Solid phase sediment and pore water data (Al, Fe, K, nitrate, organic carbon) from the Amazon continental shelf (cruise M147)

Sediment and pore water samples were collected during the M147 cruise of Research Vessel Meteor in April and May 2018. Additional sediment samples (GeoB 4417-5 and GeoB 4409-2) were collected during the M38-2 cruise in March 1997. Total element concentrations (Fe, Al, K) of the solid phase were measured after acid digestion (HF, HNO3 and HClO4) by inductively coupled plasma optical emission spectrometry (Varian ICP 720-ES). Solid phase iron speciation data were measured following single step sodium dithionite extraction (FeD) or sequential Fe extraction (FeAc, FeDith, FeOxal) by inductively coupled plasma optical emission spectrometry (Varian ICP 720-ES). Solid phase pyrite concentrations (FePy) were calculated stoichiometrically from photometrically measured S2- released via chromium(II) chloride reduction. Total organic carbon (TOC) of the sediment samples was measured in an Elemental Analyzer (Euro EA). Prior to analysis carbon bound to carbonate minerals was removed by leaching the sediment with 0.25 N HCl. Pore water nitrate concentrations were measured on board with a SEAL QuAAtro continuous flow auto analyzer. Pore water samples for dissolved element analysis were acidified with HCl to pH < 2 after sampling. Depending on the concentration range, pore water K and Fe was measured by inductively coupled plasma optical emission spectrometry (Varian 720 ES) or inductively coupled plasma mass spectrometry (Agilent 7500).