Waeles M., Maguer J. F., Baurand François, Riso R. D. (2013). Off Congo waters (Angola Basin, Atlantic Ocean) : a hot spot for cadmium-phosphate fractionation. Limnology and Oceanography, 58 (4), p. 1481-1490. ISSN 0024-3590.
Titre du document
Off Congo waters (Angola Basin, Atlantic Ocean) : a hot spot for cadmium-phosphate fractionation
Waeles M., Maguer J. F., Baurand François, Riso R. D.
Source
Limnology and Oceanography, 2013,
58 (4), p. 1481-1490 ISSN 0024-3590
We report the distribution of cadmium at 13 stations along 5.83 degrees S in the Angola Basin. The studied area (which is influenced by the plume of the Congo River, doming, and relatively high primary production) is characterized by relatively low-circulation regime, which results in a strong oxygen minimum. In subsurface, very low cadmium : phosphate (Cd : P) ratios (0.05-0.10 nmol L-1 : mu mol L-1) were observed below the euphotic zone (depth range = 50-200 m), indicating that mineralization is the main process explaining the Cd-P fractionation. Cd-P decoupling is not restricted to subsurface waters, but occurs also throughout the oxygen minimum zone. An isopycnal analysis of the Cd : P ratio throughout the Atlantic Ocean shows that upper and intermediate waters in the South-east Atlantic are highly altered in terms of Cd-P properties. Benthic inputs at 4000 m were associated with degradation of organic matter with an important siliceous component, but were not accompanied by substantial changes in the Cd : P ratio.
