Distribution And Ecology Of Ammonia Oxidizing Bacteria In The Palmer LTER Study Area

Palmer LTER 研究区氨氧化细菌的分布和生态

• 批准号: 0234249
• 负责人: James Hollibaugh
• 金额: --
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0234249&HistoricalAwards=false
• 关键词: Distribution; Ecology; Ammonia; Oxidizing; Bacteria

This project will investigate the distribution, phylogenetic affinities and ecological aspects of ammonium-oxidizing bacteria in the Palmer Long-Term Ecological Research study area. Ammonia oxidation is the first step in the conversion of regenerated nitrogen to dinitrogen gas via denitrification, a 3-step pathway mediated by three distinct guilds of bacteria. As such, ammonia oxidation is important to the global nitrogen cycle. Ammonia oxidation and the overall process of nitrification-denitrification have received little attention in polar oceans where it is significant and where the effects of climate change on biogeochemical rates are likely to be pronounced. The goals of the studies proposed here are A) to obtain more conclusive information concerning composition of Antarctic ammonia oxidizers; B) to begin characterizing their ecophysiology and ecology; and C) to obtain cultures of the organism for more detailed studies. Water column and sea ice AOB assemblages will be characterized phylogenetically and the different kinds of AOB in various samples will be quantified. Nitrification rates will be measured across the LTER study area in water column, sea ice and sediment samples. Grazing rates on AOB will be determined and their sensitivity to UV light evaluated. In addition, the significance of urea nitrogen as a source of reduced nitrogen to AOB will be assessed and the temperature response of nitrification over temperature ranges appropriate to polar regions will be evaluated. This work will provide insights into the ecology of AOB and the knowledge needed to model how water column nitrification will respond to changes in the polar ecosystems accompanying global climate change.

该项目将调查帕尔默长期生态研究区域内氨氧化细菌的分布、系统发育亲缘关系和生态方面。氨氧化是通过反硝化将再生氮转化为氮气的第一步，反硝化是由三种不同的细菌介导的三步反应。因此，氨氧化对全球氮循环非常重要。氨氧化和硝化-反硝化的整个过程在极地海洋中很少受到关注，因为在极地海洋中，氨氧化和硝化-反硝化作用的重要性很大，气候变化对生物地球化学速率的影响可能很大。这里提出的研究的目标是A)获得关于南极氨氧化菌组成的更确凿的信息；B)开始描述它们的生态生理学和生态学；以及C)获得生物体的培养，以便进行更详细的研究。将对水柱和海冰的AOB组合进行系统发育分析，并对不同样品中不同类型的AOB进行定量化。将在LTER研究区的水柱、海冰和沉积物样本中测量硝化速率。将测定AOB上的放牧速率，并评估其对紫外线的敏感性。此外，还将评估尿素氮作为还原氮源对AOB的重要性，并将评估在适合极地地区的温度范围内硝化作用的温度响应。这项工作将提供对AOB生态的洞察，以及建模水柱硝化将如何应对伴随全球气候变化的极地生态系统变化所需的知识。