Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

Sarthou, Géraldine; Lherminier, Pascale; Achterberg, Eric P.; Alonso-Pérez, Fernando; Bucciarelli, Eva; Boutorh, Julia; Bouvier, Vincent; Boyle, Edward A.; Branellec, Pierre; Carracedo, Lidia I.; Casacuberta, Núria; Castrillejo, Maxi; Cheize, Marie; Pereira, Leonardo Contreira; Cossa, Daniel; Daniault, Nathalie; Saint-Léger, Emmanuel de; Dehairs, Frank; Deng, Feifei; Gésincourt, Floriane Desprez de; Devesa, Jérémy; Foliot, Lorna; Fonseca-Batista, Debany; Gallinari, Morgane; García-Ibáñez, Maribel I.; Gourain, Arthur; Grossteffan, Emilie; Hamon, Michel; Heimbürger, Lars Eric; Henderson, Gideon M.; Jeandel, Catherine; Kermabon, Catherine; Lacan, F.; Bot, Philippe Le; Goff, Manon Le; Roy, Emilie Le; Lefèbvre, Alison; Leizour, Stéphane; Lemaitre, Nolwenn; Masqué, Pere; Ménage, Olivier; Barraqueta, Jan‐Lukas Menzel; Mercier, Herlé; Perault, Fabien; Pérez, Fíz F.; Planquette, Hélène; Planchon, F.; Roukaerts, Arnout; Sanial, Virginie; Sauzède, Raphaëlle; Schmechtig, Catherine; Shelley, Rachel; Stewart, Gillian; Sutton, Jill; Tang, Yi; Tisnérat‐Laborde, Nadine; Tonnard, Manon; Tréguer, Paul; Beek, Pieter van; Zurbrick, Cheryl M.; Zunino, Patricia

doi:10.5194/bg-15-7097-2018

Cited by 13 publications

(8 citation statements)

References 75 publications

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“…All sections and surface layer plots were prepared using Ocean Data View (Schlitzer, 2016). The water mass structure in the North Atlantic Ocean from the GEOVIDE voyage was quantitatively assessed by means of an extended optimum multiparameter (eOMP) analysis with 14 water masses (for details see García-Ibáñez et al, 2015;this issue).…”

Section: Discussionmentioning

confidence: 99%

Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

et al. 2020

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Abstract. Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analyzed using a seaFAST-pico™ coupled to an Element XR sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interesting insights into the Fe sources in this area. Overall, DFe concentrations ranged from 0.09±0.01 to 7.8±0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland, and Newfoundland margins likely due to riverine inputs from the Tagus River, meteoric water inputs, and sedimentary inputs. Deep winter convection occurring the previous winter provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth and lead to relatively elevated DFe concentrations within subsurface waters of the Irminger Sea. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles in the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers located in the different basins and at the Iberian Margin were found to act as either a source or a sink of DFe depending on the nature of particles, with organic particles likely releasing DFe and Mn particle scavenging DFe.

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Section: Discussionmentioning

confidence: 99%

Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

et al. 2020

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“…The properties display gradients at the bottom of the layer. The bottom depth of the surface mixed layer varies due to atmospheric forcing, with turbulent mixing caused by wind stress (Risien and Chelton, 2008), convection caused by heat exchange (Yu and Weller, 2007), in addition to salinity changes due to evaporation and precipitation at the surface (Schanze et al, 2010). Thus, the thickness of the MLD is an indication of the amount of water that directly interacts with the atmosphere.…”

Section: Mixed-layer Depth (Mld)mentioning

confidence: 99%

Atmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case study

et al. 2019

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Abstract. Atmospheric deposition is an important source of micronutrients to the ocean, but atmospheric deposition fluxes remain poorly constrained in most ocean regions due to the limited number of field observations of wet and dry atmospheric inputs. Here we present the distribution of dissolved aluminium (dAl), as a tracer of atmospheric inputs, in surface waters of the Atlantic Ocean along GEOTRACES sections GA01, GA06, GA08, and GA10. We used the surface mixed-layer concentrations of dAl to calculate atmospheric deposition fluxes using a simple steady state model. We have optimized the Al fractional aerosol solubility, the dAl residence time within the surface mixed layer and the depth of the surface mixed layer for each separate cruise to calculate the atmospheric deposition fluxes. We calculated the lowest deposition fluxes of 0.15±0.1 and 0.27±0.13 g m−2 yr−1 for the South and North Atlantic Ocean (>40∘ S and >40∘ N) respectively, and the highest fluxes of 1.8 and 3.09 g m−2 yr−1 for the south-east Atlantic and tropical Atlantic Ocean, respectively. Overall, our estimations are comparable to atmospheric dust deposition model estimates and reported field-based atmospheric deposition estimates. We note that our estimates diverge from atmospheric dust deposition model flux estimates in regions influenced by riverine Al inputs and in upwelling regions. As dAl is a key trace element in the GEOTRACES programme, the approach presented in this study allows calculations of atmospheric deposition fluxes at high spatial resolution for remote ocean regions.

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“…Ellwood et al, 2014). Indeed, dissolved iron can be scavenged onto particles (Rijkenberg et al, 2014;Gerringa et al, 2015), incorporated into biogenic particles (Berger et al, 2008), or produced by remineralization of particles (Dehairs et al, 2008;Sarthou et al, 2008). Interestingly, the concept of "reversible scavenging" of iron (i.e.…”

Section: Introductionmentioning

confidence: 99%

Inputs and processes affecting the distribution of particulate iron in the North Atlantic along the GEOVIDE (GEOTRACES GA01) section

et al. 2019

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Abstract. The aim of the GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) was to provide a better understanding of trace metal biogeochemical cycles in the North Atlantic Ocean. As marine particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe), in relation to the distribution of particulate aluminium (PAl), manganese (PMn), and phosphorus (PP). Overall, 32 full vertical profiles were collected for trace metal analyses, representing more than 500 samples. This resolution provides a solid basis for assessing concentration distributions, elemental ratios, size fractionation, and adsorptive scavenging processes in key areas of the thermohaline overturning circulation. Total particulate iron concentrations ranged from as low as 9 pmol L−1 in surface waters of the Labrador Sea to 304 nmol L−1 near the Iberian margin, while median PFe concentrations of 1.15 nmol L−1 were measured over the sub-euphotic ocean interior. Within the Iberian Abyssal Plain, the ratio of PFe to PAl was identical to the continental crust molar ratio (0.21 mol mol−1), indicating the important influence of crustal particles in the water column. Overall, the lithogenic component explained more than 87% of PFe variance along the section. Within the Irminger and Labrador basins, the formation of biogenic particles led to an increase in the PFe∕PAl ratio (up to 0.64 mol mol−1) compared to the continental crust ratio. Continental margins induce high concentrations of particulate trace elements within the surrounding water masses (up to 10 nmol L−1 of PFe). For example, horizontal advection of PFe was visible more than 250 km away from the Iberian margin. Additionally, several benthic nepheloid layers were observed more than 200 m above the seafloor along the transect, especially in the Icelandic, Irminger, and Labrador basins, suspending particles with high PFe content of up to 89 nmol L−1.

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Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

Cited by 13 publications

References 75 publications

Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

Atmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case study

Inputs and processes affecting the distribution of particulate iron in the North Atlantic along the GEOVIDE (GEOTRACES GA01) section

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