大亚湾沉积物磷的形态特征及其潜在可释放性

为了认知沉积物磷释放对海湾磷负荷的影响，本文以SMT分级方法分析了大亚湾表层沉积物中磷的形态结构，探讨了沉积物磷的释放潜力的时空性差异及其影响因素。结果表明，大亚湾沉积物中总磷（TP）的平均含量为429.65×10-6，无机磷（IP）、有机磷（OP）的平均含量分别为286.57×10-6和143.08×10-6，IP占TP的67.83%；IP以酸提取态磷（HCl-P）为主，HCl-P的平均含量为237.10×10-6，碱提取态磷（NaOH-P）的平均含量为56.13×10-6；生物有效磷（OP+NaOH-P）占到总磷的45.63%。大亚湾沉积物磷具有较高的释放潜力，并呈现出夏季高于冬季，近岸区域高于湾中心及湾口的变化规律。相关性分析表明，沉积物粒径、氧化还原电位及有机质含量（尤其是浮游藻类的自生有机质）对沉积物磷的释放潜力有较大影响。

Form characteristics of phosphorus and its releasing potential in the sediments of Daya bay

To understand the effect of phosphorus released from sediments to water of the semi-enclosed bay, the characteristics of phosphorus forms, critical influences and the temperal-spatial differences of phosphorus releasing potential were studied in the surface sediments of Daya bay. The results showed that the average concentration of total phosphorus (TP) in sediments was 429.65×10-6. Inorganic phosphorus (IP) and organic phosphorus (OP) were 286.57×10-6 and 143.08×10-6, respectively. IP accounted for 67.83% of TP. Acid-extracted phosphorus (HCl-P) was the main component in IP, and the average concentration of HCl-P and alkali-extractive phosphorus (NaOH-P) were 237.10×10-6 and 56.13×10-6, respectively. Biological effective phosphorus (OP+NaOH-P) accounted for 45.63% of TP. There was a high releasing potential of sediments phosphorus in Daya bay. In addition, there was a clear temperal-spatial distribution pattern that the releasing potential of phosphorus was higher in summer than that in winter and, higher in near-shore than that in offshore or bay mouth. The grain size, Eh, content of organic matter (especially those from phytoplankton blooms) had an important influence on releasing potential of sediment phosphorus.