Celtic Sea and Armorican current structure and the vertical distributions of temperature and chlorophyll

Pingree, R. D.; Mardell, G. T.; Holligan, Patrick M.; Griffiths, D. K.; Smithers, J.

doi:10.1016/0278-4343(82)90033-4

Cited by 113 publications

(60 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These situations occur where the influence of freshwater is relatively weak and tidal cycle is dominant, as in south San Francisco Bay. In the Gironde plume waters, tidal currents are weak (Pingree et al 1982), and their influence is limited to the Gironde estuary mouth at depths shallower than 20 m. The primary sources of turbulence are the wind and the density-driven flows (Lazure & Jegou 1998). In such conditions, the haline stratification due to freshwater outflows is persistent for several months when established.…”

Section: Determining Factors Acting On Light Availabilitymentioning

confidence: 99%

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay

Labry¹,

Herbland²,

Delmas³

et al. 2001

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Thermostratification and seasonal light increase are generally considered the first causes of phytoplankton spring blooms in temperate waters. The objective of this study is to confirm the existence of winter phytoplankton blooms, responsible for the early exhaustion of phosphate, within the Gironde plume waters (southeast Bay of Biscay), and to understand what may initiate them so early. Two cruises, BIOMET 2 and BIOMET 3, were carried out respectively in early (8 to 21 January) and late winter 1998 (25 February to 11 March). An increase of phytoplankton biomass (chl a) between the 2 cruises and non-conservative nutrients observed in late winter confirm an early phytoplankton growth both in the Gironde plume and adjacent oceanic waters. Among factors that possibly initiate these blooms, light availability seems to be the best candidate. First, the status of available light for phytoplankton changed dramatically between the 2 cruises when comparing the instantaneous depth-averaged irradiance (E m ) received by phytoplankton with the light saturation parameter E k determined from P versus E curves. Light was limiting for phytoplankton growth in early winter according to systematically lower values of E m than E k in the daytime. However, light was not limiting during a large part of the day in late winter since E m was above E k during 40% of the daylight.

show abstract

Section: Determining Factors Acting On Light Availabilitymentioning

confidence: 99%

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay

Labry¹,

Herbland²,

Delmas³

et al. 2001

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Over the Armorican shelf, instantaneous tidal currents are stronger (~30 cm s -1 ) with several maximum local values in the vicinity of islands (>50 cm s -1 ). In this northern part, minimum values (<10 cm s -1 ) are found near the Vendée and the southern Brittany coast between the Glenan and Belle-Ile islands (Pingree et al, 1982;Le Cann, 1990). Tidal residual currents are very weak over the whole continental shelf, so water mass circulation is principally governed by windinduced and density currents.…”

Section: Mesoscale Hydrological Variability Induced By Northwesterly mentioning

confidence: 96%

“…In this coastal area, tidal currents are weak (Pingree et al, 1982), allowing strong stratification in spring and the development of an Ekman layer which is well separated from the bottom layer. These observations support the model results of Lazure and Jégou (1998) for the different wind directions that can induce upwelling along the French Atlantic coast (see Introduction Section).…”

Section: Southern Brittany Upwellingmentioning

confidence: 99%

Mesoscale hydrological variability induced by northwesterly wind on the French continental shelf of the Bay of Biscay

Puillat¹,

Lazure²,

Jégou³

et al. 2006

Sci. Mar.

View full text Add to dashboard Cite

SUMMARY: On the French continental shelf of the Bay of Biscay the variability of the surface salinity distribution has been mainly investigated at the seasonal and inter-annual scales. Here, new mesoscale features such as lower-salinity lenses observed in model results are investigated by hydrological measurements acquired during 8 cruises (1997)(1998)(1999)(2000). These lenses are 50-80 km wide and ~30 m thick and occur during westerly to northerly wind events that push offshore the less saline water of river plumes. These water masses detached from the coast are replaced with upwelled saltier water at the coast, so coastal upwelling is often observed at the same time along Landes and southern Brittany coasts. We show that in addition to the influence of seasonal and inter-annual variability of the wind and river outflows, short term meteorological variability may drive mesoscale structures on this continental shelf.Keywords: salinity, mesoscale, lens, upwelling, river plume. RESUMEN: VARIABILIDAD HIDROLÓGICA DE MESOESCALA INDUCIDA POR LOS VIENTOS DEL NOROESTE SOBRE LA PLATAFORMA CONTINENTAL DEL GOLFO DE VIZCAYA. -La salinidad de la plataforma continental francesa del golfo de Vizcaya fue estudiada a escalas anuales e interanuales principalmente. A partir de medidas efectuadas durante ocho campañas marinas (1997)(1998)(1999)(2000) y del empleo de modelos matemáticos han podido estudiarse nuevas estructuras hidrológicas aisladas de menor salinidad en forma de lentejas. Estas lentejas han medido entre 50 y 80 km de diámetro y 30 m de espesor. Este fenómeno ha sido observado durante, o después, de fuertes vientos del cuadrante oeste o noroeste que favorecen el desplazamiento del agua desalada de las plumas fluviales hacia el mar abierto. Al separarse de la pluma, estas masas de agua son remplazadas por otra, mas salada, que resurge en la zona costera. De esta manera, puedan observarse simultáneamente afloramientos costeros en las regiónes francesas de Landes y del sur de Bretaña. Se muestra que, además de la variabilidad anual e interanual de los vientos y del caudal de los ríos, los fenómenos meteorológicos a corto plazo pueden condicionar las estructuras hidrológicas de la meso escala de la plataforma continental.Palabras clave: salinidad, meso escala, afloramientos costeros, pluma fluvial.

show abstract

“…This bloom occurs mainly between the middle of April and the beginning of May (Gowen et al 1999;Rees et al 1999;Joint et al 2001). Over the shelf, phytoplankton production is influenced by changes in nutrient advection at the shelf edge (Pingree et al 1981(Pingree et al , 1982. The phytoplankton species composition varies both annually and geographically and it is influenced by dissolved nutrient ratios as well as vertical mixing events (Martin-Jézéquel and Videau 1992;Van Oostende et al 2012).…”

Section: Productivitymentioning

confidence: 99%

Recent benthic foraminiferal assemblages from the Celtic Sea (South Western Approaches, NE Atlantic)

Dorst

Schönfeld

Walter³

2014

Paläontol Z

View full text Add to dashboard Cite

The faunal composition and diversity pattern of Recent benthic foraminifera from the shelf and slope of the South Western Approaches (Celtic Sea) were assessed. The sampling stations cover a depth range from 100 to 500 m. A total number of 294 species was recorded, of which 89 were found exclusively in the living fauna and 118 only in the dead assemblage, whereas 87 species were found in both assemblages. The faunal composition revealed a distinct bisection of the living fauna on the shelf. While certain distribution patterns of living dominant species were recognized along a NE-SW trending transect towards the shelf edge, the living fauna changed within small depth intervals and geographic position on the slope.Causes for this structured slope assemblages were probably along-slope currents of varying strengths, as well as variations in topography and bottom sediments. Analyses of population densities and diversity patterns determined high densities along the shelf edge and at one slope station, as well as an increasing diversity with water depth. A comparison with literature data from the same area yields distinct differences in faunal composition on the shelf and slope. The diversity was similar on the shelf, but higher at corresponding stations on the slope. We conclude that the faunal composition was highly influenced by the time and methods of sampling. In order to obtain consistent results in regional studies, all samples 1 should be taken in a short time interval and by using the same sampling device. In addition, we depicted the influences of environmental parameters on dead faunal assemblages and their consequences for paleoenvironmental interpretations of fossil foraminiferal assemblages. Keynotes

show abstract

Celtic Sea and Armorican current structure and the vertical distributions of temperature and chlorophyll

Cited by 113 publications

References 12 publications

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay

Mesoscale hydrological variability induced by northwesterly wind on the French continental shelf of the Bay of Biscay

Recent benthic foraminiferal assemblages from the Celtic Sea (South Western Approaches, NE Atlantic)

Contact Info

Product

Resources

About