Collaborative Research: Forest productivity and hydrological patterns regulate methane fluxes from peatlands in the Amazon basin

亚马逊盆地拥有近100万平方公里的湿地，主要是泥炭地，众所周知，这些湿地生产力很高，并在植物生物量和土壤中储存了大量的碳。泥炭地以富含有机质的土壤为特征，这些土壤经常被水饱和，因此通常氧气含量较低。这些条件通常会导致甲烷的释放，甲烷是一种温室气体，其吸热能力是二氧化碳的约25倍，而泥炭地被认为是全球重要的甲烷来源。直到最近，人们还认为泥炭地不会成为亚马逊盆地的重要组成部分，因为这些湿地在寒冷的北纬地区更为常见，而且很少有记录表明它们在亚马逊地区的存在。然而，近年来，在卫星图像和有指导的野外勘探的帮助下，多项研究记录了亚马逊西部和中部盆地的数百块泥炭地。据估计，这些新发现的亚马逊泥炭地含有300-600万吨有机碳，这也可能是每年甲烷的一个重要来源，以前没有记录过。每年储存在植物和土壤中的有机碳与从这些泥炭地释放出来的甲烷相比，其大小尚不清楚。该项目提议首次评估一组不同的亚马逊泥炭地的有机碳含量，以及森林生产力和甲烷形成和释放的速率。这项工作还将包括对水位的试验性操作，以评估生产力和甲烷释放对气候变暖可能发生的环境变化的反应。该项目还将开发这些生态系统的数学模型，以评估泥炭地在更大范围内的影响，并对未来的生产力和甲烷排放提出量化预测。这项研究将检验两个假设，包括(I)植被变化和水分状况是否决定甲烷的产生和释放，以及(Ii)甲烷产生对水状况变化的响应是否受到亚马逊泥炭地多样性的调节。这项工作将大大有助于我们理解大气化学变化和气候变化之间的反馈，因为亚马逊泥炭地的碳贮量很大，而且它们可能成为甲烷的主要来源。这项研究将首次对亚马逊地区的泥炭地进行全面分析，并对亚马逊地区未来的甲烷排放量进行定量预测。该项目还将提供碳储量和碳通量的数据，以供未来在气候变化下进行比较，并将为监测热带泥炭地提供证据，以便今后进行保护和决策工作。这项合作包括三个美国机构和一个秘鲁机构，将培养一名博士后研究员、两名研究生和一名本科生。该项目还将开发一个虚拟教室计划，将亚利桑那州和秘鲁伊基托斯的高中生联系起来，讨论亚马逊泥炭地生态研究的影响，并跟踪探险活动。高中一级的教育活动将有针对性地产生一个有效的保护教学工具，以接触到更广泛的公众。

The Amazon basin contains nearly one million square kilometers of wetlands, predominantly peatlands, which are known to be highly productive and to store significant quantities of carbon in plant biomass and soil. Peatlands are characterized by soils rich in organic matter that are often saturated with water, and are therefore often low in oxygen. These conditions often lead to the release of methane, a greenhouse gas with ~25 times the heat-trapping capacity of carbon dioxide, and peatlands are known to be important global sources of methane. Until very recently, peatlands were not expected to be a significant component of the Amazon basin since these wetlands are more common in cold, northern latitudes and there were few records of their existence in the Amazon. In recent years, however, multiple studies aided by satellite imagery and guided field explorations have documented hundreds of peatlands across basins in the West and Central Amazon. An estimated 3-6 millions of tons of organic carbon are contained in these newly discovered Amazon peatlands, which may also represent a significant, previously unrecorded, source of methane annually. The magnitude of organic carbon stored in plants and soils every year vs. that released as methane from these peatlands is not known. This project proposes to evaluate for the first time a set of diverse Amazonian peatlands their organic carbon content, and rates of forest productivity and methane formation and release. This work will also include experimental manipulations of water levels to evaluate responses of productivity and methane release to environmental changes likely to occur as the climate warms. This project will also develop mathematical models of these ecosystems to evaluate the impact of peatlands at larger scales and to propose quantitative predictions for future productivity and methane emissions. Two hypotheses will be tested in this study including (i) whether vegetation change and water regime determine methane production and release, and (ii) whether the response of methane production to altered water regimes is modulated by the diversity of Amazon peatlands. This work will contribute substantially to our understanding of feedbacks between changes in atmospheric chemistry and climate because of the magnitude of carbon storage in Amazonian peatlands and their potential to be major sources of methane. The research will provide the first comprehensive analysis of these peatlands in the Amazon, and provide quantitative predictions of future methane emissions from the Amazon. This project will also provide data on carbon stocks and fluxes for future comparisons under climatic change and will provide evidence to monitor tropical peatlands for future conservation and policy-making efforts. This collaborative effort including three US and one Peruvian institution, will train a postdoctoral researcher, two graduate and one undergraduate student. This project will also develop a virtual classroom program connecting high school students in Arizona and Iquitos Peru to discuss the impact of ecological research in Amazon peatlands and to track expeditions. Educational activities at the high school level will be targeted to generate an effective conservation-teaching tool to reach a broader public.