Submarine groundwater discharge (SGD) and various solutes released with SGD have received particular attention recently; however, understanding of the impact of SGD on trace metal fluxes in the coastal ocean is limited. To understand the contribution of SGD to the coastal Hg input, the Hg mass fluxes associated with SGD were estimated from Hampyeong Bay, a coastal embayment in the Yellow Sea. Hg concentrations in filtered groundwater and seawater ranged from 1.3 to 4.4pM and from 0.83 to 2.0pM, respectively, and Hg concentrations in unfiltered seawater ranged from 1.7 to 4.6pM. The Hg flux estimation showed that SGD was the prime input source of Hg in the bay (18±12molyr(-1)), contributing 65% of the total input. Atmospheric deposition was the second dominant source of Hg (8.5±2.7molyr(-1)), contributing 31% to the total input. The results of the current study suggest that SGD can be a significant source of Hg in estuarine/coastal systems; therefore, estimating the coastal mass budgets of Hg must include SGD as a prime source of Hg.
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http://dx.doi.org/10.1016/j.chemosphere.2012.11.052 | DOI Listing |
Sci Adv
January 2025
Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden.
Coastal ecosystems play a major role in marine carbon budgets, but substantial uncertainties remain in the sources and fluxes of coastal carbon dioxide (CO). Here, we assess when, where, and how submarine groundwater discharge (SGD) releases CO to shallow coastal ecosystems. Time-series observations of dissolved CO and radon (Rn, a natural groundwater tracer) across 40 coastal systems from 14 countries revealed large SGD-derived CO fluxes.
View Article and Find Full Text PDFMar Pollut Bull
December 2024
Department of Environmental Science, American University, 4400 Massachusetts Ave., NW, Washington, DC 20016, United States of America; Department of Environmental Science and Studies, Washington College, Chestertown, MD 21620, United States of America.
Saipan, the largest and most populated island of the Commonwealth of the Northern Mariana Islands, has coastal areas with high submarine groundwater discharge (SGD) and heavy metal pollution of sediments. Here, we measured metal concentrations in coastal Saipan groundwater and surface water and explored spatial correlations with pollution sources. Concentrations of Cd, Pb, Cu, and Zn were highest in inland wells, with 3 wells exceeding USEPA guidelines for Cu or Pb.
View Article and Find Full Text PDFEnviron Microbiol
December 2024
Department of Earth System Science, Stanford University, Stanford, California, USA.
Subterranean estuaries (STEs) are critical ecosystems at the interface of meteoric groundwater and subsurface seawater that are threatened by sea level rise. To characterize the influence of tides and waves on the STE microbial community, we collected porewater samples from a high-energy beach STE at Stinson Beach, California, USA, over the two-week neap-spring tidal transition during both a wet and dry season. The microbial community, analyzed by 16S rRNA gene (V4) amplicon sequencing, clustered according to consistent physicochemical features found within STEs.
View Article and Find Full Text PDFIsotopes Environ Health Stud
November 2024
Geochemistry & Isotope Biogeochemistry Group, Leibniz Institute for Baltic Sea Research, Rostock, Germany.
The impact of freshwater sources like surface river runoff and submarine groundwater discharge (SGD) on coastal waters is currently in focus of intense debate and investigation. One of the ongoing challenges in SGD research is the characterization and quantification of the freshwater endmember contributions to the subsurface mixing zone and their influences on element balance and biogeochemical transformations. Long-term investigations of the sediment porewater composition provide characterization and understanding of the physical, hydrological and biogeochemical processes controlling the substance exchanges.
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