The carbon cycle at the ocean margin in the northern Gulf of Biscay

Wollast, Roland; Chou, Lei

doi:10.1016/s0967-0645(01)00040-6

Cited by 55 publications

(40 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Ocean Margin EXchange project (OMEX) I, 1993-1996, was over Goban Spur (e.g. Wollast and Chou, 2001). Celtic Sea studies include internal tides (e.g.…”

Section: Observationsmentioning

confidence: 99%

Deep ocean exchange with west-European shelf seas

2009

View full text Add to dashboard Cite

Abstract. We review mechanisms and studies of exchange between the north-east Atlantic and the adjacent shelf seas. Well-developed summer upwelling and associated filaments off Portugal and north-west Spain give exchange O(3 m 2 /s per unit length of shelf). Prevailing westerly winds further north drive exchange O(1 m 2 /s). Poleward flow along most of the upper slope has associated secondary circulation O(1 m 2 /s), meanders and eddies. Eddies are shed from slope waters into the Bay of Biscay, and local exchanges occur at shelf spurs and depressions or canyons (e.g. dense-water cascading of order 1 m 2 /s). Tidal transports are larger, but their reversal every six hours makes exchange largely ineffective except where internal tides are large and non-linear, as in the Celtic Sea where solitons carry water with exchange O(1 m 2 /s). These various physical exchanges amount to an estimated 2-3 m 2 /s per unit length of shelf, between ocean and shelf. A numerical model estimate is comparable: 2.5×10 6 m 3 /s onto and off the shelf from Brittany to Norway. Mixing controls the seasonal thermocline, affecting primary production and hence fluxes and fate of organic matter. Specifically, CO 2 take-up by primary production, settling below the thermocline before respiration, and then off-shelf transport, make an effective shelf-sea "pump" (for CO 2 from the atmosphere to the deep ocean). However, knowledge of biogeochemical fluxes is generally sparse, giving scope for more measurements, model validation and estimates from models.

show abstract

“…The Ocean Margin EXchange project (OMEX) I, 1993-1996, was over Goban Spur (e.g. Wollast and Chou, 2001). Celtic Sea studies include internal tides (e.g.…”

Section: Observationsmentioning

confidence: 99%

Deep ocean exchange with west-European shelf seas

2009

View full text Add to dashboard Cite

show abstract

“…4a), with temperatures in surface waters ranging from 13.0 to 14.0 1C (Table 2) Table 2). Stations located on the continental slope (2 and 5) showed less stratification due to enhanced vertical mixing related to internal tides (Pingree et al, 1999;Wollast and Chou 2001). Stratification increased from the first to the second leg.…”

Section: Biogeochemical Settings In June 2006mentioning

confidence: 99%

“…These hydrographic properties are evidenced by the distribution of sea surface temperature (SST) on satellite images, where a cold patch of water streches during spring and summer, when sufficient stratification has developed, between the 200 m and the 2000 m isobaths . The vertical mixing occurs by pulses at the shelf break and erodes the seasonal thermocline leading to the upward transport of deeper water, sustaining biological activity during spring and summer by supplying nutrients to the photic zone (Pingree et al, 1986;Joint et al, 2001;Wollast and Chou, 2001;Sharples et al, 2007Sharples et al, , 2009). Sharples et al (2007) showed that during spring tides, enough nitrate pulses are released to the photic zone to sustain new production of phytoplankton and to induce shifts in the plankton community on a fortnighly basis (spring and neap tide oscillations).…”

Section: Study Sitementioning

confidence: 99%

“…Along the shelf break, several patches of cold water (SST o14 1C) were observed in the studied area (Fig. 4a), corresponding to the signature of enhanced vertical mixing due to internal tides (Pingree et al, 1999;Wollast and Chou 2001). These patches of cold waters were characterized by lower Chl-a levels ( $ 0.4 mg L À 1 ) and were surrounded by waters exhibiting higher Chl-a values ( 40.8 mg L À 1 ) on-shelf and off-shore (Fig.…”

Section: Biogeochemical Settings In June 2006mentioning

confidence: 99%

See 1 more Smart Citation

Biogeochemistry and carbon mass balance of a coccolithophore bloom in the northern Bay of Biscay (June 2006)

Harlay

Chou

Bodt

et al. 2011

Deep Sea Research Part I: Oceanographic Research Papers

View full text Add to dashboard Cite

a b s t r a c tPrimary production (PP), calcification (CAL), bacterial production (BP) and dark community respiration (DCR) were measured along with a set of various biogeochemical variables, in early June 2006, at several stations at the shelf break of the northern Bay of Biscay. The cruise was carried out after the main spring diatom bloom that, based on the analysis of a time-series of remotely sensed chlorophyll-a (Chl-a), peaked in mid-April. Remotely sensed sea surface temperature (SST) indicated the occurrence of enhanced vertical mixing (due to internal tides) at the continental slope, while adjacent waters on the continental shelf were stratified, as confirmed by vertical profiles of temperature acquired during the cruise. The surface layer of the stratified water masses (on the continental shelf) was depleted of inorganic nutrients. Dissolved silicate (DSi) levels probably did not allow significant diatom development. We hypothesize that mixing at the continental slope allowed the injection of inorganic nutrients that triggered the blooming of mixed phytoplanktonic communities dominated by coccolithophores (Emiliania huxleyi) that were favoured with regards to diatoms due to the low DSi levels. Based on this conceptual frame, we used an indicator of vertical stratification to classify the different sampled stations, and to reconstruct the possible evolution of the bloom from the onset at the continental slope (triggered by vertical mixing) through its development as the water mass was advected on-shelf and stratified. We also established a carbon mass balance at each station by integrating in the photic layer PP, CAL and DCR. This allowed computation at each station of the contribution of PP, CAL and DCR to CO 2 fluxes in the photic layer, and how they changed from one station to another along the sequence of bloom development (as traced by the stratification indicator). This also showed a shift from net autotrophy to net heterotrophy as the water mass aged (stratified), and suggested the importance of extracellular production of carbon to sustain the bacterial demand in the photic and aphotic layers.

show abstract

“…Water masses from the Bay of Biscay run alongside the shelf edge in a NNW direction. This flow is connected with a higher supply of food particles (New 1988;Wollast and Chou 2001) by enhanced primary production (Joint et al 2001;Van Oostende et al 2012). This process seems to favor the abundance of C. obtusa.…”

Section: Distribution Pattern Of Abundant Species In the Living Faunamentioning

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

The carbon cycle at the ocean margin in the northern Gulf of Biscay

Cited by 55 publications

References 57 publications

Deep ocean exchange with west-European shelf seas

Deep ocean exchange with west-European shelf seas

Biogeochemistry and carbon mass balance of a coccolithophore bloom in the northern Bay of Biscay (June 2006)

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

Contact Info

Product

Resources

About