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We report marine dissolved organic carbon (DOC) concentrations, and DOC Δ¹⁴C and δ¹³C values in seawater collected from the Southern Ocean and eastern Pacific GOSHIP cruise P18 in 2016/2017. The aging of¹⁴C in DOC in circumpolar deep water northward from 69°S to 20°N was similar to that measured in dissolved inorganic carbon in the same samples, indicating that the transport of deep waters northward is the primary control of¹⁴C in DIC and DOC. Low DOC ∆¹⁴C and δ¹³C measurements between 1,200 and 3,400 m depth may be evidence of a source of DOC produced in nearby hydrothermal ridge systems (East Pacific Rise).

We report marine dissolved organic carbon (DOC) concentrations, and DOC ∆¹⁴C and δ¹³C values in seawater collected from the central Pacific. Surface ∆¹⁴C values are low in equatorial and polar regions where upwelling occurs and high in subtropical regions dominated by downwelling. A core feature of these data is that¹⁴C aging of DOC (682 ± 86¹⁴C years) and dissolved inorganic carbon (643 ± 40¹⁴C years) in Antarctic Bottom Water between 54.0°S and 53.5°N are similar. These estimates of aging are minimum values due to mixing with deep waters. We also observe minimum ∆¹⁴C values (−550‰ to −570‰) between the depths of 2,000 and 3,500 m in the North Pacific, though the source of the low values cannot be determined at this time.