Mayfield, K. K., Eisenhauer, A., Santiago-Ramos, D., Higgins, J., Horner, T., Auro, M., Magna, T., Moosdorf, Nils, Charette, M., Eagle-Gonneea, M., Brady, C., Komar, N., Peucker-EHrenbrinck, B. and Payta, A. (2018) The Role of Submarine Groundwater Discharge in Marine Isotope Budgets. [Poster] In: AGU Fall meeting. , December 2018, San Francisco .

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Our understanding of Earth’s surficial biogeochemical evolution is informed by shifts in seawater chemistry, using proxies such as major and trace element concentrations and their isotopic compositions (1). Interpreting the significance of these fluctuations is critically dependent on well-constrained input/output fluxes of solutes to the ocean (1–4). An important source of continentally-derived solutes to the ocean, submarine groundwater discharge (SGD), has remained generally unconstrained or absent from marine mass balance budgets to date. We provide evidence that SGD constitutes a previously under-estimated source of dissolved Li, Mg, Ca, and Ba to the global ocean and further constrain the previously published (5) SGD-derived strontium (Sr) flux. The SGD-derived fluxes of Li+, Mg2+, Ca2+, Sr2+, and Ba2+ to the ocean are 2109, 21012, 21012, 9109, and 2109 moles yr−1, which represent 18%, 33%, 17%, 19%, and 20% of global riverine fluxes, respectively (2, 5–8). The average isotopic compositions of these SGD-derived fluxes are δ7Li = 23.0‰, δ26Mg = −1.34‰, δ44/42Ca = 0.54‰, 87Sr/86Sr = 0.70908, δ88/86Sr = 0.318‰, and δ138/134Ba = 0.11‰. These results highlight the hitherto overlooked role of SGD in marine isotope budgets and we will suggest mechanisms through which SGD should be incorporated into models for global mass balance of these elements in the future.

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Document Type: Conference or Workshop Item (Poster)
Research affiliation: Affiliations > Not ZMT
Biogeochemistry and Geology > Submarine Groundwater Discharge
Date Deposited: 01 Sep 2020 12:53
Last Modified: 01 Oct 2020 13:01

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