10.1594/PANGAEA.987321Pérez-Rodríguez, MartaMartaPérez-Rodríguez0000-0001-7139-3049Technische Universität BraunschweigBiester, HaraldHaraldBiesterTechnische Universität BraunschweigWenzhöfer, FrankFrankWenzhöferAlfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, BremerhavenGlud, Ronnie NRonnie NGlud0000-0002-7069-893XUniversity of Southern DenmarkPANGAEA2026Hadal trenchMercuryMethylmercurySouth Georgia IslandSouth Sandwich IslandsSouth Sandwich TrenchEvent labelDATE/TIMELATITUDELONGITUDEELEVATIONDEPTH, sediment/rockDepth, top/minDepth, bottom/maxMercuryMonomethylmercuryCarbon, totalMultiCorerThermal decomposition amalgamation - atomic absorption spectrometer (TDA AAS), Milestone, DMA-80Gas chromatograph - cold vapor atomic fluorescence spectrometery (GC-CVAFS), Brooks Rand, Methylmercury Manual SystemElemental analyser (EA), HEKAtech, Euro EA 3000PS133/1Polarstern2022-11-03T17:46:18/2022-11-09T04:52:09Dataset10.1029/2025GB008767339 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)Sediment cores for total mercury (Hg), monomethylmercury (MMHg), and total carbon (TC) were collected in the Southern Ocean and the South Sandwich Trench between 3 and 9 November 2022 during the PS133/1 expedition. Sampling depths ranged from approximately 3700 to 8000 m, using a multicorer (MUC) system. Total Hg concentrations were determined by thermal decomposition, amalgamation, and atomic absorption spectrophotometry (TDA–AAS) using a DMA-80 Direct Mercury Analyzer (Milestone). Monomethylmercury (MMHg) was analyzed by gas chromatography–cold vapor atomic fluorescence spectrometry (GC–CVAFS) following ethylation with sodium tetraethylborate on a KOH-digested aliquot, using a Brooks Rand manual system. Total carbon (TC) was measured using an elemental analyzer Euro EA 3000 (HEKAtech GmbH).-39.92533-24.83905-56.24056-51.30116Danish National Research Foundationhttps://doi.org/10.13039/501100001732DNRF145Danish Center for Hadal Research, HADALGerman Research Foundationhttps://doi.org/10.13039/501100001659528941462Controls of Primary Production on Southern Ocean Mercury Cycling (COPPSOM)German Research Foundationhttps://doi.org/10.13039/501100001659GPF 20-1_053Island Impact: Understanding the Regional Impact of South Georgia on Southern ACC Biogeochemistry and Ecosystem FunctionGerman Research Foundationhttps://doi.org/10.13039/501100001659GPF 20-2_024South Polar Carbon: Benthic Carbon Mineralization and Preservation in Southern Ocean Bathyal, Abyssal and Hadal Sediments