MIDDLE PLEISTOCENE DIATOM PALEOECOLOGY AND HYDROCLIMATIC RECONSTRUCTION FROM LAKE MALAWI, EAST AFRICA

Due to environmental and geopolitical factors Africa is especially vulnerable to climate change. Despite these risks, the dominant drivers of hydroclimate are poorly constrained, and predicting future water availability is challenging. Lake Malawi is one of the worlds oldest lakes, and records from this basin are well-suited to adding to our understanding of hydroclimate in the region. A 1.3 ma drill core collected from Lake Malawi in 2005 has been studied extensively, revealing periods of significant lowstands and highstands which are relevant to early human development and key to understanding the hydroclimatic history of the region. However, the diatom paleoecology has only been examined in this core back to ~150 ka, extending this diatom record provides new insights into the lacustrine and regional history. The Middle Pleistocene diatom assemblage is dominated by Aulacoseira with isolated intervals of dominance by Cyclostephanos and Cyclotella. This assemblage indicates alternations between high, moderate, and low nutrient conditions, potentially concomitant with changes in lake level. This extended diatom record will help refine the history of Lake Malawi and regional hydroclimates.