基于水淘选分级的长江口及邻近海域表层沉积物中磷的形态分布和迁移转化

发布时间：2018-11-21 21:22

【摘要】：磷是一种重要的生源要素,在河口、边缘海的初级生产中发挥重要作用,了解沉积物中磷的形态分布和迁移转化有助于深入了解该区域生态系统动力学。于2013年3月在长江口及邻近海域采集了表层沉积物样品,利用水淘选方法对沉积物进行了分级,并采用化学连续提取法分析了未分级和分级沉积物样品中的6种磷形态含量:可交换态磷、活性有机磷、铁结合态磷、自生磷灰石磷、碎屑磷和难分解有机磷,讨论了该区域沉积物中磷的形态分布、选择性输运过程和迁移转化。沉积物中总磷含量在14.0~18.4μmol/g,其中碎屑磷是其主要成分,占54.5%,其次是有机磷和难分解有机磷,分别占到15.1%和13.1%。不同粒级沉积物中磷形态含量不同,可交换态磷、活性有机磷、铁结合态磷、自生磷灰石磷和难分解有机磷随粒级增加含量逐渐降低,而碎屑磷主要集中在粗粒级(大于32μm)沉积物中。基于各粒级磷形态的质量分布,发现小于32μm粒级的沉积物中各磷形态含量从长江口向浙闽沿岸逐渐增加,向外海方向逐渐减小,而大于32μm沉积物的变化趋势与此相反,体现了不同形态磷的选择性输运。随粒径增大,总有机碳对有机磷比值(TOC/Or-P)先降低后升高,在大粒级沉积物中,TOC/Or-P比值较高主要是因为陆源有机碳贡献较高,而在小粒级沉积物中,主要是由于有机磷的迁移和转化更为活跃,体现了细颗粒物中有机磷相对有机碳的优先分解。本研究表明,从分级的角度可以对河口、边缘海的磷循环有一个更全面的认识。
[Abstract]:Phosphorus is an important biogenic factor, which plays an important role in primary production of estuaries and marginal seas. Surface sediment samples were collected in the Changjiang Estuary and adjacent waters in March 2013. The contents of six phosphorus forms in ungraded and graded sediment samples were analyzed by chemical continuous extraction method: exchangeable phosphorus, active organic phosphorus, iron bound phosphorus, autogenous apatite phosphorus, detritus phosphorus and refractory organic phosphorus. The distribution of phosphorus species, the selective transport process and the transport and transformation of phosphorus in the sediments of this area were discussed. The content of total phosphorus in sediments was 14.0 ~ 18.4 渭 mol/g, among which detritus phosphorus was the main component, accounting for 54.5%, followed by organic phosphorus and indecomposable organic phosphorus, accounting for 15.1% and 13.1g respectively. The contents of phosphorus forms in different grain sediments were different. The contents of exchangeable phosphorus, active organic phosphorus, iron bound phosphorus, autogenous apatite phosphorus and refractory organic phosphorus decreased with the increase of grain size. Detrital phosphorus is mainly concentrated in coarse grained (> 32 渭 m) sediments. Based on the mass distribution of phosphorus species, it was found that the contents of phosphorus forms in sediments with grain size less than 32 渭 m gradually increased from the Changjiang Estuary to the coast of Zhejiang and Fujian, and gradually decreased to the offshore, but the change trend of sediments larger than 32 渭 m was opposite. The selective transport of different forms of phosphorus was demonstrated. With the increase of grain size, the ratio of total organic carbon to organic phosphorus (TOC/Or-P) decreased first and then increased. In large grain sediments, the higher TOC/Or-P ratio was mainly due to the higher contribution of terrestrial organic carbon, while in small grain sediments. It is mainly due to the more active migration and transformation of organophosphorus, which reflects the preferential decomposition of organophosphorus relative to organic carbon in fine particles. This study shows that a more comprehensive understanding of the phosphorus cycle in estuaries and marginal seas can be obtained from the point of view of classification.
【作者单位】：中国海洋大学海洋化学理论与工程技术教育部重点实验室;中国海洋大学化学化工学院;
【基金】：国家重点研发计划“全球变化及应对”重点专项(2016YFA0600902) 国家自然科学基金项目(41676063,41620104001,41521064)
【分类号】：P736.4

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