9407377 Kilham This research addresses one of the major concerns of the ecological agenda: the relationship of climate change to the structure, function and survival of ecological communities. The objectives of the study are (1) to characterize the physiological responses of the eight dominant diatom species from selected lakes of the Yellowstone National Park region to temperature, light, silicon, phosphorus, and nitrogen, (2) to determine the relative competitive abilities of the species, and (3) to perform field studies on the abundances and relative competitive abilities of the species. A set of lacustrine sedimentary records, coupled with active and intense investigations on landscape, climatic and limnological changes underway in Yellowstone ecosystems, provides an unparalleled opportunity to incorporate resource competition theory with field observations on diatom assemblages, evolution and extinction. This study will integrate the predictions and results based on resource competition theory with observations with changes in the structure of diatom assemblages in the lakes of the Yellowstone Region to explain the present diatom distributions and to test the causal factors proposed to explain diatom distributions over the Holocene. %%% This research provides a strong causal linkage between limnology and process-oriented physiological ecology to acquire information necessary for a detailed interpretation of the paleorecord and a firm basis for developing landscape-level transfer functions that will lead to fine-scale climate reconstructions.
