A CASE STUDY ON BIOGEOCHEMISTRY OF NITROGEN REMOVAL FROM THE LITTORAL ZONE IN EUTROPHICTAIHU LAKE
Our former studies showed that macrophyte-covered littoral zone is the potential area for reduction of internal nitrogen pollution load， which is mainly carried by algae and transported to the littoral area by lake current.In this study， nitrogen release and its removal were studied in undisturbed sediment cores from the macrophytecovered littoral and pelagic sediments in Taihu Lake.The cores were incubated for one month in static state under oxic conditions.Temporal variation of nitrogen in the overlying water， exchangeable nitrogen and total soil nitrogen in sediment before and after incubation，and related environmental variables were determined. During the incubation，only the microphyte-covered littoral cores release nitrogen and showed distinctly temporal variation of inorganic nitrogen in the overlying water during incubation，which indicated that unusually strong nitrogen processes and interaction between sediment and overlying water occurred here.In the non-growing season，large amounts of exchangeable nitrogen was stored in the surface sediment in both pelagic and littoral cores，the release of these mineralized nitrogen maybe account for the highest inorganic nitrogen contents we formerly observed in winter during one-year period.After the incubation，total soil nitrogen and soil organic matter significantly reduced in the surfaced sediment in the microphyte-covered littoral zone，and here nitrogen removal rate was about 2.3 kg N m-2Y-1， which is about 148 times higher than that in the pelagic cores.Therefore，microphyte-covered littoral zone controls the whole lake internal nitrogen removal，to restore the destroyed littoral area is an practical natural method for eutrophicaiton control now.
Eutrophication littoral zone pelagic zone internal load nitrogen incubation
Wang Yuchun Wang Hongjun
Department of water environment,China Institute of Water Resources and Hydroelectric Power Research， Laboratory of Vegetation and Environmental Change,Institute of Botany,CAS,20 Xiangshan，Beijing 10009
国际会议
High-level International Forum on Water Resources and Hydropower(第一届国际水利水电高层论坛)
北京
英文
466-479
2008-10-17（万方平台首次上网日期，不代表论文的发表时间）