Portable photosynthesis/respirometer system for the measurement of carbon dioxide fluxes in forest and grassland ecosystems

科学界普遍认为，气候变化正在发生，而且部分是由人类活动引起的，因为它是由大气中温室气体的增加引起的。最臭名昭著的温室气体二氧化碳的增加主要是由于化石燃料的燃烧和土地利用的变化。陆地生态系统有可能通过将大量碳封存到其生物量或土壤成分中来遏制这些排放。然而，使用陆地生态系统作为一种缓解措施需要进一步的定量证据。我的研究项目考察了气候变化、自然和人为干扰的影响，以及对森林和草原生态系统碳封存的管理实践。我采用自下而上的方法，利用光合作用和呼吸作用的二氧化碳通量室测量，将二氧化碳的组分通量划分和扩大到生态系统水平。通过量化土壤、草地和森林植被的贡献，我确定了这些生态系统的汇源强度，并评估了它们对不同管理措施（如氮肥和放牧）的反应。在这个提案中，申请资金用于购买我的研究项目的核心仪器，即便携式光合作用/呼吸计系统，将用于各种实地研究。该仪器获得的结果对于参数化和验证基于过程的碳交换模型以及提高气候变化与陆地生态系统过程之间相互作用的模拟精度具有重要意义。

There is a general scientific consensus that climate change is occurring and that it is partly induced by human activity as it is caused by an increase in greenhouse gases in the atmosphere. The increase of the most notorious greenhouse gas, carbon dioxide, is mainly due to the burning of fossil fuels and land-use change. Terrestrial ecosystems have the potential to curb these emissions by sequestering large amounts of carbon into their biomass or the soil component. The use of terrestrial ecosystems as a mitigation measure requires, however, further quantitative evidence. My research program examines the influence of climate variability, natural and anthropogenic disturbances, as well as management practices on the carbon sequestration of forest and grassland ecosystems. I use a bottom-up approach, using carbon dioxide flux chamber measurements of photosynthesis and respiration, to partition and scale up component fluxes of carbon dioxide to the ecosystem level. By quantifying the contribution of the soil, grassland and forest vegetation, I determine the sink or source strength of these ecosystems and I assess their responses to different management practices such as nitrogen fertilization and cattle grazing. In this proposal, funds are requested for the acquisition of the core instrument of my research program, i.e. a portable photosynthesis/respirometer system that will be used in various field studies. The results obtained with this instrument will be important to parameterize and validate process-based models of carbon exchange and improve the accuracy of simulations regarding the interactions between climate change and terrestrial ecosystem processes.