| 英文摘要: | Since the Pleistocene, slow organic matter decomposition has led to the accumulation of vast amounts of organic carbon in permafrost. However, while ongoing climate warming and permafrost thaw are expected to increase plant productivity (CO2 uptake), continued warming is also expected to weaken prior constraints on decomposition (CO2 emissions). The net effect of these changes on the Arctic?s carbon budget and the global climate system are poorly understood, as most observations have been made during the short growing season, when root and rhizosphere respiration dominate CO2 emissions. This project will focus on the development of a new technology for the continuous collection of CO2 emitted from arctic tundra soils. This passive diffusive sieve (zeolite) trap for measuring soil respired CO2 will be rugged, small, lightweight, low-cost, and require little in the way of power (batteries) low power. It has the potential to transform our understanding of carbon cycling in the Arctic, as it allows for the year-round CO2 collection, including during the winter and shoulder seasons when sites are often inaccessible, and over multiple weeks (3 weeks/sample), thus integrating both diffusive and episodic emissions. Outreach activities will strengthen the existing NSF-supported K-12 training programs at UC Irvine that are aimed to increase the participation of underprivileged populations in the STEM fields. THE Investigators will engage middle school students with lab tours and activities during a ?Day at College?-experience and class room visits. The project will also train a graduate student, and contribute to educating researchers (via an international summer course) in the use of 14C analysis in Ecology and Earth System Science.
The investigators will develop and deploy a novel system to continuously trap CO2 emitted from arctic tundra soils over several weeks for radiocarbon (14C) analysis. However, typical canister-based systems for measuring soil respired CO2, can be relatively large, expensive to ship, and require line power. This project will develop and deploy a novel system to continuously trap CO2 emitted from Arctic tundra soils over several weeks for radiocarbon (14C) analysis. This continuous collection system has the potential to transform carbon cycle research. Such devices would obviate the need for shipping large canisters to the Arctic as well and the need for line power. Moreover, such devices are relatively inexpensive and lightweight, and therefore, permit for high spatial resolution monitoring. These new traps, however, have never been tested in the Arctic, where the environmental conditions can be harsh, especially in winter. Thus the focus of this work is to develop, harden, and test such devices through a number of winter seasons at the Toolik Lake Long Term Ecological Station, on the north slope of Alaska. If successful, this device will provide the first year-round, quasi-continuous dataset on soil-respired 14CO2 in moist acidic tussock tundra, which is the dominant tundra type of arctic Alaska and globally accounts for over 20% of the tundra land surface. Moreover, this research will point the way for other experimental groups working in similar harsh environments throughout the Arctic. |