Iron binding ligands in the Atlantic sector of the Southern Ocean (Scale Cruise 2019, Spring and Winter)

SEMINARIOS IOCAG: Víctor Coussy
Abstract:
The study of the Southern Ocean is important because of its influence on the global ocean by its role as a motor of global oceanic circulation with the downwelling. Furthermore, this oceanic region is also considered like one of the most important HNLC (High Nutriments Low Chlorophyll) areas. Iron is an essential trace metal for marine life because of its needs in the enzymatic reactions of phytoplankton. Iron can be discriminated in particulate (pFe > 0.2 μm) and dissolved (dFe 0.2 μm) size fractions, which is composed of colloidal (0.02 μm cFe 0.2 μm) and soluble (sFe 0.02 μm) iron. In the ocean, more than 99.9% of the dissolved Fe(III) is strongly bound to complex mixtures of organic ligands (FeL). Iron cycle and its ligands are controlled by sources (aerosol deposition to the surface ocean, upwelling, ice melting, sediment leaching, and hydrothermal events) and sinks (biological uptake, photoreduction, bacterial activity, adsorption of settling particles). We focus on the study of binding ligands of Iron in this area for a better determination of the seasonal cycle. The analysis of Iron Speciation followed the method of the Cathodic Stripping Voltammetry in Seawater Using the Competing Ligand 2-(2-Thiazolylazo)-p-cresol (TAC).