Limitierende Faktoren der marinen Methanoxidation

海洋甲烷氧化的限制因素

• 批准号: 225214419
• 负责人: Dr. Susan Mau
• 金额: --
• 依托单位: Fachgebiet Allgemeine Geologie / Marine Geologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/225214419?language=en
• 关键词: Limitierende; Faktoren; der; marinen; Methanoxidation

Despite the high production of the greenhouse gas methane in ocean and ocean sediments, only ~2% of the gas finally reaches the atmosphere. Specialized bacteria in the ocean use methane as their source of carbon and energy and, hence, are thought to maintain nanomolar methane concentrations in the bulk of the ocean. The proposed project aims to investigate different chemical, biological, and physical factors that enhance or limit microbial methane oxidation as an important sink of methane in the ocean. For example, often low methane oxidation rates have been found in surface waters, which may be caused by copper and/or iron limitation or light inhibition of methane oxidizing bacteria. In addition, methane as substrate for the bacteria may be limited due to increased sea surface air gas exchange by increased wind speed. In contrast, high methane oxidation rates have been measured in bottom water of coastal basins with limited water exchange. These high oxidation rates often correlate with lower oxygen concentrations and/or increased suspended material content in the surrounding water. Field studies in different climatic zones (polar: Spitsbergen and Antarctica, subtropical: Santa Barbara Basin, tropical: Gulf of Mexico) in combination with laboratory experiments are planned to study factors enhancing and limiting microbial methane oxidation in the ocean. Mainly the process of methane oxidation will be investigated by using radioactive tracers and stable carbon isotopes. Thereby maximum uptake rates of in situ methane oxidizing bacterial communities will be measured at different conditions. Finally, the results of the field and laboratory studies will be combined to develop a box model that can be used to estimate and possibly predict aerobic methane oxidation, one of the important methane sinks in the ocean.

尽管海洋和海洋沉积物中温室气甲烷的产量很高，但只有约2％的气体最终到达大气中。海洋中的专门细菌使用甲烷作为其碳和能量的来源，因此被认为可以在大部分海洋中保持纳摩尔甲烷浓度。拟议的项目旨在研究不同的化学，生物学和物理因素，以增强或限制微生物甲烷氧化作为海洋中甲烷的重要水槽。例如，通常在地表水中发现甲烷氧化速率低，这可能是由铜和/或铁的限制或对甲烷氧化细菌的轻抑制引起的。此外，由于风速提高，由于海面空气气体交换增加，甲烷作为细菌的底物可能受到限制。相反，在沿海盆地的底水中测量了高甲烷氧化速率，水交换有限。这些高氧化速率通常与较低的氧气浓度和/或周围水中悬浮材料含量增加相关。在不同气候区（极性：Spitsbergen和Antarctica，亚热带：圣塔芭芭拉盆地，热带：墨西哥湾）与实验室实验结合使用，以研究增强和限制海洋中微生物甲烷氧化的因素。主要将使用放射性示踪剂和稳定的碳同位素研究甲烷氧化的过程。因此，将在不同条件下测量原位甲烷氧化细菌群落的最大摄取速率。最后，将合并现场和实验室研究的结果，以开发一个框模型，该模型可用于估计并可能预测有氧甲烷氧化，这是海洋中重要的甲烷下沉之一。