Doctoral Dissertation Research: The impact of permafrost thaw on the fate and magnitude of carbon aquatic transport from Arctic tundra soil

博士论文研究：永久冻土融化对北极苔原土壤碳水运输的命运和程度的影响

• 批准号: 2310630
• 负责人: Edward Schuur
• 金额: $ 5.71万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310630&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; impact; permafrost

Permafrost thaw in Arctic watersheds triggers the release of previously sequestered, ancient carbon to the atmosphere and to stream systems - a feedback that accelerates climate warming. Atmospheric release of carbon has been well-documented for decades; however, water is more difficult to monitor and its role in the Arctic carbon cycle has often been overlooked. This research will explore the environmental drivers that Arctic groundwater and headwater streams play in long-term permafrost carbon release. Better understanding the emerging role that water plays in the carbon cycle in a warming Arctic will help improve regional carbon budgets, quantifying the amount of carbon lost from the land that is exported via rivers in a watershed underlain by permafrost. The research will also aid in monitoring the impacts that climate change and resulting permafrost thaw have on ancient permafrost carbon release by carbon dating the dissolved carbon carried away in rivers to identify ancient permafrost signatures. At a long-term experimental study site in interior Alaska, 50% of the soil carbon lost from soils annually was unaccounted for in atmospheric carbon flux measurements. The missing 50% of carbon lost is hypothesized to be exported in dissolved organic carbon fluxes and that an increasing amount of ancient, permafrost carbon is released each year with increasing permafrost thaw. This research will (1) help to resolve the Arctic net ecosystem carbon budget and help to parameterize future Earth System Models; (2) identify the proportion of dissolved organic carbon that is ancient permafrost carbon, using radiocarbon dating; and (3) identify how environmental drivers, such as thaw, impact dissolved organic carbon concentration and age in order to help constrain future predictions of dissolved organic carbon export. Further, the project team will facilitate various outreach activities in Arizona and within the local community surrounding the field site in interior Alaska, to include the broader public as well as a future cohort of young scientists in this work.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.

北极流域的永久冻土融化引发了以前封存的古老碳释放到大气和河流系统中，这种反馈加速了气候变暖。几十年来，大气中碳的释放已有充分记录。然而，水更难以监测，而且它在北极碳循环中的作用常常被忽视。这项研究将探讨北极地下水和水源流在长期永久冻土碳释放中发挥的环境驱动因素。更好地了解水在北极变暖的碳循环中所扮演的新角色将有助于改善区域碳预算，量化通过永久冻土下流域河流输出的土地损失的碳量。该研究还将通过对河流中带走的溶解碳进行碳测年来识别古代永久冻土特征，从而帮助监测气候变化和由此产生的永久冻土融化对古代永久冻土碳释放的影响。 在阿拉斯加内陆的一个长期实验研究地点，每年从土壤中流失的土壤碳中有 50% 在大气碳通量测量中没有被计算在内。假设缺失的 50% 的碳以溶解有机碳通量的形式输出，并且随着永久冻土融化的增加，每年释放出越来越多的古老永久冻土碳。这项研究将（1）帮助解决北极净生态系统碳预算问题，并帮助参数化未来的地球系统模型； (2) 利用放射性碳测年法确定溶解有机碳（即古代永久冻土碳）的比例； (3) 确定解冻等环境驱动因素如何影响溶解有机碳浓度和年龄，以帮助限制未来对溶解有机碳出口的预测。此外，项目团队将促进亚利桑那州和阿拉斯加内陆现场现场周围的当地社区内的各种外展活动，让更广泛的公众以及未来的年轻科学家参与这项工作。该奖项反映了 NSF 的法定使命和通过使用基金会的智力优点和更广泛的影响审查标准进行评估，该项目被认为值得支持。