Three-Dimensional Detection of Cyanobacteria Harmful Algal Blooms from a Hyperspectral Aircraft Sensor and Autonomous Underwater Vehicles

The Great Lakes experience episodic cyanobacteria harmful algal blooms (CHABs) and recent monitoring efforts heavily focus on the western basin of Lake Erie. CHABs negatively impact the municipal drinking water supply in Lake Erie, shutting down the drinking water supply for Toledo residents in 2014. Monitoring efforts since that catastrophic event are aimed at tracking CHAB toxicity levels, the subsurface expression, and the surface bloom extent through several sampling detection platforms. Bloom toxicity is monitored with the 2G Environmental Sample Processor (ESP) at a single point location in the western basin and recently with a 3G ESP integrated with an autonomous underwater vehicle (AUV), with a second sentinel/mapping AUV. Both are operated by the Monterey Bay Aquarium Research Institute (MBARI) and NOAA. AUV depth-integrated CHAB and toxicity data are critical for subsurface CHAB assessments at municipal drinking water intakes in combination with surface sampling. The surface expression of CHABs is monitored through shipboard and buoy measurements, along with a hyperspectral imager flown weekly over extent of the western basin of Lake Erie by NOAA’s Great Lakes Environmental Research Laboratory. The combination of the surface CHAB hyperspectral surveys with AUV depth integrated profiles, provides regional water managers with an important tool to interrogate CHABs throughout the water column. This three-dimensional view of bloom dynamics is inherently lacking from airborne or space-borne sensors and the combination of these two coincident datasets allows NOAA to provide unprecedented new capabilities in CHAB detection, early-warning, and forecasting for municipalities.