Analysis of diatoms in lake sediments is a powerful tool to detect recent environmental change, or to place modern conditions in a regional and historical context. Interpretation of diatom data is dependent on accurate environmental measurements including the concentrations of nutrients and chlorophyll in water. The objective is to identify diatoms collected from lake sediment and analyze water samples for nutrient and chlorophyll levels. STATEMENT OF JOINT OBJECTIVES/PROJECT MANAGEMENT PLAN: The principal investigator and NPS GLKN Aquatic Ecologist will jointly serve as co-investigators and project managers throughout the project. The co-investigators, along with the Midwest Regional Aquatic Ecologist, will collaborate on data analysis and interpretation, and will serve as co-authors on any final reports and/or peer-reviewed journal articles arising from the project. National Park Service and Recipient Tasks follow: RECIPIENT INVOLVEMENT: 1. Appoint Dr. Mark Edlund, senior scientist from the SCWRS, a field station of the Science Museum of Minnesota, as the principal investigator for administering this work. 2. Analyze and provide results for water samples provided by the National Park Service. Parameters to be analyzed include total phosphorus, total nitrogen, nitrate+nitrite nitrogem, ammonium nitrogen, and chlorophyll a, with approximately ~200 samples for each parameter annually. Results will include detection limits, reporting limits, QAQC report, and any appropriate data flags (with corresponding explanation). Maximum (lower) detection limits and methods will be as follows: Analyte Method detection limit Method TP 5 Âµg/L Alkaline Persulfate Digestion TN 15 Âµg/L Alkaline Persulfate Digestion NO3+NO2-N 3 Âµg/L 4500 -NH3(F) NH4-N 5 Âµg/L 4500 -NH3(F) Chlorophyll-a 1 Âµg/L 445: In-Vitro Determination of Chlorophyll 3. Analyze diatoms from lake surface sediments. Samples will be collected from approximately 10 lakes per year. Diatom samples will be prepared and counted as described in Ramstack et al. (2008) for surface sediment samples. From each sample a lake-specific inventory of diatom species richness and relative abundance will be assembled. Transfer functions created from existing diatom calibration models will be applied to the relative abundance data to reconstruct environmental variables of interest. 4. Analyze quality assurance/quality control samples for diatoms according to Ramstack et al. (2008). 5. Conduct numerical analysis of diatom results. In addition to applying calibration set transfer functions using weighted averaging regression and calibration to reconstruct specific environmental variables, multivariate ordination techniques will be used to explore community-level changes. The diatom assemblages from each surface sediment sample will be ordinated relative to surface sediment calibration sets using detrended canonical correspondence analysis (DCCA) to construct historical environmental lake trajectories (Engstrom et al. 2000). For lakes that have had longer sediment cores analyzed, the environmental lake trajectories will extend back over 200 years. Using the GLKN diatom training set and other regional sets including Ramstack et al. (2003), Edlund and Kingston (2004), or Kingston's (unpublished), if necessary, to create lake trajectories will allow analysis of both direction and magnitude of community and environmental change (e.g., TP, alkalinity, color, recovery to natural conditions) among lakes or samples. Magnitude of change will reflect specific environmental reconstructions. Direction of change will be interpreted in two ways: 1) at a community level, analysis of a sample will be placed in the context of other analyzed diatom communities. For example, do the most recent samples begin to "return" to the pre-settlement condition (community) of a lake; 2) community data will be passively plotted against an environmental-diatom training set to identify the environmental gradients along which the community is changing (e.g., is the diatom community changing along a trophic gradient or a pH gradient?). 6. Produce a technical report summarizing results of diatom analysis in the context of the historical natural range of variation as well as the trajectory of recent change on an every-other-year basis. Interpretation regarding the causes of recent changes in diatom communities relative to water chemistry will be included. NATIONAL PARK SERVICE INVOLVEMENT: 1. Assign Great Lakes Inventory and Monitoring Network (GLKN) Aquatic Ecologist David VanderMeulen as the NPS Principle Investigator. 2. Collect surface sediment from approximately 10 lakes per year. A line-operated gravity corer will be used to collect the upper 0-2 cm of sediment, separated into 0-1 cm and 1-2 cm subsamples according to Ramstack et al. (2008), for an integrated assessment of lake conditions during the past 1-5 years. Collection will occur at previously located sites (via GPS) at the central depositional basin in each lake. 3. Collect water samples. Field collection of water samples will follow the protocols according to Elias et al. (2008) for lakes and Magdalene et al. (2008) for rivers. All supplies (field equipment, bottles, chain of custody forms, coolers) will be provided by GLKN. Samples will be preserved appropriately according to methods agreed upon by SCWRS and GLKN and sent to SCWRS for analysis. 4. Provide water quality data to SCWRS. All field-collected data and water chemistry data from labs other than SCWRS will be provided to SCWRS as soon as available following the end of the field season. These data will be used for interpretation of diatom community analyses and in collaborative reports. 5. Manage data and metadata. GLKN will ensure that data and metadata from the project are entered into appropriate databases and made available to other state and federal agencies, partners, and the public. 6. Acquire permits. GLKN will acquire all necessary park permits to conduct the field work. 7. Prepare reports. GLKN will prepare annual park briefs according the internal guidelines, submit Investigatorâ€™s Annual Reports to the online NPS database, review SCWRS annual reports, and collaborate with SCWRS on comprehensive synthesis reports.