海州湾秋季沉积物磷的形态分布及生物有效性

采用改进的连续提取法（SEDEX法）对2016年秋季（10月）海州湾的表层和柱状沉积物进行磷形态测定，研究不同形态磷的分布特征并分析其生物有效性.结果表明：表层沉积物样品总磷的含量为0.340~0.445mg/g，无机磷的含量为0.271~0.350mg/g；柱状沉积物中总磷的含量为0.367~0.614mg/g，无机磷的含量为0.302~0.443mg/g.总磷中以无机磷为主要赋存形态，无机磷中又以原生碎屑磷为主，各形态磷的含量大小顺序为；总磷（TP） > 无机磷（IP） > 原生碎屑磷（DAP） > 自生钙结合态磷（ACa-P） > 有机磷（OP） > 不稳态磷及铁结合态磷（Fe-P）.通过对磷的生物有效性研究发现，本次调查海域表层沉积物中的生物有效磷（BAP）含量为0.069~0.143mg/g，在TP中所占的百分比为19.44%~32.66%，平均值为24.17%；柱状沉积物的BAP含量为0.062~0.217mg/g，在TP中所占的百分比为16.11%~43.54%，平均值为30.77%，磷的释放风险较小.沉积物各形态磷与粒径的相关性结果显示，在柱状沉积物中，Fe-P、OP和ACa-P与细粘土、粗粘土和细粉砂为正相关性，而与粗粉砂、细砂和中砂则为负相关性，DAP则主要与粗粉砂、细砂和中砂表现出了极显著正相关性，与细粘土、粗粘土和细粉砂表现出显著负相关性，BAP与颗粒物粒径的相关性则具有一定的差异性，具体表现在不同粒径组成和平面分布上.

Speciation and bioavailability of phosphorus in sediments (autumn) of Haizhou Bay

A modified sequential extraction (SEDEX) method was used for the determination of phosphorus in surface and columnar sediments of Haizhou Bay in October, 2016. The distribution characteristics of various phosphorus forms were studied and their bioavailability speciation and bioavailability of phosphorus in autumn sediments of Haizhou Bay analyzed. The results showed that the total phosphorus varied from 0.340mg/g to 0.445mg/g and inorganic phosphorus varied from 0.271mg/g to 0.350mg/g in surface sediments; the total phosphorus in columnar sediments varied from 0.367mg/g to 0.614mg/g and inorganic phosphorus varied from 0.302mg/g to 0.443mg/g. Inorganic phosphorus was the predominant form of total phosphorus and detrital phosphorus was the main form of inorganic phosphorus in both types of sediments. The concentration of different forms of phosphorous followed the following order:total phosphorus (TP) > inorganic phosphorus (IP) > detrital phosphorus (DAP) > authigenic calcium bound phosphorus (ACa-P) > organic phosphorus (OP) > unstable phosphorus and Fe-bound phosphorus (Fe-P). Through the study of the phosphorus bioavailability, the bioavailable phosphorus (BAP) in surface sediments of this investigated area varied from 0.069mg/g to 0.143mg/g (19.44%~32.66%), with an average of 0.092mg/g (24.17%).The BAP in columnar sediments varied from 0.062mg/g to 0.217mg/g (16.11%~43.54%), and the average was 0.143mg/g, or 30.77% of the total phosphorous, which illustrated that the release risk of phosphorus was less. The correlation between phosphorus content and grain size in sediments showed that Fe-P, OP and ACa-P were positively correlated with fine clay, coarse clay and fine silt, but negatively correlated with coarse sand, fine sand and medium sand in the columnar sediments. DAP showed a significant positive correlation with coarse sand, fine sand and medium sand, and showed a significant negative correlation with fine clay, coarse clay and fine silt. The correlation between BAP and particle size was weak, as indicated by the different particle size composition and plane distribution.