Author: Veronica  Arnone, Ph.D.  (Universidad de Las Palmas de Gran Canaria)

Designation: 

Description:
The concentration of dissolved iron (dFe), copper (dCu) and metal binding ligands (L_Fe and L_Cu) in the vicinity of oceanic islands are influenced by a dynamic environment with complex interactions between the topography and the general water circulation that overlap the usual sources. During the POS533 cruise (February to March 2019) surface samples from coastal and oceanic waters were taken in the Macaronesia region (Cape Verde, Canary Islands and Madeira). The competitive ligand exchange adsorptive cathodic stripping voltammetry was the technique used to evaluate the concentration and binding strength of metals and binding ligand. In the region, more than 98% of dFe (0.46-1.32 nM) was organically complexed with L_Fe (0.56-2.96 nM). The conditional stability constant (logK^cond_Fe³⁺L) presented values between 20.77 and 21.90. In the case of dCu (0.07-4.03 nM), more than 99% was complexed with L_Cu (0.54-2.59 nM). The conditional stability constant (logK^cond_Cu²⁺L) showed values between 13.40 and 14.42. Fe and Cu ligands concentrations overlap in many stations suggesting a common source of ligand or that at least some of these are not specific to a single metal. The processes that take place around the islands enhance the concentrations dissolved metals and ligands compared to the values observed in the open ocean. In addition, it has been observed that the increase in concentrations on the east coasts could be related with a greater incidence of wind and dynamic processes.

Category: Scientific Program Abstract > Special Sessions > SS03 Distribution and impacts of ocean nutrient limitation