太湖梅梁湾和五里湖沉积物磷形态的垂向变化

应用淡水沉积物中磷形态的标准测试程序(SMT),分析了太湖北部梅梁湾和五里湖沉积物中磷形态的垂向变化.结果表明,在同一湖泊,不同地点沉积物磷形态的垂向变化有差异.五里湖西部沉积物中铁/铝磷、无机磷和总磷在深度7～12cm处含量最高,往深层方向呈先增后减的垂向分布特征,而有机磷和钙磷含量则随深度增加呈减小趋势;梅梁湾小湾里沉积物中铁/铝磷、无机磷、有机磷和总磷含量均随深度增加呈减小趋势,至22cm以下略有增加,而钙磷却在柱样下部随深度增加呈累积趋势.研究还发现,近年来五里湖西部人为源的磷输入逐渐减小,可能得益于污水排放的削减;而梅梁湾小湾里沉积物中人为源的磷含量明显增加,可能与污水和农业径流输入有关.

Vertical variation of the phosphorus form in the sediments of Meiliang Bay and Wuli Lake of Taihu Lake

The vertical variation of phosphorus forms in the sediment of Meiliang Bay and Wuli Lake in the northern part of Taihu Lake was analyzed, applying the standard measurement and test (SMT) procedure of phosphorus forms in the freshwater sediments. The vertical variation of the phosphorus form in the sediment in different sites might also be different even in the same lake. In the west part of Wuli Lake, the contents of Fe/Al bound phosphorus, inorganic phosphorus and total phosphorus were the highest at the depth of 7~12cm, with vertical distribution character of increase at first and then decrease; while organic phosphorus and calcium-bound phosphorus had a tendency to decrease with the downwards decrease of depth. In the small Meiliang Bay, the contents of Fe/Al-bound phosphorus, inorganic phosphorus, organic phosphorus and total phosphorus decreased with the increase of depth, but also increased a little below the depth of 22cm, while calcium-bound phosphorus at lower part tended to accumulate with the increase of depth. In recent years, anthropogenic phosphorus inputs to the west part of Wuli Lake decreased gradually, possibly favorable for reducing the sewage discharge; while the content of anthropogenic phosphorus in sediment of Meiliang Bay increased markedly, possibly related to the inputs of sewage and agricultural runoff.