RUI: Collaborative Research: How does changing glacial coverage affect the transport and fate of DOM and nutrients in coastal watersheds on the Gulf of Alaska?

沿阿拉斯加湾（GOA）的冰川变薄速率通常高达6-8米/年。这种快速的冰川消退对沿海流域水文学和生物地球化学具有重要意义，因为冰川冰的损失减少了水文储量，并通过使新的土地暴露于初级演替过程而急剧改变了流域土地覆盖。冰川消融后陆地和水生生态系统的生态发展已经得到了广泛的探讨，然而，关于土地覆盖变化如何改变物质进入和通过河网进入沿海河口的研究却很少。该项目将通过评估冰川消退如何改变阿拉斯加东南部沿海流域的水文和生物地球化学过程来填补这一关键的知识空白。特别是，我们的研究将全面了解正在进行的冰川退缩如何改变河流营养物质和溶解有机物（DOM）的物种形成、命运和运输。每周和暴雨取样结合连续排放测量，将提供配对冰川和非冰川流域之间养分和DOM产量的第一次详细和完整的比较。对流量、氧气、温度和浊度的连续测量将用于量化冰川融水对水文和物理参数的影响。实验方法（实验室和现场规模）结合纵向调查和河流示踪剂将用于阐明下游运输过程中营养物质和DOM的命运。最后，还将利用纵向天气学和源采样来获取河流中营养物质和碳的主要景观来源。最终，项目结果将提供新的见解，以了解沿果阿地区和其他冰川覆盖的沿海地区的冰川衰退如何改变有机和无机营养物质的陆地到海洋的通量。该项目将为阿拉斯加东南大学（UAS）的本科生提供实验室和实地研究的机会，这是一所规模较小的本科大学，阿拉斯加本土学生的入学率很高（16%）。此外，该项目还将培养1名研究生和1名博士后研究员。本研究项目将整合本科生，为学生和研究人员合作研究沿海流域气候、土地覆盖变化、水文和生物地球化学过程之间的重要联系提供一个框架。此外，该项目将加强美国科学院的科学家和门登霍尔冰川游客中心的博物学家之间现有的合作伙伴关系，他们将共同努力，将项目结果纳入中心的解释性展示。门登霍尔冰川是美国访问量最大的冰川，每年接待超过30万游客，因此为公众宣传和教育提供了一个独特而有效的机会。最后，一位来自弗吉尼亚州蒙哥马利县的科学教育家将在一个夏天参加实地工作。科学教育工作者将把他们的经验带到当地的教室，并与他们的同龄人分享他们的经验。

Glacier thinning rates along the Gulf of Alaska (GOA) are commonly as high as 6-8 m yr-1. This rapid glacial recession has important implications for coastal watershed hydrology and biogeochemistry because the loss of glacier ice decreases hydrologic storage and dramatically alters catchment landcover by exposing new land to the process of primary succession. The ecological development of terrestrial and aquatic ecosystems following deglaciation has been explored extensively, however there has been very little research on how landcover change will alter material delivery into and through the river network to coastal estuaries. This project will fill this critical knowledge gap by evaluating how glacial recession is altering hydrologic and biogeochemical processes in coastal watersheds in southeastern Alaska. In particular, our research will develop a comprehensive understanding of how the speciation, fate and transport of riverine nutrients and dissolved organic matter (DOM) will be altered by ongoing glacial retreat. Weekly and storm sampling combined with continuous discharge measurements will provide the first detailed and complete comparison of nutrient and DOM yields between paired glacial and non-glacial watersheds. Continuous measurements of discharge, oxygen, temperature and turbidity will be used to quantify the effects of glacial meltwater on hydrologic and physical parameters. Experimental approaches (laboratory and field-scale) combined with longitudinal surveys and stream tracers will be used to elucidate the fate of nutrients and DOM during downstream transport. Finally, longitudinal synoptics and source sampling will also be used to access the primary landscape sources of nutrients and carbon to the stream. Ultimately, project findings will provide new insights into how land-to-ocean fluxes of organic and inorganic nutrients are being altered by glacial recession along the GOA and in other glaciated coastal regions.The project will provide laboratory and field research opportunities for undergraduates at the University of Alaska Southeast (UAS), a small, undergraduate university with a high (16%) enrollment of native Alaskan students. Additionally, the project will provide training for one graduate student and one post-doctoral researcher. The integration of undergraduate students in this research project will provide a framework for students and researchers to cooperatively investigate important linkages among climate, landcover change, and hydrological and biogeochemical processes in coastal watersheds. In addition, the project will strengthen an existing partnership between scientists at UAS and naturalists at the Mendenhall Glacier Visitor Center who will work collaboratively to incorporate project results into an interpretive display at the center. The Mendenhall Glacier is the most visited glacier in the United States and hosts over 300,000 visitors each year and thus provides a unique and effective opportunity for public outreach and education related to the findings of this project. Finally, a science educator from Montgomery County, VA will partake in field work during one of the summers. The science educator will bring their experience into the local classrooms and share their experience with their peers.