Lake Tahoe Nearshore Periphyton Study

Periphyton, a type of algae, is growing on bottom sediment and rocks along nearshore areas of Lake Tahoe. Periphyton is seen as a nuisance and negatively impacts the recreational value of the lake. Periphyton biomass (PB) data collected along the nearshore of Lake Tahoe exhibit increasing trends over the last decade. However, the mechanisms that have caused these changes are not well understood.

We are working with the University of Nevada-Reno, in cooperation with the Lahontan Regional Control Board, to investigate the cause and effect relationships between periphyton biomass and chemical and physical characteristics of the lake and shallow groundwater surrounding Ward Creek, near Tahoe City, California.

Our research provides important information on what are considered the most influential variables controlling the growth of periphyton including

  • Is Ward Creek an important source of nutrients to periphyton assemblages at distal locations along the Lake Tahoe shoreline?
  • What chemical and physical variables are important to periphyton growth?
  • Specifically, are there correlations among these variables to patterns in productivity, nutrient limitation, and taxonomic composition?

Five monitoring transects have been installed to help to distinguish whether nutrients are coming from Ward Creek, other on-shore locations, groundwater, or from lake upwelling to the Pineland Periphyton Monitoring Site (PPMS). Ultimately, our results will assist in providing the context for managing water quality in the Tahoe basin.