胶州湾不同形态磷的沉积记录及生物可利用性研究

利用磷的连续分级浸取法,研究了胶州湾柱状沉积物不同粒级中磷的赋存形态,并探讨了影响磷含量与分布的因素和沉积物中磷的生物可利用性.结果表明,在细、中和粗3个粒级的沉积物中,无机磷是磷的主要赋存形态,Ca-P则是无机磷的优势形态,有机磷只占较小的比例.粒度、有机碳(OC)、pH以及氧化还原电位等是影响胶州湾沉积物中磷的地球化学特征的重要因素.其中除Ca-P外,其他形态的磷大都随着粒度的变细,含量逐渐增加.磷的生物可利用性分析表明,胶州湾潜在的生物可利用磷主要包括可交换态磷、铝结合态磷、铁结合态磷和有机磷等4种赋存形态,并且潜在的生物可利用磷的含量随着粒度的变细,其所占的比例也逐渐增加.沉积物中生物可利用性磷与浮游植物的数量和水体中的磷酸盐大致呈正相关关系.

Sediment Record of Phosphorus and the Primary Study of Its Bioavailability in Jiaozhou Bay Sediments

The geochemical characteristics of phosphorus forms in different grain size sediments, the influencing factors as well as the bioavailability of phosphorus in Jiaozhou Bay were investigated employing the sequential extraction method. The results showed that inorganic phosphorus was the dominant form of total phosphorus and organic phosphorus was only the minor part. The detrital carbonate-bound phosphorus was the largest part of total phosphorus. The grain size, organic carbon, temperature, pH and etc. are the main controlling factors of phosphorus in sediments. Except for Ca-P, most of other phosphorus forms contents increased as the grain size decreased. The bioavailability research showed that the bioavailable phosphorus was mainly the exchangeable phosphorus, phosphorus bound to Al and Fe and organic phosphorus. Moreover, the potential bioavailable phosphorus proportion in total phosphorus increased as the grain size decreased. The bioavailable phosphorus in different grain size sediments has positive correlationship with phytoplankton abundance and phosphate in overlying water.