In 2005-2006, the Minnehaha Creek Watershed District (MCWD) conducted a paleoecological examination of several MCWD water bodies to identify historical water quality parameters prior to European settlement.
This information is used to set priorities for water quality improvement projects and programs. Since lake sediments faithfully record changes that have occurred within a lake and its watershed, paleoecology offers a unique tool to determine natural or background nutrient conditions in lakes.Diatoms are microscopic, single-celled or colonial algae that are characterized by an ornamented two-part siliceous (glass) cell wall. They are often referred to as the "golden-brown" algae, a testament to their pigment complement.
Diatoms are present in lakes, rivers, streams, and other water bodies that experience even emphemeral moisture. Because of their siliceous cell walls, diatoms are usually well preserved in lake sediments and their presence, absence, abundance, and community makeup provide a snapshot of historical environmental conditions and change. Diatom calibration and training sets have become powerful tools for paleoecological reconstruction and monitoring of surface water quality using standardized methods to reconstruct specific environmental parameters from modern or fossil diatom assemblages.