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Precipitation, submarine groundwater discharge of nitrogen, and red tides along the southwest Florida Gulf coast

Heliyon
By: , , and 
https://doi.org/10.1016/j.heliyon.2023.e16046

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Abstract

Blooms of the dinoflagellate Karenia brevis occur almost every year along the southwest Florida Gulf coast. Long-duration blooms with especially high concentrations of K. brevis, known as red tides, destroy marine life through production of neurotoxins. Current hypotheses are that red tides originate in oligotrophic waters far offshore using nitrogen (N) from upwelling bottom water or, alternatively, from blooms of Trichodesmium, followed by advection to nearshore waters. But the amount of N available from terrestrial sources does not appear to be adequate to maintain a nearshore red tide. To explain this discrepancy, we hypothesize that contemporary red tides are associated with release of N from offshore submarine groundwater discharge (SGD) that has accumulated in benthic sediment biomass by dissimilatory nitrate reduction to ammonium (DNRA). The release occurs when sediment labile organic carbon (LOC), used as the electron donor in DNRA, is exhausted. Detritus from the resulting destruction of marine life restores the sediment LOC to continue the cycle of red tides. The severity of individual red tides increases with increased bloom-year precipitation in the geographic region where the SGD originates, while the severity of ordinary blooms is relatively unaffected.

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Publication type Article
Publication Subtype Journal Article
Title Precipitation, submarine groundwater discharge of nitrogen, and red tides along the southwest Florida Gulf coast
Series title Heliyon
DOI 10.1016/j.heliyon.2023.e16046
Volume 9
Issue 5
Year Published 2023
Language English
Publisher Elsevier
Contributing office(s) South Atlantic Water Science Center
Description e16046, 19 p.
Country United States
State Florida
Other Geospatial West Florida shelf
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