Temporal variability of dissolved trace metals at the DYFAMED time-series station, Northwestern Mediterranean

We present here results of an 18-month survey (July 2007–March 2009) of a suite of selected trace metals (TM: Co, Ni, Cu, Pb) in a 2350 m-deep offshore water column in the Ligurian Sea (Northwestern Mediterranean Sea). This low-nutrient low-chlorophyll region is characterised by a long stratificatio...

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Bibliographic Details
Published in:Marine Chemistry
Main Authors: Migon, Christophe, Heimbürger-boavida, Lars-eric, Dufour, Aurélie, Chiffoleau, Jean-francois, Cossa, Daniel
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier BV 2020
Subjects:
Ligurian Sea
Trace metals
Seasonal variation
Mediterranean
Open water
North Atlantic
Online Access:https://archimer.ifremer.fr/doc/00635/74691/74602.pdf
https://doi.org/10.1016/j.marchem.2020.103846
https://archimer.ifremer.fr/doc/00635/74691/
Description
Summary:We present here results of an 18-month survey (July 2007–March 2009) of a suite of selected trace metals (TM: Co, Ni, Cu, Pb) in a 2350 m-deep offshore water column in the Ligurian Sea (Northwestern Mediterranean Sea). This low-nutrient low-chlorophyll region is characterised by a long stratification period (May–November) during which surface waters are depleted of macronutrients. Trace metals exhibit a range of biogeochemical behaviours from surface-enriched (scavenged-type) to surface-depleted (nutrient-like) with Co and Ni as representative cases. Cobalt (28–172 pM) distributions are governed by external inputs of aeolian dust deposition and removal by adsorption onto particles in surface, intermediate and deep waters as well. Nickel (3.57–5.52 nM) distributions are governed by internal biogeochemical cycles, together with physical mixing and circulation patterns. Nickel is primarily removed from surface waters with biogenic particles and then remineralised at depth. Copper (1.39–2.89 nM) distributions illustrate a mixture of the two typical behaviours mentioned above. Distributions of typically anthropogenic and particle-reactive Pb (82–235 pM) are in agreement with a Mediterranean flow source of Pb for the adjacent North Atlantic Ocean. The mechanisms controlling the biogeochemical cycling of TMs, such as atmospheric inputs, physical forcing, and interactions with primary production, are discussed according to the TM physico-chemical properties and biological importance.

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