Spatial and seasonal fluctuations in fresh submarine groundwater discharge revealed by marine continuous resistivity profiling
Tur-Piedra, Jose (Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental)
Ledo, Juanjo (Universidad Complutense de Madrid.Departamento de Física de la Tierra y Astrofísica)
Diego-Feliu, Marc (Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental)
Queralt, Pilar (Universitat de Barcelona. Departament de Dinàmica de la Terra i de l'Oceà)
Marcuello, Álex (Universitat de Barcelona. Departament de Dinàmica de la Terra i de l'Oceà)
Rodellas, Valentí (Universitat Autònoma de Barcelona. Departament de Física)
Folch, Albert (Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental)

Date:	2024
Abstract:	Submarine Groundwater Discharge (SGD) is a major pathway for the discharge of fresh and saline groundwater and associated dissolved compounds into marine environments. However, assessing SGD processes in coastal aquifers is challenging due to inaccessibility, dynamic conditions, complex subsurface geology, and the need for long-term monitoring to capture temporal and spatial variations in SGD rates accurately. This study employs marine continuous resistivity profiling (MCRP) as a main method to assess the presence of freshwater or brackish SGD offshore and to examine its potential seasonal variations. The method has been applied in the coastal alluvial aquifer of Maresme (Spain) and validated with other methods to trace SGD, including salinity profiles, Ra isotopes, and piezometric levels. Several MCRP transects of 700 m long, perpendicular to the coastline, were performed in a coastal marine area to obtain electrical resistivity data of the seabed covering an area of 3 km2. The data was acquired in two field campaigns with contrasting hydrological conditions (dry and wet seasons). The MCRP results allow the identification of areas of fresh SGD in marine sediments, with a clear seasonal variability that indicates a higher discharge of fresh groundwater in the wet season.
Grants:	Agencia Estatal de Investigación PID2022-140862OB-C21 Generalitat de Catalunya 2022FI_B_00601 Agencia Estatal de Investigación JDC2022-050316-I
Note:	Altres ajuts: Agència Catalana de l'Aigua (grant no. ACA210/18/00007); Agència de Gestió d'Ajuts Universitaris i de Recerca SGR-609
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Marine geophysics ; SGD ; Seasonality ; Mediterranean sea ; Electrical resistivity tomography ; Coastal groundwater
Published in:	Scientific reports, Vol. 14 (October 2024) , art. 24854, ISSN 2045-2322

DOI: 10.1038/s41598-024-75984-z
PMID: 39438573

13 p, 2.7 MB

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