洞庭湖沉积物及上覆水体氮的空间分布

2009年12月底在洞庭湖全湖20个采样点采样,通过测量该20个沉积物样和对应的20个上覆水样的总氮、氨氮、硝氮浓度和沉积物的含水率,揭示洞庭湖沉积物及其上覆水体氮的空间分布。研究表明:洞庭湖各点位沉积物全氮平均浓度为547.0mg/kg,与滇池、太湖和巢湖相比较低。洞庭湖各分区沉积物氮形态分布比例相差不大,主要形态为有机氮,占全氮的比例达59.9%。洞庭湖各点位沉积物上覆水体总氮平均浓度为2.45mg/L,已经达《地表水环境质量标准》劣V类水体的标准。洞庭湖各分区沉积物上覆水体氮形态分布不一,硝氮所占比例最大,为35.6%。其中东洞庭湖水体主要氮形态为氨氮,西、南洞庭水体主要氮形态为硝氮。造成这种差异的主要原因是东西洞庭湖的人类生活方式以及城市、工业发展水平的不同。

Spatial Distribution Research of Aitrogen in Sediments and the Overlying Water of Lake Dongtinghu

20 sediment and overlying water samples were collected from entire Lake Dongtinghu at the end of December,2009.Reveal the spatial distribution of nitrogen forms in sediments and the overlying water of Lake Dongtinghu by determine the total nitrogen(TN),ammonia nitrogen(NH3-N),nitrate nitrogen(NO3——N) concentration and the moisture content of the sediment samples.The results show that: the average TN concentration of the 20 sediment samples is 547.0 mg/kg,is quite low compared with other eutrophication lakes.The distribution ratio of nitrogen forms of the various sediments from different sampling points is similar,organic nitrogen(ON) is the main form,accounting for the total proportion 59.9%.The average TN concentration of the 20 overlying water samples is 2.45mg/L and has reached the standard of water inferior class V.The distribution ratio of nitrogen forms of the various overlying water from different sampling points is different,and NO3——N occupy the max proportion 35.6%.Where main nitrogen form of the water in East Dongtinghu is NH3-N,and Southwest is NO3——N.The primary cause to produce the diversity is the various humanity life style and urban,industrial development level between West and East of Lake Dongtinghu.