Seasonal cycling of zinc and cobalt in the south-eastern Atlantic along the GEOTRACES GA10 section

Abstract. We report the distributions and stoichiometry of dissolved zinc (dZn) cobalt (dCo) in sub-tropical sub-Antarctic waters south-eastern Atlantic Ocean during austral spring 2010 summer 2011/2012. In surface waters, mixed-layer dZn dCo concentrations early were 1.60 ± 2.58 nM 30 11 pM, respectively, compared with values 0.14 0.08 24 6 pM. The elevated resulted from an apparent offshore transport at depths between 20–55 m, derived Agulhas Bank. contrast, open-ocean displayed largely consistent inter-seasonal 0.10 0.07 5 respectively. Trace metal stoichiometry, calculated concentration inventories, suggests a greater overall removal for relative to upper water column Atlantic, inter-seasonally decreasing / inventory ratios 19–5 13–7 mol mol?1 water, this paper, we investigate how seasonal influences external input phytoplankton succession may relate distribution variation across these two distinct ecological regimes Atlantic.