The Willamette National Forest has worked with Portland State University, Center for Lakes and Reservoirs (PSU) and the University of Oregon (UO) to investigate ecosystem changes, provide guidance on long-term monitoring methods, assess monitoring data, develop predictive water quality models, and conduct research that will lead to better protection and understanding of the Waldo Lake ecosystem. This report summarizes the second year of collaborative PSU-UO research at Waldo Lake. Research has focused on understanding physical, chemical and biological characteristics of Waldo Lake across a range of spatial and temporal scales. Research tasks that continued from 2003 into 2004 included temperature monitoring, hydrodynamic and water quality model development, climate and hydrological forcing scenario investigation, bathymetric map refinement, and analysis of phytoplankton and zooplankton community changes. Research tasks initiated in 2004 included evaluation of wavelength-specific light attenuation, diel phytoplankton and zooplankton vertical distribution patterns, phytoplankton photoinhibition and photoprotection, and the role of mixotrophy in the pelagic microbial food web.

Preliminary efforts were made to characterize Waldo Lake benthos through assessment of algal species diversity and chemical composition of the benthic community, as very little is currently known about the Waldo Lake benthic ecosystem. In addition, an attempt was made to map benthic substrate types through reinterpretation of data collected during the 2003 bathymetric survey.