Algal blooms in the Salt River Reservoirs

The Salt River reservoirs are a major water supply system for the Phoenix Metro area. In addition to water storage and hydropower, the lakes also have a great recreational value, including boating and fishing. In recent years (2003 onwards) however, fish mortality has been a recurrent problem in the Salt River Lakes. Recurrent blooms of algae known to release toxins, such as the chrysophytePrymnesium parvum (Golden Alga), as well as cyanobacteria (Anabaena, Anabaenopsis, and Cylindrospermopsis) have been linked to these fish kills. In a project funded by the NSF Water Quality Center at ASU as well as by the Salt River Project, the Neuer lab investigated the succession of plankton populations in the Salt River Reservoirs, specifically Saguaro and Roosevelt Lake, with the goal to develop an early warning system of noxious algal blooms using satellite remote sensing.

To the right are microscope images of plankton (from top to bottom):

Epifluoresence microscopy image of a plankton assemblage (cells are illuminated by their pigment autofluorescence after blue light excitation) collected in March 2007 from the surface water of Saguaro Lake and filtered onto a 0.2 µm pore size membrane filter. The string of cells is a filamentous cyanobacterium.

Epifluoresence microscopy image of a diatom from the genus Asterionella.

Light microscopy image of colonial green algae from the genus Scenedesmus.

References:

Tarrant, P. E., J. A. Amacher, and S. Neuer (2010), Assessing the potential of Medium-Resolution Imaging Spectrometer (MERIS) and Moderate-Resolution Imaging Spectroradiometer (MODIS) data for monitoring total suspended matter in small and intermediate sized lakes and reservoirs, Water Resour. Res., 46, W09532, doi:10.1029/2009WR008709.

Tarrant P. and S. Neuer. 2009. Monitoring Algal Blooms in a Southwestern U.S. Reservoir System. EOS Transactions. 90(5) 38-39.