Mapping and Quantifying Methane Seeps on the Eastern Siberian Shelf and Slope -- A Component of the Swedish Russian U.S. Climate-Cryosphere-Carbon Interactions (SWERUS-C3) Program

甲烷是一种强有力的温室气体，在北极的冻土和海洋沉积物中大量存在。在海洋沉积物中，甲烷可能存在于永久冻土或天然气水合物中。北极变暖可能会导致储存的甲烷释放，导致进一步变暖，然后在一个强化循环中进一步释放甲烷。东西伯利亚海位于北冰洋，是一大片区域，有大量的海底永久冻土，很可能还储存着甲烷。最近的研究表明，东西伯利亚海部分海域有大量甲烷来源，但该地区需要更详细地绘制地图和进行更详细的研究，才能完全了解那里储存的甲烷数量或正在释放的数量。2014年夏天，一个名为瑞典-俄罗斯-美国北冰洋气候-冰冻圈-碳相互作用调查(SWERUS-C3)的国际项目将进行为期90天的考察，绘制和研究东西伯利亚海的碳循环。这一提议的主要调查人员是海洋测绘领域的领军人物，他们最近开创了对墨西哥湾海底释放的甲烷羽流进行声学成像的技术。他们受到SWERUS-C3团队领导的邀请，参加了探险的一段。他们建议使用奥登号上的多波束声纳来定位和表征水柱中的气体渗漏，然后将新开发的宽带收发机应用于奥登号上的分束回声探测仪，以限制上升到表面的气泡的大小和命运。总之，这些声学观测将帮助SWERUS-C3团队了解甲烷从海底进入水柱的流量，并可能进入大气。如果成功，这些技术将使绘制北极气体流量的比例尺成为可能，这是前所未有的。该提案要求支持UNH小组参加这次考察，并支持巡航后的数据整理工作。该项目将支持UNH的一名全日制研究生。UNH的一名本科生也将参加。作为一个整体，SWERUS-C3项目将支持超过15名博士后研究人员和研究生，并计划开展一系列广泛的外联活动。联合国卫生组织沿海海洋测绘中心也将把这项工作纳入正在进行的外联和教育活动。

Methane is a potent greenhouse gas that is present in large amounts in frozen soils and marine sediments in the Arctic. In marine sediments, methane may be present either in permafrost or in gas hydrates. Warming of the Arctic may lead to the release of stored methane, leading to further warming and then to further methane releases in a reinforcing cycle. The East Siberian Sea, in the Arctic Ocean, is a large area with a great deal of undersea permafrost and, likely, stored methane. Recent work has suggested large sources of methane from parts of the East Siberian Sea, but the area needs to be mapped and studied in much greater detail before either the amount of methane stored there or the amount being released can be fully understood. In the summer of 2014, an international program called the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) will undertake a 90-day expedition to map, and study the carbon cycle in, the East Siberian Sea. The principal investigators of this proposal are leaders in ocean mapping and they have recently pioneered techniques for acoustic imaging of methane plumes released from the seafloor in the Gulf of Mexico. They have been invited by the leaders of the SWERUS-C3 team to participate in one leg of the expedition. They propose to use the multibeam sonar on board the ODEN to locate and characterize gas seeps in the water column and then apply a newly developed wideband transceiver to the split-beam echosounder on board the ODEN to constrain the size and fate of gas bubbles rising to the surface. Together, these acoustic observations will help the SWERUS-C3 team understand the flux of methane from the seafloor into the water column and potentially into the atmosphere. If successful, these techniques will allow the mapping of the gas flux in the Arctic over scales never before possible. This proposal requests support for the participation of the UNH team on this expedition and for post-cruise work-up of the data. The project will support a full time graduate student at UNH. A UNH undergraduate student will participate as well. The SWERUS-C3 program as a whole will support over 15 postdoctoral researchers and graduate students, and has a broad suite of outreach activities planned. The UNH Center for Coastal Ocean Mapping will also incorporate this work into ongoing outreach and education activities.