Measuring the Oxidative Ratio of the Terrestrial Biosphere

测量陆地生物圈的氧化比率

• 批准号: 0445282
• 负责人: Caroline Masiello
• 金额: $ 10万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0445282&HistoricalAwards=false
• 关键词: Measuring; Oxidative; Ratio; Terrestrial; Biosphere

Photosynthesis causes small increases in atmospheric O2 and concomitant small decreases in atmospheric CO2, and decomposition reverses this process. Because the terrestrial biosphere leaves an atmospheric imprint of its activities, fluctuations in atmospheric gases can be used to infer the behavior of the biosphere. Key to interpreting this behavior is the oxidative ratio (OR) of the organic carbon that is created by photosynthesis: that is, the ratio of O2 released to CO2 consumed during photosynthesis. This value is commonly assumed to be about 1.07, but early results show that natural variability in oxidative ratio can be large. Small changes in the terrestrial biosphere's oxidative ratio, on the order of 0.02 units, would cause a major change in our understanding of carbon and oxygen fluxes between the atmosphere, biosphere, and ocean. The goal of this grant is to make the first detailed measurements of an ecosystem's oxidative ratio. Our field site, Kellogg Biological Station in southwest Michigan, contains a series of sites which will allow us to compare ecosystem oxidative ratio over a range of land uses typical of much of the U.S.

光合作用导致大气中O2的小幅增加和伴随的大气中CO2的小幅减少，而分解则逆转了这一过程。 由于陆地生物圈会留下其活动的大气印记，因此大气气体的波动可以用来推断生物圈的行为。 解释这种行为的关键是光合作用产生的有机碳的氧化率（OR）：即光合作用过程中释放的O2与消耗的CO2的比率。 这个值通常被假定为1.07左右，但早期的结果表明，氧化率的自然变化可能很大。 陆地生物圈氧化率的微小变化，大约0.02个单位，将导致我们对大气、生物圈和海洋之间碳和氧通量的理解发生重大变化。 这项资助的目标是对生态系统的氧化比率进行首次详细测量。 我们的实地考察地点是密歇根州西南部的凯洛格生物站，它包含一系列地点，这些地点将使我们能够比较美国大部分地区典型土地利用范围内的生态系统氧化率。