Images of Cylindrospermopsis and Pseudanabaena from Several Reservoirs in Indiana, U.S.A.

Carole A. Lembi

Over the summer 2001, surveys of planktonic algae collected from several Indiana reservoirs showed the presence of the taste and odor causing cyanobacterium Pseudanabaena limnetica throughout the summer, and the presence of the coiled morph of Cylindrospermopsis raciborskii in late summer. Cylindrospermopsis raciborskii, when found in large quantities, can produce toxins.

The images shown here were taken of samples that were preserved in Lugol's solution within one day of collection. Photography was with a light microscope at either 400X or 900X (oil immersion). Both Cylindrospermopsis and Pseudanabaena are extremely small cyanobacterial filaments (also called trichomes); trichome widths are only between 2-2.5 µm. Information on Cylindrospermopsis and other toxic blue-green algae can be found at the Indiana DNR web site.

Acknowledgements:

• Dan Rabb for providing water samples
• Ann St. Amand, PhycoTech, Inc., for assisting with identification
• Ralph Nicholson and Katie Wilkinson, Purdue University, for assisting with photomicroscopy