95th ESA Annual Meeting (August 1 -- 6, 2010)

COS 105-9 - Characteristics of Lake George periphyton communities and their responses to change

Thursday, August 5, 2010: 4:20 PM
321, David L Lawrence Convention Center
Emily R. Porter-Goff, Darrin FreshWater Institute, Rensselaer Polytechnic Institute, Troy, NY

The composition of periphytic communities within streams change in response to the surrounding anthropogenic and natural conditions of the watershed in which they exist. Nutrients, flow, light, biotic competition, anthropogenic development, canopy cover, drainage basin and watershed characteristics are potential factors in periphytic community change. A summation of several studies investigating which factors have the greatest effects on Lake George stream periphyton community dynamics is presented. The relative quantities and types of algal, bacterial, and fungal communities and total organic matter were evaluated in three Lake George sub-watersheds using the following basic analytical methods: ash free dry mass, chlorophyll a analysis, bacterial counts and ergosterol quantification.


It was found that there was greater periphytic biomass in more developed streams or reaches. Community composition was greatly affected by sampling time, producing a change of dominant species or periphytic group at different times. Community structures were not consistent between seasons of different years. While light was found to have a primary influence on community structure, nutrients did not. Each stream was found to have a unique periphytic community structure. When a community was relocated to a new stream, the relocated community would shift in composition of biotic groups to match the new environment. This research lays the foundation for development of periphyton monitoring protocols.