Collaborative Research: LTREB Renewal: Soil Warming and Forest Ecosystem Feedbacks to the Climate System

合作研究：LTREB更新：土壤变暖和森林生态系统对气候系统的反馈

基本信息

批准号：
1949882
负责人：
Kristen DeAngelis
金额：
$ 14.94万
依托单位：
University of Massachusetts Amherst
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1949882&HistoricalAwards=false
关键词：
Collaborative Research LTREB Renewal Soil

项目摘要

Soils are the largest repository of carbon (as organic matter) in the terrestrial biosphere. If this stored soil carbon is transferred to the atmosphere by a warming-induced acceleration of organic matter decomposition, it will result in a self-reinforcing (positive) feedback to the global environment. Despite the potential importance of this soil feedback, there is incomplete understanding of the mechanisms that affect the temperature response of organic matter decomposition. This project is quantifying the soil and ecosystem-level responses to nearly three decades of experimental soil warming and documenting the magnitude of soil carbon feedback to global environmental processes. Extensive training of undergraduates, graduate students and postdoctoral researchers will be another feature of this project. Data analysis from the study will also be incorporated into courses taught by the project leaders, and will be used to refine terrestrial ecosystem model projections.This project is investigating the mechanisms underlying feedback from forest ecosystems to the climate system resulting from more than two decades of in situ soil warming. Specifically, we are quantifying the biogeochemical and microbial responses to chronic soil warming, with an emphasis on soil organic matter (SOM) dynamics. This research is testing the hypothesis that long-term warming causes cycles of SOM decay punctuated by periods of structural and functional changes in the soil microbial community. Three ongoing warming experiments at the Harvard Forest Long-term Ecological Research (LTER) site have experienced 5 degrees C above ambient soil temperatures for 13, 16 and 28 years. Together, these sites represent a dynamic time-series based on a common perturbation in a single ecosystem type. Research activities to complete the decadal plan of this LTREB project are organized around four targeted research questions which are being addressed through (1) continuation of core data measurements; (2) temperature manipulations both in situ and under laboratory conditions to examine the underlying mechanistic basis for the observed pattern of temporal non-linearity in the soil respiration response to long-term warming; (3) measurements of SOM chemistry and microbial community dynamics to determine if long-term warming enables and accelerates decay of recalcitrant soil carbon due to a fundamental shift in the structure and/or function of the microbial community; (4) measurements of N mineralization and above-ground carbon storage to determine if long-term warming will continue to accelerate the N cycle and stimulate carbon storage in trees; and (5) data integration activities, including cross-site data syntheses and microbial trait-based and ecosystem modeling efforts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

土壤是陆地生物圈中最大的碳（有机物）储存库。如果这些储存的土壤碳通过变暖引起的有机物分解加速转移到大气中，就会对全球环境产生自我强化（正）反馈。尽管这种土壤反馈具有潜在的重要性，但对影响有机物分解温度响应的机制尚不完全了解。该项目正在量化土壤和生态系统水平对近三十年实验性土壤变暖的反应，并记录土壤碳对全球环境过程的反馈程度。对本科生、研究生和博士后研究人员的广泛培训将是该项目的另一特色。该研究的数据分析也将纳入项目负责人教授的课程中，并将用于完善陆地生态系统模型预测。该项目正在研究二十多年来森林生态系统对气候系统的反馈机制。原位土壤变暖。具体来说，我们正在量化生物地球化学和微生物对长期土壤变暖的反应，重点是土壤有机质（SOM）动态。这项研究正在验证这样的假设：长期变暖会导致土壤微生物群落结构和功能变化期间的有机质腐烂周期。哈佛森林长期生态研究 (LTER) 站点正在进行的三项变暖实验在 13 年、16 年和 28 年中经历了比环境土壤温度高出 5 摄氏度的情况。这些站点共同代表了基于单一生态系统类型中常见扰动的动态时间序列。完成该 LTREB 项目十年计划的研究活动围绕四个有针对性的研究问题进行组织，这些问题通过以下方式解决：（1）继续进行核心数据测量；（2）现场和实验室条件下的温度操纵，以检查土壤呼吸对长期变暖的响应中观察到的时间非线性模式的潜在机制基础； (3) 测量 SOM 化学和微生物群落动态，以确定长期变暖是否会由于微生物群落结构和/或功能的根本转变而导致和加速顽固土壤碳的腐烂；（4）测量氮矿化和地上碳储存，以确定长期变暖是否会继续加速氮循环并刺激树木的碳储存； (5) 数据集成活动，包括跨站点数据合成以及基于微生物性状和生态系统的建模工作。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。