Collaborative Research: Climate-mediated coupling of hydrology and biogeochemistry in arctic hillslopes

这项研究将评估气候引起的陆地水和养分循环变化如何传播到河流网络。从河流网络向北冰洋输出的水和营养物氮和磷的增加反映了北极地区水和营养物流动模式的变化。气候变化可能会导致这种变化，因为它会导致永久冻土融化释放出营养物质，改变降水模式，增加土壤地球化学反应的速率，或扩大融化土壤的储存能力。这些变化可能会产生深远的影响，因为流动的水将陆地连接到下游的水生生态系统，但连接陆地生态系统和河流网络的流动路径仍然知之甚少。这项研究将侧重于水和溶质在水轨道内的运输和反应，水轨道是连接山坡和溪流的地表和地下流动的线性区域，占北极苔原流域面积的35%。具体目标是：1）量化水和溶解营养物的来源到水轨迹，2）确定积雪、融化深度和风暴特征对水和溶质的储存和运输的影响，3）估计水文学对水轨迹中营养物循环速率的影响。通过水文循环和营养循环之间的联系，这项研究将对预测北极对持续气候变化的反应具有重要意义。此外，研究将增加对山坡在连接陆地生态系统和河流网络方面的作用的了解，有助于填补水文学和地球化学研究的空白。此外，该项目还将培训青年科学家（从小学到研究生）掌握研究水和养分循环对气候变化的反应所用的技能和方法。北极苔原是大多数学生无法进入的，但最容易受到气候变化的影响。该项目将包括本科生和研究生在北极进行研究的机会，在线教学材料的开发，为水文本科课程带来前沿课题和研究方法，以及为K-6学生提供的包含实时现场数据的科学课程。

This research will evaluate how climate-induced changes in water and nutrient cycles on land are propagated to stream networks. Increased export of water and the nutrients nitrogen and phosphorus from river networks to the Arctic Ocean reflects shifts in patterns of water and nutrient movement in the arctic. Changing climate may contribute to such shifts by causing release of nutrients from thawing permafrost, altering precipitation patterns, increasing rates of biogeochemical reactions, or expanding storage capacity in thawed soils. These changes may have far-reaching effects because flowing water connects land to downstream aquatic ecosystems, but the flowpaths connecting terrestrial ecosystems to stream networks remain poorly understood. This research will focus on transport and reaction of water and solutes within water tracks, which are linear regions of surface and subsurface flow that connect hillslopes to streams and account for up to 35% of watershed area in arctic tundra. Specific objectives are to: 1) quantify sources of water and dissolved nutrients to water tracks, 2) identify effects of snow accumulation, thaw depth, and storm characteristics on storage and transport of water and solutes, and 3) estimate the effects of hydrology on rates of nutrient cycling in water tracks. The research will have significance for predicting responses of the arctic to continued climate change through links between hydrologic and nutrient cycles. Further, research will increase understanding of the role of hillslopes in connecting terrestrial ecosystems to stream networks, contributing to filling a research gap in hydrology and biogeochemistry. In addition, this project will train young scientists (grade school through post-graduate) in the skills and methods used to study responses of water and nutrient cycles to climate change. Arctic tundra is inaccessible to most students, yet one of the environments most susceptible to climate-induced changes. This project will include opportunities for undergraduate and graduate students to conduct research in the arctic, development of online instructional materials that bring cutting-edge topics and research methods to undergraduate courses in hydrology, and science lessons for K-6 students that incorporate real-time field data.