Carbon sequestration and greenhouse gas emissions in forests, wetlands and agricultural fields

***我的研究目标是更好地了解陆地生态系统（包括森林、湿地和农田）中决定碳(C)固存和温室气体（GHG）即CH4、CO2和N2O排放的过程和环境控制。本研究旨在促进技术和政策的发展，以更好地管理陆地生态系统，以增加碳固存，减少温室气体排放和气候变化的影响，同时最大限度地提高生产力和水利用效率。净生态系统产量（NEP）、蒸散发、CH4和N2O通量将使用涡流协方差（EC）技术进行测量。我还将使用通量室测量来量化土壤温室气体通量的时空变异性和管理对土壤温室气体通量的影响，并评估将通量室测量扩大到林分和田间水平的可靠性。***我的目标之一是通过估计西海岸29年树龄道格拉斯杉木林分白天叶片呼吸的光抑制作用，来完善生态系统净CO2交换在生态系统呼吸(R)和总生态系统光合作用（GEP）之间的分配。这将通过使用可调谐二极管激光-红外气体分析仪系统对13CO2和12CO2的通量进行EC测量来完成，并分别根据13CO2和12CO2在白天和夜间的通量比估算NEE （NEE）和R (R)的同位素通量比。在我对卑诗省内陆山松甲虫影响的森林的研究中，重点将是进一步改进基于过程的森林生长模型3-PG，我的博士生Gesa Meyer已经修改了该模型，通过分别处理林下和林下生长来包括昆虫攻击对林分的影响，包括用于确定NEP的异营养呼吸（Rh），以及由于死树的粗木屑增加而导致Rh增加的程度。在弗雷泽河谷下游（LFV）的一个城市沼泽中，重点将是了解控制ec测量的CH4和CO2通量的主要过程的动态，以及通过再湿润恢复的进展，并使用安装的室在洪水事件期间继续测量沼泽中泥炭苔藓深度、土壤湿度和植被变化的不同地点。我对农业用地的研究目的是提高我们对LFV主要农业种植系统控制温室气体排放过程的理解。这将涉及使用连续取样的土壤空气在几个深度研究温室气体的生产、消耗和运输，以便应用梯度技术。***这些研究项目将有助于了解和量化陆地生态系统的碳平衡和温室气体通量，以及它们在减缓气候变化方面的潜力，并为高素质人才提供良好的培训环境

***The goal of my research is to better understand the processes and environmental controls that determine carbon (C) sequestration and greenhouse gas (GHG), namely CH4, CO2 and N2O, emissions in terrestrial ecosystems including forests, wetlands, and agricultural fields. This research aims to advance the development of technology and policy to better manage terrestrial ecosystems to increase C sequestration, minimize GHG emissions and the impacts of climate change, while maximizing productivity and water use efficiency. Net ecosystem production (NEP), evapotranspiration, and CH4 and N2O fluxes will be measured using the eddy-covariance (EC) technique. I will also use flux chamber measurements to quantify the temporal and spatial variability of, and effect of management on, soil GHG fluxes, and assess the reliability of scaling up chamber measurements to stand and field level. ***One of my aims will be to refine the partitioning of net ecosystem exchange of CO2 between ecosystem respiration (R) and gross ecosystem photosynthesis (GEP) by estimating light inhibition of leaf respiration during the daytime in a 29-yr-old West-Coast Douglas-fir stand. This will be accomplished by making EC measurements of 13CO2 and 12CO2, fluxes using a tunable diode laser - infrared gas analyzer system, with the isotopic flux ratios of NEE (NEE) and R (R) estimated from the ratios of the 13CO2 to 12CO2 fluxes during daytime and nighttime, respectively. In my research on mountain-pine-beetle impacted forest in the BC Interior, the focus will be to further improve the process-based forest growth model 3-PG that my PhD student Gesa Meyer has modified to include the effects of insect attack on a stand by treating understory and overstory growth separately, to include heterotrophic respiration (Rh) for determining NEP, and the extent of the increase in Rh due to increased coarse woody debris from dead trees. In an urban bog in the Lower Fraser Valley (LFV), the focus will be to understand the dynamics in the dominant processes controlling EC-measured CH4 and CO2 fluxes with the progression of restoration by rewetting, and to compare distinct sites characterized by peat-moss depth, soil wetness, and vegetation variations within the bog using mounted chambers to continue measurements during flooding events. The objective of my research on agricultural land is to improve our understanding of the processes controlling GHG emissions in major agricultural cropping systems in the LFV. This will involve studying the production, consumption, and transport of GHGs in the soil in situ using continuously sampled soil air at several depths in order to apply the gradient technique. ***These research projects will help understand and quantify the C balance of, and the GHG fluxes from, terrestrial ecosystems, and their potential in climate change mitigation, and also provide an excellent training environment for highly qualified personnel.**