Remote sensing of cyanobacterial blooms in Lake Champlain with a focus on Missisquoi Bay

Abstract

At 1270 km², Lake Champlain, is the 13th largest lake in the United States. Lake Champlain experiences annual blooms of cyanobacteria, particularly in Missisquoi Bay. Here the Cyanobacteria Index, a previously published algorithm, was applied to satellite imagery from OLCI (available from 2016 through the present) and MODIS (available from 2000-present). The remotely sensed timeseries of the CI was derived and described from each sensor, along with cross-calibration among OLCI and MODIS. The resultant timeseries described when and where cyanobacteria blooms generally occur. Five distinct regions of Lake Champlain were considered for analysis: Malletts Bay, the Northeast Arm, Saint Albans Bay, Missisquoi Bay, and the Main Lake. Saint Albans and Missisquoi Bay were the only basins shown to have consistent cyanobacteria blooms. Saint Albans Bay, due to its small size was not an ideal fit for the methods used here, and the focus of this manuscript was Missisquoi Bay. The objective of this study is to explore the interannual variability of blooms in Missisquoi Bay and compare the variability to cyanobacteria blooms in Lake Erie, Saginaw Bay, and Green Bay. The blooms in Missisquoi Bay showed interannual variability in size, intensity, and start and end date. Observed data from the Burlington International Airport and modeled data from NASA’s Giovanni program were used in an effort to explain this bloom variability. A 2-parameter multiple regression model fit the cyanobacterial data well and showed that the interannual variability of blooms in Missisquoi Bay are a function of atmospheric instability and temperature.