Natural and anthropogenic impacts on Lake Ladoga and its catchment area through the late glacial and Holocene according to a new paleolimnological record

A ca. 12,700 year-long pollen and diatom record, as well as data on lithology, geochemistry, and grain size were obtained from two sediment cores retrieved in the southwest part of Lake Ladoga. Changes in phosphorus content during the Holocene were recorded from this sequence dated by the radiocarbon method. An increase in phosphorus, loss-on-ignition and the Fe/Mn ratio was recorded during the climatic optimum of the Holocene ca. 7500–7250 cal yr BP. At the same time, pollen data showed the spread of broad-leaved forests. The peak in phosphorus in the upper part of the core associated with anthropogenic activities is smaller to the peak corresponding to the Holocene climatic optimum. This may indicate that climatic factors affect the ecosystems of large lakes more significantly than anthropogenic ones. According to our new pollen data, first human impact is recorded in Lake Ladoga sediments ca. 2580 cal yr BP.