Growth of the harmful benthic cyanobacterium Microseira wollei is driven by legacy sedimentary phosphorous.

Models for cyanobacterial harmful algae blooms (cHABs) in fresh waters are usually predicated on the relationship between cyanobacterial ecology and dissolved nutrients, particularly phosphorous. Here we show legacy sediment-associated phosphorous as the primary driver of a benthic cHAB, not phosphorous in the water column. Biogeographical surveys by teams of citizen science volunteers working with the University of South Carolina identified over 200 distinct mats of Microseira wollei in Lake Wateree, SC based on toxin characterization.