organisms. [ABSTRACT FROM AUTHOR]

The central eastern Florida shelf edge is a highly dynamic area that supports an important yet vulnerable deep-sea coral reefs ecosystem, the Oculina Coral Habitat Area of Particular Concern. Rapid and large short-terms (days to weeks) changes of bottom temperature (up to 9 °C) and p CO 2 (up to 180 μatm) were observed at the shelfbreak during a two-month (May 13-July 10, 2017) deployment of a lander package. An analysis suggests that these changes are the combined results of tides, the Gulf Stream meandering, and submesoscale eddies and filaments. The processes responsible for sub-tidal variability may include 1) the Gulf Stream frontal movements, 2) upwelling/downwelling of slope waters in association with the Gulf Stream variability, and 3) submesoscale processes and associated vertical movements. Satellite images also frequently show a narrow plume of elevated chlorophyll concentration that stretches from the coast northward up to >200 km along the Gulf Stream front during late spring and early summer. Our analysis indicates that these phytoplankton blooms in the plume are likely supported by the nutrient supply from the nutrients-rich slope waters to the shelf edge and subsequent local vertical mixing. Carbon export associated with these blooms can be an important food source to the Oculina corals. Upwelling of slope waters, on the other hand, will lead to increased CO 2 and reduced pH and aragonite saturation state along the shelf edge. Therefore, these dynamic processes may have strong impacts on the health and sustainability of the Oculina coral ecosystem. • Rapid short-terms changes of bottom temperature (up to 9 °C) and p CO 2 (up to 180 μatm). • A high chlorophyll plume stretches from the coast northward along the Gulf Stream front. • Short-terms variability are associated with GS meandering and submesoscale features. • The biogeochemical processes may have strong impacts on the deep coral ecosystem. [ABSTRACT FROM AUTHOR]