不同生境中生物硅的含量、组成及溶解过程

发布时间：2018-01-23 18:14

本文关键词： 北极长江口黄河口湿地马来西亚河流生物硅植硅体硅藻溶解　出处：《国家海洋局第一海洋研究所》2015年硕士论文　论文类型：学位论文

【摘要】：硅元素因其巨大的储量以及与碳循环的密切联系,成为陆海相互作用、区域生物地球化学循环与气候变化研究的关键元素。生物硅(BSi)是地表和水体中硅循环中的实际参与者,也是陆源硅向海洋输送的重要载体,其现存量、输送及转化机制是硅循环研究中的关键环节。本文选择四个代表性区域——北极新奥尔松地区、黄河口湿地、长江口、马来西亚河流,对不同生境内生物硅的含量、组成进行分析,并对生物硅在不同盐度水体中的溶解动力学过程进行了初步研究,旨在揭示不同温度带生物硅的组成、来源及溶解动力过程,为区域硅循环提供科学依据。主要结论如下:(1)不同生境中的生物硅含量不同:北极新奥尔松地区表层土壤中,BSi的含量为5.60-9.97 mg/g,均值为7.56 mg/g;黄河口湿地表层土壤中,生物硅含量为2.48-19.3 mg/g,均值为9.91 mg/g;长江口地区,表层水体中生物硅含量为2.39-44.9μmol/L,均值为15.2μmol/L,B3和C5柱状样沉积物中生物硅均值分别为2.73 mg/g和3.86 mg/g;沉积物马来西亚河流近岸沉积物中,BSi含量为5.17-10.2 mg/g,平均含量为8.55 mg/g。BSi含量与分布具有一定的季节性和区域性,受地表植被、p H及土壤粒径等因素的影响。河口地区,BSi的含量与分布受海洋与河流的共同影响。(2)长江口水体、沉积物及马来西亚河流沉积物中的活性硅不同程度地发生了反风化过程;长江口水体和马来西亚河流沉积物中生物硅的反风化现象并不明显,而长江口沉积物中约有28%的生物硅参与反风化过程。(3)研究区域的生物硅颗粒主要由植硅体、浮游植物、海绵骨针构成,不同生境中不同形态生物硅的贡献比例不同。陆源生物硅(植硅体)是生物硅的主要贡献者,不同地区有不同的特征植硅体出现;部分河口区站位硅藻的贡献量较大。(4)生物硅的形态观测结果显示,植硅体有明显的侵蚀痕迹,且含有大量硅藻碎片,反映了生物硅在输送过程中的溶解现象。此外,植硅体成分分析结果表明,除Si、O两种主要元素外,还有部分C、Al、K、Mg、Fe等元素,为植硅体参与自成岩反风化过程及碳封存作用提供了直接证明。此外,约占植硅体5%干重的碳被封存于热带地区河流沉积物的生物硅中。(5)生物硅颗粒在不同盐度水体中的溶解趋势相同,均在培养初期大量溶解,其后比溶解速率急剧下降,最终维持在较为稳定的状态。在稳定状态下,盐度为5的培养体系中生物硅的溶出量和比溶解速率最大。
[Abstract]:Because of its huge reserves and close relationship with the carbon cycle, silicon has become the interaction between land and sea. Biogeochemical cycle and climate change are the key elements in the study of regional biogeochemical cycle. Biological silicon (BSi) is a practical participant in the silicon cycle in the surface and water, and is also an important carrier for the transport of terrestrial silicon to the ocean. Transport and transformation mechanism is the key link in the study of silicon cycle. In this paper, four representative regions, namely, the New Olsson region in the Arctic, the Yellow River Estuary Wetland, the Yangtze River Estuary, and the Malaysian River are selected. The content and composition of biological silicon in different living areas were analyzed and the dissolution kinetics of biological silicon in different salinity water was studied in order to reveal the composition of biological silicon in different temperature zones. The source and dissolution dynamics provide scientific basis for the regional silicon cycle. The main conclusions are as follows: the biological silicon content in different habitats is different: in the surface soil of the new Olsson area in the Arctic. The content of BSi was 5.60-9.97 mg / g, the mean value was 7.56 mg / g; In the surface soil of the Yellow River Estuary wetland, the content of biological silicon is 2.48-19.3 mg / g, the mean value is 9.91 mg / g; In the Changjiang Estuary, the content of biological silicon in the surface water is 2.39-44.9 渭 mol / L, with an average of 15.2 渭 mol/L. The mean values of biological silicon in B3 and C5 columnar sediments were 2.73 mg/g and 3.86 mg / g, respectively. The content of BSi in sediments of Malaysian rivers is 5.17-10.2 mg/g. The average content and distribution of 8.55 mg/g.BSi are seasonal and regional, which are affected by the factors such as vegetation pH and soil particle size. The content and distribution of BSi are influenced by ocean and river. (2) the reverse weathering process of active silicon in Yangtze Estuary, sediment and Malaysian river sediment has taken place in varying degrees. The reverse weathering of biological silicon in the Yangtze Estuary and Malaysian river sediments is not obvious. In the Yangtze Estuary sediment, about 28% of the biological silicon involved in the reverse weathering process. 3) the biological silicon particles in the study area are mainly composed of phytoplankton, phytoplankton and spongy bone needle. The contribution ratio of biological silicon in different habitats is different. Terrestrial biogenic silicon (phytosilicon) is the main contributor of biological silicon, and there are different characteristics of phytosilicon in different regions. The morphological observation of biosilicon showed that the phytolith had obvious erosion trace and contained a large number of diatom fragments. It reflects the dissolution of biogenic silicon in the transportation process. In addition, the results of phytosilicon composition analysis show that in addition to the two main elements of Sio, there are also some elements, such as C _ (Al) Al _ (K) K _ (+) mg _ ((Fe)). It provides a direct proof for the phytonite to participate in the process of diagenetic reverse weathering and carbon sequestration. Carbon, which accounts for about 5% dry weight of the phytosilicon body, was sequestered in the biogenic silicon of river sediments in tropical regions.) the dissolution trend of biogenic silicon particles in different salinity water was the same, and they were dissolved in a large amount at the early stage of culture. The dissolution rate and specific dissolution rate of biological silicon in the culture system with salinity of 5 were the largest.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P593

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