海洋生物固氮研究进展

Marine nitrogen fixation plays an important role in the global carbon and nitrogen cycles because it can support the nitrogen required for primary production. The importance of unicellular nitrogen-fixing cyanobacteria and heterotrophic nitrogen-fixing bacteria has gradually been known since the application of molecular biology and ¹⁵N₂ isotope tracing in nitrogen fixation study in the 1990s. Firstly, it is suggested that the nitrogen fixation amount estimated based on Trichodesmium may be underestimated. Secondly, traditional study of marine biological nitrogen fixation is limited to the tropical and subtropical oligotrophic regions, while less attention has been paid to high nutrient regions such as upwelling and estuaries. Therefore, it is necessary to re-evaluate and re-understand the nitrogen fixation in these regions. This article reviewed the recent progress of nitrogen fixation, including biodiversity and distribution of diazotrophs, limiting factors, methods, and existing question. In addition, the latest progress and question of nitrogen fixation in the South China Sea were also reviewed.