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体甲烷的产量很高，但只有约 2% 的气体最终到达大气中。海洋中的特殊细菌使用甲烷作为碳和能量的来源，因此被认为可以在大部分海洋中维持纳摩尔甲烷浓度。该项目旨在研究增强或限制微生物甲烷氧化作为海洋中重要甲烷汇的不同化学、生物和物理因素。例如，在地表水中经常发现低甲烷氧化率，这可能是由于铜和/或铁的限制或甲烷氧化细菌的轻度抑制造成的。此外，由于风速增加导致海面空气气体交换增加，作为细菌底物的甲烷可能受到限制。相比之下，在水交换有限的沿海盆地的底层水中测得较高的甲烷氧化率。这些高氧化率通常与周围水中较低的氧气浓度和/或增加的悬浮物质含量相关。计划在不同气候带（极地：斯匹次卑尔根岛和南极洲，亚热带：圣巴巴拉盆地，热带：墨西哥湾）进行实地研究并结合实验室实验，以研究增强和限制海洋中微生物甲烷氧化的因素。主要利用放射性示踪剂和稳定碳同位素研究甲烷氧化过程。因此，将在不同条件下测量原位甲烷氧化细菌群落的最大吸收率。最后，现场和实验室研究的结果将结合起来开发一个盒模型，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汇之一。