EAR-PF: Nitrogen processing in Arctic deltas and role of channel network orientation on flux to the coast

EAR-PF：北极三角洲的氮处理以及河道网络方向对海岸通量的作用

• 批准号: 1952914
• 负责人: Deon Knights
• 金额: $ 17.4万
• 依托单位: Knights, Deon H
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952914&HistoricalAwards=false
• 关键词: EAR; PF; Nitrogen; processing; Arctic

An EAR Postdoctoral Fellowship has been awarded to Dr. Deon Knights to work at West Virginia University to undertake research and educational activities. The research will examine how deltas control the flux of terrestrially derived nitrate to the Arctic Ocean, which contains only 1% of global ocean volume but receives 10% of global river discharge. Consequently, the Arctic Ocean is sensitive to high riverine flux of particulates and nutrients, with implications on global carbon cycling, marine biogeochemistry, and fishery health. Although Arctic deltas may alter the nutrient composition of river water discharging to the ocean, almost all discharge and nutrient data for Arctic rivers are based on measurements upstream of deltas, so the extent to which Arctic deltas alter nutrient fluxes to the ocean remains largely unexplored. Through field measurements, laboratory analyses, and modeling efforts, this research will investigate the capacity of Arctic deltas to remove nitrate that would otherwise discharge to the Arctic Ocean. Findings will give insight into the response of nutrient processing in Arctic deltas in response to potential scenarios of climate change which may be used to improve global climate ocean and atmospheric models. This project relies on new field and remote sensing techniques which will be used as a teaching tool for laboratory and field-based courses at West Virginia University at the undergraduate and graduate level. With assistance from project mentor Professor Christopher Russoniello, Dr. Deon Knights will lead seminars through service organizations at West Virginia University aimed at mentoring and supporting underrepresented students in STEM fields.This proposal aims to use a multi-scale approach to investigate how the morphology of channel networks within Arctic deltas influences nitrate retention and transport under current and future climate scenarios. Three main objectives will be met: (1) measure how the percent nitrate removal within delta channels varies as a function of channel size, (2) quantitatively relate nitrate retention in large Arctic deltas to structural differences between deltas to inform the potential of different Arctic delta types to act as nitrate removal hotspots and (3) explore and compare nitrate retention under future climatic scenarios in the six Arctic Great River deltas. The relationship between stream size and nitrate removal will inform the removal kinetics necessary for upscaling to network-wide models. Morphologic and hydrologic models of the six largest Arctic deltas will be developed based on remotely-sensed surface water observations and delta morphometrics will be used to compare nitrate retention between deltas of differing structures. Except for insight from a few studies, nitrate processing downstream of delta apexes and upstream of the coast are virtually unknown. This study provides a necessary step to understanding nitrate removal across vast remote areas of the Arctic by using remotely-sensed surface water observations coupled with removal kinetics. This project received co-funding from the Hydrologic Science program in the Division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).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.

Deon Knights博士在西弗吉尼亚大学开展研究和教育活动，已授予Deon Knights博士的耳朵博士后奖学金。该研究将研究三角洲如何控制向北极海洋衍生的硝酸盐的通量，北极海洋仅包含全球海洋量的1％，但收到了全球河流排放的10％。因此，北极海洋对颗粒和养分的河流通量很敏感，对全球碳循环，海洋生物地球化学和渔业健康具有影响。尽管北极三角洲可能会改变排放到海洋的河水的营养成分，但北极河流的几乎所有排放和养分数据都是基于三角洲上游的测量值，因此北极三角洲改变了北极三角洲的养分范围，而对海洋的营养磁通量仍然在很大程度上无法解释。通过现场测量，实验室分析和建模工作，这项研究将调查北极三角洲去除硝酸盐的能力，否则将出现到北极海洋。调查结果将洞悉北极三角洲中养分加工的反应，以应对气候变化的潜在情况，这可用于改善全球气候海洋和大气模型。该项目依赖于新的领域和遥感技术，该技术将用作西弗吉尼亚大学本科和研究生层的实验室和现场课程的教学工具。 With assistance from project mentor Professor Christopher Russoniello, Dr. Deon Knights will lead seminars through service organizations at West Virginia University aimed at mentoring and supporting underrepresented students in STEM fields.This proposal aims to use a multi-scale approach to investigate how the morphology of channel networks within Arctic deltas influences nitrate retention and transport under current and future climate scenarios.将实现三个主要目标：（1）衡量如何随着通道大小的函数而变化的硝酸含百分比，（2）定量将大北极三角洲的硝酸盐保留与三角洲之间的结构差异相关联，以使不同北极的六型二氮的现场（3）的现场（3）探索nItrate dextore（3）的现场（3）北极大河三角洲。溪流大小和去除硝酸盐的关系之间的关系将为升级到网络模型所需的去除动力学。将根据远程感知的地表水观测值开发六个最大北极三角洲的形态和水文模型，并将使用三角洲形态计量学来比较不同结构的三角洲之间的硝酸盐保留率。除了一些研究的洞察力外，硝酸盐在三角洲先端和海岸上游的下游几乎是未知的。这项研究提供了必要的步骤，通过使用远程感应的地表水观测以及去除动力学的远程表地表水观测来理解北极广阔区域的硝酸盐去除。该项目获得了地球科学部的水文科学计划的共同资助和启发竞争研究的既定计划（EPSCOR）。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估标准通过评估来支持的。

项目成果

Seasonal and Morphological Controls on Nitrate Retention in Arctic Deltas

• DOI: 10.1029/2022gl102201
• 发表时间: 2023-04
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: D. Knights;A. Piliouras;J. Schwenk;J. Hariharan;Christopher J. Russoniello