Environmental change within the Balkan region during the past ca. 50 ka recorded in the sediments from lakes Prespa and Ohrid

摘要

Abstract. Lakes Prespa and Ohrid, in the Balkan region,udare considered to be amongst the oldest lakes in Europe.udBoth lakes are hydraulically connected via karst aquifers.udFrom Lake Ohrid, several sediment cores up to 15m longudhave been studied over the last few years. Here, we documentudthe first long sediment record from nearby Lake Prespaudto clarify the influence of Lake Prespa on Lake Ohrid andudthe environmental history of the region. Radiocarbon datingudand dated tephra layers provide robust age control and indicateudthat the 10.5m long sediment record from Lake Prespaudreaches back to 48 ka. Glacial sedimentation is characterizedudby low organic matter content and absence of carbonates inudthe sediments, which indicate oligotrophic conditions in bothudlakes. Holocene sedimentation is characterized by particularlyudhigh carbonate content in Lake Ohrid and by particularlyudhigh organic matter content in Lake Prespa, which indicatesuda shift towards more mesotrophic conditions in the latter.udLong-term environmental change and short-term events,udsuch as related to the Heinrich events during the Pleistoceneudor the 8.2 ka cooling event during the Holocene, are welludrecorded in both lakes, but are only evident in certain proxies.udThe comparison of the sediment cores from both lakesudindicates that environmental change affects particularly theudtrophic state of Lake Prespa due to its lower volume and wateruddepth.