Ammonia Oxidation Versus Heterotrophy in Crenarchaeota Populations from Marine Environments West of the Antarctic Peninsula

南极半岛西部海洋环境中的泉古菌种群中的氨氧化与异养

• 批准号: 0838996
• 负责人: James Hollibaugh
• 金额: $ 64万
• 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: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838996&HistoricalAwards=false
• 关键词: Ammonia; Oxidation; Versus; Heterotrophy; Crenarchaeota

Ammonia oxidation is the first step in the conversion of regenerated nitrogen to dinitrogen gas, a 3-step pathway mediated by 3 distinct guilds of bacteria and archaea. Ammonia oxidation and the overall process of nitrification-denitrification have received relatively little attention in polar oceans where the effects of climate change on biogeochemical rates are likely to be pronounced. Previous work on Ammonia Oxidizing Archaea (AOA) in the Palmer LTER study area West of the Antarctic Peninsula (WAP), has suggested strong vertical segregation of crenarchaeote metabolism, with the "winter water" (WW, ~50-100 m depth range) dominated by non-AOA crenarchaeotes, while Crenarchaeota populations in the "circumpolar deep water" (CDW), which lies immediately below the winter water (150-3500 m), are dominated by AOA. Analysis of a limited number of samples from the Arctic Ocean did not reveal a comparable vertical segregation of AOA, and suggested that AOA and Crenarchaeota abundance is much lower there than in the Antarctic. These findings led to 3 hypotheses that will be tested in this project: 1) the apparent low abundance of Crenarchaeota and AOA in Arctic Ocean samples may be due to spatial or temporal variability in populations; 2) the WW population of Crenarchaeota in the WAP is dominated by a heterotroph; 3) the WW population of Crenarchaeota in the WAP "grows in" during spring and summer after this water mass forms. The study will contribute substantially to understanding an important aspect of the nitrogen cycle in the Palmer LTER (Long Term Ecological Research) study area by providing insights into the ecology and physiology of AOA. The natural segregation of crenarchaeote phenotypes in waters of the WAP, coupled with metagenomic studies in progress in the same area by others (A. Murray, H. Ducklow), offers the possibility of major breakthroughs in understanding of the metabolic capabilities of these organisms. This knowledge is needed to model how water column nitrification will respond to changes in polar ecosystems accompanying global climate change. The Principal Investigator will participate fully in the education and outreach efforts of the Palmer LTER, including making highlights of our findings available for posting to their project web site and participating in outreach (for example, Schoolyard LTER). The research also will involve undergraduates (including the field work if possible) and will support high school interns in the P.I.'s laboratory over the summer.

氨氧化是再生氮转化为二氮气体的第一步，这是一个由3种不同的细菌和古菌群介导的3步途径。在气候变化对生物地球化学速率的影响可能很明显的极地海洋中，氨氧化和硝化-反硝化的整个过程受到的关注相对较少。在南极半岛西部Palmer LTER研究区，对氨氧化古菌（AOA）的研究表明，泉古菌代谢具有强烈的垂直分离，（WW，~50-100 m深度范围）以非AOA crenarchaeotes为主，而Crenarchaeota种群在“环极深水”（CDW），位于冬季水（150-3500米）以下，以AOA为主。对北冰洋有限数量样本的分析没有显示AOA的垂直分离，并表明AOA和Crenarchaeota丰度远低于南极。这些研究结果导致了3个假设，将在本项目中进行测试：1）在北冰洋样品中的Crenarchaeota和AOA的明显低丰度可能是由于种群的空间或时间变化; 2）在WAP中Crenarchaeota的WW种群由异养生物主导; 3）在WAP中Crenarchaeota的WW种群在春季和夏季“生长”在这个水团形成后。 这项研究将大大有助于了解帕尔默LTER（长期生态研究）研究区的氮循环的一个重要方面，提供深入了解AOA的生态和生理。 在WAP的沃茨中，泉古菌表型的自然分离，加上其他人在同一地区进行的宏基因组研究（A.默里，H。Ducklow），为理解这些生物体的代谢能力提供了重大突破的可能性。 需要这些知识来模拟水柱硝化作用如何对伴随全球气候变化的极地生态系统的变化做出反应。 首席研究员将充分参与帕尔默LTER的教育和外联工作，包括将我们的调查结果重点发布到他们的项目网站上，并参与外联活动（例如，校园LTER）。这项研究也将涉及本科生（包括实地工作，如果可能的话），并将支持高中实习生在PI。的实验室。