An ecosystem model newly developed by NCCOS and NMFS scientists reveals the complexecosystem interactions and environmental factors that promote the formation and severity ofharmful blooms that disrupt and degrade ecosystems.
The model shows that such ecosystemdisruptive algal blooms (EDABs) are caused by complex interactions among a number of keyfactors that were previously not known to interact. These factors include competition betweenharmful and beneficial algal species for growth-limiting nutrients, different grazing mortalityrates for harmful species and competing beneficial ones, and positive feedback interactionstied to grazer-linked recycling of nutrients.
The model predicts that the incidence and severityEDAB events are promoted by decreased flushing rates of coastal bays, and that bloom severityis greatly increased by increased nutrient concentrations. Thus, both decreases in rainfall linkedto climate change and anthropogenic inputs of nutrients should promote such blooms andtheir harmful effect on ecosystems and fisheries.
The new model should help environmentalmanagers to identity causative factors, and to design strategies to minimize or mitigate harmfulblooms and their negative environmental and societal impacts. The new findings will appearin an upcoming issue of Marine Ecology Progress Series.