TY - JOUR
T1 - Groundwater discharge impacts marine isotope budgets of Li, Mg, Ca, Sr, and Ba
AU - Mayfield, Kimberley K.
AU - Eisenhauer, Anton
AU - Santiago Ramos, Danielle P.
AU - Higgins, John A.
AU - Horner, Tristan J.
AU - Auro, Maureen
AU - Magna, Tomas
AU - Moosdorf, Nils
AU - Charette, Matthew A.
AU - Gonneea, Meagan Eagle
AU - Brady, Carolyn E.
AU - Komar, Nemanja
AU - Peucker-Ehrenbrink, Bernhard
AU - Paytan, Adina
N1 - Funding Information:
We thank A. Beck, H. Dulai, I. Santos, C. Benitez-Nelson, W. Moore, A. Martin, and H. Windom for sample access. We also thank A. Kolevica, A. Heuser, H. Pryer, J. Middleton, R. Franks, F. Lon, N. Slater, and O. Šebek for their laboratory and analytical assistance. This material is based upon research supported by the National Science Foundation Graduate Research Fellowship Program and an internship provided through the U.S. Geological Survey Graduate Research Internship Program (GRIP). This research was also supported by grants from: the German Academic Exchange Service (DAAD), Northern California chapter of the Achievement Rewards for College Scientists Foundation, International Association of GeoChemistry, Geological Society of America, Northern California Geological Society, Myers Trust, Friends of Long Marine Lab, and UC MEXUS (to K.K.M.). We acknowledge funding from EU-ITN Horizon project 643084 (to A.E. and T.M.) and NSF grant Award Number 1259440 (to A.P.). We also acknowledge funding from NSF grant award number OCE-1736949 (to T.J.H.). Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Groundwater-derived solute fluxes to the ocean have long been assumed static and subordinate to riverine fluxes, if not neglected entirely, in marine isotope budgets. Here we present concentration and isotope data for Li, Mg, Ca, Sr, and Ba in coastal groundwaters to constrain the importance of groundwater discharge in mediating the magnitude and isotopic composition of terrestrially derived solute fluxes to the ocean. Data were extrapolated globally using three independent volumetric estimates of groundwater discharge to coastal waters, from which we estimate that groundwater-derived solute fluxes represent, at a minimum, 5% of riverine fluxes for Li, Mg, Ca, Sr, and Ba. The isotopic compositions of the groundwater-derived Mg, Ca, and Sr fluxes are distinct from global riverine averages, while Li and Ba fluxes are isotopically indistinguishable from rivers. These differences reflect a strong dependence on coastal lithology that should be considered a priority for parameterization in Earth-system models.
AB - Groundwater-derived solute fluxes to the ocean have long been assumed static and subordinate to riverine fluxes, if not neglected entirely, in marine isotope budgets. Here we present concentration and isotope data for Li, Mg, Ca, Sr, and Ba in coastal groundwaters to constrain the importance of groundwater discharge in mediating the magnitude and isotopic composition of terrestrially derived solute fluxes to the ocean. Data were extrapolated globally using three independent volumetric estimates of groundwater discharge to coastal waters, from which we estimate that groundwater-derived solute fluxes represent, at a minimum, 5% of riverine fluxes for Li, Mg, Ca, Sr, and Ba. The isotopic compositions of the groundwater-derived Mg, Ca, and Sr fluxes are distinct from global riverine averages, while Li and Ba fluxes are isotopically indistinguishable from rivers. These differences reflect a strong dependence on coastal lithology that should be considered a priority for parameterization in Earth-system models.
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U2 - 10.1038/s41467-020-20248-3
DO - 10.1038/s41467-020-20248-3
M3 - Article
C2 - 33420047
AN - SCOPUS:85098956482
SN - 2041-1723
VL - 12
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 148
ER -