Methane Venting from Forearc Faults in the Puget Sound Estuary

普吉特湾河口弧前断层的甲烷排放

• 批准号: 2221821
• 负责人: Harlan Johnson
• 金额: $ 50.86万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2221821&HistoricalAwards=false
• 关键词: Methane; Venting; Forearc; Faults; Puget

Methane Venting from the Puget Sound EstuaryShallow coastal waters found on the margins of continents are areas of active methane emissions to the air. These areas supply a major part of the greenhouse effect responsible for modern climate warming. Recent studies have shown that methane from shallow coastal waters supply half of all methane emissions to the air that in turn produce global warming. Puget Sound is the largest of these inland seas in North America and is a large source of methane to the air. Gas from newly-discovered bubble plumes from the seafloor increases the amount of methane in the Puget Sound seawater. This gas from the seafloor escapes to the air from the sea surface where it becomes a greenhouse gas. Showing the location of the sub-surface deposits of methane in the newly discovered vents is the primary goal of this research project. The amount of methane gas coming from the seafloor will be measured using a robotic instrument called a Remotely Operated Vehicle (ROV). This robotic device will place measuring instruments directly in the path of the methane bubble stream to show the flow speed and capture fluid from the vents. Five students from under-represented communities of color in the university’s Engineering Department will be invited as members of the science party on the ship. This experience will substantially broaden their education experience in marine sciences.To find the source of methane gas recently discovered venting into Puget Sound seawater, this project will carefully measure changes in the rate of methane gas flowing from the seafloor. The changes in gas and fluid coming from seafloor vents over a six month period will be compared to environmental events that could be causing the flow changes. Examples of events that could cause vent flow changes include unusual water tides, temperature changes due to seasons, passing waves from earthquakes, and unusually large rainfall events in the nearby land. The two research cruises in the program will occur in late Fall 2022 and in Spring of 2023 to see changes in vent flow as the temperature and rainfall vary with the seasons. The shipboard part of the research will use a camera system towed near the seafloor to map the details of the vent field. A small Remotely Operated Vehicle (ROV) will also capture gas and fluid that is flowing from the seafloor vents using specially constructed sample bottles. The ROV will then place instruments on the seafloor to see variations in the gas flow rate for a six-month period. These captured fluid samples will show whether the methane is coming from deep within the earth or if it is coming as runoff of rain from the nearby land. Data from the research program will be freely available to the public through publication on university websites and placed in the federal archives. University of Washington undergraduates from the Engineering Department’s program for under-represented students of color will take part in both ocean field programs on the ship and during the processing of the data in the laboratory. This firsthand experience at sea and in the laboratory will increase the student’s awareness of marine sciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

从延伸缘边缘发现的海湾河口沿沿海水域中排出的甲烷排气是空气中积极的甲烷排放的区域。这些地区提供了负责现代气候变暖的温室效应的主要部分。最近的研究表明，来自浅沿海水域的甲烷向空气中供应所有甲烷排放的一半，从而产生全球变暖。普吉特海湾是北美内陆海洋中最大的海湾，是空中甲烷的大量来源。来自海底的新发现气泡羽毛的气体增加了普吉特海水中的甲烷量。这种从海底的气体从海面变成温室气体的海面逃到空气中。该研究项目的主要目标是显示甲烷在新发现的通风孔中的地下沉积物的位置。来自海底的甲烷气体量将使用称为远程操作的车辆（ROV）的机器人仪器进行测量。该机器人装置将直接将测量仪器直接放在甲烷气泡流的路径中，以显示流速并从通风口捕获流体。来自大学工程系中代表性不足的有色社区的五名学生将被邀请作为船上科学党的成员。这种经验将大大扩大他们在海洋科学方面的教育经验。要找到最近发现进入普吉特海水海水的甲烷气的来源，该项目将仔细测量从海底流出的甲烷气体速率的变化。将六个月内海底通风口的气体和流体变化与可能导致流动变化的环境事件进行比较。可能导致排气流量变化的事件的例子包括异常的水潮，由于季节引起的温度变化，地震传播的波浪以及近土地上异常大的降雨事件。该计划的两项研究巡游将于2022年秋末进行，并在2023年春季看到，随着季节温度和降雨量的变化，排气流量变化。研究的一部分将使用在海底附近拖曳的摄像头系统来绘制通风口场的细节。小型远程操作的车辆（ROV）还将使用特殊构造的样品瓶捕获从海底通风口流出的气体和流体。然后，ROV将在海底放置乐器，以查看六个月的气流流量的变化。这些被捕获的液体样品将表明甲烷是否来自地球深处，还是从近土地降雨来降临。研究计划的数据将通过大学网站上的出版物免费提供，并放置在联邦档案中。华盛顿大学的工程系计划的本科生针对代表性不足的有色学生的计划将参加船上的海洋野外计划，并在实验室的数据处理过程中。在海上和实验室中，这种第一手的经验将提高学生对海洋科学的认识。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为是通过评估来获得的支持。