鄱阳湖表层沉积物有机质和营养盐分布特征

Space-time Variety of Organic Matter and Nutrition Salt in Sediments from Poyang Lake

  • 摘要: 通过历史数据分析及沉积物样品测定,研究了鄱阳湖表层沉积物OM、TN和TP的时空变化特征。结果表明:鄱阳湖表层沉积物中OM(0.420%~3.175%)和TN浓度(0.026%~0.235%)以“五河”尾闾最高,其次是湖心,而TP浓度(0.010%~0.094%)最高值出现在赣江、抚河及信江尾闾,并且均由南向北至长江入湖口呈降低趋势。丰水期“五河”来水量的增加显著提高了湖心及北部湖区沉积物中OM、TN和TP浓度,尤其以北部湖区增加较明显。但南部尾闾区沉积物TN浓度在枯水期明显高于丰水期。1992—2008年鄱阳湖沉积物中OM、TN和TP浓度均呈明显的增加趋势,尤其是OM和TP浓度增幅较大。2008年鄱阳湖沉积物中OM、TN和TP污染水平已经达到或超过富营养化湖泊沉积物的污染水平,与其他四大淡水湖泊相比,尽管鄱阳湖目前水质相对较好,但呈下降趋势,高氮磷营养底质则增大了其富营养化风险。

     

    Abstract: The space-time variation of organic matter (OM), total nitrogen(TN) and total phosphorus(TP) in surface sediments from Poyang Lake was studied. The result indicated that: The OM, TN and TP contents in surface sediments decreased from south to north of Poyang Lake. The highest OM(0.420%~3.175%) and TN(0.026%~0.235%) contents were found in sediments from the rump parliament of ‘five rivers’, the center of lake was second, but the highest TP content was presented in sediments from the rump parliament of Gan River, Wu River and Xin River. The increment of come water from ‘five rivers’ significantly enhanced the OM, TN and TP contents in sediments from the Poyang Lake, especially for the north area of the lake, but the TN contents in sediments from the rump parliament of south lake in dry season were. Higher than that in flooding season. The OM, TN and TP contents in sediments of Poyang Lake trended to increase from 1992 to 2008, especially for OM and TP. The pollution level of OM, TN and TP in sediment from Poyang Lake had exceeded the level of that in sediment from the eutrophication lake. Comparing to the other four large fresh-water lakes, the water quality of Poyang Lake was well, but presented decrease trend, the higher TN and TP contents in sediments from Poyang Lake lead to the larger risk of eutrophication.

     

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