The regulatory effects of environmental factors on denitrification were studied in the sediments of Meiliang Bay, Talhu Lake, in a monthly sampling campaign over a one-year period. Denitrification rates were measured ...The regulatory effects of environmental factors on denitrification were studied in the sediments of Meiliang Bay, Talhu Lake, in a monthly sampling campaign over a one-year period. Denitrification rates were measured in slurries of field samples and enrichment experiments using the acetylene inhibition technique. Sediment denitrification rates in inner bay and outer bay ranged from 2.8 to 51.5 nmol N2/（g dw （dry weight）·hr） and from 1.5 to 81.1 nmol N2/（g dw·hr）, respectively. Sediment denitrification rates were greatest in the spring and lowest in the summer and early autumn, due primarily to seasonal differences in nitrate concentration and water temperature. For each site, positive and linear relationships were regularly observed between denitrification rate and water column nitrate concentration. Of various environmental factors on denitrification that we assessed, nitrate was determined to be the key factor limiting denitrification rates in the sediments of Meiliang Bay. In addition, at the two sites denitrification rates were also regulated by temperature. The addition of organic substrates had no significant effect on denitrification rate, indicating that sediment denitrification was not limited by organic carbon availability in the sediments. Nitrate in the water column was depleted during summer and early autumn, and this suppressed effective removal of nitrogen from Taihu Lake by denitrification.展开更多
2011年4月至2012年2月,以2个月为周期,在上海市不同地点浦东(PD)、金山(JS)、嘉定(JD)、青浦(QP)、崇明(CM)、闵行(MH)采集不同类型城市河岸带土壤,采用乙炔抑制法测定土壤反硝化速率.结果表明,上海河岸带土壤反硝化速率介于1.00～82.92...2011年4月至2012年2月,以2个月为周期,在上海市不同地点浦东(PD)、金山(JS)、嘉定(JD)、青浦(QP)、崇明(CM)、闵行(MH)采集不同类型城市河岸带土壤,采用乙炔抑制法测定土壤反硝化速率.结果表明,上海河岸带土壤反硝化速率介于1.00～82.92μmol·m-·2h-1之间,时空差异明显.不同区域,农田背景下的河岸带土壤反硝化速率(浦东:29.51μmol·m-·2h-1,嘉定:36.99μmol·m-·2h-1)要高于以草地(青浦:4.95μmol·m-·2h-1,闵行:7.84μmol·m-·2h-1)、矮灌丛(金山:27.83μmol·m-·2h-1,崇明:23.26μmol·m-·2h-1)背景为主的河岸带土壤;垂直变化上,2～5cm深度处的河岸带土壤反硝化速率最大,随深度增加反硝化速率呈逐步降低趋势;季节变化上,河岸带土壤反硝化速率呈现夏秋高冬春低的特点,夏季是反硝化作用最为强烈的季节.温度、pH值、土壤有机碳(Soil Organic Carbon,SOC)、土壤总氮(Soil Total Nitrogen,STN)等是影响反硝化速率的重要因子,其中,反硝化速率与温度、SOC、STN含量呈正相关关系,与pH值呈负相关关系.展开更多
基金supported by the National Basic Research Program (973) of China (No. 2008CB418105)the National Natural Science Foundation of China (No. 40730528, 40901253)+1 种基金the Natural Science Foundation of Jiangsu Province (No. BK2009333)the Knowledge Innovation Program of Chinese Academy of Sciences (No. CXNIGLAS200804)
文摘The regulatory effects of environmental factors on denitrification were studied in the sediments of Meiliang Bay, Talhu Lake, in a monthly sampling campaign over a one-year period. Denitrification rates were measured in slurries of field samples and enrichment experiments using the acetylene inhibition technique. Sediment denitrification rates in inner bay and outer bay ranged from 2.8 to 51.5 nmol N2/（g dw （dry weight）·hr） and from 1.5 to 81.1 nmol N2/（g dw·hr）, respectively. Sediment denitrification rates were greatest in the spring and lowest in the summer and early autumn, due primarily to seasonal differences in nitrate concentration and water temperature. For each site, positive and linear relationships were regularly observed between denitrification rate and water column nitrate concentration. Of various environmental factors on denitrification that we assessed, nitrate was determined to be the key factor limiting denitrification rates in the sediments of Meiliang Bay. In addition, at the two sites denitrification rates were also regulated by temperature. The addition of organic substrates had no significant effect on denitrification rate, indicating that sediment denitrification was not limited by organic carbon availability in the sediments. Nitrate in the water column was depleted during summer and early autumn, and this suppressed effective removal of nitrogen from Taihu Lake by denitrification.
文摘2011年4月至2012年2月,以2个月为周期,在上海市不同地点浦东(PD)、金山(JS)、嘉定(JD)、青浦(QP)、崇明(CM)、闵行(MH)采集不同类型城市河岸带土壤,采用乙炔抑制法测定土壤反硝化速率.结果表明,上海河岸带土壤反硝化速率介于1.00～82.92μmol·m-·2h-1之间,时空差异明显.不同区域,农田背景下的河岸带土壤反硝化速率(浦东:29.51μmol·m-·2h-1,嘉定:36.99μmol·m-·2h-1)要高于以草地(青浦:4.95μmol·m-·2h-1,闵行:7.84μmol·m-·2h-1)、矮灌丛(金山:27.83μmol·m-·2h-1,崇明:23.26μmol·m-·2h-1)背景为主的河岸带土壤;垂直变化上,2～5cm深度处的河岸带土壤反硝化速率最大,随深度增加反硝化速率呈逐步降低趋势;季节变化上,河岸带土壤反硝化速率呈现夏秋高冬春低的特点,夏季是反硝化作用最为强烈的季节.温度、pH值、土壤有机碳(Soil Organic Carbon,SOC)、土壤总氮(Soil Total Nitrogen,STN)等是影响反硝化速率的重要因子,其中,反硝化速率与温度、SOC、STN含量呈正相关关系,与pH值呈负相关关系.
