Dataset: Barium stable isotopes from seawater and sediment core samples collected during the R/V Falkor 160115 and R/V Thomas G. Thompson TT013 cruises in the Equatorial Pacific in 2016 and 1992

Pore-water sampling. Pore-waters were extracted from the upper N 30 cm of sediments along an Equatorial Pacific transect at 14O”W, from 12% to 9”N, at a water depth of approximately 4300 m (JGOFS-EqPac, Leg TTO13, November 1993); sample locations and water depths are listed in Table 1. Sediments were collected using a multi-corer. All cores had a well-preserved sediment-water interface with an occasional fluff of phyto-detritus, overlain by clear bottom seawater. Thus, sediment disturbance seems to have been minimal during the coring and recovery operations. Sub-cores were transferred within minutes of arrival on board into a cold room of 2”C, where they were sectioned into 0.5, 1 and 2 cm intervals in a nitrogen atmosphere glove bag and centrifuged at 700010,000 rpm. The pore-waters obtained were passed through pre-washed Nucleopore 0.45 km filters in a nitrogen atmosphere, acidified to a pH of 2 with distilled HNO3, and stored in acid-cleaned polypropylene bottles at 2°C. The pore-water sampling procedure was usually completed within less than 24 h of core recovery. Two cores from each latitude were processed in order to identify spatial variability. All the equipment used for sample processing was thoroughly pre-cleaned with 8 N HNO3, in order to reduce the blank.

Pore fluid sampling methods: Paytan et al., 1996 (see related publications). 

Barite and seawater sampling. Dissolved seawater samples were collected on the ProteOMZ FK150116 expedition (Jan-Feb 2016) using a 12-bottle trace metal clean rosette equipped with 8 L X-Niskin bottles (Ocean Test Equipment), a titanium frame, and a Kevlar cable, as described in (Cutter and Bruland 2012). Seawater from the Go-Flo bottles was subsampled in a trace metal clean plastic "bubble" equipped with HEPA filters providing positive air pressure. Dissolved Ba subsamples were filtered using a 142 mm polycarbonate plastic sandwich filter (Geotech Environmental Equipment) equipped with a 0.2 um Supor membrane filter (Pall Corporation) and stored until analysis in the laboratory in a 60 mL HDPE bottle (Nalgene) that had been soaked for ~1 week in Citranox, an acidic detergent, rinsed with Milli-Q water (Millipore), soaked for ~2 weeks in 10% trace metal grade HCl (Optima), and rinsed with lightly acidic Milli-Q water (<0.1% HCl). Samples were stored at 4⁰C.