Algal blooms in a river-dominated estuary and nearshore region of Florida, USA: the influence of regulated discharges from water control structures on hydrologic and nutrient conditions

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