Terrestrial Groundwater Drives Coastal Ecosystem Shifts
Abstract Saltwater intrusion (SWI) is accelerating along coastlines globally. This process is visually evident in low‐lying regions as conversion of forests and agricultural fields to saltmarsh. Marsh migration is largely attributed to ocean forcings such as sea‐level rise and storm surges. Here we...
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| Format: | Article |
| Language: | English |
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Wiley
2025-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2025GL116251 |
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| author | D. Pratt J. A. Guimond E. S. Bacmeister S. Fagherazzi H. A. Michael |
| author_facet | D. Pratt J. A. Guimond E. S. Bacmeister S. Fagherazzi H. A. Michael |
| author_sort | D. Pratt |
| collection | DOAJ |
| description | Abstract Saltwater intrusion (SWI) is accelerating along coastlines globally. This process is visually evident in low‐lying regions as conversion of forests and agricultural fields to saltmarsh. Marsh migration is largely attributed to ocean forcings such as sea‐level rise and storm surges. Here we show that terrestrial hydrology may also be a major driver of coastal ecosystem change. Data from the Delmarva Peninsula, USA show that declining upland groundwater head weakens the hydraulic gradient, causing shallow saline groundwater to push inland from coastal marshes. This drives SWI into coastal freshwater forests and farms at magnitudes that can exceed SWI from storms. We show that storm events often contribute to groundwater freshening through rainfall that restores the hydraulic gradient and flushes saline groundwater. Our findings highlight terrestrial groundwater as a primary control on root‐zone saltwater intrusion and suggest that changes in upland head may be a dominant, yet overlooked, driver of marsh migration. |
| format | Article |
| id | doaj-art-b5c3d61dd234425db1be2a0fa2f3ed30 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-b5c3d61dd234425db1be2a0fa2f3ed302025-08-20T03:08:48ZengWileyGeophysical Research Letters0094-82761944-80072025-07-015214n/an/a10.1029/2025GL116251Terrestrial Groundwater Drives Coastal Ecosystem ShiftsD. Pratt0J. A. Guimond1E. S. Bacmeister2S. Fagherazzi3H. A. Michael4Department of Civil, Construction, & Environmental Engineering University of Delaware Newark DE USADepartment of Applied Ocean Physics & Engineering Woods Hole Oceanographic Institution Woods Hole MA USADepartment of Earth Sciences University of Delaware Newark DE USADepartment of Earth & Environment Boston University Boston MA USADepartment of Civil, Construction, & Environmental Engineering University of Delaware Newark DE USAAbstract Saltwater intrusion (SWI) is accelerating along coastlines globally. This process is visually evident in low‐lying regions as conversion of forests and agricultural fields to saltmarsh. Marsh migration is largely attributed to ocean forcings such as sea‐level rise and storm surges. Here we show that terrestrial hydrology may also be a major driver of coastal ecosystem change. Data from the Delmarva Peninsula, USA show that declining upland groundwater head weakens the hydraulic gradient, causing shallow saline groundwater to push inland from coastal marshes. This drives SWI into coastal freshwater forests and farms at magnitudes that can exceed SWI from storms. We show that storm events often contribute to groundwater freshening through rainfall that restores the hydraulic gradient and flushes saline groundwater. Our findings highlight terrestrial groundwater as a primary control on root‐zone saltwater intrusion and suggest that changes in upland head may be a dominant, yet overlooked, driver of marsh migration.https://doi.org/10.1029/2025GL116251seawater intrusionsalt marshescritical zonecoastal processesclimate changesea‐level rise |
| spellingShingle | D. Pratt J. A. Guimond E. S. Bacmeister S. Fagherazzi H. A. Michael Terrestrial Groundwater Drives Coastal Ecosystem Shifts Geophysical Research Letters seawater intrusion salt marshes critical zone coastal processes climate change sea‐level rise |
| title | Terrestrial Groundwater Drives Coastal Ecosystem Shifts |
| title_full | Terrestrial Groundwater Drives Coastal Ecosystem Shifts |
| title_fullStr | Terrestrial Groundwater Drives Coastal Ecosystem Shifts |
| title_full_unstemmed | Terrestrial Groundwater Drives Coastal Ecosystem Shifts |
| title_short | Terrestrial Groundwater Drives Coastal Ecosystem Shifts |
| title_sort | terrestrial groundwater drives coastal ecosystem shifts |
| topic | seawater intrusion salt marshes critical zone coastal processes climate change sea‐level rise |
| url | https://doi.org/10.1029/2025GL116251 |
| work_keys_str_mv | AT dpratt terrestrialgroundwaterdrivescoastalecosystemshifts AT jaguimond terrestrialgroundwaterdrivescoastalecosystemshifts AT esbacmeister terrestrialgroundwaterdrivescoastalecosystemshifts AT sfagherazzi terrestrialgroundwaterdrivescoastalecosystemshifts AT hamichael terrestrialgroundwaterdrivescoastalecosystemshifts |