SGER: Assessing respiratory responses of plant respiration to climate change at the ecosystem level: a stable isotope tracer approach

SGER：在生态系统层面评估植物呼吸对气候变化的呼吸反应：稳定同位素示踪剂方法

• 批准号: 0528069
• 负责人: Miguel Gonzalez-Meler
• 金额: $ 10万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0528069&HistoricalAwards=false
• 关键词: SGER; Assessing; respiratory; responses; plant

ABSTRACTTerrestrial ecosystems exchange about 120Gt of carbon (C) with the atmosphere, through the processes of photosynthesis (leading to gross primary productivity, GPP) and ecosystem respiration (Re). Increasing evidence indicates that raising atmospheric CO2 enhances carbon uptake in most ecosystems, however, responses of Re and its components to elevated CO2 are unclear. Net ecosystem productivity (NEP), is determined as the net balance between GPP and Re and is often a sensitive predictor of functional ecosystem properties. A large component of Re is plant respiration. Plant respiration at the ecosystem level is difficult to measure because is embedded with respiration from soil heterotrophs. The major thrust of this proposal is to develop a method to measure stand level plant respiration and its components using isotope tracers in current Free Air CO2 Enrichment (FACE) facilities in which the isotope label can be readily delivered. The proposal is to do a series of one-day isotopic CO2-pulse experiments several times during two growing season. These experiments are aimed at deconvolute whole-plant C processing, to estimate the mean residence time (MRT) of photosynthetic carbon and to separate autotrophic from heterotrophic respiration. These experiments will be done in a deciduous forest consisting of a sweet gum plantation exposed to ambient and elevated CO2 using FACE during two growing seasons. Depending on the initial success of these experiments the method will be extended to an Agroecosystem -SOYFACE- exposing soybean fields to elevated CO2 and O3 also using FACE. Results from the project will have direct relevance and utility to global climate models aimed at determining the carbon cycle of the biosphere. The broad outcome of the study will have direct relevance to C-flux monitoring initiatives (Ameriflux, EuroFlux), Biosphere-Atmosphere-Stable-Isotope-Network and other large-scale ecosystem studies. This project also offers an excellent opportunity for a vertically integrated student training in multidisciplinary research. Undergraduates will be involved with summer internships for field and laboratory research. Graduate students will have unique opportunities to explore fundamental scientific questions in ecology of societal importance, within a multidisciplinary effort at unique field facilities. Participation of underrepresented minorities in research will be promoted with the SROP and the Bridge programs. The project will also integrate undergraduate and graduate education by the initiation of courses that emphasize convergence of various disciplines. With more than 1500 undergraduates enrolled in the reformed biology degree, the teaching plan outlined here is based on this expanding program and builds upon outreach activities developed during the last two years. These teaching and outreach activities include research and mentoring for undergraduate and graduate students, participation in science education through established undergraduate science scholarships, and the use of the Internet for teaching, outreach, and research.

陆地生态系统通过光合作用（产生总初级生产力，GPP）和生态系统呼吸作用（Re）与大气交换约120 Gt的碳（C）。越来越多的证据表明，大气CO2浓度升高会增强大多数生态系统的碳吸收，但Re及其组分对CO2浓度升高的响应尚不清楚。生态系统净生产力（NEP）是GPP和Re之间的净平衡，通常是生态系统功能特性的敏感预测因子。Re的一个很大的组成部分是植物呼吸作用。生态系统水平上的植物呼吸是难以测量的，因为它嵌入了土壤异养生物的呼吸。该提案的主要目的是开发一种方法，以测量林分水平的植物呼吸及其组分使用同位素示踪剂在当前的自由空气CO2富集（FACE）设施，其中同位素标记可以很容易地交付。建议在两个生长季节进行一系列为期一天的同位素CO2脉冲实验。这些实验的目的是在deconvolute全植物C处理，估计光合碳的平均停留时间（MRT），并从异养呼吸分离自养。这些实验将在落叶林组成的枫香种植园暴露于环境和升高的CO2使用FACE在两个生长季节。根据这些实验的初步成功，该方法将扩展到农业生态系统-SOYFACE-暴露大豆领域，以提高CO2和O3也使用FACE。该项目的成果将与旨在确定生物圈碳循环的全球气候模型直接相关和有用。这项研究的广泛成果将与碳通量监测倡议（Ameriflux、EuroFlux）、生物圈-大气-稳定同位素网络和其他大规模生态系统研究直接相关。该项目还为多学科研究中的垂直整合学生培训提供了绝佳的机会。本科生将参与暑期实习，进行实地和实验室研究。研究生将有独特的机会探索社会重要性生态学中的基本科学问题，在独特的现场设施中进行多学科的努力。将通过SROP和桥梁方案促进代表性不足的少数群体参与研究。该项目还将通过开设强调各学科融合的课程，整合本科生和研究生教育。有超过1500名本科生参加了改革后的生物学学位，这里概述的教学计划是基于这个不断扩大的计划，并建立在过去两年中开发的推广活动。这些教学和推广活动包括为本科生和研究生提供研究和指导，通过设立本科生科学奖学金参与科学教育，以及使用互联网进行教学，推广和研究。