Radiocarbon in dissolved organic and inorganic carbon of the Arctic Ocean

Dissolved organic carbon (DOC) in the ocean is thousands of C-14 years old, yet a portion of the DOC cycles on much shorter time scales (days to decades). We present C-14 measurements of DOC in the Arctic Ocean and estimate that 8% of the DOC in the deep Eurasian Basin contains bomb C-14. While this is a limited data set, there appears to be selective loss of modern DOC in the surface and halocline waters of the open Beaufort Sea versus the Beaufort slope. At one of the Beaufort Sea stations, there is a linear relationship between DOC C-14 values and previously measured total hydrolysable amino acid concentrations as reported by Shen et al. (2012), indicating that deep DOC contains small amounts of bioavailable DOC. The C-14 data show that not all of the deep DOC is recalcitrant.