DIATOM RESPONSE TO RAPID CLIMATE CHANGE DURING THE PLEISTOCENE-HOLOCENE TRANSITION IN THE CENTRAL SIERRA NEVADA, CALIFORNIA, USA

High-resolution (~40 - ~170 cal yr) diatom analysis was performed on lake sediments spanning the last ~10,000 - ~14,500 cal yr B.P. from three alpine lakes in the central Sierra Nevada, California, USA, to investigate climatic and environmental conditions in this region during the Pleistocene-Holocene transition, a period of documented rapid global climate change. Five distinct and abrupt shifts in diatom community composition occurred concurrently at all three sites during the interval studied. While the specific diatom assemblages varied at each site, suggesting differences in local limnology, the overall climatic conditions inferred from the diatoms were similar at the sites, providing evidence in support of a regional response. The results of this study aid in our understanding of how diatoms and alpine lakes in the central Sierra Nevada responded to a rapid climate change event and may serve as a proxy for climate change that could affect the western United States in the future.