Measuring Methyl Halide Fluxes in Temperate Grasslands Using Stable Isotope Tracers

使用稳定同位素示踪剂测量温带草原中的卤代甲烷通量

• 批准号: 0526750
• 负责人: Robert Rhew
• 金额: --
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526750&HistoricalAwards=false
• 关键词: Measuring; Methyl; Halide; Fluxes; Temperate

This project seeks to quantify fluxes of atmospheric methyl halides in temperate North American grassland ecosystems, employing a recently developed stable isotope tracer technique to separate simultaneous production and consumption fluxes. Methyl halides are major carriers of halogens in the atmosphere and consequently play important roles in stratospheric ozone chemistry. Field measurements will be conducted in three different types of grasslands ecosystems located in California, Colorado, and Kansas. The primary objectives of this work are: (1) to determine whether or not temperate grasslands are net sources or net sinks of methyl halides; (2) to separately quantify the production and consumption fluxes of methyl bromide and methyl chloride using a stable isotope tracer technique, and (3) to investigate the environmental, biological and biogeochemical drivers of the fluxes, ultimately improving our understanding of their atmospheric lifetimes and ozone depletion potentials.Four undergraduate students and a post-doctoral researcher will participate in this research. At least two undergraduate researchers will be from underrepresented groups in the sciences, as selected through the Berkeley Leadership Excellence through Advanced Degrees program. Methyl bromide is a broad-spectrum agricultural fumigant whose use is scheduled to be phased out in accordance with the Montreal Protocol. Understanding the biogeochemistry of methyl halides is prerequisite to understanding how changes in policy, climate, and land use will affect the halogen loading in the atmosphere.

该项目旨在量化北美温带草原生态系统中大气中甲基卤化物的通量，采用最近开发的稳定同位素示踪技术来分离同时生产和消费通量。卤代甲烷是大气中卤素的主要载体，因此在平流层臭氧化学中起着重要作用。实地测量将在位于加州、科罗拉多和堪萨斯的三种不同类型的草原生态系统中进行。本工作的主要目的是：（1）确定温带草原是卤代甲烷的净源还是净汇;（2）使用稳定同位素示踪技术分别量化甲基溴和甲基氯的生产和消费通量，以及（3）调查通量的环境、生物和地球化学驱动因素，最终提高我们对它们的大气寿命和臭氧消耗潜力的理解。四名本科生和一名博士后研究员将参与这项研究。至少有两名本科生研究人员将来自科学界代表性不足的群体，通过伯克利卓越领导力通过高级学位计划选择。甲基溴是一种广谱农业熏蒸剂，根据《蒙特利尔议定书》的规定，其用途将逐步淘汰。了解卤代甲烷的地球化学是了解政策、气候和土地利用变化如何影响大气中卤素含量的先决条件。