长江口柱状沉积物中磷的存在形态及其分布特征研究

Study on the chemical forms of phosphorus and their vertical distributions in core sediments from the Yangtze Estuary

对长江口的柱状沉积物进行了总磷测定,并运用SEDEX方法分析了长江口柱状沉积物中5种形态磷的含量和分布。研究结果表明,柱状样沉积物不同站位各种形态磷的垂直分布各不相同,由表至底呈现多种分布状态,与沉积环境、沉积后的成岩作用有关。长江口柱状样沉积物有机磷的降解速率常数变化结果表明,长江口海域有机磷的降解主要发生在沉积物表层和次表层。2个柱状样沉积物中氮磷比远低于16∶1,说明长江口近岸海域沉积物中的磷主要来自陆源。对柱状样的年代分析表明,总磷含量随年代的变化有明显的区域特征性,长江口总磷含量的髙值与长江较大输沙量的年份具有一致性。

The total phosphorous determination is conducted for the core sediments at the estuary of the Yangtze River,and the content and distribution of phosphorous in 5 forms in the core sediments at the estuary of the Yangtze River is analyzed with the method of SEDEX. The result of the research shows that the vertical distribution of the phosphorous in different forms at different stations of the core sediments appears with the status of multiple kinds of distributions which is related to the sedimentary environment and the diagenesis after the sedimentation. The result for the change of constant of degradation rate of the organic phosphorous in the core sediments at the estuary of the Yangtze River shows that the degradation of the organic phosphorous at the sea area of the estuary of the Yangtze River mainly happens at the surface and subsurface of the sediments. The nitrogen-phosphorus ratio in the 2 core sediments is far lower than16∶ 1; it indicates that the phosphorus in the sediments at the sea area close to the estuary of the Yangtze River is mainly originated from the source of land. The age analysis for the core samples shows that there are obvious regional characteristics for the total phosphorus due to the change by the age; the high value of the total phosphorus at the estuary of the Yangtze River is consistent with the age of which there is larger sediment transport rate for the Yangtze River.