A Novel Molecular Approach to Nitrogen-Fixation in Marine Ecosystems

固氮是海洋氮循环的重要组成部分。目前，群体蓝藻Trichodesum似乎是公海真光区的主要重氮藻。其他一些物种可能对氮气的固定有很大的贡献，但由于培养和原位测量氮气固定的困难，可能没有引起注意。在这个项目中，Zehr博士和他的合作者将提出一种新的方法来检测和表征海洋环境中固定氮气的微生物。他们将使用一种非常敏感的分子技术-聚合酶链式反应(PCR)-来识别和表征各种海洋环境中的固氮基因。这项技术的使用将解决一些长期存在的问题，即浮游和底栖环境中存在固定氮气的潜力。此外，这项研究的成果将是一个DNA序列数据库和克隆的nif基因，可以用于详细调查海洋中固氮微生物的生态多样性。

Nitrogen fixation is an important component of the nitrogen cycle in the sea. Presently, it appears that the colonial cyanobacterium Trichodesmium is the major diazotroph in the euphotic zone of the open ocean. A number of other species could potentially contribute significantly to the fixation of N2, but may have escaped attention due to the difficulties of culture and the measurement of N2-fixation in situ. In this project, Dr. Zehr and collaborators will present a new approach to the detection and characterization of N2-fixing microorganisms in the marine environment. They will use a very sensitive molecular technique, the polymerase chain reaction (PCR), to identify and characterize nitrogen-fixing genes in a variety of marine environments. The use of this technique will settle a number of long-standing issues of the presence of N2-fixation potential i planktonic and benthic environments. Furthermore, the product of this research will be a DNA sequence database and cloned nif genes which can be used for detailed investigations of the ecological diversity of N2-fixing microorganisms in the sea.