Climate impact on the carbon emission and export from Siberian inland waters (SIWA)

了解气候系统需要了解气候对陆地-水-大气耦合系统中碳循环和温室气体动力学的影响，以及这些影响如何反馈到气候系统中。一个主要的知识缺口是在多大程度上从永久冻土释放的C在内陆沃茨中运输、加工和排放为CO2和CH 4，而不是输出到下游沿海和海洋沃茨。高纬度地区的湖泊和溪流向大气中释放大量的CO2和CH 4。这些通量在很大程度上受气候相关因素（温度、风、降水）和流向水体的水文路径控制，直接或通过其对陆地生产和C6，7输出的调节。特别重要的是从融化的永久冻土中释放的有机碳，这些碳在很大程度上可以被代谢，导致CO2和CH 4排放量增加。不连续多年冻土区湖泊和溪流的碳排放已被证明与陆地大气碳交换相当，并超过下游的碳输出，这意味着内陆沃茨在碳循环中的重要作用。尽管我们对湖泊和溪流中碳通量的理解取得了这些进展，但气候对高纬度内陆沃茨碳传输和循环的影响仍存在基础知识空白，尤其是在尝试推断和预测大规模模式和未来趋势时。这一点在俄罗斯北部和北极地区/西伯利亚的广大地区尤其如此。该项目提出了一项西伯利亚西部跨气候梯度（北部-北极）的湖流网络的比较研究（图2），涵盖了大范围的永久冻土条件（缺失-零星-间断-连续）。该项目包括（1）对大约50个湖泊和50条溪流中的CO2和CH 4浓度进行实地调查，以及（2）对选定集水区的年度横向和垂直C通量进行更详细的量化。方法包括手动和连续测量相结合的溶解有机和无机碳，二氧化碳，甲烷和气体传输速度（k）使用室和测井技术。同位素示踪剂（2 H，18 O）采样和建模将允许在每个集水区和水生网络的水文过境时间进行估计，并将河流流量分为集水区内流量贡献的不同地理来源16，17。生物测定实验18将用于评估降解速率和总生物利用度对温度的依赖性，河流DOC跨越梯度。其他测量包括每个区域的深度，pH值，营养物，水温，风和流量。所需的大部分设备已经在该组中提供。该项目将可以使用已建立的实地考察点、该地区的数字地图以及俄罗斯托木斯克州立大学的实验室设施。该项目的碳足迹将通过遵循JPI气候网站提供的旅行、会议、办公室和基础设施指南尽可能最小化。对于这一项目来说，特别重要的是通过虚拟会议、由当地工作人员进行抽样、通过规划会议以尽量缩短旅行距离和能够使用夜间火车来尽量减少旅行。

Understanding climate systems requires knowledge of climatic effects on C cycling andgreenhouse gas dynamics in coupled land-water-atmospheric systems, and in-turn, how thesefeedback into the climate system. A major knowledge gap is to what extent C released frompermafrost soils is transported, processed and emitted as CO2 and CH4 in inland waters vs.exported to downstream costal and ocean waters. Lakes and streams at high latitudes releasesignificant amounts of CO2 and CH4 to the atmosphere. These fluxes are largely controlledby climate dependent factors (temperature, wind, precipitation) and hydrological flowpaths towater bodies, either directly or via its regulation of the terrestrial production and export ofC6,7. Of particular importance is the organic C released from thawing permafrost which couldlargely be metabolized leading to increased CO2 and CH4 emissions. C emission fromlakes and streams in areas of discontinuous permafrost has been shown to be comparable toterrestrial atmospheric C exchange and to exceed downstream C export, implying animportant role of inland waters in the C cycle.Despite these advances in our understanding of C fluxes in lakes and streams there is afundamental knowledge gap of climate impact on C transport and cycling in inland waters athigh latitudes, and especially when attempting to extrapolate and predict large scale patternsand future trends. This is particularly true for the vast areas of boreal and arcticRussia/Siberia.This project proposes a comparative study of lake-stream networks across a climate gradient (boreal-arctic) in western Siberia (Fig. 2) covering a large range of permafrost conditions (absence-sporadic-discontinuous-continuous). The project includes (1) field surveys of CO2 and CH4 concentrations in approximately 50 lakes and 50 streams, and a more (2) detailed quantification of annual lateral and vertical C fluxes in selected catchments. Methods include a combination of manual and continuous measurements of dissolved organic and inorganic C, CO2, CH4 and gas transfer velocity (k) using chamber and logger techniques. Isotopic tracer (2H, 18O) sampling and modelling will allow hydrological transit times in each catchment and aquatic network to be estimated, and stream flow to be separated into different geographic sources of flow contribution within catchments16,17. Bioassay experiments18 will be used to assess temperature dependency in degradation rates, and in total bioavailability, of river DOC across the gradient. Additional measurements include depth, pH, nutrients, water temperature, wind, and discharge for each region. Most of the equipment needed is already available in the group. The project will have access to established field sites, digital maps of the region and to laboratory facilities at Tomsk State University, Russia.The C footprint of the project will be minimized as far as possible by following the guidelines provided by JPI Climate website for travel, meetings, office and infrastructure. For this project it is of particular importance to minimize travel by virtual meetings, by having local staff for sampling, by planning meetings to minimize travel distances and to enable use of night trains.