Dissertation Research: Winter soil respiration in southeast Wyoming

论文研究：怀俄明州东南部的冬季土壤呼吸

• 批准号: 1110537
• 负责人: Elise Pendall
• 金额: $ 1.49万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1110537&HistoricalAwards=false
• 关键词: Dissertation; Research; Winter; soil; respiration

In seasonally snow covered regions, the metabolism of living roots and microorganisms in the soil over the winter may be an important part of the total annual transfer of carbon dioxide from ecosystems on land into the atmosphere. This project will measure wintertime soil respiration in southeast Wyoming and determine the factors that control it. Measurement plots have been established across a range of ecosystems from short grass prairies to subalpine forests that experience a wide range of winter weather conditions. The highest elevation site, at about 10,000 feet, is a subalpine forest that has snow cover for more than eight months at depths up to ten feet. The lowest elevation site, at 5400 feet, has only four months of snow that is shallow and patchy. This results in contrasting midwinter soil environments. At the high elevation site, snow provides a deep insulating layer that effectively insulates the soil from extremely cold air temperatures and prevents soil freezing. In contrast, soils at the lowest elevation site are often directly exposed to the air and often freeze in midwinter. This has the counterintuitive result that soils in the coldest, snowiest ecosystems at the highest elevations are actually the warmest in midwinter. The organisms responsible for soil respiration, mainly bacteria, fungi and plant roots, rely on the presence of liquid water to be biologically active. Therefore, it is expected that the highest elevation sites will have higher rates of soil respiration during the winter than the lowest elevation sites. Measurements will be made of soil respiration at the different study sites in ways that will enable the relative amounts coming from microbes and roots to be determined. Laboratory experiments will be done to determine the controls over respiration at cold temperatures. Over a year the flux of carbon dioxide from the land into the atmosphere is many times greater than the amount released by the burning of fossil fuels. Over the earth, most of the released carbon is taken back up by plants. But small shifts in the relative rates of release and uptake can have a large impact on atmospheric concentrations of carbon dioxide. Current computer models generally contain overly simple descriptions of soil processes and how they may respond to climate change, particularly at cold temperatures. Therefore, it is important to learn about the interacting biological and physical factors that control these processes. In addition to addressing the socially relevant issue of global climate change, this project will help educate and train a new generation of scientists through the employment of an undergraduate research assistant.

在季节性的积雪中，冬季，生命根和微生物的代谢可能是二氧化碳从陆地上生态系统中二氧化碳总转移到大气中的重要组成部分。该项目将测量怀俄明州东南部的冬季土壤呼吸，并确定控制冬季的因素。从短草大草原到亚高山林的各种生态系统都建立了测量地块，这些森林经历了各种冬季天气状况。最高的海拔位置约为10,000英尺，是一个亚高山森林，其雪覆盖范围超过八个月，深度高达十英尺。最低的海拔位置在5400英尺处，只有四个月的雪，浅斑。这导致对比仲冬的土壤环境。在高海拔地点，雪提供了一个深层绝缘层，可有效地隔离土壤，从极冷的空气温度中隔离并防止土壤冷冻。相比之下，最低海拔位点的土壤通常直接暴露于空气中，并经常在仲冬冻结。这具有违反直觉的结果，即最冷的生态系统中最高海拔的土壤实际上是仲冬中最温暖的土壤。负责土壤呼吸的生物，主要是细菌，真菌和植物根，依赖于液态水具有生物学活性。因此，可以预期，高海拔位点在冬季的呼吸率将比最低的高度部位更高。 在不同研究地点，将以土壤呼吸的方式进行测量，以确定来自微生物和根的相对量。将进行实验室实验，以确定在冷温下呼吸的控制。一年多以来，二氧化碳从土地进入大气的通量比燃烧化石燃料释放的数量要大很多倍。在地球上，大多数释放的碳被植物撤回。但是，相对释放率和吸收速率的小变化可能会对二氧化碳的大气浓度产生巨大影响。当前的计算机模型通常包含过度简单的土壤过程描述以及它们如何应对气候变化，尤其是在寒冷温度下。因此，了解控制这些过程的相互作用的生物学和物理因素很重要。 除了解决全球气候变化的社会相关问题外，该项目还将通过雇用本科研究助理来教育和培训新一代科学家。