2019年10月31日,环测学院教师李致春博士在Elsevier出版集团旗下的期刊Ecological indicators(影响因子4.490,中科院环境科学与生态学学科SCI期刊分区2区,汤森路透JCR分区Q1区)在线发表了题为“Isotopic evidence revealing spatial heterogeneity for source and composition of sedimentary organic matters in Taihu Lake, China”()的研究论文,该论文受到安徽省高校自然科学基金重点项目(KJ2019A0667)的资助。
论文摘要:Tracing the formation processes of sedimentary organic matter (SOM) pools is crucial for understanding the carbon cycling of lake ecosystems, yet the source and composition of SOM, especially their spatial heterogeneity, in large and shallow lakes are still far from clear. In this study, SOM and its potential organic matter (OM) sources, including terrestrial particulate organic matter (POM), algae and aquatic macrophytes, were systematically investigated in Taihu Lake. We highlight the application of the end-member mixing model (EMM) based on Monte Carlo simulations of δ13C and δ15N ratios to more precisely depict the spatial heterogeneity for source and composition of SOM in such a large and shallow lake. The isotopically distinct signatures of SOM well displayed its sources obviously corresponded to the observed ecotypes of algae-type lakeshores, macrophyte-type lakeshore and groove in reed-belt. The results of EMM presented the higher proportion of terrestrial POM (46.8%–55.0%) than algae source (13.8%–23.4%) and macrophytes sources (20.0%–30.0%) in sediments from estuary and open water regions. The relative contribution proportions from three potential OM sources statistically correlated with relative contents of clay, silt and sand in sediments. The hydrodynamic force affected the grain size of sediments and drove the gradient distribution of SOM source contributions. These isotopic evidences revealed that aquatic macrophytes, algae bloom, inflow/outflow rivers and hydrodynamic changes could cause the spatial heterogeneity of SOM source and composition in large and shallow eutrophic lakes.