Dissolved inorganic carbon budgets in the eastern subpolar North Atlantic in the 2000s from in situ data

Zunino, Patricia; Lherminier, Pascale; Mercier, Herlé; Pad́ın, X. A.; Rı́os, Aida F.; Pérez, Fíz F.

doi:10.1002/2015gl066243

Cited by 12 publications

(16 citation statements)

References 48 publications

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“…The net nitrate input into the eSPNA must be balanced by an equivalent net biological consumption (Figure 1c), reinforcing the observation of a net full-depth autotrophic balance in the eSPNA, in good agreement with previous studies in the area (Mazé et al, 2012;Zunino et al, 2015). Our budgets also show that the water column-integrated rates of net uptake of nitrate (7.5 ± 6.6 TgN/year) and net production of DON (7.1 ± 2.6 TgN/year) are roughly equivalent within error bars, such that the net nitrate consumption could be counterbalanced by net DON production.…”

Section: 1029/2018gl080284supporting

confidence: 91%

Dissolved Organic Nitrogen Production and Export by Meridional Overturning in the Eastern Subpolar North Atlantic

Fernández-Castro

Álvarez

Nieto‐Cid

et al. 2019

Geophysical Research Letters

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Dissolved organic matter (DOM) is produced in the surface and exported towards the deep ocean, adding ∼2 PgC/year to the global carbon export. Due to its central role in the Meridional Overturning Circulation, the eastern subpolar North Atlantic (eSPNA) contributes largely to this export. Here we quantify the transport and budget of dissolved organic nitrogen (DON) in the eSPNA, in a box delimited by the OVIDE 2002 section and the Greenland‐Iceland‐Scotland sills. The Meridional Overturning Circulation exports >15.9 TgN/year of DON downward and, contrary to the extended view that these are materials of subtropical origin, up to 33% of the vertical flux derives from a net local DON production of 7.1 ± 2.6 TgN/year. The low C:N molar ratio of DOM production (7.4 ± 4.1) and the relatively short transit times in the eSPNA (3 ± 1 year) suggest that local biogeochemical transformations result in the injection of fresh bioavailable DOM to the deep ocean.

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Section: 1029/2018gl080284supporting

confidence: 91%

Dissolved Organic Nitrogen Production and Export by Meridional Overturning in the Eastern Subpolar North Atlantic

Fernández-Castro

Álvarez

Nieto‐Cid

et al. 2019

Geophysical Research Letters

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“…In terms of circulation, the comparison with the 2002-2012 mean state shows a different repartition of the northward warm currents that compose the upper limb of the MOC, with a more intense Irminger Current (station 39-41) and a weaker North Atlantic Current (NAC) in the West European Basin, these anomalies being compatible with the variability previously observed along the OVIDE section in the 2000s (Zunino et al, 2017). The distribution of the volume transport in the three branches of the NAC (Fig.…”

Section: Hydrographic and Physical Characteristicssupporting

confidence: 81%

“…This last point has improved very quickly as significant improvements in the instrumental techniques now allow the measurements of concentrations, speciation (physical and chemical forms), and isotopic compositions for most of the elements of the periodic table which have been identified either as relevant tracers or key nutrients in the marine environment. These recent advances provide the marine geochemistry community with a significant opportunity to make sub- Daniault et al (2016) and Zunino et al (2017). Bathymetry is plotted in color with color changes at 100 and 1000 m and every 1000 m below 1000 m. Black dots represent the Short station, yellow stars the Large ones, orange stars the XLarge ones, and red stars the Super ones.…”

Section: Scientific Context and Objectivesmentioning

confidence: 99%

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

Sarthou¹,

Lherminier²,

Achterberg³

et al. 2018

Biogeosciences

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Abstract. The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.

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“…Climate feedback mechanisms that involve natural carbon cycling in the ocean are relevant to elucidate. While Zunino et al (2015) found steady-state conditions for the natural carbon cycle in the entire eastern subpolar North Atlantic between 2002 and 2010, this was not the case for the Irminger Sea from 1991-2015. A possible explanation for this discrepancy could be the longer time period considered here or that if both the Irminger Sea and the Iceland Basin are regarded, inventory changes might cancel each other out.…”

Section: Discussionmentioning

confidence: 94%

Inorganic carbon and water masses in the Irminger Sea since 1991

et al. 2018

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Abstract. The subpolar region in the North Atlantic is a major sink for anthropogenic carbon. While the storage rates show large interannual variability related to atmospheric forcing, less is known about variability in the natural dissolved inorganic carbon (DIC) and the combined impact of variations in the two components on the total DIC inventories. Here, data from 15 cruises in the Irminger Sea covering the 24-year period between 1991 and 2015 were used to determine changes in total DIC and its natural and anthropogenic components. Based on the results of an extended optimum multiparameter analysis (eOMP), the inventory changes are discussed in relation to the distribution and evolution of the main water masses. The inventory of DIC increased by 1.43 ± 0.17 mol m −2 yr −1 over the period, mainly driven by the increase in anthropogenic carbon (1.84 ± 0.16 mol m −2 yr −1 ) but partially offset by a loss of natural DIC (−0.57 ± 0.22 mol m −2 yr −1 ). Changes in the carbon storage rate can be driven by concentration changes in the water column, for example due to the ageing of water masses, or by changes in the distribution of water masses with different concentrations either by local formation or advection. A decomposition of the trends into their main drivers showed that variations in natural DIC inventories are mainly driven by changes in the layer thickness of the main water masses, while anthropogenic carbon is most affected by concentration changes. The storage rates of anthropogenic carbon are sensitive to data selection, while changes in DIC inventory show a robust signal on short timescales associated with the strength of convection.

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Dissolved inorganic carbon budgets in the eastern subpolar North Atlantic in the 2000s from in situ data

Cited by 12 publications

References 48 publications

Dissolved Organic Nitrogen Production and Export by Meridional Overturning in the Eastern Subpolar North Atlantic

Dissolved Organic Nitrogen Production and Export by Meridional Overturning in the Eastern Subpolar North Atlantic

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

Inorganic carbon and water masses in the Irminger Sea since 1991

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