Carbon gas dynamics in aquatic ecosystems: integrating physical processes and biogeochemical cycling

我研究的中心目标是建立一个可靠的量化框架，从地方到全球，评估内陆水域在景观C预算中的作用。我们团队和其他机构最近的研究发现，CH4是一个重要的参与者。由于相对于二氧化碳，甲烷的生物地球化学循环的性质要复杂得多，因此对其目前对温室气体总排放量的贡献的估计仍然受到宽松的限制。然而，由于其高度的升温潜力和温度敏感性，它未来的作用可能要重要得多，但更不可预见。我认为，评估和预测其贡献的困难在于缺乏一个物理-生物地球化学框架来综合主要通量，即生产途径、传输机制、氧化程度和最终逃逸到大气中。拟议的研究方案围绕着几个子项目，重点是甲烷动力学，重点是物理限制对生物地球化学过程速率所起的作用。这项研究将首先在一个模型湖(L.croche)上进行，然后扩展到具有代表性的湖泊的横截面，涵盖生态系统大小、形状和营养状况的梯度。我们还将进行详细的调查，以加深我们对排放的一个关键组成部分-气体交换(K600)的了解，重点是它所起的生态作用。总而言之，研究计划的这些组成部分将提供必要的框架，以更好地了解湖泊中的CH4动态，最终将导致对水生生态系统CH4排放的更好预测。

The central goal of my research is to establish a solid quantitative framework to assess the role of inland waters in landscape C budgets, from local to global. Recent research by our group and elsewhere has identified CH4 as a significant player. Owing to the much more complex nature of the biogeochemical cycling of methane relative to CO2, estimates of its current contribution to total GHG emissions are still loosely constrained. However, with its high warming potential and temperature sensitivity, its future role is potentially much more important but even less foreseeable. I contend that part the difficulty in assessing and predicting its contribution is the lack of a physical-biogeochemical framework in which to integrate the main fluxes, namely production pathways, transport mechanisms, degree of oxidation and ultimately evasion to the atmosphere. The proposed research program is articulated around several sub-projects focussing on methane dynamics with an emphasis on the role played by physical constraints impinging on the rates of biogeochemical processes. The study will first be conducted on a model lake (L. Croche) and then be extended to a cross section of representative lakes covering gradients of ecosystem size, shape and nutrient status. We will also conduct detailed investigations to further our understanding of a key component of emission, gas exchange (k600), with an emphasis on the ecological role it plays. Together, these components of the research program will provide the necessary framework to better understand CH4 dynamics in lakes that will ultimately lead to the better predictions of CH4 emission from aquatic ecosystems.