沉积物中磷形态与湖泊富营养化的关系

应用乙二胺四乙酸法对长江中下游太湖、巢湖和龙感湖等3个湖泊表层沉积物中磷的形态进行连续提取和测定.结果发现,在表层沉积物中,3个湖泊钙磷的百分含量比较接近,占总磷的30%左右,太湖和巢湖铁磷的百分含量显著高于龙感湖,而龙感湖有机磷的相对含量较高,可达40%~50%.这3个湖泊沉积物中有机磷形态差别十分明显,其中太湖沉积物中的有机磷主要以酸可提取有机磷形式存在,巢湖沉积物中酸可提取有机磷约占总有机磷的一半,而龙感湖的有机磷大部分与腐殖酸结合.沉积物中酸可提取有机磷的释放可能又是一个导致湖泊富营养化的重要过程.

Relation between phosphorus forms in the sediments and lake eutrophication

The forms of phosphorus in the surface sediments were extracted and determined sequentially with ethylene dinitrilo tetracetic acid (EDTA) technique in Lake Taihu, Lake Chaohu and Lake Longganhu in the middle and lower reaches of the Yangtze River. In the surface sediments of these 3 lakes, the contents of calcium-bound phosphate were similar relatively with occupation of about 30% of total phosphorus. The percentage contents of iron bound phosphate in Lake Taihu and Lake Chaohu were higher than that of Lake Longganhu, while the related content of organic phosphorus in Longganhu was higher, reaching 40%~50%. The forms of organic phosphorus in the sediments of these three lakes differed markedly. The organic phosphorus existed mainly in the form of acid extractable phosphorus in Lake Taihu sediments and the acid extractable organic phosphorus occupied 50% of total organic phosphorus in Lake Chaohu sediments; while the major organic phosphorus combined with humic acid in Lake Longganhu. The release of acid extractable organic phosphate in sediment might be an important process leading lake eutrophication except iron-bound phosphorus.