Holocene climate vs. catchment forcing on a shallow, eutrophic lake in eastern Poland

• Published in: Boreas
• Main Authors: Zawiska, Izabela, Apolinarska, Karina, Woszczyk, Michał
• Other Authors: Narodowe Centrum Nauki
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: permafrost
• Online Access: http://dx.doi.org/10.1111/bor.12347; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbor.12347; https://onlinelibrary.wiley.com/doi/pdf/10.1111/bor.12347

This paper presents a sedimentary record from Lake Łukie located in the southeastern part of the Central European Plain, beyond the reach of the maximum extent of the last glaciation. The lake has thermokarstic origin and developed during the last glacial termination due to subsidence of the sub‐Quaternary carbonate basement triggered by permafrost thawing. A sediment core was investigated to reconstruct water trophic state and lake depth changes during the Holocene. We aimed at showing the relationship between ecological and geochemical changes in the lake and regional/supraregional climatic and hydrological trends throughout the Holocene. Results of subfossil Cladocera analysis were combined with data on the geochemistry and stable C and O isotopes in sedimentary carbonates. Isotopic and geochemical proxies helped to detect sources of sedimentary particles in the lake and thus to reconstruct changes in the intensity of atmospheric and catchment processes (e.g. precipitation and surface runoff). The Cladocera analysis results indicated endogenic processes in the lake such as trophic changes. Our data revealed that Lake Łukie has always been a rather eutrophic water body and the periods of particularly high productivity were in the lower Preboreal and upper Subatlantic. Periods of increased water depth were recorded in the lower Preboreal, lower Boreal and upper Subboreal, whereas low water stands were obtained during the late Preboreal, late Boreal, late Atlantic and Atlantic/Subboreal transition as well as during the lower Subboreal. The sediment succession from Lake Łukie provides the first full Holocene record of carbon and oxygen stable isotopes in lacustrine carbonates from the eastern part of the Central European Lowland. The record is characterized by uncommonly high δ 13 C and δ 18 O values of the carbonates resulting from a combination of within‐lake processes and dissolution of the carbonate bedrock of Cretaceous age. The impact of the old carbonates on isotope values was helpful in the reconstruction ...