Basin-scale changes of total organic carbon profiles in the eastern South Atlantic

Authors

  • X. A. Alvarez-Salgado CSIC, Instituto de Investigacións Mariñas
  • F. F. Pérez CSIC, Instituto de Investigacións Mariñas
  • A. F. Ríos CSIC, Instituto de Investigacións Mariñas
  • M. D. Doval CSIC, Instituto de Investigacións Mariñas

DOI:

https://doi.org/10.3989/scimar.2001.65n11

Keywords:

Dissolved Organic Carbon (DOC), Apparent Oxygen Utilisation (AOU), stratification, mixing, water masses, SE Atlantic Ocean

Abstract


Total organic carbon (TOC) samples were collected at 6 stations spaced ~800 km apart in the eastern South Atlantic, from the Equator to 45°S along 9°W. Analyses were performed by high temperature catalytic oxidation (HTCO) in the base laboratory. Despite the complex advection and mixing patterns of North Atlantic and Antarctic waters with extremely different degrees of ventilation, TOC levels below 500 m are quasi-constant at 55±3 µmol C l-1, pointing to the refractory nature of deep-water TOC. On the other hand, a TOC excess from 25 to 38 g C m-2 is observed in the upper 100 m of the permanently stratified nutrient-depleted Equatorial, Subequatorial and Subtropical upper ocean, where vertical turbulent diffusion is largely prevented. Conversely, TOC levels in the nutrient-rich upper layer of the Subantarctic Front only exceeds 9 g C m-2 the deep-water baseline. As much as 70% of the TOC variability in the upper 500 m is due to simple mixing of reactive TOC formed in the surface layer and refractory TOC in deep ocean waters, with a minor contribution (13%) to oxygen consumption in the prominent subsurface AOU maximum at 200-400 m depth.

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Published

2001-03-30

How to Cite

1.
Alvarez-Salgado XA, Pérez FF, Ríos AF, Doval MD. Basin-scale changes of total organic carbon profiles in the eastern South Atlantic. scimar [Internet]. 2001Mar.30 [cited 2021Apr.22];65(1):1-10. Available from: http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/631

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Articles