Department of Geology, Lund University, Sölvegaten 12, 223 62 Lund, Sweden.
Department of Geology, Lund University, Sölvegaten 12, 223 62 Lund, Sweden.
Sci Total Environ. 2021 Jun 20;774:145517. doi: 10.1016/j.scitotenv.2021.145517. Epub 2021 Feb 2.
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.
湖泊沉积物中的有机碳埋藏在全球碳循环中起着重要作用，并且受到陆地有机物质输入的强烈影响。然而，很少有研究关注陆地有机物质输入到湖泊中以响应土地利用变化的长期变化。本研究的目的是基于来自瑞典西南部 Skottenesjön 湖的两个沉积物岩芯中的木质素生物标志物记录，评估过去 1000 年来沉积物中陆地有机物质的变化。结合基于花粉的定量土地覆盖重建，我们研究了百年尺度土地利用变化对湖泊沉积物中陆地有机物质输入的影响。结果表明，集水区内的人类活动通过改变植被覆盖对陆地有机物质的输出产生了重大影响。18 世纪和 19 世纪森林的集约化利用导致了土壤侵蚀的加剧，并增加了陆地有机物质向湖泊的输入。尽管 12 世纪至 14 世纪中叶农田面积有所扩大，但当时并未观察到陆地有机物质输入的显著变化。与 11 世纪等以前的森林干扰较小时期相比，20 世纪现代林业时期观察到更多的陆地有机和矿物质向湖泊的输出。集水区内植被覆盖的变化极大地改变了沉积在湖泊沉积物中的陆地有机物质的组成，这反映在木质素酚的组成上。本研究表明，木质素酚分析与基于花粉的定量土地覆盖重建的结合是研究陆地有机物质向湖泊生态系统输送的长期变化的有用方法。
