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海洋中氮的生物地球化学循环影响着海洋生态系统的结构和功能,并和全球气候变化有着密切的联系,一直是海洋科学研究的重点和热点。海水硝酸盐的15N/14N和18O/16O比值可以反映海洋中氮循环的主要过程,因而成为研究海洋氮循环的一个重要手段。综述海水硝酸盐氮、氧同位素组成的测定方法,同化吸收作用、硝化作用、反硝化作用、生物固氮作用等氮循环过程所导致的氮、氧同位素分馏及其在海洋学研究中的应用。海洋生态系中硝酸盐氮、氧同位素的分布可以提供支持生物生产力的氮来源信息,以及氮在不同储库迁移转化的路径与机制。未来的研究需要发展适用于低含量硝酸盐的同位素测量方法,构筑海洋氮的收支平衡,掌握影响上层海洋硝酸盐氮、氧同位素变化的过程,获取全球海域有关硝酸盐氮、氧同位素组成的更多数据。
The biogeochemical cycle of nitrogen in the oceans affects the structure and function of marine ecosystems and is closely linked with global climate change. It has always been the focus and focus of marine scientific research. The ratios of 15N / 14N and 18O / 16O of seawater nitrate can reflect the main process of nitrogen circulation in the ocean and therefore become an important means to study the marine nitrogen cycle. The nitrogen and oxygen isotopic fractionation of nitrogen and oxygen isotope composition in seawater and their application in oceanographic research are summarized. The methods of determination of nitrate nitrogen and oxygen isotope composition in seawater, assimilation and absorption, nitrification, denitrification and biological nitrogen fixation are reviewed. Distribution of nitrate nitrogen and oxygen isotopes in marine ecosystems can provide nitrogen source information that supports biological productivity and the pathways and mechanisms by which nitrogen migrates and transforms in different reservoirs. Future research needs to develop isotope measurement methods suitable for low nitrate content, construct the balance of ocean nitrogen budget, master the processes that affect the changes of nitrogen and oxygen isotopes of nitrate in the upper ocean, and obtain the isotopic composition of nitrate and oxygen in the global ocean More data.