Biofilm colonization and succession in Didymosphenia geminata dominated waters

Session: Poster Session

Anthony Budrick, University of Wisconsin - Oshkosh , [email protected]
Robert Pillsbury, University of Wisconsin-Oshkosh, Biology Dept., [email protected]
Sabrina Mueller-Spitz, University of Wisconsin - Oshkosh , [email protected]

Abstract

Didymosphenia geminata (commonly called Didymo) is a photosynthetic diatom capable of producing nuisance blooms composed of thick benthic mats in cold nutrient poor rivers. These mats are composed of interwoven extracellular stalks produced by Didymo and provide a surface for attachment by epiphytes. These stalks become the foundation for a complex community of bacteria, algae, and invertebrates. The goal of this research is to understand the development of the Didymo matrix community over time. The field site for this study was a stretch of the St. Mary’s river (Michigan, USA) which had visual evidence of Didymo colonization. To characterize the developing community, an artificial matrix was made from cotton gauze adhered to unglazed ceramic tiles and mounted to patio bricks. Experimental tiles and control tiles were submerged and allowed to colonize for 7, 14, 21, and 28 days then collected for analysis of the attached algae. Algae were identified to genus level and enumerated to characterize the developing community. Characterizing the changes in the algal community composition associated with the complex architecture of the Didymo matrix is necessary to further understand the perplexing nature of Didymosphenia geminata, and the potential long-term impact Didymo blooms have on native and invaded ecosystems.