| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | April 8, 2020 |
| Latest Amendment Date: | July 12, 2021 |
| Award Number: | 1952627 |
| Award Instrument: | Fellowship Award |
| Program Manager: |
Aisha Morris
armorris@nsf.gov (703)292-7081 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | July 1, 2020 |
| End Date: | December 31, 2022 (Estimated) |
| Total Intended Award Amount: | $174,000.00 |
| Total Awarded Amount to Date: | $217,500.00 |
| Funds Obligated to Date: |
FY 2021 = $43,500.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
Barrington NH US 03825-0000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Halifax CA |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Hydrologic Sciences, Postdoctoral Fellowships |
| Primary Program Source: |
01002122DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Dr. Julia A. Guimond has been granted an NSF EAR Postdoctoral Fellowship to study coastal high-latitude hydrology at Dalhousie University in collaboration with the Water Cycle Branch of the U.S. Geological Survey. Through field data collection and numerical modeling analyses, this research will investigate interactions between high-latitude groundwater reservoirs and the coastal ocean. In the Arctic and subarctic, water flow patterns and storage are rapidly changing due to pronounced atmospheric warming. Alterations in groundwater flow and aquifer-ocean connectivity due to permafrost thaw will have profound impacts on global climate and high-latitude coastal zones, including marine and freshwater resources. Coastal systems are particularly vulnerable to climate-induced change due to changes in sea level and sea ice in addition to permafrost distribution. The primary goal of this research is to identify the mechanisms mediating aquifer-ocean exchange in permafrost regions to better understand how these processes will be modified under changing climatic conditions. Results from this study will help inform water and marine-resource management and climate adaptation strategies for Indigenous communities and northern governments and identify where coastal water resources are most vulnerable to climate change-induced contamination mobilization.
The integrated field and modeling study undertaken by Dr. Guimond aims to unravel the feedbacks between climate change and aquifer-ocean exchange in high-latitude permafrost regions. Results will identify the factors influencing Arctic and subarctic submarine groundwater discharge and saltwater intrusion and characterize the spatial and temporal scales over which they occur, improving predictive capacity under changing climatic and hydrologic conditions. Results of this study will enhance our knowledge of 1) present-day rates of groundwater discharge to the ocean, 2) processes controlling aquifer-ocean exchange in permafrost-bound regions, and 3) aquifer-ocean exchange response to climate-induced change (e.g. permafrost thaw). The field portion of this study will be conducted in Sanikiluaq, Canada and in Cambridge Fjord, Baffin Island, Canada. A suite of hydrogeological and geochemical field tools and methods will be used to assess present-day conditions, such as conductivity, temperature, depth loggers and radium isotopes. Also, numerical, hydrological models with freeze-thaw, coupled surface-subsurface processes, and variable density capabilities will be used to expand understanding in space and time. The processes and mechanisms elucidated through this integrated study will promote development of new conceptual and quantitative models that predict feedbacks between climate-change driven permafrost thaw and land-sea water exchange in high-latitude coastal systems that can inform groundwater management policies. The PI will help develop a cyber-seminar series as educational outreach to the broader geoscience community on climate-change driven issues in Arctic and subarctic regions. The Hydrological Science program in the Earth Science division provided co-funding for this fellowship.
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.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Along Earth′s coldest coastlines, permafrost, ground below zero degrees Celsius for two or more consecutive years, mediates the movement of groundwater in the subsurface. Permafrost limits how deep groundwater can flow and how much groundwater exchanges with surface water reservoirs such as the ocean. Because the Arctic is one of the fastest warming regions in the world, reduction of permafrost is a growing threat. Arctic coastlines have the additional stressor of sea-level rise, which inundates and salinizes terrestrial areas. Knowledge of how these stressors (e.g., warming and sea-level rise) impact the exchange of groundwater between terrestrial ecosystems and the ocean is limited. Groundwater in these regions often has high concentrations of solutes such as carbon and nitrogen and thus may be an important source of carbon and nutrients to coastal marine ecosystems.
The goal of this project was to better understand how warming and sea-level rise impact the movement of groundwater and its exchange with the ocean along Arctic coastlines. To do this, we developed a model that allowed us to better simulate the movement of freshwater and saltwater in the subsurface in environments that undergo freezing and thawing. We found that the movement of saltwater into terrestrial environments can impact the spatial extent of permafrost. Saltwater has a lower freezing temperature than freshwater. When saltwater is pushed onto land (e.g., from sea-level rise), its presence decreases the freezing temperature of the ground and can trigger permafrost thaw.
Results from these numerical models also suggest that warming and sea-level rise will change the magnitude of water exchanged between groundwater reservoirs and the ocean with implications for the exchange of associated solutes. However, the magnitude of change depends on a combination of the rate of warming and the rate of sea-level rise. In regions of high sea-level rise but relatively lower warming rates such as the north slope of Alaska, groundwater discharge to the ocean may decrease over the next century. However, areas with low sea-level rise and high warming rates (e.g., Nunavut, Canada) may see an increase in groundwater flow and discharge to the coastal ocean.
Upon completion of these numerical studies, coastal groundwater levels and fluxes were measured in the field along Alaska′s Beaufort Sea coast. Results suggest that wind plays a large role in surface water level and groundwater exchange with the coastal ocean.
This project has provided new understanding of groundwater flow along Arctic coastlines and how it may change with climate change. One of the most significant contributions is a greater understanding of links between sea-level rise and enhanced permafrost thaw with potential implications for coastal infrastructure, ecosystem function, and carbon mobilization.
Results from this study have been shared with the scientific community through conference presentations and with an Inuit community through presentations and one-page descriptions.
Last Modified: 02/08/2023
Modified by: Julia Guimond
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