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地球表层硅(Si)的生物地球化学循环与大气CO2浓度变化、大洋生物泵作用以及海岸带富营养化等过程密切相关,因此成为全球环境变化研究的核心问题之一。在地质时间尺度上,硅酸盐矿物的化学风化是地球表层所有次生Si的来源。陆地生态系统各次生Si库具有不同的形成机制和驱动因子,这导致各Si库的贮存量和循环周期存在明显差异。土壤Si库中的黏土矿物Si、溶解硅(DSi)和淀积在其他矿物表面的无定形Si都源自硅酸盐矿物的化学风化过程;植物生长过程中吸收土壤中的DSi形成生物Si,然后经微生物分解过程返还给土壤;地表径流将流域陆源Si以悬移质Si和DSi的形式输入河流、海洋。迄今,陆地不同形态Si库的大小及其对全球Si循环的贡献仍不确定。因此,在研究陆地Si的生物地球化学循环过程中,综合考虑各种地表过程及其耦合作用是非常必要的。
The biogeochemical cycle of the Earth’s surface silicon (Si) is closely related to changes in atmospheric CO2 concentration, oceanic biological pumping and coastal zone eutrophication, and has therefore become one of the core issues in global environmental change research. At the geological time scale, the chemical weathering of silicate minerals is the source of all secondary Si on the Earth’s surface. Each secondary Si pool in terrestrial ecosystems had different formation mechanism and driving factors, which led to significant differences in the storage and circulation cycles of each Si pool. Clay minerals Si, dissolved silicon (DSi) and amorphous Si deposited on other minerals originate from the chemical weathering of silicate minerals in soil Si reservoirs; during the growth of plants, DSi in soil is absorbed to form biogenic Si, And then returned to the soil through the microbial decomposition process. The surface runoff transferred the terrestrial Si into the rivers and oceans in the form of suspended Si and DSi. To date, the size of the various land Si libraries and their contribution to the global Si cycle remain uncertain. Therefore, it is necessary to comprehensively consider various surface processes and their coupling effects when studying the biogeochemical cycle of Si on land.