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

Author:IMBeR IPO Date:2023-02-23 Hits:26


Hydrothermal-derived black carbon 

as a source of recalcitrant dissolved organic carbon in the ocean

作者:Youhei Yamashita, Yutaro Mori, Hiroshi Ogawa

期刊:Science Advances

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.

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Figure. 1 Spatial distribution of δ3He values at a depth of approximately 2500 m and the sampling sites. The δ3He data were derived from Jenkins et al. (30). The open circles are sampling sites with site numbers in the present study along a zonal transect in the subtropical North Pacific Ocean and a meridional transect in the eastern South Pacific Ocean. The closed circles are sampling sites from Yamashita et al. (16), which determined the linear relationship between the DBC concentration and AOU in the central and western Pacific Ocean. The black dashed line shows the position of the EPR axis (37). Two major helium jets extend westward from the EPR axis at 10°N and at 15°S (37).