Dataset is comprised of stable isotopes (oxygen and carbon) of benthic foraminifera from sediments from International Ocean Discovery Program (IODP) Expedition 382, Site U1534, South Falkland Sediment Drift. 53.18967 S, 58.76083 W (605 m water depth). The sediment cores were collected from 3 holes using the advanced piston corer onboard RV Joides Resolution from site U1534 between 29/03/2019 and 02/04/2019. Suitable specimens of benthic foraminifera were identified and picked from the >250 micron size fraction sediment at BAS between March 2020 and May 2021. Isotope analysis was carried out between March-August 2021. The data were collected as part of a project aiming to investigate the sensitivity of the Atlantic Meridional Overturning Circulation to variability in Pacific-Atlantic connectivity via the ''cold water route''. Dr Victoria Louise Peck was the principle investigator for this project. Funding provided by NERC UKIODP moratorium grant NE/T010908/1 and analytical support from NEIF steering committee application IP-1950-119.

Glacier meltwater supplies a significant amount of silicon (Si) and iron (Fe) sourced from weathered bedrock to downstream ecosystems. However, the extent to which these essential nutrients reach the ocean is regulated by the nature of the benthic cycling of dissolved Si and Fe within fjord systems, given the rapid deposition of reactive particulate fractions at fjord heads. The dataset is used to examine the benthic cycling of the two nutrients at Patagonian fjord heads through geochemical analyses of sediment pore waters and reaction-transport modeling for Si. The dataset contains: (i) pore water redox-sensitive nitrate (NO3-) and dissolved manganese (DMn) concentration data, nutrient dissolved silicon (DSi) and iron (DFe) concentration and isotope data (delta30 Si, delta56 Fe); (ii) mild alkaline leachable (Si-Alk) and acid leachable (Si-HCl) sediment silica content and isotope data; and (iii) reaction transport model output for the benthic cycling of Si. The pore water and sediment samples were collected from four sites: SJ (48.228o S, 73.502o W, 106 m depth), SH (47.679 S, 73.715 W, 203 m depth), SP (48.179 S, 73.347 W, 248 m depth) and SB (47.787 S, 73.610 W, 151 m depth) in the Baker-Martinez Fjord Complex on the research vessel Sur-Austral in February 2017. Funded by NERC-CONICYT grant NE/P003133/1-PII20150106.