洱海湖滨带与湖中心带表层沉积物磷的形态对比分析与环境学意义

Comparative analysis of phosphorus fraction in surface sediment between lakeside and middle zone of Erhai Lake and its environmental significance

采用连续提取方法对洱海湖滨带和湖中心带表层沉积物磷的形态及其分布特征进行了分析。结果表明湖滨带TP的含量为741.35—1061.36 mg·kg^(-1),平均为872.61 mg·kg^(-1),显著高于湖中心带(含量范围576.38—722.98 mg·kg^(-1),平均值663.67 mg·kg^(-1))。两区域均以IP为主赋存形态,分别占TP的79.70—84.97%(湖滨带)和78.1—92.28%(湖中心带),而IP中以Ca-P为主,分别占IP的26.76—63.38%(湖滨带)和28.67—55.16%(湖中心带)。从各形态磷的含量分布特征来看,湖滨带的TP、IP、OP、Ads-P、Fe-P和Ca-P均显著高于湖中心带,而De-P则相反,反映了磷在迁移过程中与环境因子变化之间响应关系。相关分析表明湖滨带TP与IP、OP、Ads-P均呈显著的正相关关系,而在湖中心带这种关系则仅存于TP与IP之间,说明湖滨带磷具有较强的释放潜力,而湖中心带则更多的体现了洱海区域的地质特点。该研究对于正确认识环境因子与沉积物中磷的形态之间的内在联系与响应关系,揭示高原湖泊磷的地球化学特征与环境效应具有重要意义。

The contents and fractions of phosphorus in surfaced sediments of lakeside and middle zone of Erhai Lake were comparably analyzed. The results showed that the content of total phosphorus in lakeside of Erhai Lake had a range of 576.38-722.98 mg·kg^（-1） with an average of 663.67 mg·kg^（-1）, being significantly higher than that of the middle zone of Erhai Lake（range of 576.38-722.98 mg·kg^（-1）, average 663.67 mg·kg^（-1））. The main fraction of total phosphorus in surface sediments from both zones of Erhai Lake was inorganic phosphorus, which accounted for 79.70%-84.97%（lakeside）and 78.1%%-92.28%（middle zone）. Given fractions in inorganic phosphorus, Ca-P was the major one in both zones. The distribution pattern of various fractions of phosphorus showed that TP, IP, OP, Ads-P, Fe-P and Ca-P were significantly higher in lakeside than those of middle zone of Erhai Lake, however, De-P had an opposite trend with a higher content in middle zone. The results reflected the responding relationship between transport processes and environmental factor changes, indicating that phosphorus in sediments of lakeside had potential release to surface water, however, reflected much more geologic characteristic of Erhai Lake in its middle zone. It is great helpful for understanding the internal and correspond relationship between environmental factors and phosphorus speciation, and is of great significance for revealing geochemical characteristic and environmental effect of phosphorus.