Impacts of long-term land use on terrestrial organic matter input to lakes based on lignin phenols in sediment records from a Swedish forest lake

Bingjie Yang; Karl Ljung; Anne Birgitte Nielsen; Elise Fahlgren; Dan Hammarlund

doi:10.1016/j.scitotenv.2021.145517

Impacts of long-term land use on terrestrial organic matter input to lakes based on lignin phenols in sediment records from a Swedish forest lake

Sci Total Environ. 2021 Jun 20:774:145517. doi: 10.1016/j.scitotenv.2021.145517. Epub 2021 Feb 2.

Authors

Bingjie Yang¹, Karl Ljung², Anne Birgitte Nielsen², Elise Fahlgren³, Dan Hammarlund²

Affiliations

¹ Department of Geology, Lund University, Sölvegaten 12, 223 62 Lund, Sweden. Electronic address: bingjie.yang@geol.lu.se.
² Department of Geology, Lund University, Sölvegaten 12, 223 62 Lund, Sweden.
³ Department of Earth Sciences, University of Gothenburg, Guldhedsgatan 5a, 413 20 Gothenburg, Sweden.

PMID: 33609828
DOI: 10.1016/j.scitotenv.2021.145517

Abstract

Organic carbon burial in lake sediments plays an important role in the global carbon cycle, and is heavily affected by the terrestrial organic matter input. However, few studies have focused on long-term changes in terrestrial organic matter input to lakes in response to land-use changes. The aim of this study was to assess variations in sedimentary terrestrial organic matter over the last 1000 years based on lignin biomarker records from two sediment cores from Lake Skottenesjön, southwestern Sweden. In combination with pollen-based quantitative land cover reconstruction, we investigated the impacts of centennial-scale land-use changes on terrestrial organic matter input to lake sediments. The results show that human activities in the catchment had significant impacts on terrestrial organic export by modifying the vegetation cover. Intensified use of the forest in the 18th and 19th centuries led to enhanced soil erosion, and increased terrestrial organic matter input to the lake. Although farmland expanded between the 12th and the middle of 14th century, no significant change in terrestrial organic matter input was observed at that time. Much higher export of terrestrial organic and minerogenic matter to the lake was observed during the period of modern forestry in the 20th century as compared to previous periods of minor forest disturbance, such as 11th century. The changes in the vegetation cover in the catchment considerably modified the composition of terrestrial organic matter deposited in the lake sediments, which is reflected by the composition of lignin phenols. This study demonstrates that the combination of lignin phenols analysis and pollen-based quantitative land cover reconstruction is a useful approach for investigating long-term changes in terrestrial organic matter delivery to lake ecosystems.

Keywords: Lake sediments; Land use; Lignin phenols; Terrestrial organic matter.