Dataset: Concentrations and radiocarbon signatures of SPE-DOC extracted from seawater samples on GO-SHIP cruises P16N, P18, and IO7N in the North Pacific, Eastern Pacific, and Western Indian Oceans

Seawater was sampled from Niskin bottles on GO-SHIP P16N, P18, and IO7N cruises using acid-cleaned silicone tubing (soaked in 10% HCl). Seawater from depths shallower than 200m was filtered using pre-combusted Whatman GF/F 0.7 micrometer (µm) filters. Solid-phase extracted dissolved organic carbon (SPE-DOC) was extracted using Bond Elut PPL 1 gram resins and established protocols (Dittmar et al., 2008). On P18 and IO7N, SPE-DOC was extracted on the vessel. Seawater from P16N was stored frozen until processing at the laboratory at University of California, Irvine (UCI).

SPE-DOC elutions in methanol follow established protocols (Dittmar et al., 2008), that have been slightly adapted to increase carbon yields (Lewis et al., 2020). After elution, SPE-DOC was dried using a centrifugal evaporator, sealed on a vacuum line, and combusted at 850C for 2 hours. SPE-DOC concentrations were measured manometrically on a vacuum line, and radiocarbon measurements were performed at the Keck Carbon Cycle Accelerator Mass Spectrometry Lab at the University of California, Irvine.

Refer to "Related Datasets" for the related Niskin bottle data from these GO-SHIP cruises. Seawater from multiple Niskin bottles was integrated for solid-phase extraction. The stations and depth ranges listed (between the minimum and maximum depths) refer to the Niskin bottles from the GO-SHIP bottle file in related datasets.