Groundwater is a valuable source of freshwater in coastal areas. The groundwater flux in coastal aquifers generally occurs in two processes: seawater intrusion (SWI) and submarine groundwater discharge (SGD). SWI, the subsurface movement of seawater into freshwater aquifers, is a natural phenomenon in coastal areas. As a result of SWI, the salinity of groundwater in the aquifer increases, thereby reducing the availability of freshwater in coastal areas. The total efflux (including fresh groundwater and circulating seawater) to the sea is commonly referred to as SGD. SGD is an important source of freshwater, nutrients, metals, and carbon to the ocean, thereby affecting coastal water quality and ecosystems. The study of the hydrological behaviors of these two processes in coastal aquifers is beneficial for the sustainable management of marine and groundwater resources in coastal areas.Coastal hydrology behaviors in the two processes are not independent but interrelated. Previous studies has shown that increasing fresh groundwater output in coastal aquifers leads to a seaward shift of the SWI. The movement of the SWI also affects the density-driven circulation flux. Moreover, coastal hydrology is associated with ocean forcing such as density gradient, waves, tides, and storm surges. These ocean forcings result in the hysteresis, concealment, and complexity of coastal hydrology, thus making it difficult to forecast and regulate marine and groundwater resources in coastal areas. However, to reduce the difficulty of scientific research, previous work usually generalizes the complex ocean boundaries to a static condition, so that the related conclusions may not be applicable to real-world aquifers. Our understanding of how the multiple ocean forcings influence the coupled mechanism between SWI and SGD accompanied with biogeochemical cycles is still limited.We invite researchers to submit original research work or comprehensive review that advances understanding of the impact of ocean forcing on the interaction of SWI, SGD, and related biogeochemical cycles in coastal aquifers. New methods (e.g., deep learning and big data analysis), new technologies (e.g., electrical resistivity tomography), and new phenomena (e.g., tide-induced salt-fingering flow) are encouraged to achieve innovative findings in complex coastal hydrology. This research topic welcomes the collaboration between biogeochemical oceanographers, coastal hydrogeologists, and microbial ecologists. Potential topics include but are not limited to the following:• Application of new methods and techniques to reveal the interrelated relationship between SWI, SGD, and biogeochemical cycles.• Impact of multiple ocean forcings (e.g., waves, tides, and storm surges) on coastal groundwater and surface water environment.• New phenomena associated with ocean forcing and its implications for coastal hydrology.• Groundwater pollution subjected to the combined effects of multiple ocean forcings and the development of effective protection technologies.• Evolution and mechanism of aquifer parameters due to ocean forcing during the SWI and SGD processes.
Groundwater is a valuable source of freshwater in coastal areas. The groundwater flux in coastal aquifers generally occurs in two processes: seawater intrusion (SWI) and submarine groundwater discharge (SGD). SWI, the subsurface movement of seawater into freshwater aquifers, is a natural phenomenon in coastal areas. As a result of SWI, the salinity of groundwater in the aquifer increases, thereby reducing the availability of freshwater in coastal areas. The total efflux (including fresh groundwater and circulating seawater) to the sea is commonly referred to as SGD. SGD is an important source of freshwater, nutrients, metals, and carbon to the ocean, thereby affecting coastal water quality and ecosystems. The study of the hydrological behaviors of these two processes in coastal aquifers is beneficial for the sustainable management of marine and groundwater resources in coastal areas.Coastal hydrology behaviors in the two processes are not independent but interrelated. Previous studies has shown that increasing fresh groundwater output in coastal aquifers leads to a seaward shift of the SWI. The movement of the SWI also affects the density-driven circulation flux. Moreover, coastal hydrology is associated with ocean forcing such as density gradient, waves, tides, and storm surges. These ocean forcings result in the hysteresis, concealment, and complexity of coastal hydrology, thus making it difficult to forecast and regulate marine and groundwater resources in coastal areas. However, to reduce the difficulty of scientific research, previous work usually generalizes the complex ocean boundaries to a static condition, so that the related conclusions may not be applicable to real-world aquifers. Our understanding of how the multiple ocean forcings influence the coupled mechanism between SWI and SGD accompanied with biogeochemical cycles is still limited.We invite researchers to submit original research work or comprehensive review that advances understanding of the impact of ocean forcing on the interaction of SWI, SGD, and related biogeochemical cycles in coastal aquifers. New methods (e.g., deep learning and big data analysis), new technologies (e.g., electrical resistivity tomography), and new phenomena (e.g., tide-induced salt-fingering flow) are encouraged to achieve innovative findings in complex coastal hydrology. This research topic welcomes the collaboration between biogeochemical oceanographers, coastal hydrogeologists, and microbial ecologists. Potential topics include but are not limited to the following:• Application of new methods and techniques to reveal the interrelated relationship between SWI, SGD, and biogeochemical cycles.• Impact of multiple ocean forcings (e.g., waves, tides, and storm surges) on coastal groundwater and surface water environment.• New phenomena associated with ocean forcing and its implications for coastal hydrology.• Groundwater pollution subjected to the combined effects of multiple ocean forcings and the development of effective protection technologies.• Evolution and mechanism of aquifer parameters due to ocean forcing during the SWI and SGD processes.