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dc.contributor.authorArgentino, Claudio
dc.contributor.authorKalenitchenko, Dimitri
dc.contributor.authorLindgren, Johan Matteus
dc.contributor.authorPanieri, Giuliana
dc.date.accessioned2023-04-12T10:52:58Z
dc.date.available2023-04-12T10:52:58Z
dc.date.issued2023-04-03
dc.description.abstractThe conventional use of mercuric chloride (HgCl<sub>2</sub>) as an antimicrobial agent in water samples for dissolved inorganic carbon (DIC) analysis poses health and environmental risks related to its handling and disposal. Even though there is an increasing interest in quantifying pore water DIC contribution to the ocean carbon cycle and deep-sea acidification, the paucity of comparative studies on marine pore waters prevents the modification of sampling protocols and HgCl<sub>2</sub> still remains widely used. Here, we compared DIC concentrations and δ<sup>13C</sup>DIC composition in pore water samples from methane seepage areas in the Barents Sea and offshore N. Svalbard. Samples were extracted using 0.15 μm rhizon filters and split into two aliquots with 2–3 replicates each. Only one aliquot was treated with 10 μL saturated HgCl<sub>2(aq)</sub> and all samples were stored in the dark at 4 ◦C, prior to measurements ~30 days later. The samples yielded extremely wide ranges of DIC concentrations, from 1.8 mM to 20.1 mM, and δ<sup>13C</sup>DIC values, from − 36.0‰ to − 1.6‰ (VPDB), due to variable contributions of methane-derived DIC to the pore water system. Overall, we obtained lower [DIC] (77% samples; N = 26) and heavier δ<sup>13</sup>C values (79% samples; N = 42) in Hg-treated samples. Isotopic and concentration differences larger than the uncertainties on the mean of replicated measurements (±0.2–0.5‰; ± 0.5 mM) and analytical precision (0.15‰; 0.71 mM) represent the 38% and 19% of the samples, with offsets of up to 7.4‰ and 1.9 mM, respectively. The largest offsets are in agreement with our CO<sub>2</sub>-degassing model, suggesting an interaction between mercuric chloride and dissolved hydrogen sulfide released by sulfate-driven methane oxidation. We therefore caution against further use of HgCl<sub>2</sub> for DIC studies of marine pore waters from cold seeps.en_US
dc.identifier.citationArgentino C, Kalenitchenko D, Lindgren M, Panieri G. HgCl<sub>2</sub> addition to pore water samples from cold seeps can affect the geochemistry of dissolved inorganic carbon ([DIC], δ<sup>13C</sup>DIC). Marine Chemistry. 2023;251en_US
dc.identifier.cristinIDFRIDAID 2139836
dc.identifier.doi10.1016/j.marchem.2023.104236
dc.identifier.issn0304-4203
dc.identifier.issn1872-7581
dc.identifier.urihttps://hdl.handle.net/10037/28954
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalMarine Chemistry
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2023 The Author(s)en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0en_US
dc.rightsAttribution 4.0 International (CC BY 4.0)en_US
dc.titleHgCl2 addition to pore water samples from cold seeps can affect the geochemistry of dissolved inorganic carbon ([DIC], δ13CDIC)en_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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Attribution 4.0 International (CC BY 4.0)
Except where otherwise noted, this item's license is described as Attribution 4.0 International (CC BY 4.0)