Hydrothermal-derived black carbon as a source of recalcitrant dissolved organic carbon in the ocean

Youhei Yamashita; Yutaro Mori; Hiroshi Ogawa

doi:10.1126/sciadv.ade3807

Hydrothermal-derived black carbon as a source of recalcitrant dissolved organic carbon in the ocean

Sci Adv. 2023 Feb 10;9(6):eade3807. doi: 10.1126/sciadv.ade3807. Epub 2023 Feb 10.

Authors

Youhei Yamashita^{1

2}, Yutaro Mori², Hiroshi Ogawa³

Affiliations

¹ Faculty of Environmental and Earth Science, Hokkaido University, Sapporo, Japan.
² Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
³ Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan.

Abstract

Deep-sea hydrothermal vents are a possible source of thermogenic dissolved black carbon (DBC), which is a component of recalcitrant dissolved organic carbon, but little is known about the distribution of hydrothermal DBC in the deep ocean. Here, we show basin-scale distributions of DBC along two transects in the eastern Pacific Ocean, which are located outside the jet-like hydrothermal plumes from the East Pacific Rise. The DBC concentration in the deep waters did not show a strong linear relationship with apparent oxygen utilization (AOU), as previously observed in the central and western Pacific Ocean. Deviations in DBC concentration from the DBC-AOU relationship observed in the central and western Pacific Ocean were quantified. The deviation was linearly correlated with excess ³He, a tracer for hydrothermal input, indicating that a fraction of the DBC in the deep ocean is transported long distances from hydrothermal systems.