Greenhouse gas - nitrous oxide (N2O)- production by marine nitrifiers

海洋硝化器产生的温室气体 - 一氧化二氮 (N2O)

• 批准号: 2107302
• 金额: --
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2107302
• 关键词: Greenhouse; gas; nitrous; oxide; N2O

Nitrous oxide (N2O) is a stratospheric ozone-depleting agent and a potent greenhouse gas with a global warming potential 300 times that of CO2. Approximately 1/3 of global N2O emissions occur in the oceans. Although its production is particularly intense in oxygen-deficient waters within the so-called oxygen minimum zones, at least half occurs in the wider oxic ocean. Marine nitrifiers - comprising two groups of microorganisms that respectively mediate the oxidation of ammonia to nitrite and then to nitrate - are known to be capable of producing N2O. Most notably, culture studies and natural stable isotopic signatures of N2O have shown that ammonia-oxidising archaea are largely responsible for oceanic N2O production [1]. However, the molecular mechanisms of such archaeal N2O production remain poorly understood. Despite some postulations on possible pathways from laboratory studies (e.g. [2]), their importance remains unconfirmed in the environment, and whether the same mechanism is employed in both oxic and oxygen-deficient conditions is unknown. Meanwhile, the nitrite-oxidiser Nitrococcus has recently been found to be ubiquitous across global oceans and it is also able to produce N2O [3]. This project aims to employ state-of-the-art molecular techniques, combined with activity measurements, to investigate the molecular mechanisms dictating the production of N2O production by marine nitrifiers.

一氧化二氮（N2 O）是一种平流层臭氧消耗剂，也是一种强效温室气体，其全球变暖潜能值是二氧化碳的300倍。全球约1/3的N2 O排放发生在海洋。虽然在所谓的最低含氧区的缺氧沃茨中，其生产特别密集，但至少有一半发生在更广阔的含氧海洋中。海洋硝化菌-包括两组微生物，分别介导氨氧化为亚硝酸盐，然后硝酸盐-已知能够产生N2 O。最值得注意的是，N2 O的培养研究和天然稳定同位素特征表明，氨氧化古菌是海洋N2 O产生的主要原因[1]。然而，这种古细菌N2 O生产的分子机制仍然知之甚少。尽管实验室研究对可能的途径提出了一些假设（例如[2]），但它们在环境中的重要性仍未得到证实，并且在有氧和缺氧条件下是否采用相同的机制尚不清楚。与此同时，最近发现亚硝酸盐氧化剂Nitrococcus在全球海洋中无处不在，它也能够产生N2 O [3]。本项目旨在采用最先进的分子技术，结合活性测量，研究海洋硝化菌产生N2 O的分子机制。