Exploring the biodiversity, interactions and controls of prokaryotic communities driving methane flux in marine sediments.

探索驱动海洋沉积物中甲烷通量的原核生物群落的生物多样性、相互作用和控制。

• 批准号: NE/F018983/1
• 负责人: Ronald Parkes
• 金额: $ 46.32万
• 依托单位: CARDIFF UNIVERSITY
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF018983%2F1
• 关键词: Exploring; biodiversity; interactions; controls; prokaryotic; Exploring; biodiversity; interactions; controls; prokaryotic

Methane is a potent greenhouse gas, second in importance only to carbon dioxide. Most methane is produced by microorganisms and methane concentrations in the atmosphere had been increasing rapidly, but now is quite variable. This is important to understand as atmospheric methane increases in the geological past have been linked to global warming. Global methane production in marine sediments is very significant and these sediments contain the largest, global reservoir of methane. This includes huge stores of methane in an ice matrix called hydrates, which might be a future energy store, as well as being a sensitive trigger for rapid climate change. Surprisingly, we know relatively little about the methanogens in ocean sediments that produce this methane, as only a few have been isolated and studied (11 species, representing less than 10% of cultured methanogen species). Also uncultured and little understood, are the microbes related to methanogens, which currently remove approximately 80% of all methane produced in sediments before it can enter the ocean and atmosphere above. These two groups of microbes are intimately connected and together have major influence on the flux of methane from sediments. There are even suggestions that anaerobic methane production and consumption may be due to the same microbes, but nobody knows for sure. Hence, our lack of understanding of the microbes controlling methane flux in marine sediments severely limits our ability to predict controls and future changes in the extremely important global methane cycle. We intend to significantly increase knowledge of the controls on ocean methane flux, and the microorganisms driving this process, by investigating methane production in high-pressure systems. These systems mimic sediment conditions, and within which both methane-producing and methane-consuming microbial communities are active. We will conduct similar experiments with microbial communities from marine gas hydrate sediments to determine their response to temperature and pressure changes, the supply of compounds for methane oxidation or production, and other factors controlling methane concentrations. From these experiments and a range of marine sediments we will isolate a number of methanogens, many of which may be new marine types, as their presence has been indicated by DNA surveys. Study sites include coastal sediments which are strongly influenced by human activity, globally significant gas hydrate sediments and mud volcanoes, which have recently been suggested as being an important potential source of methane. We will identify the physiology and metabolism of these methanogens to significantly increase our knowledge of the biodiversity and function of this important group of microorganisms. This will include, for the first time, investigating their response to high pressure.

甲烷是一种有效的温室气体，仅次于二氧化碳。大多数甲烷是由微生物和大气中的甲烷浓度产生的，但现在已经变化很大。这一点很重要，因为大气甲烷在地质过去的增加与全球变暖有关。海洋沉积物中的全球甲烷产量非常重要，这些沉积物包含最大的全球甲烷储层。这包括在称为水合物的冰基质中的大量甲烷存储，这可能是未来的能源商店，也是快速气候变化的敏感触发因素。令人惊讶的是，我们对产生这种甲烷的海洋沉积物中的甲烷剂相对较少，因为只有少数人是被隔离和研究的（11种，占培养的甲烷原质的不到10％）。与甲烷剂有关的微生物也没有培养，几乎没有理解，目前，该微生物在沉积物中消除了大约80％的甲烷，然后才能进入上面的海洋和大气。这两组微生物密切相关，并共同对沉积物的甲烷通量产生重大影响。甚至有建议，厌氧甲烷的产生和消费可能是由于相同的微生物所致，但没人知道。因此，我们缺乏对控制甲烷通量的微生物在海洋沉积物中的了解，严重限制了我们预测极其重要的全球甲烷周期中控制和未来变化的能力。我们打算通过研究高压系统中的甲烷产生，显着提高对海洋甲烷通量控制的了解以及推动这一过程的微生物的知识。这些系统模仿了沉积物的条件，并在其中产生甲烷和甲烷的微生物群落都活跃。我们将对来自海洋气体水合物沉积物的微生物群落进行类似的实验，以确定它们对温度和压力变化的反应，甲烷氧化或生产的化合物的供应以及其他控制甲烷浓度的因素。从这些实验和一系列海洋沉积物中，我们将分离出多种甲烷剂，其中许多可能是新的海洋类型，因为它们的存在是通过DNA调查表明的。研究地点包括受人活动强烈影响，全球意义的气体水合物沉积物和泥土火山的沿海沉积物，最近被认为是甲烷的重要潜在来源。我们将确定这些甲烷植物的生理和代谢，以显着提高我们对这一重要微生物群体的生物多样性和功能的了解。这将首次研究他们对高压的反应。