OPP-PRF: Linking the Physical and Chemical Drivers of Carbon Cycling in Arctic Source-to-sink Systems

全球碳循环调节着我们星球的气候和可居住性。北极地区，特别是永久冻土，储存了大量的碳-几乎是大气的两倍。随着北极气温的升高，永久冻土层融化，富含碳的有机物可以释放出来。一旦释放，这些碳可以转化为二氧化碳和甲烷-温室气体。从永久冻土层释放的碳也可能被运送到海洋中，在那里它可以被埋葬多年，使其远离大气层。这项研究的主要目标是找到北极地区永久冻土融化的热点，并了解碳从永久冻土中释放出来后会发生什么。该项目支持一名博士后学者，并提供资金来分析从阿拉斯加北极的一条河流中收集的样本。这项工作将产生一个数学模型，模拟整个北极景观的碳流动。PI还将创建一个教育工具，向学生讲授碳气候反馈。该项目旨在发展对北极景观中物理侵蚀，氧化风化和有机碳（OC）转化之间反馈的机械理解。本项目采用“源-汇”方法研究冻土融化的物理和化学效应，并评估有机碳在动员和下游运输过程中的转化。关注阿拉斯加北方的坎宁河，PI将比较现代河流有机碳通量与来自宇宙成因放射性核素地球化学的长期流域平均有机碳输出。为了确定是否永冻层衍生的OC在整个北极景观的运输过程中被氧化为CO2，该项目采用了新的地球化学方法，包括斜坡热解氧化-14 C和溶解的CO2分析。这些结果将限制从融化的永久冻土中动员的OC的分解速率，这在很大程度上是未知的，但需要预测北极未来的二氧化碳排放量。利用该项目产生的数据，PI将构建一个北极河流集水区侵蚀、风化和碳循环耦合模型。这个耦合模型的进一步应用将揭示气候，侵蚀，沉积物路由和OC循环之间的反馈，这将促进我们对北极景观对未来气候变化的响应的理解。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The global carbon cycle regulates the climate and habitability of our planet. The Arctic landscape, particularly permafrost (frozen ground), stores a massive amount of carbon – nearly twice as much as the atmosphere. As air temperatures in the Arctic increase, the permafrost thaws and carbon-rich organic matter can be released. Once released, this carbon can be transformed into carbon dioxide and methane – greenhouse gases. The carbon released from permafrost may also be transported to the ocean where it can be buried for many years, keeping it out of the atmosphere. The primary goals of this research are to find hotspots of permafrost thaw in the Arctic landscape and to understand what happens to carbon after it is released from the permafrost. This project supports one postdoctoral scholar and provides funding to analyze samples collected from a river in Arctic Alaska. This work will result in a mathematical model that simulates the flow of carbon across the Arctic landscape. The PI will also create an educational tool to teach students about carbon-climate feedbacks.This project aims to develop a mechanistic understanding of the feedbacks between physical erosion, oxidative weathering, and organic carbon (OC) transformation in Arctic landscapes. This project uses a “source-to-sink” approach to study the physical and chemical effects of permafrost thaw at the landscape-scale and assess the transformation of OC upon mobilization and downstream transport. Focusing on the Canning River in northern Alaska, the PI will compare modern river OC fluxes with long-term catchment-average OC export derived from cosmogenic radionuclide geochemistry. To determine whether permafrost-derived OC is oxidized to CO2 during transport across the Arctic landscape, this project applies novel geochemical methods, including ramped pyrolysis oxidation-14C and dissolved rhenium analyses. The results will constrain decomposition rates of OC mobilized from thawing permafrost, which are largely unknown but needed to predict future CO2 emissions from the Arctic. Using data generated from this project, the PI will construct a model of coupled erosion, weathering, and carbon cycling in Arctic river catchments. Further application of this coupled model will reveal the feedbacks among climate, erosion, sediment routing, and OC cycling that will advance our understanding of Arctic landscape response to future climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.