TY - JOUR A1 - Aichner, Bernhard A1 - Ott, Florian A1 - Slowinski, Michal A1 - Norygkiewicz, Agnieszka M. A1 - Brauer, Achim A1 - Sachse, Dirk T1 - Leaf wax n-alkane distributions record ecological changes during the Younger Dryas at Trzechowskie paleolake (northern Poland) without temporal delay JF - Climate of the past : an interactive open access journal of the European Geosciences Union N2 - While of higher plant origin, a specific source assignment of sedimentary leaf wax n-alkanes remains difficult. In addition, it is unknown how fast a changing catchment vegetation would be reflected in sedimentary leaf wax archives. In particular, for a quantitative interpretation of n-alkane C and H isotope ratios in terms of paleohydrological and paleoecological changes, a better understanding of transfer times and dominant sedimentary sources of leaf wax n-alkanes is required. In this study we tested to what extent compositional changes in leaf wax n-alkanes can be linked to known vegetation changes by comparison with high-resolution palynological data from the same archive. We analyzed leaf wax n-alkane concentrations and distributions in decadal resolution from a sedimentary record from Trzechowskie paleolake (TRZ, northern Poland), covering the Late Glacial to early Holocene (13 360-9940 yr BP). As an additional source indicator of targeted n-alkanes, compound-specific carbon isotopic data have been generated in lower time resolution. The results indicated rapid responses of n-alkane distribution patterns coinciding with major climatic and paleoecological transitions. We found a shift towards higher average chain length (ACL) values at the Allerod-Younger Dryas (YD) transition between 12 680 and 12 600 yr BP, co-evaled with a decreasing contribution of arboreal pollen (mainly Pinus and Betula) and a subsequently higher abundance of pollen derived from herbaceous plants (Poaceae, Cyperaceae, Artemisia), shrubs, and dwarf shrubs (Juniperus and Salix). The termination of the YD was characterized by a successive increase in n-alkane concentrations coinciding with a sharp decrease in ACL values between 11 580 and 11 490 yr BP, reflecting the expansion of woodland vegetation at the YD-Holocene transition. A gradual reversal to longer chain lengths after 11 200 yr BP, together with decreasing n-alkane concentrations, most likely reflects the early Holocene vegetation succession with a decline of Betula. These results show that n-alkane distributions reflect vegetation changes and that a fast (i.e., subdecadal) signal transfer occurred. However, our data also indicate that a standard interpretation of directional changes in biomarker ratios remains difficult. Instead, responses such as changes in ACL need to be discussed in the context of other proxy data. In addition, we find that organic geochemical data integrate different ecological information compared to pollen, since some gymnosperm genera, such as Pinus, produce only a very low amount of n-alkanes and for this reason their contribution may be largely absent from biomarker records. Our results demonstrate that a combination of palynological and n-alkane data can be used to infer the major sedimentary leaf wax sources and constrain leaf wax transport times from the plant source to the sedimentary sink and thus pave the way towards quantitative interpretation of compound-specific hydrogen isotope ratios for paleohydrological reconstructions. Y1 - 2018 U6 - https://doi.org/10.5194/cp-14-1607-2018 SN - 1814-9324 SN - 1814-9332 VL - 14 IS - 11 SP - 1607 EP - 1624 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Dietze, Elisabeth A1 - Slowinski, Michal A1 - Zawiska, Izabela A1 - Veh, Georg A1 - Brauer, Achim T1 - Multiple drivers of Holocene lake level changes at a lowland lake in northeastern Germany JF - Boreas N2 - Many German lakes experienced significant water level declines in recent decades that are not fully understood due to the short observation period. At a typical northeastern German groundwater-fed lake with a complex basin morphology, an acoustic sub-bottom profile was analysed together with a transect of five sediment cores, which were correlated using multiple proxies (sediment facies, -XRF, macrofossils, subfossil Cladocera). Shifts in the boundary between sand and mud deposition were controlled by lake level changes, and hence, allowed the quantification of an absolute lake level amplitude of similar to 8m for the Holocene. This clearly exceeded observed modern fluctuations of 1.3m (AD 1973-2010). Past lake level changes were traced continuously using the calcium-record. During high lake levels, massive organic muds were deposited in the deepest lake basin, whereas lower lake levels isolated the sub-basins and allowed carbonate deposition. During the beginning of the Holocene (>9700cal. a BP), lake levels were high, probably due to final melting of permafrost and dead-ice remains. The establishment of water-use intensive Pinus forests caused generally low (3-4m below modern) but fluctuating lake levels (9700-6400cal. a BP). Afterwards, the lake showed an increasing trend and reached a short-term highstand at c.5000cal. a BP (4m above modern). At the transition towards a cooler and wetter late Holocene, forests dominated by Quercus and Fagus and initial human impact probably contributed more positively to groundwater recharge. Lake levels remained high between 3800 and 800cal. a BP, but the lake system was not sensitive enough to record short-term fluctuations during this period. Lake level changes were recorded again when humans profoundly affected the drainage system, land cover and lake trophy. Hence, local Holocene water level changes reflect feedbacks between catchment and vegetation characteristics and human impact superimposed by climate change at multiple temporal scales. Y1 - 2016 U6 - https://doi.org/10.1111/bor.12190 SN - 0300-9483 SN - 1502-3885 VL - 45 SP - 828 EP - 845 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Müller, Daniela A1 - Tjallingii, Rik A1 - Plociennik, Mateusz A1 - Luoto, Tomi P. A1 - Kotrys, Bartosz A1 - Plessen, Birgit A1 - Ramisch, Arne A1 - Schwab, Markus Julius A1 - Blaszkiewicz, Miroslaw A1 - Slowinski, Michal A1 - Brauer, Achim T1 - New insights into lake responses to rapid climate change BT - The Younger Dryas in Lake Goscia(z) over dot, central Poland JF - Boreas N2 - The sediment profile from Lake Goscia(z) over dot in central Poland comprises a continuous, seasonally resolved and exceptionally well-preserved archive of the Younger Dryas (YD) climate variation. This provides a unique opportunity for detailed investigation of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination). The new varve record of Lake Goscia(z) over dot presented here spans 1662 years from the late Allerod (AL) to the early Preboreal (PB). Microscopic varve counting provides an independent chronology with a YD duration of 1149+14/-22 years, which confirms previous results of 1140 +/- 40 years. We link stable oxygen isotopes and chironomid-based air temperature reconstructions with the response of various geochemical and varve microfacies proxies especially focusing on the onset and termination of the YD. Cooling at the YD onset lasted similar to 180 years, which is about a century longer than the terminal warming that was completed in similar to 70 years. During the AL/YD transition, environmental proxy data lagged the onset of cooling by similar to 90 years and revealed an increase of lake productivity and internal lake re-suspension as well as slightly higher detrital sediment input. In contrast, rapid warming and environmental changes during the YD/PB transition occurred simultaneously. However, initial changes such as declining diatom deposition and detrital input occurred already a few centuries before the rapid warming at the YD/PB transition. These environmental changes likely reflect a gradual increase in summer air temperatures already during the YD. Our data indicate complex and differing environmental responses to the major climate changes related to the YD, which involve different proxy sensitivities and threshold processes. KW - central Poland KW - Younger Dryas KW - sedimentation pattern KW - lake sediments Y1 - 2021 U6 - https://doi.org/10.23689/fidgeo-4033 SN - 0300-9483 SN - 1502-3885 VL - 50 IS - 2 SP - 535 EP - 555 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Müller, Daniela A1 - Tjallingii, Rik A1 - Plociennik, Mateusz A1 - Luoto, Tomi P. A1 - Kotrys, Bartosz A1 - Plessen, Birgit A1 - Ramisch, Arne A1 - Schwab, Markus Julius A1 - Blaszkiewicz, Miroslaw A1 - Slowinski, Michal A1 - Brauer, Achim T1 - New insights into lake responses to rapid climate change BT - The Younger Dryas in Lake Goscia(z) over dot, central Poland T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The sediment profile from Lake Goscia(z) over dot in central Poland comprises a continuous, seasonally resolved and exceptionally well-preserved archive of the Younger Dryas (YD) climate variation. This provides a unique opportunity for detailed investigation of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination). The new varve record of Lake Goscia(z) over dot presented here spans 1662 years from the late Allerod (AL) to the early Preboreal (PB). Microscopic varve counting provides an independent chronology with a YD duration of 1149+14/-22 years, which confirms previous results of 1140 +/- 40 years. We link stable oxygen isotopes and chironomid-based air temperature reconstructions with the response of various geochemical and varve microfacies proxies especially focusing on the onset and termination of the YD. Cooling at the YD onset lasted similar to 180 years, which is about a century longer than the terminal warming that was completed in similar to 70 years. During the AL/YD transition, environmental proxy data lagged the onset of cooling by similar to 90 years and revealed an increase of lake productivity and internal lake re-suspension as well as slightly higher detrital sediment input. In contrast, rapid warming and environmental changes during the YD/PB transition occurred simultaneously. However, initial changes such as declining diatom deposition and detrital input occurred already a few centuries before the rapid warming at the YD/PB transition. These environmental changes likely reflect a gradual increase in summer air temperatures already during the YD. Our data indicate complex and differing environmental responses to the major climate changes related to the YD, which involve different proxy sensitivities and threshold processes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1359 KW - central Poland KW - Younger Dryas KW - sedimentation pattern KW - lake sediments Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-563386 SN - 0300-9483 SN - 1502-3885 SN - 1866-8372 IS - 2 ER -