| 项目编号: | 1624623
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| 项目名称: | RAPID: COLLABORATIVE RESEARCH: ENSO and Tropical Rain Forest Soil Carbon (CH4, CO2) Fluxes |
| 作者: | Michael Allen
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| 承担单位: | University of California-Riverside
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| 批准年: | 2016
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| 开始日期: | 2016-03-01
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| 结束日期: | 2018-02-28
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| 资助金额: | 126247
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Biological Sciences - Environmental Biology
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| 英文关键词: | tropical forest
; ch4
; carbon dioxide
; enso
; co2
; wet rainy season
; soil
; methanotroph
; pre-enso
; methane
; ch4 release
; enso event
; co2 production
; wet soil condition
; normal rainy season
; costa rican rain forest
; carbon management
; enso-associated drought
; terrestrial carbon
; soil carbon dynamics
; natural carbon
; soil carbon cycle
; carbon budget
; respired soil co2
; enso cycle
; post-enso climate condition
; rapid project
; tropical rainforest
; anaerobic soil condition
; microorganism
; rainforest soil
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| 英文摘要: | Carbon management is essential to reduce the intensity and impact of climate change. While high-latitude climates show the largest temperature changes, tropical forests take up and sequester forty percent of the anthropogenic and natural carbon exchanged with the atmosphere. Soils in these forests are the largest pool of terrestrial carbon. Under high water, low oxygen conditions, decomposition results in the production and release of methane gas (CH4)by microorganisms known as methanogens. During dry seasons, deeper rainforest soils remain wet, but dry at the surface. When that happens, a different group of microorganisms consume the methane and convert it to carbon dioxide. Methane gas has a ten to one hundred-fold greater greenhouse warming effect compared to that of carbon dioxide (CO2). Consequently, the relative release of these two gases in tropical rainforests has a large impact on the warming of climate. An unusually strong El Niño Southern Oscillation (ENSO) event is beginning to impact North America in 2015 and 2016. It is predicted that this ENSO will result in a major drought in tropical forests of Central America. Given the governing role of precipitation in soil carbon cycle, the impact of the drought from the developing ENSO is likely to be substantial. This RAPID project will test the idea that the ENSO cycle controls much of the year-to-year variability in the global carbon dioxide and methane cycle, by turning tropical forest soils from a strong source for methane during the normal rainy season, to a year-round sink for methane and source of carbon dioxide during El Niño-induced drought events.
Soil carbon dynamics have been measured through imaging of root and microbial production and turnover, and direct measurements of CO2 production and efflux. However, even with detailed measurements of outputs, the carbon budget developed for the Costa Rican rain forest near La Selva Biologcial Station fails to account for nearly ten percent of the total fixed C. One potential missing component in these measurements is methane (CH4). Tropical forests are both consumers and producers of CH4. During normal wet years, increased activity of methanogens relative to methanotrophs in anoxic, wet soil conditions results in methane release. Then as soils dry between storms, methanotrophs may dramatically increase rates of methane oxidation, resulting in the release of higher amounts of respired soil CO2. An unusually strong 2015-16 ENSO event has been detected in North America. ENSO-associated drought in tropical forests of Central America are likely to be extreme at the La Selva site. Specifically, it is hypothesized that: (1) large amounts of CO2 produced underground during normal, wet rainy seasons are converted to CH4, which is eventually released to the atmosphere; (2) the anaerobic soil conditions of wet rainy seasons cause even greater CH4 release through methanogenesis coupled to decomposition, and (3 during a strong El Niño event, drier conditions will result in an increase in methane oxidation by methanotrophs in these soils. To test these questions, CO2 and CH4 will be continuously measured, through the pre-ENSO, ENSO, and post-ENSO climate conditions. qPCR and RT-qPCR will be used to quantify the abundance and activity of both methane-producing (methanogens) and -consuming (methanotrophs) microorganisms. These measures will be coupled with root, understory and litter surveys to compare living and dead plant biomass that contributes the C to these microbes. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92826
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Michael Allen. RAPID: COLLABORATIVE RESEARCH: ENSO and Tropical Rain Forest Soil Carbon (CH4, CO2) Fluxes. 2016-01-01.
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