ORCID Profile
0000-0001-5055-0180
Current Organisation
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
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Publisher: American Geophysical Union (AGU)
Date: 04-2009
DOI: 10.1029/2008GC002292
Publisher: Copernicus GmbH
Date: 10-2023
DOI: 10.5194/BG-2022-148
Abstract: Abstract. For millennia humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is, therefore, complicated by both natural and human-driven environmental changes at the land-sea interface. In particular, ongoing sea level rise, warming and deoxygenation might exacerbate such perturbations. In this context, an improved understanding of the nature and variability of groundwater fluxes across the land-sea continuum is timely, yet remains out of reach. The flow of terrestrial groundwater across the coastal transition zone as well as the extent of freshened groundwater below the present-day seafloor are receiving increased attention in marine and coastal sciences because they likely represent a significant, yet highly uncertain component of (bio)geochemical budgets, and because of the emerging interest in the potential use of offshore freshened groundwater as a resource. At the same time, “reverse” groundwater flux from offshore to onshore is of prevalent socio-economic interest as terrestrial groundwater resources are continuously pressured by overpumping and seawater intrusion in many coastal regions worldwide. An accurate assessment of the land-ocean connectivity through groundwater and its potential responses to future anthropogenic activities and climate change will require a multidisciplinary approach combining the expertise of geophysicists, hydrogeologists, (bio)geochemists and modellers. Such joint activities will lay the scientific basis for better understanding the role of groundwater in societal-relevant issues such as climate change, pollution and the environmental status of the coastal oceans within the framework of the United Nations Sustainable Development Goals. Here, we present our perspectives on future research directions to better understand land-ocean connectivity through groundwater, including the spatial distributions of the essential hydrogeological parameters, highlighting technical and scientific developments, and briefly discussing its societal relevance in rapidly changing coastal oceans.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Authorea, Inc.
Date: 23-07-2023
DOI: 10.22541/ESSOAR.169008320.06546433/V1
Abstract: Although marine controlled source electromagnetic (CSEM) methods are effective for investigating offshore freshened groundwater (OFG) systems, interpreting the spatial extent and salinity of OFG remains challenging. Integrating CSEM resistivity models with information on sub-surface properties, such as host-rock porosity, allows for estimates of pore-water salinity. However, deterministic inversion approaches pose challenges in quantitatively analyzing these estimates as they provide only one best-fit model with no associated estimate of model parameter uncertainty. To address this limitation, we employ a trans-dimensional Markov-Chain Monte-Carlo inversion on marine CSEM data, under the assumption of horizontal stratification, collected from the Canterbury Bight, New Zealand. We integrate the resulting posterior distributions of electrical resistivity with borehole and seismic reflection data to quantify pore-water salinity with uncertainty estimates. The results reveal a low-salinity groundwater body in the center of the survey area at varying depths, hosted by consecutive silty- and fine-sand layers approximately 20 to 60 km from the coast. These observations support the previous study’s results obtained through deterministic 2-D inversion and suggest freshening of the OFG body closer to the shore within a permeable, coarse-sand layer 40 to 150 m beneath the seafloor. This implies a potential active connection between the OFG body and the terrestrial groundwater system. We demonstrate how the Bayesian approach constrains the uncertainties in resistivity models and subsequently in pore-water salinity estimates. Our findings highlight the potential of Bayesian inversions in enhancing our understanding of OFG systems, providing crucial boundary conditions for hydrogeological modeling and sustainable water resource development.
Publisher: Copernicus GmbH
Date: 10-02-2023
Abstract: Abstract. For millennia, humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is, therefore, complicated by both natural and human-driven environmental changes at the land–sea interface. In particular, ongoing sea-level rise, warming and deoxygenation might exacerbate such perturbations. In this context, an improved understanding of the nature and variability of groundwater fluxes across the land–sea continuum is timely yet remains out of reach. The flow of terrestrial groundwater across the coastal transition zone and the extent of freshened groundwater below the present-day seafloor are receiving increased attention in marine and coastal sciences because they likely represent a significant yet highly uncertain component of (bio)geochemical budgets and because of the emerging interest in the potential use of offshore freshened groundwater as a resource. At the same time, “reverse” groundwater flux from offshore to onshore is of prevalent socio-economic interest, as terrestrial groundwater resources are continuously pressured by over-pumping and seawater intrusion in many coastal regions worldwide. An accurate assessment of the land–ocean connectivity through groundwater and its potential responses to future anthropogenic activities and climate change will require a multidisciplinary approach combining the expertise of geophysicists, hydrogeologists, (bio)geochemists and modellers. Such joint activities will lay the scientific basis for better understanding the role of groundwater in societally relevant issues such as climate change, pollution and the environmental status of the coastal oceans within the framework of the United Nations Sustainable Development Goals. Here, we present our perspectives on future research directions to better understand land–ocean connectivity through groundwater, including the spatial distributions of the essential hydrogeological parameters, highlighting technical and scientific developments and briefly discussing the societal relevance of that connectivity in rapidly changing coastal oceans.
Location: No location found
Location: Brazil
No related grants have been discovered for Christian Berndt.