Quantifying the relationship between erosion and permafrost thaw in a changing Arctic environment

北极环境正在经历快速变化。例如，永久冻土的融化可能会向大气中释放大量的碳，并导致大范围的土壤侵蚀。暴露出深层永久冻土的侵蚀反过来又可以将沉积物和水重新分配到陆地和河流系统中。研究人员将采取综合方法，分析古气候波动和跨越时空的流域地形，以了解气候、永久冻土融化和土壤侵蚀之间的关系。结果将提高我们预测北极系统变化的能力。对K-12学校的教育推广将包括为一个以卡车为基础的流动科学实验室设计动手实验，该实验室访问匹兹堡及其周围的学校，包括那些服务于少数族裔和代表不足的人口的学校。作为这项研究的一部分，研究生和本科生将参加研究和推广活动，培训新一代科学家。迄今为止，多年冻土融化对土壤侵蚀的影响在很大程度上还没有量化，永久冻土融化和土壤侵蚀对地形属性、纬度位置和气候的依赖也是如此。本研究旨在：(1)在古气候波动的背景下量化北极环境中土壤侵蚀和多年冻土融化之间的关系；(2)探索这些过程对地形属性和纬度位置的依赖性；(3)评估和改进景观演变模型模拟北极环境侵蚀的能力。为了实现这些目标，研究人员将对阿拉斯加不同纬度位置的两个湖泊群的沉积物岩心进行采样和分析。他们将把地形分析和地貌建模与来自融化的永久冻土并保存在湖泊沉积物中的陈年碳的化学特征结合起来。这一方法将改进和指导未来的建模工作，以预测北极系统对不断变化的环境的反应。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Arctic environments are undergoing rapid change. The thawing of permafrost soils, for example, can release vast amounts of carbon to the atmosphere and cause widespread soil erosion. Erosion that exposes deep permafrost soil can in turn redistribute sediment and water across terrestrial and riverine systems. The investigators will take an integrative approach, analyzing paleoclimate fluctuations and watershed topography across space and time, to understand the relationship among climate, permafrost thaw, and soil erosion. Results will improve our ability to predict Arctic system change. Educational outreach to K-12 schools will involve designing hands-on experiments for a truck-based mobile science laboratory that visits schools in and around Pittsburgh, including those serving minorities and under-represented populations. Graduate and undergraduate students supported as part of this study will participate in both research and outreach activities, training a new generation of scientists. The influence of permafrost thaw on soil erosion is largely unquantified to date, as is the dependence of permafrost thaw and soil erosion on topographic attributes, latitudinal location, and climate. This study seeks to: (1) quantify the relationship between soil erosion and permafrost thaw in Arctic environments in the context of paleoclimate fluctuations; (2) explore the dependence of these processes on topographic attributes and latitudinal location; and (3) evaluate and improve the capability of landscape evolution models to simulate erosion in Arctic environments. To accomplish these objectives, the investigators will sample and analyze sediment cores from two clusters of lakes at different latitudinal locations in Alaska. They will integrate topographic analysis and geomorphologic modeling with the chemical signature of aged carbon that is sourced in thawed permafrost and preserved in lake sediments. This approach will improve and guide future modeling efforts to predict the response of the Arctic system to a changing environment.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.