Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event

Kramer, Benjamin J.; Davis, Timothy W.; Meyer, Kevin A.; Rosen, Barry H.; Goleski, Jennifer A.; Dick, Gregory J.; Genesok, Oh; Gobler, Christopher J.

doi:10.1371/journal.pone.0196278

Cited by 89 publications

(87 citation statements)

References 61 publications

(69 reference statements)

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“…In particular, worsening eutrophication is evident in bays and estuaries south of the Tampa Bay region that receive drainage from the greater Everglades ecosystem. In order to manage flooding in heavily populated areas in southeastern Florida, large quantities of water that naturally flowed through the Everglades from Lake Okeechobee, situated in the center of the Florida peninsula, are diverted to both coasts into the St. Lucie Estuary on the Atlantic coast (Kramer et al, 2018) and the Caloosahatchee River estuary on the Gulf of Mexico coast (Heil et al, 2014). These flows deliver large loads of nutrients from agricultural lands north of the lake or from internal phosphorus loads within the lake.…”

Section: Tampa Baymentioning

confidence: 99%

Barriers and Bridges in Abating Coastal Eutrophication

Boesch

2019

Front. Mar. Sci.

127

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Over the past 30 years concerted campaigns have been undertaken to reverse nutrient-driven eutrophication in coastal waters in Europe, North America, Asia, and Australia. Typically, eutrophication abatement has proven a more recalcitrant challenge than anticipated, with ecosystem improvements only recently beginning to emerge or falling short of goals. Reduction in nutrient loads has come mainly from advanced treatment of wastewaters and has lagged targets set for diffuse agricultural sources. Synthesis of the major campaigns-varying in terms of physical settings, ecosystem characteristics, nutrient sources, socio-economic drivers, and governance-identified barriers inhibiting eutrophication abatement and potential bridges to overcome them. Actionable science can be advanced by: application of the well-established and emerging knowledge and experience around the globe, client-responsive strategic research, and timely and conclusive adjudication of scientific controversies. More accountable governance requires: enduring engagement of high-level officials of the responsible governments; effective communication of the causes, risks and benefits to the public and stakeholders; quantitative and accountable allocation of responsibility for nutrient load reductions; and binding requirements, as opposed to simply voluntary actions. Effective reduction in nutrient loads requires: reduction strategies for both nitrogen and phosphorus; inclusion of actions that reduce atmospheric emissions of nitrogen in addition to direct inputs to waterways; efficacious regulations; public subsidies based on performance; limitations on biofuel production that increases nutrient loads; and enhancing the sinks and losses for legacy nutrients retained in soils and groundwater. Outcomes must be measured and strategies appropriately adjusted through: sustained monitoring of essential indicators and processes, the use of multiple models, truly adaptive management, and cautious interventions within the coastal ecosystem. The changing climate must be taken into account by reassessing achievable future conditions and seeking alternatives for mitigating and adapting to climate change that also reduce nutrient loads.

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Section: Tampa Baymentioning

confidence: 99%

Barriers and Bridges in Abating Coastal Eutrophication

Boesch

2019

Front. Mar. Sci.

127

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“…As a consequence, the accumulation of transferred MCs was described in marine fauna such as sea otters and shellfish [11][12][13]. The occurrence of M. aeruginosa and/or MCs in brackish waters was reported in many locations in the United States, South America, Australia, Europe including France, Japan, or India [14][15][16][17][18][19][20] and even became recurrent in San Francisco Bay, USA [21] and in the Patos Lagoon, Brazil [22]. Long-term survey and model predictions pointed out the positive impact of climate change on the intensity and frequency of this phenomenon through the intensification of precipitation and longer drought periods [15,16,23,24].…”

Section: Introductionmentioning

confidence: 99%

Salt Shock Responses of Microcystis Revealed through Physiological, Transcript, and Metabolomic Analyses

Aulnois

Réveillon

Robert

et al. 2020

Toxins

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The transfer of Microcystis aeruginosa from freshwater to estuaries has been described worldwide and salinity is reported as the main factor controlling the expansion of M. aeruginosa to coastal environments. Analyzing the expression levels of targeted genes and employing both targeted and non-targeted metabolomic approaches, this study investigated the effect of a sudden salt increase on the physiological and metabolic responses of two toxic M. aeruginosa strains separately isolated from fresh and brackish waters, respectively, PCC 7820 and 7806. Supported by differences in gene expressions and metabolic profiles, salt tolerance was found to be strain specific. An increase in salinity decreased the growth of M. aeruginosa with a lesser impact on the brackish strain. The production of intracellular microcystin variants in response to salt stress correlated well to the growth rate for both strains. Furthermore, the release of microcystins into the surrounding medium only occurred at the highest salinity treatment when cell lysis occurred. This study suggests that the physiological responses of M. aeruginosa involve the accumulation of common metabolites but that the intraspecific salt tolerance is based on the accumulation of specific metabolites. While one of these was determined to be sucrose, many others remain to be identified. Taken together, these results provide evidence that M. aeruginosa is relatively salt tolerant in the mesohaline zone and microcystin (MC) release only occurs when the capacity of the cells to deal with salt increase is exceeded.

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“…2). Previous studies have indicated that phosphorus and nitrogen are the main causes of freshwater eutrophication, and long-lasting Cyanobacteria blooms are tightly associated with nutrient dynamics [38][39][40][41] . In the inundated areas, dissolved phosphorus and nitrogen can be released into sedimentary pore water and lake water in a short time 18,21 and used in microbial growth in the water 42 .…”

Section: Discussionmentioning

confidence: 99%

Microbial community structure and functional properties in permanently and seasonally flooded areas in Poyang Lake

Liu

Ren

et al. 2020

Sci Rep

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Water level fluctuations are an inherent feature regulating the ecological structures and functions of lakes. It is vital to understand the effects of water level fluctuations on bacterial communities and metabolic characteristics in freshwater lakes in a changing world. However, information on the microbial community structure and functional properties in permanently and seasonally flooded areas are lacking. Poyang Lake is a typical seasonal lake linked to the Yangtze River and is significantly affected by water level fluctuations. Bottom water was collected from 12 sampling sites: seven inundated for the whole year (inundated areas) and five drained during the dry season (emerged areas). High-throughput 16S rRNA gene sequencing was used to identify the bacterial communities. The results showed that the taxonomic structure and potential functions of the bacterial communities were significantly different between the inundated and emerged areas. Cyanobacteria was dominant in both areas, but the relative abundance of Cyanobacteria was much higher in the emerged areas than in the inundated areas. Bacterial communities were taxonomically sensitive in the inundated areas and functionally sensitive in the emerged areas. Nitrogen, phosphorus, and dissolved organic carbon concentrations and their ratios, as well as dissolved oxygen, played important roles in promoting the bacterial taxonomic and functional compositional patterns in both areas. According to the metabolic predictions based on 16S rRNA gene sequences, the relative abundance of functional genes related to assimilatory nitrate reduction in the emerged areas was higher than in the inundated areas, and the relative abundance of functional genes related to dissimilatory nitrate reduction in the inundated areas was higher. These differences might have been caused by the nitrogen differences between the permanently and seasonally flooded areas caused by intra-annual water level fluctuations. The relative abundance of functional genes associated with denitrification was not significantly different in the inundated and emerged areas. This study improved our knowledge of bacterial community structure and nitrogen metabolic processes in permanently and seasonally flooded areas caused by water level fluctuations in a seasonal lake.Microbial assemblages are fundamental components of aquatic ecosystems and play important roles in driving global energy fluxes and biogeochemical cycling 1 . Microbial communities have high species diversity and genetic diversity 2-5 , which make them sensitive to environmental perturbations 6,7 . The relative balance of external nutrient loading influences microbial functional genes and associated metabolic processes in lake ecosystems 8 . Understanding the taxonomic and functional compositions of microbial communities is essential to elucidating the responses of natural bacterial communities to environmental perturbations, such as hydrological fluctuations and nutrient pollution 9-11 . Poyang Lake (PYL) is a seasonal lake characterized by ...

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Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event

Cited by 89 publications

References 61 publications

Barriers and Bridges in Abating Coastal Eutrophication

Barriers and Bridges in Abating Coastal Eutrophication

Salt Shock Responses of Microcystis Revealed through Physiological, Transcript, and Metabolomic Analyses

Microbial community structure and functional properties in permanently and seasonally flooded areas in Poyang Lake

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