Oral Presentation Society for Freshwater Science 2025 Annual Meeting

Composition and temporal variability of suspended algae in North Fork Shenandoah River, Virginia, USA (117661)

Rwan Alsaadi 1 , Hannah Toney 1 , R Christian R. Jones 1 , Carly M. Maas 2 , Brendan M. Foster 2 , Mike Selckmann 3 , Rosalina Christova 1
  1. Potomac Environmental Research and Education Center and the Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030, USA
  2. U.S. Geological Survey , Virginia/West Virginia Water Science Center, 1730 E Parham Road, Richmond, VA 23228, USA
  3. Interstate Commission on the Potomac River Basin, 401 N. Washington Street, Ste 300, Rockville, MD 20850, USA

The North Fork of Shenandoah River experiences proliferations of benthic algae, some of which are considered harmful cyanobacteria. These benthic algae blooms resulted in precautionary recreational advisories in the summer of 2021. In 2024, algae suspended in the water column were analyzed in conjunction with benthic mats to evaluate if there was a relation between the two communities. Whole water samples were collected monthly and during storm events by USGS and benthic mats were sampled by the Interstate Commission on the Potomac River Basin as part of a project commissioned by Virginia Department of Environmental Quality. Water samples were collected from two stations, 93-km apart, that bracket areas that have experienced blooms historically. Algal community taxonomy and abundance, and photosynthetic pigments were analyzed to understand the magnitude, composition, and seasonality of these communities and how they interact with streamflow.