Halomethane gas exchange in northern Alaskan coastal ecosystems

阿拉斯加北部沿海生态系统的卤甲烷气体交换

• 批准号: 0435870
• 负责人: Robert Rhew
• 金额: $ 29.1万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0435870&HistoricalAwards=false
• 关键词: Halomethane; gas; exchange; northern; Alaskan

Coastal ecosystems are believed to be globally important sources of methyl halides (CH3Br, CH3Cl, and CH3I) to the atmosphere, but fluxes from the arctic coastal zone have not yet been measured. CH3Br and CH3Cl are the dominant carriers of bromine and natural chlorine to the stratosphere, where they catalyze the destruction of ozone. CH3Br is also a widely used agricultural fumigant whose use is regulated by international agreement. CH3I is involved in tropospheric ozone chemistry and aerosol production and is a potential replacement fumigant for CH3Br. Our understanding of the tropospheric budgets of these compounds remains out of balance, with major uncertainties about the magnitude of biosphere-atmosphere fluxes. The biogeochemical cycles of these halomethanes must be understood in order to assess how halogen loading in the atmosphere will respond to changes in public policy, land use, and climate. The proposed project will a) determine whether arctic coastal terrestrial ecosystems are significant sources or sinks of atmospheric methyl halides and chloroform; b) examine the environmental and biological controls on their fluxes; and c) help understand and possibly predict the potential effect that climatic change in the Arctic will have on the overall fluxes of these compounds, based on their biogeochemical controls. Flux chambers will be deployed in coastal tundra ecosystems near Barrow, Alaska, in 2005 and 2006. Air samples will be analyzed by gas chromatography-mass spectrometry for the halomethanes and the inert tracers SF6 and F-113, and the sampling strategy will address the expected spatial and temporal variability of the fluxes. CO2 fluxes will also be measured. This work will complement the prior research of the principal investigator (P.I.) on halomethane fluxes in temperate coastal ecosystems. This project will provide scientific training and thesis research opportunities for a doctoral graduate student and 3-6 undergraduate students. The students and P.I. will present results at regional and international geoscience meetings, and results will be published in peer- reviewed journals. Ilisagvik College students from Barrow, Alaska, will be invited to participate in the field research, and two students will be invited to UC-Berkeley to learn the associated laboratory analytical techniques. In concert with the Barrow Arctic Science Consortium, the P.I. and students will participate in science outreach classes at northern Alaskan schools and community centers.

沿海生态系统被认为是全球重要的卤代甲烷（CH 3Br，CH 3Cl和CH 3 I）排放到大气中的来源，但北极沿海地区的通量尚未得到测量。CH 3Br和CH 3Cl是溴和天然氯进入平流层的主要载体，它们在平流层中催化臭氧的破坏。溴甲烷也是一种广泛使用的农业熏蒸剂，其使用受国际协定的管制。碘甲烷参与对流层臭氧化学和气溶胶的产生，是溴甲烷的潜在替代熏蒸剂。我们对这些化合物的对流层预算的理解仍然不平衡，生物圈-大气通量的大小存在重大不确定性。必须了解这些卤代甲烷的地球化学循环，以评估大气中的卤素负荷将如何应对公共政策，土地使用和气候的变化。拟议的项目将：（a）确定北极沿海陆地生态系统是大气中甲基卤化物和氯仿的重要来源还是汇;（B）审查对其通量的环境和生物控制;（c）根据其生物地球化学控制，帮助了解并可能预测北极气候变化对这些化合物总通量的潜在影响。通量室将于2005年和2006年部署在阿拉斯加巴罗附近的沿海苔原生态系统中。将用气相色谱-质谱法分析空气样品中的卤代甲烷和惰性示踪剂SF6和F-113，取样战略将处理通量的预期空间和时间变化。还将测量CO2通量。这项工作将补充首席研究员（P.I.）的先前研究。关于温带沿海生态系统中卤甲烷通量的研究。 该项目将为一名博士研究生和3-6名本科生提供科学培训和论文研究的机会。学生和PI。将在区域和国际地球科学会议上介绍研究结果，并将结果发表在同行评审的期刊上。来自阿拉斯加州巴罗的伊利萨维克学院学生将被邀请参加现场研究，两名学生将被邀请到加州大学伯克利分校学习相关的实验室分析技术。在与巴罗北极科学联盟的合作中，P.I.学生们将参加北方阿拉斯加学校和社区中心的科学推广课程。