Details of the oceanic DOC distribution were reported by Dennis A. Hansell & Craig A. Carlson, Nature, (1998) and Hansell et al. Their color contour map is shown below.

Figure A below shows the horizontal distribution of dissolved organic carbon (DOC) in the ocean surface layer (30 m). It can be seen that DOC is high in the tropical and subtropical, and low in the subarctic (especially the Southern Ocean). Note that even though it is low in the subarctic, the minimum color scale is 40 (or so), not zero. Even on the sea ice surface, the DOC concentration in seawater never approaches zero. The higher DOC concentration in warmer waters is likely due to the rapid decomposition of organic particles produced in the surface layer to the dissolved form. High DOC concentrations are seen in the Arctic Ocean. The area shown in the figure below is limited to the shelf area, even in the Arctic Ocean. This may be due to the high biological productivity of the continental shelf area of the Arctic Ocean, supply from the seafloor surface of the continental shelf, and the inflow of terrestrial organic matter from river water.

Horizontal distribution of dissolved organic carbon (DOC) in the ocean; A: ocean surface layer (30 m); B: ocean deep layer (3000 m). Circles indicate locations where water was sampled and DOC concentrations were measured by oceanographic observations.

Reference Information: We quote Figure 1 from Hansell et al., Oceanography, 22(4) 202-211 (2009). This magazine is under a Creative Commons Attribution 4.0 International License.

Figure B above shows the distribution of DOC concentrations in the deep layer (3000 m). The DOC concentration is highest in the high latitudes of the North Atlantic, which is the start of the deep circulation, and lowest in the high latitudes of the North Pacific. The DOC concentration decreases in the order of the deep circulation. Note that the minimum color scale in this figure is 37 (or so), not zero. Even in the deep ocean, the DOC concentration never reaches zero.

Last modified: Tuesday, 18 July 2023, 1:48 PM