Multiple drivers of Holocene lake level changes at a lowland lake in northeastern Germany

Abstract

ELISABETH DIETZE, MICHAŁ SŁOWIŃSKI, IZABELA ZAWISKA, GEORG VEH AND ACHIM BRAUER 2 3Dietze, E., Słowiński, M., Zawiska, I., Veh, G., Brauer, A.: Multiple drivers of Holocene lake 4 level changes at a lowland lake in northeastern GermanyMany German lakes experienced significant water level declines in the last decades that are 7 not fully understood due to the short observation period. At a typical northeastern German 8 groundwater-fed lake with complex basin morphology, an acoustic sub-bottom profile was 9 analysed together with a transect of five sediment cores, which were correlated using multiple 10 proxies (sediment facies, µ-XRF, macrofossils, subfossil Cladocera). Shifts in the boundary 11 between sand and mud deposition were controlled by lake level changes, and hence, allowed traced continuously using the Calcium-record. During high lake levels, massive organic muds 15 were deposited in the deepest lake basin, whereas lower lake levels isolated the sub-basins 16 and allowed carbonate deposition. 17During the beginning of the Holocene (>9700 cal. a BP), lake levels were high likely due to final 18 melting of permafrost and dead-ice remains. The establishment of water use intensive Pinus 19 forests caused generally low (3-4 m below modern) but fluctuating lake levels (9700-6400 cal. 20 a BP). Afterwards, the lake showed an increasing trend and reached a short-term high-stand 21 ~5000 cal. a BP (4 m above modern). At the transition towards a cooler and wetter late 22 Holocene, forests dominated by Quercus and Fagus and initial human impact likely 23 contributed more positively to groundwater recharge. Lake levels remained high between 24 3800 and 800 cal. a BP, but the lake system was not sensitive enough to record short-term 25 fluctuations during this period. Lake level changes were recorded again, when humans 26 profoundly affected the drainage system, land cover and lake trophy. Hence changes, e.g. macrofossils and the position of the sediment limit, i.e., the upper limit for the 68 predominant deposition of organic-rich mud related to sediment focusing (Digerfeldt 1986; 69 Dearing 1997). The "Digerfeldt approach" has provided reliable lake level reconstructions 70 across the globe (e.g. Punning et al. 2004; Shuman et al. 2010;Haig et al. 2013), but so far has 71 been restricted to shallow lakes <100 ha with simple basin morphologies (e.g. low-angled In the central European lowlands, hydrological reconstructions primarily rely on records from 74 small lakes or peat bogs (Gałka et al. 2013(Gałka et al. , 2014 Słowiński et al. 2015). In northeastern Germany, a high sensitivity of lakes to Holocene hydrological changes has been suggested (e.g. 76Lampe et al. 2009; Kaiser et al. 2012 Kaiser et al. , 2014b Küster et al. 2014); however, well-dated lake 77 level reconstructions remained restricted to certain times. 78Lake Fürstenseer See, a typical groundwater fed lake with complex morphology has 79 already showed pronounced changes in lake level and size during the instrumental period 80 (Germer et ...

Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

“…3). Similar variations have been observed in postglacial lakes in Northern Germany, which are situated in a similar glaciofuvial landscape (Dietze et al 2016). The relative calcite variations observed in the lake sediments of Lake Strzeszyńskie could be linked to lake-level fluctuations, where periods of elevated water level correspond to lower calcite content in sediments.…”

“…Lake records have been used, for instance, to reconstruct Late Quaternary lake-level variations and associated changes in effective precipitation (Magny 2004). Changes in water volume often reflect ecological, physical and chemical processes that control the rate of calcite carbonate precipitation and dissolution, which can effectively be traced in the sedimentary record (Haberzettl et al 2005;Pompeani et al 2012;Ohlendorf et al 2013;Dietze et al 2016).…”

A submerged pine forest from the early Holocene in the Mecklenburg Lake District, northern Germany

“…2012a and Dietze et al . for early Holocene examples in the region) and a thermokarst lake formation in ice‐rich permafrost, i.e. a (shallow) thaw lake development (Grosse et al .…”

Holocene fire activity during low-natural flammability periods reveals scale-dependent cultural human-fire relationships in Europe

“…confidence interval, this study) based on n available sites (see Fig. S1 for sample availability per time); b) relative lake 14 levels of lake Fürstenseer See based on the log-ratio transformed µ-XRF Calcium record, after Dietze et al (2016); c) probability density function of 14 C ages of colluvial deposits, Mecklenburg Lake District, Germany (Küster, 2014)…”

“…Water level changes in northeastern Germany are based on the only available, continuous Holocene lake level reconstruction inferred from carbonate deposition in lake Fürstenseer See (Dietze et al, 2016), from which we reassembled the µXRF-Ca record considering 1000 age-depth models within the 2σ range of the 14 C dates (Fig. 3b shows the median and 95 % confidence interval).…”