Wetlands in a changing world: processes, feedbacks and the climate benefits of wetlands

在湿地提供的众多生态系统服务中，从野生动物栖息地到水质改善，气候调节被认为是其对社会最重要的好处之一。湿地生态系统在全球碳（C）循环中发挥着重要作用;它们为C固存和长期储存大气二氧化碳（CO2）提供了理想的环境，但它们也是大气甲烷（CH 4）的最大单一来源，甲烷是一种在短期内比CO2更强大的温室气体（GHG）。气候变化有可能增加湿地的温室气体排放，然而，温度上升对湿地温室气体动力学和碳循环的后果仍然不确定。此外，防止湿地进一步丧失和恢复湿地生态系统被认为是限制未来排放以帮助实现气候目标的重要因素。虽然湿地有可能扩大和减缓全球变暖，但湿地对气候和土地使用变化的反应仍然知之甚少。该研究计划旨在通过提供对湿地碳和温室气体动态对气候变化和管理的响应的更好的机械理解来解决这一知识缺口。在接下来的五年里，我们将调查三个不同的自然和管理的湿地生态系统的陆地-大气相互作用，以量化和比较年度温室气体和碳预算，确定痕量气体通量的关键控制，并改善湿地碳通量的预测。本研究计划的四个短期目标是通过相关的研究活动，结合联合收割机实地测量，遥感和建模，提供新的见解的控制和湿地碳和温室气体通量的时间在一系列的空间和时间尺度。这项研究计划的核心将是新的和正在进行的生态系统规模的CO2，CH 4，水和能量通量在三个湿地网站涡度协方差测量。这些地点包括在伯恩斯沼泽生态保护区，不列颠哥伦比亚省的天然和恢复沼泽，和边界湾野生动物管理区，不列颠哥伦比亚省的潮汐沼泽。通过对这些地点的痕量气体通量进行全年测量，我们将量化这些湿地生态系统的年度碳和温室气体预算，以评估和比较它们对气候的净变暖或冷却效应。我们还将调查每小时到年际时间尺度上湿地温室气体交换的主要控制因素，探索湿地类型之间以及自然和恢复站点之间的驱动因素如何变化，并描述示踪气体通量的站点内空间变异性。我们还将遥感指数通量塔测量恢复和自然湿地的模型和高档碳通量。这项研究对于更好地预测湿地对气候变化的当前和未来贡献至关重要，这与旨在限制全球气温上升水平的政策高度相关。

Among the numerous ecosystem services provided by wetlands, from wildlife habitat to water quality improvement, climate regulation is identified as one of their most important benefits to society. Wetland ecosystems play an important role in the global carbon (C) cycle; they provide the ideal environment for C sequestration and long-term storage of atmospheric carbon dioxide (CO2), yet they are also the largest single source of atmospheric methane (CH4), a much more potent greenhouse gas (GHG) than CO2 in the short term. Climate change has the potential to increase GHG emissions from wetlands, however, the consequences of rising temperatures on wetland GHG dynamics and C cycling remains uncertain. Furthermore, preventing further wetland loss and restoring wetland ecosystems has been identified as important in limiting future emissions to help meet climate goals. While wetlands have the potential to both amplify and attenuate global warming, wetland responses to climate and land-use change are still poorly understood. This research program aims to address this knowledge gap by providing an improved mechanistic understanding of the response of wetland C and GHG dynamics to climate variability and management. Over the next five years, we will investigate land-atmosphere interactions across three distinct natural and managed wetland ecosystems to quantify and compare annual GHG and C budgets, identify key controls on trace gas fluxes, and improve predictions of wetland C fluxes. The four short-term objectives of this research program are addressed through linked research activities that combine field-based measurements, remote sensing, and modeling to provide novel insights into the controls and timing of wetland C and GHG fluxes across a range of spatial and temporal scales. The core of this research program will be new and ongoing eddy covariance measurements of ecosystem-scale CO2, CH4, water and energy fluxes at the three wetland sites. These sites include a natural and restored bog in the Burns Bog Ecological Conservancy Area, BC, and a tidal marsh in the Boundary Bay Wildlife Management Area, BC. By conducting year-round measurements of trace gas fluxes across the sites, we will quantify annual C and GHG budgets across these wetland ecosystems to assess and compare their net warming or cooling effect on climate. We will also investigate the dominant controls on wetland GHG exchange across hourly to interannual time scales, explore how drivers vary across wetland types and between natural and restored sites, and characterize within-site spatial variability in trace gas fluxes. We will also link remote-sensing indices to flux tower measurements to model and upscale C fluxes in restored and natural wetlands. This research is critical to better predicting current and future contributions of wetlands to climate change, which is highly relevant for policies aiming to limit the level of global temperature rise.