Cyanobacterial blooms in eutrophic inland waters are a worldwide concern and are exacerbated by high nutrient inputs and warm waters. Blooms are appearing with increasing frequency in water bodies used for drinking water supply or recreation, a problem that will likely worsen as the climate warms. Cyanobacterial blooms are a nuisance for their unsightly surface scums and the production of taste-and-odor compounds, and some strains of cyanobacteria produce toxins that are hazardous to human and animal health. Simple and fast detection methods would greatly aid water managers in issuing proper warnings for the presence of harmful algae. Remote sensing imagery has been used to detect cyanobacterial blooms, but few studies have distinguished between genera of cyanobacteria. Because some genera are more likely to be toxic than others, this is a useful distinction. Previously, USGS researchers successfully used hyperspectral imaging reflectance microscopy to examine cyanobacteria from Upper Klamath Lake, Oregon, at high spatial and spectral resolution to determine if two genera found commonly in the lake, Aphanizomenon flos-aquae and Microcystis sp., can be separated spectrally. Presently a joint effort between the National Land Imaging, National Civil Applications Center and the Water Mission Area, Hydro-Ecological Interactions Branch, is building a hyperspectral library of HABs by spectrally analyzing HAB samples from USGS Water Science Centers around the country.
Hyperspectral microscope images of individual genera of different harmful algal blooms (HABs), along with their individual spectral profiles, are being collected from samples sent in from many USGS Water Science Centers in order to build a spectral library of HAB phenomena.