Bacteria community dynamics and metabolism are relevant to understanding the mechanism of phosphorus cycling in eutrophic lake systems. In Lake Mendota, WI, heterotrophic bacterial abundance as measured by catalyzed reporter deposition fluorescence in situ hybridization (CARD FISH), 33PO4-3 uptake and regeneration, 14C- leucine incorporation, alkaline phosphatase activity, and a suite of chemical analysis were measured during 2009 ice-off period in order to identify seasonal and spatial trends.