太湖悬浮物磷的形态分布特征

Phosphorus distribution characteristics in suspended matter in Taihu Lake

应用螯合剂分级提取法研究太湖5个湖区悬浮物和表层沉积物中磷的形态分布特征,该方法把磷的形态分为水提取弱吸附态磷(ExP)、铁结合态磷(FeP)、钙结合态磷(GaP)、酸提取有机磷(OrgPac)、碱提取有机磷(OrgPalk)和残渣态磷(ResP),并对不同形态的磷在沉积物和悬浮物质中的迁移进行了探讨。结果表明,悬浮物和沉积物中磷的形态分布差异很大,悬浮物中磷的主要形态为铁结合态磷和有机态磷,二者的相对含量之和约为80%,而表层沉积物中磷的主要形态是有机态磷,相对含量为50%;悬浮物中铁结合态磷的绝对含量平均值为1271mg/kg,表层沉积物中则为190mg/kg;悬浮物中铁结合态磷相对含量平均值是沉积物中的2.7倍。大量铁结合态磷在悬浮物的沉降过程中可能完成了形态的转化,成为藻类生长的磷营养源。

The present paper aims to report the authors＇ research on the phosphorus distribution in the suspended matter and surface sediments sampled from Taihu Lake. In our research we have made an analysis with the sequential extraction method. The results of our research have shown that due to the marked difference between the suspended matter and the surface sediments in the phosphorus distribution, the dominant forms of phosphorus are basically in ironbound form （Fe-P） and the organic phosphorus （Org-P） in suspended state, which accounts for 80 percent of the total phosphorus distribution. However, since with the surface sediments it is mainly Org-P, with its relative content taking 50 percent. The relative content of Fe-P in suspended state is 1.7 times higher than that in sediments. The Fe-P is the likelist matter to get moveable between the surface sediments and suspended matter and thus has turned to be one of the most important resources for cyan bacteria to grow up.