Multi-level Indicators of Ecosystem Integrity in Alpine Lakes of the Sierra Nevada (EPA STAR Grant) James T. Oris, Sheldon I. Guttman, and A. John Bailer Miami University, Oxford, Ohio Brant C. Allen and John E. Reuter University of California-Davis, Tahoe Research Group, Davis, CA Glenn C. Miller University of Nevada-Reno, Reno, NV      The overall objective of the research is to develop protocols for environmental assessments of alpine lakes in the Sierra Nevada with a range of human impacts. These assessments are being conducted over the range of levels of biological organization (molecular to ecosystem) utilizing currently available assessment techniques and with the addition of two new ecological indicators. The use of population genetics analysis as a response indicator and the use of molecular biomarkers of exposure to contaminants as a diagnostic indicator are being used for possible incorporation into monitoring and assessment programs for surface waters. These indicators will provide critical information concerning the status of population diversity and stability and concerning the exposure to non-persistent, non-bioaccumulative contaminants. This information is currently missing from established monitoring and assessment protocols.      Over the three-year project period, we are conducting standard environmental assessments of a select group of alpine lakes with a defined range of human impacts. The standard assessment protocols include an evaluation of each of the following: 1) physical habitat, 2) fish assemblage, 3) benthic invertebrate community, 4) fish tissue contaminants, 5) standard water chemistry, 6) zooplankton assemblage, and 7) sediment diatom assemblage. There will be a total of 16 assessment sites. Those selected for assessment include 4 minimally impacted areas (Castle Lake, Eagle Lake, Marlette Lake, and Upper Angora Lake), 8 areas with a range of moderate impacts (Fallen Leaf Lake, Gold Lake, lake Tahoe at Sand Harbor, Prosser Reservoir, Spaulding Reservoir, Stampede Reservoir, Topaz Lake, and Upper Twin Lake), and 4 highly impacted areas (Boca Reservoir, Donner lake, Lake Tahoe at Tahoe City, and Lake Tahoe at the Tahoe Keys).      In addition to the standard assessment, we are conducting population genetic assessments in fish and invertebrates at these same sites. We are also conducting contaminant exposure assessments in fish using molecular biomarkers of exposure in the gills of fish. Five markers indicative of exposure to a wide variety of chemical contaminants (persistent and non-persistent) and that can account for interactions among complex mixtures of contaminants will be measured over time in the assessment areas using caged rainbow trout.      These additional techniques will then be applied to current assessment protocols. Because we will be examining a group of lakes with defined levels of human impacts, we will be able to analyze the discriminatory ability of the assessment techniques using the current protocols compared to the protocols with the new indicators added. We hypothesize that since current protocols do not account for genetic diversity or non-persistent contaminants, the addition of these new indicators will greatly enhance monitoring and assessment programs for surface waters.