Ripon College, Department of Biology, Ripon, WI 54971
The chemical makeup of a lake is a critical indicator of its health. Unfortunately, human activity often alters lake chemistry, especially levels of phosphorus, nitrates, and ammonia. These changes can create imbalances in the biological community, sometimes leading to production of nuisance algal blooms. This results in a reduction of the ecosystem services available to other stakeholders. In the spring of 2007, the White Lake Property Owners Association (WLPOA) requested that Ripon College study the chemical profile of the lake to determine whether its phosphorus levels were elevated. This request was made in response to a high level of phosphorus seen in the surface waters the previous fall. A total of 6 trips were made to White Lake during the summer of 2007. On each collection trip oxygen concentration, temperature, and Secchi disc depth data were collected. We also collected and analyzed, using the Hach techniques, a water sample collected from each meter for phosphate, nitrate, and ammonia. In general, we found that phosphorus and nitrate concentration increased though the summer, while the levels of ammonia showed no pattern. Whole lake phosphorus concentrations for the summer fell well below the level seen the previous fall. However, phosphorus concentration was elevated above ideal levels for mesotrophic lakes. Moreover, near the end of summer phosphorus concentrations rose to levels associated with nuisance algae blooms. Preliminary analysis of sediment cores indicated that there is sufficient phosphorus present at depth to account for the elevated levels of phosphorus seen in the fall of 2006.
[Abstract (DOC)]