渤海南部海域沉积物-海水界面附近磷、硅赋存形态及其生物地球化学过程研究

	渤海南部海域沉积物-海水界面附近磷、硅赋存形态及其生物地球化学过程研究
	罗延馨
学位类型	博士
	1999
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
关键词	渤海南部海域沉积物-海水界面磷与硅的赋存形态生物地球化学循环
摘要	本文系统研究了渤海南部海域沉积物-海水界面附近（包括上覆水、悬浮颗粒物和沉积物）P、Si的赋存形态及其生物地球化学过程。其特色在于提出了“自然粒度下形态研究”的概念，探讨了能真正参与循环的P、Si及其控制关键环节，为渤海资源特别是生物资源的可持续利用战略的制定提供理论基础。得到的主要结论包括：研究了渤海南部海域覆水、悬浮颗粒物中P、Si的变异特征。上覆水体PO_4-P、SiO_3-Si的平均含量均低于大洋底层水PO_4-P、SiO_3-Si的平均含量。悬浮颗粒物中TIP、BP的来源和循环控制机制不同，TISi、BSi有一定的相似性。稀释作用和表层沉积物中可交换态P、Si的循环控制上覆水体中P、Si的地球化学行为。颗粒物中TIP、TISi的行为受离子交换和化学吸附过程影响，其中化学吸附可能与Fe（III）的氧化物有关；生物过程对颗粒物中生源P、Si的地球化学行为有重要影响。渤海南部海域沉积物P、Si的分布特征及其成岩过程研究表明。表层沉积物可交换态磷中，OSF-P是磷的优势赋存形态，占总磷的10.7%；CF-Si是硅的优势赋存形态，占总硅的0.05%。不同形态P的成岩过程有一定的相似性。TSi与其它相中的Si呈负相关或不呈显著相关，且可交换态Si的量仅占总Si的0.12%以下，说明以往采用测定总Si含量来研究Si的生物地球化学过程不可能得出有价值的信息。IMOF-P、OSF-P、IMOF-Si、CF-Si在P、Si的生物地球化学循环中有重要作用。CaCO_3、Fe（III）和Corg等对P、Si界面循环有重要影响，有机质的钙化导OSF-P的矿化作用而释放P；Fe（III）的还原引起IMOF-P， CF-P和CF-Si对P、Si的释放。Corg的成岩过程对CF-Si有影响。约79%的BP和75%的BSi沉积后转化为相对稳定状态，在较短时间内不再参与循环。柱状沉积物中，OSF-P和CF-P之间存在沉积转化。CF-Si呈双指数分布。P、Si在表层沉积物中垂向分布的差异，表明底栖生物扰动对加强界面P、Si交换的作用。室内模拟沉积物-海水界面附近P、Si交换过程表明，P、Si在沉积物、上覆海水间的交换通量分别为0.8μ mol/ (m~2 · h)。P、Si的埋藏与释放主要受OSF-P、IMOF-Si 和平共处BSi的影响。对渤海P、Si年循环的估算显示，P在渤海湾、莱州湾的年循环量达30.9 * 10~5kg 和13.8 * 10~5kg， Si则分别为22.8 * 10~7 kg和15.5 * 10~7 kg，这其中沉积物向上覆海水扩散的P占87.7%和87.0%， Si占22.4%和14.2%。就整个渤海而言，沉积物向海水释放的磷、硅在其总循环中分别占88.7%和34.0%，所以沉积物-海水界面过程对磷、硅在渤海的生物地球化学循环有重要影响，是渤海P、Si循环的关键控制过程之一。
其他摘要	Based on a new idea, studies on forms for natural grain (FNG) in sediments are put forward in this thesis. Forms (FNG) and biogeochemical cycling of phosphorus (P) and silicon (Si) near sediment-water interface (including overlying seawaters, suspended particulates and sediments) in the southern Bohai Sea are studied. Four FNGs (ion-exchangeable form (IEF), carbonate form (CF), iron-manganese oxides form (IMOF) and organic matter-sulfide form (OSF)) as well as biogenic form (BF) are determined. Geochemical behaviors of P and Si in overlying seawater are controlled by freshwater dilution and cycling of available P and Si in surface sediments. Both biotic and abiotic transfer processes are primarily responsible for the P and Si exchange between overlying seawater and suspended particulate. By considering the different forms of P and Si features and some control parameters on sediments, such as accumulation rate, chemical factors (DO, Fe(III), CaCO_3) and benthic disturbance, effects of these parameters on decomposition and dissolution of P and Si within surface sediments are used to characterize their biogeochemical process: (1) Distributions of P in surface sediments are mainly influenced by CaCO_3 and Fe(III), indicating the reduction of IMOF-P and remineralization of OSF-P are probably the most important process controlling its release from sediment. (2) CF-Si is the main form controlling Si cycling near sediment-water interface. The distributions and releasing of Si from surface sediments appear to be affected by Fe(III) and Corg. (3) There is a sink switching between OSF-P and CF-P. The result is to enhance the burial efficiency of P. Adsorption and dissolution can affect the diagenesis process of CF-Si. (4) Concentrations of BP and BSi in sediments are much higher than the available forms, indicating that most biogenic P and Si are inert. Calculation shows that about 79% BP and 75% BSi are in relatively stable state after burial, and can not recycle in short time scale. The study on diffusion fluxes of P and Si across sediment-water interface shows that the diffusion direction is from sediment to seawater. The equilibrium fluxes of P and Si are about 0.8 μmol(m~2 · h) and 16.5μmol/(m~2 · h), respectively. In Bohai Sea, the diffusion of P and Si from sediment to seawater comprises 88.7% and 34.0% of their total cycling, respectively. Therefore, the sediment-water interface process is the essential control link of biogeochemical cycling.
页数	69
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1551
专题	海洋生态与环境科学重点实验室
推荐引用方式 GB/T 7714	罗延馨. 渤海南部海域沉积物-海水界面附近磷、硅赋存形态及其生物地球化学过程研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1999.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
LW000645.pdf（2531KB）			限制开放	--	浏览