title: Response of organic carbon burial to trophic level changes in a shallow eutrophic lake in SE China.
abstract: Lakes are an important component of terrestrial carbon cycling. As the trend of eutrophication in many lakes continues, the mechanisms of organic carbon (OC) burial remain unclear. This paper aims to understand the distribution of OC and the effect of trophic level changes on OC burial in Chaohu Lake, a shallow eutrophic lake located in the lower reaches of the Yangtze River, SE China. Two hundred and one surface sediment samples (0-20cm) and 53 subsurface samples (150-200cm) from the lake were collected. The OC accumulation rates (OCARs) are relatively low, with an average of 10.01g/m(2)/year in the surface sediments. The spatial distribution of the OCARs is similar to that of allochthonous OC. The difference in total phosphate (TP) content between the surface and subsurface sediments (ΔTP) is significantly correlated with the autochthonous OC, suggesting that TP loading is a critical limiting nutrient for the lake's primary productivity. It is concluded that allochthonous OC is the dominant source of total OC in surface sediments compared to autochthonous OC. The primary productivity of Lake Chaohu increased due to increasing nutrient loading. However, the autochthonous OC contributed 11% of the total OC in the surface sediments. This could be ascribed to strong mineralization in the water column or surface sediments.
authors: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
authors: Pengbao
authors: P
authors: Wu
authors: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. Electronic address: chgao@nju.edu.cn.
authors: Chao
authors: C
authors: Gao
authors: Anhui Geological Survey, Hefei 230022, China.
authors: Furong
authors: F
authors: Chen
authors: Large Lakes Observatory, University of Minnesota Duluth, MN 55812, USA.
authors: Shiyong
authors: S
authors: Yu
mesh_terms: D002244:Carbon / Q000032:analysis; D057486:Carbon Cycle; D057965:Carbon Sequestration; D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D005068:Eutrophication; D020387:Food Chain; D060106:Lakes / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis; D010710:Phosphates; D010758:Phosphorus / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
keywords: Eutrophication; Lake Chaohu; Sediment; Total nitrogen; Total phosphorus