摘要
选取太湖梅梁湾和湖心柱状沉积物,研究了其有机碳同位素(δ13C)和氮同位素(δ15N)、C/N、总有机碳(TOC)、总氮(TN)、总磷(TP)含量,并结合210Pb和137Cs沉积物年代测定技术,探究了近百年太湖沉积物有机质和氮的来源。结果表明:太湖梅梁湾湖区在近百年来,其有机质来源总体以自生为主。20世纪50年代以前,湖区受到人类活动的影响较小,沉积物有机质主要来自于湖泊自身水生植物的沉积;50年代到70年代,湖泊内部环境发生变化,湖区逐渐出现藻类大量死亡并沉积的现象,有机质主要来自于水生植物和藻类的共同沉积;70年代到80年代沉积物机质藻类贡献进一步增大;90年代后到现在,则以藻类的沉积为主要来源方式。梅梁湾湖区沉积物氮素的来源在50年代以前主要以流域土壤流失和大型水生植物的死亡为主;50年代到70年代,人类活动的加剧导致大量工业废水、生活污水的输入,藻类开始大面积爆发,氮主要来自于外源的输入、大型植物和藻类的死亡沉积;90年代后到现在,外源氮的输入得到有效地控制,藻类对沉积物氮的贡献相对显著。湖心区域沉积物有机质和氮的来源主要来自于湖泊内部水生植物的沉积。70年代前,沉积物有机质和氮的来源主要来自于水生植物的沉积和水土流失作用;70年代至今,虽然湖泊受到人类活动外源物质输入影响逐渐增大,但总体来讲贡献较小,沉积物有机质和氮的来源仍以湖泊自生为主。
Variation in the organic carbon and nitrogen of lake sediment recorded the history of geochemistry due to natural and anthropogenic activities.In recent decades,with increasing human activities,Lake Taihu,the third largest freshwater lake in China,suffers a serious eutrophic situation,which affected the ecological balance of the lake.In this study,combining with 210Pb and 137Cs sediment dating techniques,carbon and nitrogen isotopes（δ13C and δ15N）,C/N ratio,total organic carbon（TOC）,total nitrogen and phosphorus（TN and TP） content of the lake sediment were analyzed to indicate the historical sedimentation of organic matters in Meiliang Bay and centre area of Lake Taihu.Our results showed that the sources of sediment organic matter were generally autochthonous in the past century of Meiliang Bay.Before 1950s,sediment organic matter was less affected by human activities,mainly from the deposition of aquatic plants.From 1950s to the late 1970s in the last century,the sources of the sediment organic matter were mainly from the aquatic vascular plants and algae.From 1970s to 1980s in the last century,the contribution of algae was obvious.From 1990s in the last century to the present,algae deposition was the main source of sediment organic matter.Nitrogen sources of sediment in Meiliang Bay were mainly derived from soil erosion,fertilizer use and the death of algae before 1950s,and between 1950s and the late 1970s,sediment sources of nitrogen were mainly from industrial wastewater,domestic sewage input and the death of algae deposition.From 1990s to the present,the contribution of external nitrogen in the sediment decreased with the increased contribution of algae sedimentation.In the center area of Lake Taihu,organic carbon and nitrogen of sediment were mainly derived from autochthonous sources.Before 1970s,the source of lake sediment organic matter and nitrogen were mainly from aquatic plants and deposition of soil erosion.From 1970s in the last century to the present,human activities and the increasing of extraneous material input were increasing,however,organic carbon and nitrogen of sediment were mainly composed of extraneous and internal organic matter.Our results revealed a spatial difference of sedimatation in Lake Taihu and could provide theoretical basis for further analyzing sources of organic matter and evaluating nutrition status of this lake.
出处
《生态学报》
CAS
CSCD
北大核心
2011年第16期4661-4670,共10页
Acta Ecologica Sinica
基金
国家自然科学基金(40873079)
社会基础性工作资助项目(2006FY110600)
