Quantifying The Impact of Recent Climate Change on Sedimentary Biogeochemical Cycles and The Organic Carbon Sink

量化近期气候变化对沉积生物地球化学循环和有机碳汇的影响

• 批准号: RGPIN-2022-04305
• 负责人: Pellerin, Andre
• 金额: $ 1.89万
• 依托单位: Université du Québec à Rimouski
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765289
• 关键词: Quantifying; Impact; Recent; Climate; Change

Global warming is modifying the storage and release of organic carbon (OC) in the Arctic environment both on land and at sea. To understand how climate change influences the Arctic carbon cycle, it is necessary to understand its journey from release by permafrost thaw to final destination, in the atmosphere or in the seafloor. The Mackenzie watershed and Beaufort Shelf is a key region that is affected by changing Arctic conditions and which may be an indicator of what will happen across the broader Arctic. When permafrost thaws, it releases OC that has been accumulating frozen for thousands of years, all at once. Microbes living in soil, lakes, streams and the sea, can then use this OC to grow by degrading it into greenhouse gases (GHG) such as carbon dioxide or methane, leading to more warming and, more thaw, in a positive feedback. Microbes use electron acceptors such as oxygen, nitrate, manganese, iron oxides and sulfate to degrade OC. In the seafloor, OC is likely to degrade into carbon dioxide. On land, electron acceptors are often scarce and microbes ferment OC into methane gas, which is a more potent greenhouse gas. The place, and the pathway taken to degrade OC therefore has a direct impact on the climate and can exacerbate warming. Rapid shift in biogeochemical cycles, have been observed in response to the recent warming trends, which may affect OC degradation. My long-term research goal is to forecast the responses and feedbacks between microbial-sedimentary systems and the changing Arctic. Two short-term (5-year) science objectives are (1) quantify the present and the historical distribution of organic carbon (OC) mineralization on the Beaufort shelf and the fate of marine and terrestrial sources and (2) balance the carbon budgets of production and emissions of greenhouse gases from sites undergoing abrupt permafrost thaw. Both (1) and (2) are at the forefront of Arctic research and are experimentally accessible due to the development and fine-tuning of new techniques and multidisciplinary international collaborations. The analytical program relies on the sampling of porewater, sediment and gas from field sites and analysis of microbial catabolic rates with both stable and radioactive isotope tracers in the lab. Results are then incorporated in diagenetic models that considers deposition rates, chemical fluxes in porewater and gas migration. Stable isotopes of carbon and sulfur play a critical role in this analysis. The program will anticipate changes in the carbon sink of the Mackenzie-Beaufort fluvial system. It ties into pan-Arctic assessments of OC transport, burial and degradation. This could shape government policy and relations between Arctic nations. The program is the proving ground for nine HQP that will increase their capacity to conduct respectful research alongside local communities. It will maintain Canada at the forefront of Arctic scientific research and a leader in assessing the consequences of climate change.

全球变暖正在修改有机碳（OC）在陆地和海上的北极环境中的储存和释放。为了了解气候变化如何影响北极碳循环，有必要了解其从永久冻结释放到最终目的地，大气或海底的最终目的地的旅程。 Mackenzie流域和Beaufort货架是一个关键区域，受北极状况的影响，可能是整个北极地区将发生的情况的指标。当永久冻土解冻时，它释放了几千年来积累的oc，均立即释放出来。居住在土壤，湖泊，溪流和海洋中的微生物可以通过将其降解为温室气体（GHG），例如二氧化碳或甲烷，从而使其生长，从而导致更加温暖，并以积极的反馈更加融化。微生物使用电子受体，例如氧，硝酸盐，锰，氧化铁和硫酸盐来降解OC​​。在海底，OC可能会降解为二氧化碳。在陆地上，电子受体通常是稀缺的，微生物将OC发酵成甲烷气体，这是一种更有效的温室气体。因此，该地点以及降解OC的途径对气候有直接影响，并可能加剧变暖。响应最近的变暖趋势，已经观察到生物地球化学周期的快速变化，这可能会影响OC降解。我的长期研究目标是预测微生物 - 沉积系统与北极变化之间的反应和反馈。两个短期（5年）科学目标是（1）量化博福特货架上有机碳（OC）矿化的当前和历史分布，以及海洋和地面来源的命运，以及（2）平衡的碳预算从突然的多年冻结融化的地点的温室气体的生产和排放。 （1）和（2）都处于北极研究的最前沿，并且由于新技术和多学科国际合作的开发和微调而在实验上可以访问。分析计划依赖于田间位点的孔隙水，沉积物和气体的抽样以及实验室中稳定和放射性同位素示踪剂的微生物分解率的分析。然后将结果纳入考虑沉积速率，孔隙水和气体迁移的化学通量的成岩模型中。碳和硫的稳定同位素在此分析中起着至关重要的作用。该计划将预期Mackenzie-Beaufort Fluvial系统的碳汇变量发生变化。它与OC运输，埋葬和退化的泛北极评估有关。这可以塑造政府政策和北极国家之间的关系。该计划是九个HQP的验证基础，它将增加他们与当地社区一起进行尊重研究的能力。它将使加拿大保持北极科学研究的最前沿，并成为评估气候变化后果的领导者。