The seasonal cycle of δ&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;C&amp;lt;sub&amp;gt;DIC&amp;lt;/sub&amp;gt; in the North Atlantic subpolar gyre

Racapé, Virginie; Metzl, Nicolas; Cartigny, Pierre; Reverdin, Gilles; Quay, Paul D.; Ólafsdóttir, Sólveig Rósa

doi:10.5194/bg-11-1683-2014

Cited by 38 publications

(17 citation statements)

References 36 publications

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“…This study is based on observations collected in the framework of the long-term monitoring program SURATLANT (SURveillance de l'ATLANTique) initiated in 1993. The main objective of this program is to monitor hydrological and biogeochemical properties in surface waters of the NASPG, notably sea surface salinity (SSS), to improve the understanding of the role of salinity in the variability and predictability of climate as well as the water cycle (Reverdin et al, 2018a;Holliday et al, 2020). To this end, two to four cruises per year are conducted between Reykjavík (Iceland) and Newfoundland (Canada) on board merchant ships.…”

Section: Data Collection and Measurementsmentioning

confidence: 99%

“…3.1. We tested this reconstruction for February and July data using SST and SSS data based on the binned products from Reverdin et al (2018a) and averaging the bins in the same boxes (B and CDE) used for discrete sampling ( Fig. S1 and Table S1 in the Supplement).…”

Section: Data Selection: Regions and Seasonsmentioning

confidence: 99%

“…This is in contrast with previous work where trends based on SURATLANT data were evaluated over 1993(Corbière et al, 2007Metzl et al, 2010). Second, we use new binned products based on more regular SST and SSS observations (Reverdin et al, 2018a) to separate periods that present significant interannual variability and different trends in temperature and salinity (Fig. 3a, b).…”

Section: Long-term Trend and Anthropogenic Comentioning

confidence: 99%

“…The last period, 2008-2015, was not investigated in previous studies (Corbière et al, 2007;Metzl et al, 2010). Reverdin et al (2018a) and updated data to 2018, available at https://doi.org/10.6096/ SSS-BIN-NASG (last access: 25 March 2020). The mean trends for each period selected for the carbonate data analysis (when available) are represented as black lines (1: 1993-1997; 2: 2001-2007; 3: 2008-2017).…”

Section: Winter Trends For Different Periodsmentioning

confidence: 99%

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Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017)

Leseurre¹,

Monaco²,

Reverdin³

et al. 2020

Biogeosciences

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Abstract. The North Atlantic is one of the major ocean sinks for natural and anthropogenic atmospheric CO2. Given the variability of the circulation, convective processes or warming–cooling recognized in the high latitudes in this region, a better understanding of the CO2 sink temporal variability and associated acidification needs a close inspection of seasonal, interannual to multidecadal observations. In this study, we investigate the evolution of CO2 uptake and ocean acidification in the North Atlantic Subpolar Gyre (50–64∘ N) using repeated observations collected over the last 3 decades in the framework of the long-term monitoring program SURATLANT (SURveillance de l'ATLANTique). Over the full period (1993–2017) pH decreases (−0.0017 yr−1) and fugacity of CO2 (fCO2) increases (+1.70 µatm yr−1). The trend of fCO2 in surface water is slightly less than the atmospheric rate (+1.96 µatm yr−1). This is mainly due to dissolved inorganic carbon (DIC) increase associated with the anthropogenic signal. However, over shorter periods (4–10 years) and depending on the season, we detect significant variability investigated in more detail in this study. Data obtained between 1993 and 1997 suggest a rapid increase in fCO2 in summer (up to +14 µatm yr−1) that was driven by a significant warming and an increase in DIC for a short period. Similar fCO2 trends are observed between 2001 and 2007 during both summer and winter, but, without significant warming detected, these trends are mainly explained by an increase in DIC and a decrease in alkalinity. This also leads to a pH decrease but with contrasting trends depending on the region and season (between −0.006 and −0.013 yr−1). Conversely, data obtained during the last decade (2008–2017) in summer show a cooling of surface waters and an increase in alkalinity, leading to a strong decrease in surface fCO2 (between −4.4 and −2.3 µatm yr−1; i.e., the ocean CO2 sink increases). Surprisingly, during summer, pH increases up to +0.0052 yr−1 in the southern subpolar gyre. Overall, our results show that, in addition to the accumulation of anthropogenic CO2, the temporal changes in the uptake of CO2 and ocean acidification in the North Atlantic Subpolar Gyre present significant multiannual variability, not clearly directly associated with the North Atlantic Oscillation (NAO). With such variability it is uncertain to predict the near-future evolution of air–sea CO2 fluxes and pH in this region. Thus, it is highly recommended to maintain long-term observations to monitor these properties in the next decade.

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Section: Data Collection and Measurementsmentioning

confidence: 99%

Section: Data Selection: Regions and Seasonsmentioning

confidence: 99%

Section: Long-term Trend and Anthropogenic Comentioning

confidence: 99%

Section: Winter Trends For Different Periodsmentioning

confidence: 99%

See 2 more Smart Citations

Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017)

Leseurre¹,

Monaco²,

Reverdin³

et al. 2020

Biogeosciences

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“…In particular, Metzl et al (2010) indicate very rapid change of fCO2 (up to 7 µatm/yr in [2001][2002][2003][2004][2005][2006][2007][2008] highlighting "the need for continued longâȂŘterm sea surface ocean observations of carbon properties (DIC, TA and fCO2)". The SURATLANT data for 1993-2007 (or 1993-2010) were also associated with other observations to better evaluate pCO2 and airsea flux variability at regional and larger scale in the North Atlantic (Schuster et al 2009;Watson et al, 2009;Mc Kinley et al 2011;Fay and Mc Kinley, 2013) or to describe the seasonality of sea surface δ13CDIC (Racapé et al, 2014).…”

Section: Responsementioning

confidence: 99%

Responses to review 1.

Leseurre¹

2019

Preprint

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Environmental control of the isotopic composition of subfossil coccolith calcite: Are laboratory culture data transferable to the natural environment?

Hermoso

Candelier

Browing

et al. 2015

GeoResJ

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International audienceCoccoliths contribute significantly to pelagic sediments formed over the last 200 million years, yet their geochemistry has been largely overlooked as a potential record of palaeoenvironmental information. Recently developed techniques have enabled successful extraction of coccolith-dominated sediment fractions. However, the reliability of palaeoenvironmental interpretations that can be drawn from coccolith analyses is still confounded by a poor understanding of the “vital effect” – the physiological component of the isotopic composition of biominerals. Here we demonstrate that oxygen isotope composition in core-top coccoliths is not only set by the temperature and isotopic composition of seawater, but appears to be controlled to first order by the environmental factors regulating algal growth rate. Partial registration of the isotopic signature of assimilated CO2 (with a heavy isotopic composition relative to other dissolved inorganic carbon species) is confirmed to be the dominant mechanism behind the vital effect recorded in the Noelaerhabdaceae coccoliths. Our data point towards a strong role of growth irradiance on expression of the 18O and 13C vital effects, ranging from limited (near equilibrium composition) in low light regimes to 3‰ offset in oxygen isotopes at higher growth irradiances, such as those found under light-saturated conditions typically imposed in laboratory cultures. This highlights the importance of considering environmental controls when translating oxygen isotope composition of coccoliths into temperature estimates. Furthermore, our calibration suggests that the alkenone-based CO2 palaeobarometer proxy may be refined by combining paired organic/calcite measurements during the Cenozoic

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The seasonal cycle of δ<sup>3</sup>C<sub>DIC</sub> in the North Atlantic subpolar gyre

Cited by 38 publications

References 36 publications

Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017)

Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017)

Responses to review 1.

Environmental control of the isotopic composition of subfossil coccolith calcite: Are laboratory culture data transferable to the natural environment?

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