长江口及邻近海域沉积物中氮的形态研究

发布时间：2018-01-07 18:33

本文关键词：长江口及邻近海域沉积物中氮的形态研究　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：氮是海洋浮游生物生长和繁殖的必需成分,是海洋初级生产力和食物链的基础。河流输入是海洋中氮的主要来源。海洋沉积物中的氮作为水体氮的重要源与汇,是氮的重要储库。氮在沉积物中以不同的形态存在,各形态氮具有不同的物理化学性质和生物可利用性。对不同氮形态含量的测定及其影响因素的探究是阐明长江口及邻近海域氮生物地球化学循环过程所必需的,对长江口及邻近海域生物地球化学特征的研究提供科学依据有重要意义。分别于2013年8月、2014年8月对长江口及邻近海域进行了调查,采用改进分级浸提方法对表层、柱状沉积物中离子交换态氮(IEF-N)、碳酸盐结合态氮(CF-N)、铁锰氧化态氮(IMOF-N)以及有机态和硫化物结合态氮(OSF-N)进行了测定,分析了沉积物中氮形态的分布特征及其影响因素,并对氮在循环中的作用、沉积物中氮与浮游植物总量的关系进行了初步探讨。2013年8月长江口航次表层沉积物中总氮含量为320-1356 μg/g,平均含量为713.9μg/g。2014年8月长江口航次表层沉积物中总氮平均含量为359-1468μg/g,平均含量为810.4 μg/g。TN含量分布均呈现为调查海域由北向南逐渐增大、由近岸向外海递大的趋势。这是由于长江口及邻近海域沉积物中有机质含量明显增高,海洋沉积物中TN的含量也随之增高。泥质沉积物中TN含量高于砂质沉积物中TN含量。研究区域各形态氮的分布差异很大,这种分布差异主要是影响各形态氮含量的影响因素的差异造成的。IEF-N主要受含大量有机质的陆源物质、沉积物粒径、生物活动的影响。CF-N分布主要决定于沉积物中有机质矿化作用过程中pH值的变化。IMOF-N与所处的沉积物的氧化还原环境条件有关。OSF-N分布主要与初级生产力有关。A8-6站位TN垂向变化较大,在表层随着深度的增加TN含量显著增加,达到最高值后随着深度的增加,TN含量逐渐降低。A7-5站位从表层随着深度的增加TN含量显著降低,后随着深度的增加,TN含量先增加然后逐渐降低。整体表现为随着深度的增加而降低。研究区域各形态氮的分布差异很大,这种分布差异主要是影响各形态氮含量的影响因素的差异造成的。IEF-N含量因为随着水体深度的增加,水体的混合作用和来自底栖生物的扰动作用也变得相对复杂。随着深度的增加CF-N含量波动降低,长江口及邻近海域沉积物颗粒粗,主要为粉砂质和细砂,因此其碳酸盐含量较高,CF-N含量低。IMOF-N变化比较复杂,是由于海洋沉积物大部分以粗碎屑,沉积物间的空隙相对比较大,还原性较强。OSF-N与表层氧气充足,而且微生物也大部分在沉积物表层,矿化作用充分有关。
[Abstract]:Nitrogen is an essential component of marine plankton growth and reproduction, is the foundation of marine primary productivity and food chain. The river input is the main source of nitrogen in the ocean. In marine sediment nitrogen as an important source and sink of nitrogen, is an important reservoir of nitrogen. Nitrogen in sediments exist in different forms, each form nitrogen with different physical and chemical properties and biological availability. The determination of different forms of nitrogen contents and influencing factors of the inquiry is to clarify the Yangtze River Estuary and its adjacent waters of nitrogen biogeochemical cycle required, it is important to study on the Yangtze River Estuary and adjacent sea biogeochemical characteristics respectively in August 2013 to provide a scientific basis. In August 2014, conducted a survey on the Yangtze River Estuary and its adjacent areas, the improved hierarchical extraction methods on the surface, nitrogen ion exchange column sediments (IEF-N), carbonate bound nitrogen (C F-N), Fe Mn oxide nitrogen (IMOF-N) and organic and sulfide bound nitrogen (OSF-N) were measured, analyzed the distribution characteristics and influencing factors of nitrogen forms in sediments, and the effects of nitrogen on the nitrogen cycle, the relationship with the phytoplankton in the sediments in the preliminary study of total nitrogen content the voyage of surface sediments in the Changjiang Estuary in August.2013 320-1356 g/g, the average contents of total nitrogen average content of 713.9 g/g.2014 in August in the Changjiang Estuary voyage in surface sediments is 359-1468 g/g, the average content was 810.4 g/g.TN content distribution are presented as the investigation area increased gradually from north to south, from the open sea pass big trend this is due to the content of organic matter in sediments of the Changjiang Estuary and adjacent sea area were significantly increased, TN content in marine sediments also increased accordingly. The content of TN in sediment mud is higher than that of the TN content of sandy sediments. The study area Distribution of domain of different forms of nitrogen, the distribution differences are mainly caused by influence of various forms of nitrogen content differences of.IEF-N containing large amounts of organic matter is mainly affected by the terrigenous matter, sediment grain size, the effect of.CF-N biological activity mainly depends on the distribution of sediment oxidation changes of.IMOF-N organic matter mineralization process pH value the sediment reduction condition on the distribution of.OSF-N and.A8-6 on primary productivity at TN vertical changes in the surface, with increasing content of TN depth increased significantly, reaching the highest value with the increase of depth, the content of TN decreased.A7-5 stations from the surface with increasing content of TN depth decreased significantly after with the increase of depth, the content of TN increased first and then decreased gradually. The overall performance is reduced with increasing depth. The distribution of regional differences in the various forms of nitrogen is very large This distribution, the difference is mainly caused by.IEF-N content influence the concentrations of different nitrogen species differences because with the increase of the depth of water, mixing water and the role of disturbance from benthic organisms has become relatively complex. With the increase of depth CF-N content fluctuation is reduced, the sediment in the Changjiang Estuary and adjacent waters of coarse particles, mainly for silty and fine sand, so the higher carbonate content, low.IMOF-N content change of CF-N is more complicated, because most of the marine sediments of coarse clastic sediments, the gap between the relatively large, relatively strong reduction of oxygen and.OSF-N surface is sufficient, and microbial is also mostly in surface sediments, mineralization fully.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P734

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