Water masses in the upper and middle North Atlantic Ocean east of the Azores

Rı́os, Aida F.; Pérez, Fíz F.; Fraga, Fernando

doi:10.1016/0198-0149(92)90093-9

Cited by 240 publications

(184 citation statements)

References 12 publications

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“…1) flows westwards to the Algarve coast and, during periods of prolonged southeasterly winds, can circulate around Cabo S. Vincente and flow northwards (Relvas and Barton, 2002). In relation to the overall patterns of ocean circulation in the eastern Atlantic, the northern part of the west coast of the Iberian Peninsula is influenced by the subpolar branch of the Eastern North Atlantic Central Water (ENACWsp), whereas the southern upwelled waters have characteristics of the ENACW subtropical branch (Fiuza, 1984;Ríos et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

Loureiro¹,

Newton²,

Icely³

2005

Sci. Mar.

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SUMMARY: Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal) during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling centre off Cabo S. Vicente, and 2 km west of an offshore installation for bivalve aquaculture. Three major periods were distinguished according to sea surface temperature (SST): period 1 (P1; May and June), characterised by high temperature values (17.0±1.8ºC); period 2 (P2; July), characterised by lower temperatures (14.6±0.3ºC), identified as an upwelling-blooming stage; and period 3 (P3; August), characterised by a high temperature pattern (16.25±1.14ºC). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. and Pseudo-nitzschia spp. were the major taxa contributing to the dissimilarities between P2 (July) and the other periods. In July (P2), the average gross production (GP; 52.5±12.3 µM O 2 d -1 ) and net community production (NCP; 46.9±15.3 µM O 2 d -1 ) peaked with the maximal concentrations of diatom-chl a. Dark community respiration (DCR) remained low and more constant throughout (4.6±3.6 µM O 2 d -1 ). The plankton assemblage was dominated by diatoms throughout the survey. Physical events were the primary factors determining the microplankton structure and distribution at this location.Keywords: production, respiration, microplankton community, Iberian Peninsula, Cabo S. Vicente. RESUMEN: COMPOSICIÓN DEL MICROPLANCTON, PRODUCCIÓN Y DINÁMICA DEL AFLORAMIENTO EN SAGRES (SUROESTE DE PORTUGAL) DURANTE EL VERANO DE2001. -La comunidad microplanctónica, la producción y la respiración, fueron estudiadas en Sagres (SE Portugal) durante la época de afloramiento, de Mayo a Septiembre 2001, junto con parámetros físicos y químicos. La estación de muestreo está a 5 km Este del centro de afloramiento del Cabo S. Vicente, y a 2 km Oeste de una instalación para el cultivo de bivalvos. Según los patrones de la temperatura del agua de superficie (SST) se diferenciaron tres periodos: periodo 1 (P1; Mayo y Junio), caracterizado por temperaturas altas (17.0±1.8ºC); periodo 2 (P2; Julio), caracterizado por temperaturas más bajas (14.6±0.3ºC), identificado como un estado de -afloramiento; periodo 3 (P3; Agosto), caracterizado por un patrón de temperaturas altas (16.25±1.14ºC). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. y Pseudo-nitzschia spp., fueron los principales grupos que contribuyeron a la diferenciación entre P2 (Julio) y el resto de periodos. Durante Julio (P2) la media de producción primaria bruta (GP; 52.5±12. ) alcanzaron sus valores máximos, simultáneamente con el pico de diatomeas-chl a. La respiración de la comunidad en la oscuridad (DCR) permaneció baja y constante durante el muestreo (4.6±3.6 µM O 2 d -1 ). La comunidad estaba dominada por diatomeas durante todo el muestreo. Los eventos físicos fueron el factor principal en la determinación de la estructura de la comunidad microplanctónica en esta localidad.

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Section: Introductionmentioning

confidence: 99%

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

Loureiro¹,

Newton²,

Icely³

2005

Sci. Mar.

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“…The latitudinal gradient of nitrate was a manifestation of the regional hydrography characterized by the presence of two subsurface branches of ENACW: a water branch of subpolar origin (ENACWp) to the North, with higher nitrate concentration, and a water branch of subtropical origin (ENACWt) and lower nitrate concentration to the South (Fiuza, 1984;Fiuza et al, 1998;Perez et al, 1993;Rios et al, 1992), which the model was able to reproduce. Another relevant feature known to cause the nitrate latitudinal gradient was the shallower winter vertical mixing in the south (~ 100 m) compared to that in the north (~ 300 m), resulting in a general northward increase in the nitrate concentration (Perez et al, 2005).…”

Section: Meanmentioning

confidence: 99%

Seasonal cycle of plankton production in the Iberian margin based on a high resolution ocean model

Reboreda

Nolasco

Castro

et al. 2014

Journal of Marine Systems

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“…In the eastern North Atlantic, the central waters (ENACW) are characterized by a u-S mixing line that can be split into two segments (Fig. 2) that represent the subtropical and the subpolar branches (Ríos et al 1992). The inflection point (ENACW 12 , 12.28-12.308C, 35.66 psu;Castro et al 1998) between both segments is the upper limit of the subpolar ENACW given by Harvey (1982).…”

Section: B Multiparameter Mixing (Omp) Analysismentioning

confidence: 99%

“…Originally the Subtropical Mode Water is formed at the northern margin of the Azores Current (around 368N; Fig. 1) spreading toward the Iberian Peninsula (Ríos et al 1992) and reaching the GoC region. Because its properties vary mainly due to air-sea interactions (Pollard and Pu 1985), here we will refer to this uppermost ENACW extreme as ENACW 18 , characterizing the upper layers of the GoC region with a straight line (ENACW 12 to ENACW 18 ) in the u-S diagram ( Fig.…”

Section: B Multiparameter Mixing (Omp) Analysismentioning

confidence: 99%

“…As a result of the mixing undergone, the MOW volume increases more than twice [from 1 to 3 Sv, according to Worthington (1976), or from 0.7 to 1.9 Sv, according to Baringer and Price (1997)], and the result is a less saline water mass, which we will particularly refer to as MW (Ríos et al 1992;Ambar et al 1999;van Aken 2000b;Àlvarez et al 2004, 2005Fusco et al 2008;Alves et al 2011). With MOW being the origin of MW and the real input from the Mediterranean Sea, MW will become a well-differentiated neutrally buoyant water body that will spread from the Cape St. Vincent (Fig.…”

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confidence: 99%

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On the Mediterranean Water Composition

Carracedo

Pardo

Flecha

et al. 2016

Journal of Physical Oceanography

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The Mediterranean Outflow Water (MOW) spills from the Mediterranean Sea (east North Atlantic basin) west off the Strait of Gibraltar. As MOW outflows, it entrains eastern North Atlantic Central Waters (ENACW) and Intermediate Waters to form the neutrally buoyant Mediterranean Water (MW) that can be traced over the entire North Atlantic basin. Its high salinity content influences the thermohaline properties of the intermediatedeep water column in the North Atlantic and its dynamics. Here, the composition of MW in its source region (the Gulf of Cádiz, west off Strait of Gibraltar) is investigated on the basis of an optimum multiparameter analysis. The results obtained indicate that mixing of MOW (34.1% 6 0.3%) occurs mainly with overlying ENACW (57.1% 6 0.8%) in a process broadly known as central water entrainment. A diluted form (80% of dilution) of the Antarctic Intermediate Water (AAIW) reaches the region and also takes part in MW formation (8.3% 6 0.5%). Finally, the underlying Labrador Sea Water (LSW) also contributes (0.4% 6 0.1%) to the characteristics of MW. From these results and considering 0.74 Sverdrups (Sv; 1 Sv [ 10 6 m 3 s 21) as the mean outflow of MOW, the MW exportation rate was inferred (2.2 Sv), which, decomposing MW, means that the MOW outflow is accompanied by 1.24 Sv of entrained ENACW, 0.18 Sv of AAIW, and ,0.01 Sv of LSW.

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Water masses in the upper and middle North Atlantic Ocean east of the Azores

Cited by 240 publications

References 12 publications

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

Seasonal cycle of plankton production in the Iberian margin based on a high resolution ocean model

On the Mediterranean Water Composition

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