Tuesday, May 27, 2008
323

Algal community assessment during drought conditions in Georgia

Kalina Manoylov and Andrew B. Lanier. Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA 31061

Recently many aquatic habitats in Georgia experienced prolonged conditions such as no rain and low stream flow, which dropped wetland and lake levels causing concern for many aquatic inhabitants. Little is known about algal abilities to withstand drought conditions. As part of an assessment study in Baldwin County we were able to sample aquatic habitats and observe the changes in algal communities due to drought. Sampling was done across gradients of moisture and light in forested and clear areas. 168 samples were analyzed. Changes in biomass and richness were compared between the habitats. Streams in many areas within the region were completely dry for months. Surface soil samples from known area were collected to assess presence of algal spores. Spores that developed in the lab were predominantly bluegreen algae and subareal species of the genera Eunotia and Diadesmis.  Those were found only in shaded environments, dry stream beds in open areas were barren of algal spores. Standing water showed presence of all major algal groups. Green algae persisted during the hottest months.  From October on diatoms were the most species abundant, yet remained in low biomass. Preliminary data suggests that drought conditions can cause profound changes in algal communities’ structure.


Web Page: algae, community composition, drought