Sediment cores were collected with a gravity corer (90 mm diameter; UWITEC, Mondsee, Austria) at the deepest points of the lakes, where sediment accumulation due to sediment focusing is strongest (Table ). The core length of 1 m was deemed enough to cover a time span of at least 100 years starting from the year of sampling, i.e. the year 1915, which was on average was located between 210 mm and 510 mm sediment depth, depending on the lake. Coring was performed in August 2015 (all but one lake) and December 2016 (Lake Stechlin, ST). Cores were transported to the lakeshore, and were immediately subsampled by slicing with a designated core slicer (UWITEC). Sediment slices were 5 mm (Lakes Feldberger Haussee, FH, and Breiter Luzin, BL), or 10 mm in thickness (all other lakes). Samples were transported to the laboratory at 4 °C, weighed, and immediately frozen at -20 °C until further processing.