scholarly journals Air-Sea CO<sub>2</sub> fluxes in the Atlantic as measured during boreal spring and autumn

2010 ◽  
Vol 7 (5) ◽  
pp. 1587-1606 ◽  
Author(s):  
X. A. Padin ◽  
M. Vázquez-Rodríguez ◽  
M. Castaño ◽  
A. Velo ◽  
F. Alonso-Pérez ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Surface Waters ◽  
Southern Oscillation ◽  
Atmospheric Co2 ◽  
Sea Surface Salinity ◽  
Co2 Uptake ◽  
Co2 Absorption ◽  
The North ◽  
The North Atlantic

Abstract. A total of fourteen hydrographic cruises from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean under the framework of the Spanish research project FICARAM. The underway measurements were processed and analysed to describe the meridional air-sea CO2 fluxes (FCO2) in the covered sector of the Atlantic Ocean. The data has been grouped into different biogeochemical oceanographic provinces based on thermohaline characteristics. The spatial and temporal distributions of FCO2 followed expected distributions and annual trends reproducing the recent climatological ΔfCO2 estimations with a mean difference of −3 ± 18 μatm (Takahashi et al., 2009). The reduction in the CO2 saturation along the meridional FICARAM cruises represented an increase of 0.02 ± 0.14 mol m−2 yr−1 in the ocean uptake of atmospheric CO2. The subtropical waters in both Hemispheres acted as a sink of atmospheric CO2 during the successive spring seasons and as a source in autumn. The coarse reduction of the ocean uptake of atmospheric CO2 observed in the North Atlantic Ocean was linked to conditions of negative phase of the North Atlantic Oscillation that prevailed during the FICARAM period. Surface waters in the North Equatorial Counter Current revealed a significant long-term decrease of sea surface salinity of −0.16 ± 0.01 yr−1 coinciding with a declination of −3.5 ± 0.9 μatm yr−1 in the air–sea disequilibrium of CO2 fugacity and a rise of oceanic CO2 uptake of −0.09 ± 0.03 mol m−2 yr−1. The largest CO2 source was located in the equatorial upwelling system. These tropical waters that reached emissions of 0.7 ± 0.5 and 1.0 ± 0.7 mol m−2 y−1 in spring and autumn, respectively, showed an interannual warming of 0.11 ± 0.03 °C yr−1 and a wind speed decrease of −0.58 ± 0.14 m s−1 yr−1 in spring cruises which suggest the weakening of upwelling events associated with warm El Niño – Southern Oscillation episodes. Contrary the surface waters of the Patagonian Sea behaved as an intense sink of CO2 in March and November. The oceanic waters of the convergence of Falkland and Brazil Currents showed the strongest CO2 absorption with a rate of −5.4 ± 3.6 mol m−2 yr−1 in November. The Southern Oceans sampled in the Drake Passage behave as an average uptake rate of −1.1 ± 0.9 mol m−2 yr−1 while the distal shelf of the Livingston Island acted as a slight source of CO2 to the atmosphere.

scholarly journals The circulation of the surface waters of the North Atlantic Ocean

1900 ◽  
Vol 66 (424-433) ◽  
pp. 484-485
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Surface Waters ◽  
North Atlantic Ocean ◽  
The North ◽  
The North Atlantic

In this paper an attempt is made to investigate the normal circulation of the surface waters of the Atlantic Ocean north of 40° N. lat., and its changes, by means of a series of synoptic charts showing the distribution of temperature and salinity over the area for each month of the two years 1896 and 1897.

scholarly journals Observed acidification trends in North Atlantic water masses

2012 ◽  
Vol 9 (12) ◽  
pp. 5217-5230 ◽  
Author(s):  
M. Vázquez-Rodríguez ◽  
F. F. Pérez ◽  
A. Velo ◽  
A. F. Ríos ◽  
H. Mercier
Keyword(s):  
North Atlantic ◽  
Surface Waters ◽  
Sea Water ◽  
Deep Convection ◽  
Atlantic Water ◽  
Atmospheric Co2 ◽  
Emission Rates ◽  
The North ◽  
Iceland Basin ◽  
The North Atlantic

Abstract. The lack of observational pH data has made it difficult to assess recent rates of ocean acidification, particularly in the high latitudes. Here we present a time series that spans over 27 yr (1981–2008) of high-quality carbon system measurements in the North Atlantic, which comprises fourteen cruises and covers the important water mass formation areas of the Irminger and Iceland Basins. We provide direct quantification of acidification rates in upper and intermediate North Atlantic waters. The highest rates were associated with surface waters and with Labrador Sea Water (LSW). The Subarctic Intermediate and Subpolar Mode Waters (SAIW and SPMW) showed acidification rates of −0.0019 ± 0.0001 and −0.0012 ± 0.0002 yr−1, respectively. The deep convection activity in the North Atlantic Subpolar Gyre injects surface waters loaded with anthropogenic CO2 into lower layers, provoking the remarkable acidification rate observed for LSW in the Iceland Basin (−0.0016 ± 0.0002 yr−1). An extrapolation of the observed linear acidification trends suggests that the pH of LSW could drop 0.45 units with respect to pre-industrial levels by the time atmospheric CO2 concentrations reach ~775 ppm. Under circulation conditions and evolution of CO2 emission rates similar to those of the last three decades, by the time atmospheric CO2 reaches 550 ppm, an aragonite undersaturation state could be reached in the cLSW of the Iceland Basin, earlier than surface SPMW.

scholarly journals Multi-decadal uptake of carbon dioxide into subtropical mode water of the North Atlantic Ocean

2012 ◽  
Vol 9 (7) ◽  
pp. 2649-2659 ◽  
Author(s):  
N. R. Bates
Keyword(s):  
Carbon Dioxide ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Dissolved Inorganic Carbon ◽  
Co2 Uptake ◽  
Mode Water ◽  
Subtropical Mode Water ◽  
The North ◽  
The North Atlantic

Abstract. Natural climate variability impacts the multi-decadal uptake of anthropogenic carbon dioxide (Cant) into the North Atlantic Ocean subpolar and subtropical gyres. Previous studies have shown that there is significant uptake of CO2 into subtropical mode water (STMW) of the North Atlantic. STMW forms south of the Gulf Stream in winter and constitutes the dominant upper-ocean water mass in the subtropical gyre of the North Atlantic Ocean. Observations at the Bermuda Atlantic Time-series Study (BATS) site near Bermuda show an increase in dissolved inorganic carbon (DIC) of +1.51 ± 0.08 μmol kg−1 yr−1 between 1988 and 2011, but also an increase in ocean acidification indicators such as pH at rates (−0.0022 ± 0.0002 yr−1) higher than the surface ocean (Bates et al., 2012). It is estimated that the sink of CO2 into STMW was 0.985 ± 0.018 Pg C (Pg = 1015 g C) between 1988 and 2011 (70 ± 1.8% of which is due to uptake of Cant). The sink of CO2 into the STMW is 20% of the CO2 uptake in the North Atlantic Ocean between 14°–50° N (Takahashi et al., 2009). However, the STMW sink of CO2 was strongly coupled to the North Atlantic Oscillation (NAO), with large uptake of CO2 into STMW during the 1990s during a predominantly NAO positive phase. In contrast, uptake of CO2 into STMW was much reduced in the 2000s during the NAO neutral/negative phase. Thus, NAO induced variability of the STMW CO2 sink is important when evaluating multi-decadal changes in North Atlantic Ocean CO2 sinks.

A short-term sink for atmospheric CO2 in subtropical mode water of the North Atlantic Ocean

Nature ◽  
2002 ◽  
Vol 420 (6915) ◽  
pp. 489-493 ◽  
Author(s):  
Nicholas R. Bates ◽  
A. Christine Pequignet ◽  
Rodney J. Johnson ◽  
Nicolas Gruber
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Atmospheric Co2 ◽  
Short Term ◽  
Mode Water ◽  
Subtropical Mode Water ◽  
The North ◽  
The North Atlantic

scholarly journals III. The circulation of the surface waters of the north atlantic ocean

1901 ◽  
Vol 196 (274-286) ◽  
pp. 61-203 ◽  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Surface Waters ◽  
Gulf Stream ◽  
North Atlantic Ocean ◽  
Critical Examination ◽  
Northern Latitude ◽  
The North ◽  
History Of ◽  
The North Atlantic

The history of our knowledge of the currents of the North Atlantic Ocean up to the year 1870 has been written once for all by Petermann (I), who in that year published a memoir maintaining, contrary to the opinion of Findlay, Blunt, and Carpenter, that eastern and northern extensions of the Gulf Stream were the prime factors in the circulation. Petermann subjected practically the whole of the material in the way of observations then extant to an exhaustive critical examination, and came to conclusions which are worth quoting, in the summary, inasmuch as the observations of the twenty succeeding years did not seriously modify them :— 1. The hot source and core of the Gulf Stream extends from the Strait of Florida, along the North American coast at all times.... up to the 37th degree of northern latitude.

scholarly journals Calcification in the planktonic foraminifera <i>Globigerina bulloides</i> linked to phosphate concentrations in surface waters of the North Atlantic Ocean

2012 ◽  
Vol 9 (5) ◽  
pp. 1725-1739 ◽  
Author(s):  
D. Aldridge ◽  
C. J. Beer ◽  
D. A. Purdie
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Surface Waters ◽  
North Atlantic Ocean ◽  
Planktonic Foraminifera ◽  
Growth Conditions ◽  
Optimum Growth ◽  
Globigerina Bulloides ◽  
The North ◽  
The North Atlantic

Abstract. Marine calcifiers, such as planktonic foraminifera, form a major component of the global carbon cycle, acting as both a source and sink of CO2. Understanding factors that affect calcification in these organisms is therefore critical in predicting how the oceans will respond to increased CO2 concentrations in the atmosphere. Here, size-normalised weights (SNWs) of the planktonic foraminifera Globigerina bulloides, collected from the surface waters of the North Atlantic Ocean, are compared with in situ carbonate ion concentrations ([CO32–]), sea-surface temperature, optimum growth conditions and nutrient concentrations. Changes in phosphate concentrations ([PO43–], range: 0.04–0.39 μM) explained the majority of G. bulloides SNW variation, with reduced test masses at higher concentrations. Two factors already known to influence calcification in foraminifers, [CO32–] and temperature, were also positively correlated over the range of values examined (148–181 μM kg−1 and 10.3–12.7 °C respectively). No evidence was found for increased SNWs under apparent optimum growth conditions, indicated by G. bulloides abundances. However, "growth potentials" (μ), derived from modelled growth rates (d–1), were positively correlated with SNWs, suggesting that this may be a better proxy for optimum growth conditions. These findings point to the potential importance of [PO43–] in determining calcification intensities in foraminifera, a factor which has been overlooked by previous studies on these organisms. The confirmation of this via carefully controlled culture studies is recommended in the future.

scholarly journals Subannual to Interannual Variabilities of SST in the North Atlantic Ocean

2020 ◽  
Vol 33 (13) ◽  
pp. 5547-5564
Author(s):  
Xiaofan Li ◽  
Zeng-Zhen Hu ◽  
Bohua Huang
Keyword(s):  
Atlantic Ocean ◽  
Time Scales ◽  
North Atlantic ◽  
Time Scale ◽  
North Atlantic Ocean ◽  
Southern Oscillation ◽  
The North ◽  
Sst Variability ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractBased on observational data, this work examines the multi-time-scale feature of the sea surface temperature (SST) variability averaged in the whole North Atlantic Ocean (to be referred to as NASST), as well as its time-scale-dependent connections with El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). Traditionally, the NASST index is used to characterize the SST trend and multidecadal variability in the North Atlantic. This study found that superimposed on a prominent long-term trend, NASST is nonnegligible at subannual and interannual time scales, compared with that at decadal to multidecadal time scales. Spatially, the interannual variation of NASST is characterized by a horseshoe-like pattern of the SST anomaly (SSTA) in the North Atlantic. It is mainly a lagged response to ENSO through the atmospheric bridge, and NAO plays a secondary role. At the subannual time scale, both ENSO and NAO play a role in generating the fluctuations of NASST and a horseshoe-like pattern in the North Atlantic. Nevertheless, both the ENSO- and NAO-driven variations only explain a small fraction of the variances in both the interannual and subannual time scales. Thus, other factors unrelated to ENSO or NAO may play a more important role. The associated thermodynamical processes are similar at the two time scales; however, the dynamical processes have a significant contribution to the subannual component, but not to the interannual component. Thus, the SSTA averaged in the North Atlantic as a whole varies at different time scales and is associated with different mechanisms.

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