长江中下游浅水湖泊沉积物腐殖质组分赋存特征

Humus distribution and forms in the sediments from shallow lakes in the middle and lower reaches of the Yangtze River

应用化学方法,对长江中下游浅水湖泊表层沉积物有机质含量、腐殖质组成及结合形态进行了研究.结果表明:①长江中下游浅水湖泊11个沉积物的有机质含量变化较大,在0.98%-11.0%之间波动.污染程度重的沉积物中有机质含量均较污染程度轻的高,其有机质的分布特征与沉积物污染程度和湖泊周边的人类活动有关.②腐殖质组成中,胡敏酸(HA)含量为1.03-6.73g/kg,富里酸(FA)含量介于2.73-9.77g/kg之间,胡敏素(HM)是主体,含量在5.89-55.57g/kg之间;HA/(FA+HA)比值(PQ)处于23.04%-50.56%之间,平均为32.72%.污染程度重的沉积物PQ值大于污染程度轻的沉积物,说明重污染湖泊沉积物腐殖化程度高.③腐殖质三种结合形态中紧结合态含量最高,在3.21-47.76g/kg之间;其次为松结合态腐殖质,含量在0.86-6.92g/kg之间;稳结合态腐殖质最低,含量在0.72-3.89g/kg之间;松/紧比与沉积物有机质、总磷和总氮呈显著的负相关,表明污染越严重的湖泊沉积物,沉积物腐殖化程度高,腐殖质积累.因此应重视湖泊沉积物腐殖质组分在碳循环及富营养化中的作用.

The organic matter（OM） content,compositions and fractions of shallow lake sediments were studied by chemical method from in the middle and lower reaches of Yangtze River.The results showed that the OM content varied greatly from 0.98% to 11.0 %,higher in the heavily polluted sediments than those in the light polluted ones.The distributions of OM content were closely related to lake pollution levels and human activity intensity.HA content was 1.03-6.73g/kg,and FA content is higher than the HA,from 2.73 to 9.77g/kg.Humin was the main fractions of humus,varing from 5.89 to 55.57g/kg.PQ（HA/（FA＋HA）） ratio varied from 23.04% to 50.56%,and the mean content of PQ was 32.72%.PQ content were higher in the heavily polluted sediments than those in the light polluted ones,which indicated that there was a higher degree of humification in heavy polluted sediments.Combination of three kinds of humus content in the form of tightly bound humus content was the highest,and content was 3.21-47.76g/kg;followed by loosely combined humus content between 0.86-6.92g/kg.The stable combined humus were the lowest,the content varied from 0.72 to 3.89 g/kg.The loose/tight ration in the sediments were also negatively correlated with OM,TP and TN,which showed that heavily polluted shallow lakes had higher humification and humus accumulation.So humus should be paid more attention to the carbon cycling and eutrophication control in lakes.