The role of surface water warming in the timing of Microcystis-dominated blooms in western Lake Erie

Session: Watershed and Lake Science Informing Management (1)

Timothy Davis, Bowling Green State University, [email protected]
Owen Doherty, Eagle Rock Analytics, [email protected]
Christopher Gobler, Stony Brook University, [email protected]

Abstract

It is well known that spring nutrient loads, primarily from the Maumee River watershed, play a key role in determining the magnitude of the annual cyanobacterial harmful algal bloom (cyanoHAB) in western Lake Erie (WLE).  Furthermore, shifts in regional climatology, specifically warming and more extreme hydrologic events, leading to increased nutrient loading, is predicted to exacerbate the WLE cyanoHAB. However, one factor that is often overlooked is the potential shift in the initiation and duration of the bloom that may accompany earlier increases in spring water temperatures and warmer waters later into the fall, respectively.  Currently the WLE cyanoHAB initiates around mid to late-July, peaks in August/September and dissipates by mid-October.  However, if climate shifts cause warmer springs, the timing of bloom initiation could be shifted earlier.  Furthermore, warmer fall temperatures may allow the blooms to persist longer than they currently do.  We used high-resolution lake surface temperature retrievals from 2002-2017 and temperature-dependent growth rates of multiple Microcystis strains to evaluate recent changes in the phenololgy and growth rates. Our findings suggest that if the biogeochemical conditions for bloom formation in WLE persist, rising temperatures will lead to an earlier onset and longer growing season for the Microcystis-dominated blooms.

Twitter handle of presenter
@PlanktonScience