Satellite Remote Sensing for Monitoring Cyanobacteria Blooms

摘要

Algal blooms cause extensive problems in lakes worldwide, including human and animal health risks, anoxia and fish kills, and taste and odor in potable water. Cyanobacterial blooms are a particular concern because of their dense biomass, toxins, and taste-and-odor. These cyanobacteria blooms can be successfully monitored using satellite remote sensing technologies based on algorithms to derive chlorophyll-a and phycocyanin. Satellite technology allows for the development of a unified harmful algal bloom indicator at the local scale with national coverage. Satellite instruments with the smallest spatial footprints (＜ 300m) provide the most desirable resources for studies in coastal and in-land waters. The European Space Agency MEdium Resolution Imaging Spectrometer (MERIS) and future Sentinel-3 Ocean and Land Colour Instrument (OLCI) provide the greatest potential for retrieving high spatial resolution data from lakes at 2-3 day intervals. The overarching project goal was to support the environmental management and public use of U.S. lakes and estuaries by providing a capability of detecting and quantifying algal blooms using satellite data records. This project assessed and validated the performance of an algorithm for MERIS and OLCI using existing in-situ data from the National Lakes Assessment and multiple state databases. Results indicated that MERIS provided robust estimates for low (10,000-109,000 cells/mL) and very high (＞1,000,000 cells/mL) cell enumeration ranges, with correspondence of 90% and 83% respectively. This approach may provide rapid detection of potentially harmful algae, which is essential for protecting the general population from exposure, and support monitoring of cyanobacteria cell concentrations in drinking and recreational waters to identify emerging threats.