海洋固氮生物多样性及其对海洋生产力的氮、碳贡献

Marine Nitrogen-Fixing Organisms and Their Contribution to the N and C Requirement for Marine Biological Production

固氮生物及其共生体在自然生态系统的氮素供给和生产力的持续发展中有重要作用。是贫营养盐海域和海洋生态系统中新生产力的主要贡献者。就海洋固氮生物研究的历史和现状 ,以及在世界不同海域和海洋生态环境条件下 ,海洋固氮生物的物种多样性和在海洋生态环境中的生存方式、共生互作关系多样化 ,作较全面的概述。综合分析了海洋固氮生物的固氮能力 (活性 )、在光合固碳中的作用和对初级生产力的贡献。

Nitrogen-fixing marine microorganisms and their symbiotic associations can convert the most abundant, but inert form of nitrogen into biologically available substrate and therefore, they play an important role in the introduction of N into the biosphere. This process has important significance especially in natural and oligotrophic ecosystems. This paper reviews the research development on biological nitrogen-fixation, and offers a comprehensive understanding of the nitrogen-fixation role, which nitrogen-fixers play in marine biogeochemical cycling and biological production. It summarizes the N 2-fixing contribution to C and N requirement for marine ecosystems, which include mangrove forest, coral reefs, coastal waters, estuaries, detrital sediment and microbial mats, and marine grass beds such as Syringodium, Spartina alterniflora, Diplanthera wrightii, and Thalassia testudini communities. The review of the resources, ecological distribution, community structure and function of marine N 2-fixing organisms shows that there is a strong direct relationship between photosynthesis (sinks of atmospheric CO 2) and biological N 2-fixation (uptake of new nitrogen) in every ecosystem described above. In conclusion, the research progresses have been made on the discovery of diversity of N 2-fixing organisms and their symbiotic associations. N 2-fixers include cyanobacteria Trichodesmium, Oscillatoria, Pelagothrix, Katagnymene, Synechococcus, Microcysits, Synechocystis, Calothrix, Richelia intracellularis, Lyngbya confervoides, Microcoleus chthonoplastes, Scytonema, Rivularia, Dichothrix, Tolypothrix, Hyella, Mastigocoleus, Phormidium, Gloeocapsa, Nodularia, Plectonema,Scopulonema, Aphanizomenon, Chamaesiphon, Anabaena,and Nostoc, heterotrophic N 2-fixing bacteria including members of the genera Klebstella, Vibrio, Clostridium, Desulfovibrio,and Pseudomonas, photosynthetic bacteria like Chromatium, and Beggiatoa as well as their symbiotic association such as Richelia intracellularis -Rhizosolenia; Richelia intracellulatis-Climacodium, Hemiaulus-Cyanobacteria, Sponge-Cyanobacteria and Syringodium isoetifolium-Cyanobacteria.