Collaborative Research: RUI -- Response of Nitrifying Bacteria to Fluctuating Hypoxia in Estuarine and Marine Sediments

合作研究：RUI——硝化细菌对河口和海洋沉积物中波动缺氧的响应

• 批准号: 0352216
• 负责人: James Hollibaugh
• 金额: $ 22.66万
• 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: 2004
• 资助国家: 美国
• 起止时间: 2004-03-15 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0352216&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Response; Nitrifying

ABSTRACTOCE- 0352221 / OCE- 0352216 Nitrification contributes to removing fixed nitrogen from ecosystems; it is a centrally important process modulating ecosystem productivity and the global nitrogen budget. In anoxic estuaries, nitrification is compromised, reducing the removal of fixed nitrogen. Bottom water anoxia leads to increased HS- concentrations in pore waters that can lead to extended inhibition of aerobic nitrifying bacteria. A researcher at the University of West Florida believes that the loss of nitrification activity during weeklong hypoxic events will reduce denitrification rates, although N2 production by anaerobic NH4+ oxidation (anammox) may be enhanced. In this study, the scientist from the University of West Florida will investigate how the community composition of aerobic nitrifiers differs under varying oxygen tensions. How the nitrifiers respond to short-term hypoxic events will also be considered, as well as how the degree of hypoxia and bottom water NO3- concentrations (either through denitrification or anammox) will affect N2 levels. And, finally, because adaptation by the nitrifying community to periodic hypoxia and HS- exposure has important ecological implications, the researcher will investigate the degree to which nitrifiers can adapt to intermittent hypoxia lasting hours to days, specifically when intermitted with exposure to HS-. If communities adapt to and become HS- tolerant, then they can nitrify when conditions are favorable without extended lag periods. Thus, nitrogen removal through denitrification would be more efficient in these systems. In addition, the role of anammox in estuarine environments is not well studied, particularly its contribution to estuarine nitrogen budgets. If anammox rates are significant, it will suggest a major revision of the fixed nitrogen removal processes in estuaries.

Abstractoce-0352221 / OCE- 0352216硝化有助于从生态系统中去除固定氮。这是一个非常重要的过程，可调节生态系统生产力和全球氮预算。 在缺氧河口中，硝化受到损害，从而减少了固定氮的去除。 底水缺氧导致孔隙水中的HS浓度升高，从而导致有氧硝化细菌的抑制作用扩大。西佛罗里达大学的一名研究人员认为，尽管厌氧NH4+氧化（Anammox）的N2产生可以增强，但在为期一周的低氧事件期间硝化活性的丧失将降低反硝化率。 在这项研究中，西佛罗里达大学的科学家将研究有氧硝化器的社区组成如何在不同的氧气张力下有所不同。 硝化物还将如何应对短期缺氧事件，以及缺氧和底水NO3浓度（通过反硝化或苯甲酸）的程度将如何影响N2水平。 最后，由于硝化群落对周期性缺氧和HS暴露的适应具有重要的生态影响，因此研究人员将研究硝化物可以适应持续时间持续时间至几天的间歇性缺氧的程度，特别是与暴露于HS-相互融合的程度。如果社区适应并变得宽容，那么在没有延长滞后期的情况下，它们可以在条件下时硝基化。因此，在这些系统中，通过反硝化去除氮将更有效。 此外，对Anammox在河口环境中的作用没有很好地研究，尤其是其对河口氮预算的贡献。 如果Anammox率很高，它将表明河口中固定的氮去除过程进行了重大修订。