Satellite monitoring of harmful algal blooms in the Western Basin of Lake Erie: a 20-Year History

Session: 37. - Harmful Algal Blooms (HABs) and their Toxicity: Remote Sensing and Modeling Approaches

Amanda Grimm, Michigan Tech Research Inst., [email protected]
Mike Sayers, Michigan Tech. Research Inst., [email protected]
Robert Shuchman, Michigan Technological University, [email protected]
Karl Bosse, Michigan Tech Research Inst., [email protected]
George Leshkevich, Great Lakes Env. Research Lab, NOAA, [email protected]
Steve Ruberg, NOAA - GLERL, [email protected]
Gary Fahnenstiel, Great Lakes Res Center/ Mich Tech Res Institute, Michigan Technological Univ, [email protected]

Abstract

Microcystis blooms have occurred on an annual basis in the Great Lakes, particularly in the Western Basin of Lake Erie, for more than a decade. Previously, we developed and validated an algorithm to map the extent of the submerged and surface scum components of these harmful algal blooms (HABs) using MODIS ocean color satellite data. The algorithm maps submerged HABs by identifying high chlorophyll (CHL) concentrations (>18 ?g/L) combined with water temperature greater than 20°C, while the surface scum component of the HABs is mapped using reflectance values from the near-infrared (NIR) band of the satellite. Here, we adapted this algorithm for the SeaWiFS sensor to map the annual areal extents of HABs in the Western Basin of Lake Erie for the 20-year period from 1998 to 2017. The resulting classified maps were validated by comparison with historical in situ measurements, and the predictive power of potentially important HAB drivers was evaluated in light of this longer time series. This multi-sensor time series and associated statistics extend the current understanding of the extent, location, duration, and temporal patterns of HABs in Western Lake Erie. Such historical knowledge can provide a more complete context for understanding and interpreting current patterns.

1. Keyword
harmful algal blooms

2. Keyword
remote sensing

3. Keyword
Lake Erie

4. Additional Keyword
time-series