Collaborative Research: Nitrogen Fixation as a Source of New Nitrogen in the Oligotrophic Tropical Oceans

9633510卡彭氮气固定作为贫养热带海洋中新氮源的研究本项目将研究固氮蓝藻--毛霉菌--在支持热带海洋生物生产中提供氮素的重要性。固氮细菌在世界范围内得到了广泛的研究，特别是在农业系统中，反映了它们作为氮肥来源的重要性。毛藻是最著名的海洋固氮剂，广泛分布于热带海洋，可以形成大规模的水华，并具有许多独特的新陈代谢适应固定氮。全球范围内毛霉菌的固氮作用可能会与农业系统中的固氮作用相媲美。最近的证据表明，毛霉的固氮率被严重低估，这可能是几个热带海洋生物群氮收支严重失衡的原因。这项研究将提供有关毛霉菌生理的基本信息，将量化其在全球碳和氮循环中的重要性，并将产生更准确地评估热带海洋吸收大气二氧化碳的生物能力的信息。

9633510 CAPONE N2 Fixation as a Source of New N in the Oligotrophic Tropical Oceans This project will examine the importance of the nitrogen-fixing cyanobacteria, Trichodesmium, in providing nitrogen to support biological production in tropical oceans. Nitrogen (N2) fixing bacteria are intensively studied worldwide, particularly in agricultural systems, reflecting their importance as sources of fertilizer nitrogen. Trichodesmium, the best known marine nitrogen fixer, is widely distributed throughout the tropical oceans, can form massive blooms, and possesses a number of unique metabolic adaptations for fixing nitrogen. Global nitrogen fixation by Trichodesmium may rival that in agricultural systems. Recent evidence indicates that the rate of nitrogen fixation by Trichodesmium has been severely underestimated, and this may account for the severe imbalances in the nitrogen budgets of several tropical oceanic biomes. This research will provide fundamental information on the physiology of Trichodesmium, will quantify its importance in the global carbon and nitrogen cycles, and will yield information to more accurately assess the biological capacity of tropical oceans to take up atmospheric carbon dioxide.