Dynamics of Sediments Exchange and Transport in the Bay of Cadiz and the Adjacent Continental Shelf (SW - Spain)

AbstractThe distribution of clay minerals in recent sediments on the continental shelf and in the Bay of Cádiz has been analysed as part of a wider study of sedimentary exchange between the continent and the continental margin. The clay minerals included in the muddy sediments consist mainly of illite, kaolinite, smectite, randomly mixed-layered illite-smectite, chlorite, vermiculite and randomly mixed-layered illite-chlorite. Distribution of the minerals indicates that inheritance from the adjacent continental areas is the most important process involved.The relations between the clay minerals were established by Q-mode and R-mode factor analysis. The main clay mineral associations are: (1) illite-kaolinite, (2) smectite-random mixed-layered illitesmectite, and (3) kaolinite-random mixed-layered illite-smectite-vermiculite. The main sources of sediment supply to the continental shelf are the Guadalquivir and Guadiana rivers. Sediment from these rivers and from the rivers flowing into the Bay of Cádiz (mainly the Guadalete) is transported to the part of the shelf outside the bay by ebb-tide currents. The path of this outflow to the continental shelf, where the sediment is partially deposited, is influenced by the morphology of the coast and by hydrodynamic processes.

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Composition and Transport Dynamics of Suspended Particulate Matter in the Bay of Cadiz and the Adjacent Continental Shelf (SW - Spain)

Sediment Transport Processes and Their Modelling Applications ◽

10.5772/51104 ◽

2013 ◽

Author(s):

Mohammed Achab

Keyword(s):

Particulate Matter ◽

Continental Shelf ◽

Suspended Particulate Matter ◽

Transport Dynamics ◽

Sw Spain ◽

Suspended Particulate ◽

Bay Of Cadiz ◽

Bay Of Cádiz

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Tidal and seasonal carbon and nutrient dynamics of the Guadalquivir estuary and the Bay of Cádiz (SW Iberian Peninsula)

Biogeosciences ◽

10.5194/bg-10-4481-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 4481-4491 ◽

Cited By ~ 10

Author(s):

M. Ribas-Ribas ◽

E. Anfuso ◽

A. Gómez-Parra ◽

J. M. Forja

Keyword(s):

Continental Shelf ◽

Nutrient Dynamics ◽

Diurnal Changes ◽

Gulf Of Cadiz ◽

Mean Velocity ◽

Guadalquivir Estuary ◽

Gulf Of Cádiz ◽

The Mean ◽

Bay Of Cadiz ◽

Bay Of Cádiz

Abstract. To study the effects of the physical environment on carbon and nutrient cycle dynamics on the north-eastern shelf of the Gulf of Cádiz, changes in currents, tides, salinity, temperature, carbon system parameters (fugacity of CO2 (fCO2), dissolved organic carbon, dissolved inorganic carbon (DIC) and pH) and other related parameters(dissolved oxygen, total dissolved nitrogen (TDN), nutrients and suspended particulate matter) were measured in transects across the Guadalquivir estuary and Bay of Cádiz mouths. The main objective of this study is to investigate the influence of these inner ecosystems on the carbon and nutrient distributions on the adjacent continental shelf. Three cruises were undertaken in June 2006, November 2006 and February 2007. During the whole study period, Guadalquivir estuary exported components at a rate of 3 Gmol of SiO2, 4 Gmol of DIN, 3 Gmol of TDN, 31 Gmol of DOC and 604 Gmol of DIC per year. On the other hand, Bay of Cádiz imported 3 Gmol of SiO2, 1 Gmol of DIN, 2 Gmol of TDN, 33 Gmol of DOC and 562 Gmol of DIC per year. Diurnal variability of fCO2 could have a potentially important implication on the estimate of air–sea CO2 fluxes. Tides influence velocity and transport of carbon and nutrients: we found statistically significant differences (p < 0.0001, n = 220) between the flood tide (the mean velocity was 4.85 cm s–1) and the ebb tide (the mean velocity was −5.67 cm s–1). Biological activity and diurnal changes have also an important role on the carbon and nutrient dynamics. Seasonal carbon and nutrient variations were found. During June, both systems were exporting components to the adjacent continental shelf of the Gulf of Cádiz, whereas in February both systems were importing. Monthly studies should be undertaken to completely understand this dynamic system.

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Tidal and seasonal carbon and nutrients dynamics of the Guadalquivir Estuary and the Bay of Cádiz (SW Iberian Peninsula)

Biogeosciences Discussions ◽

10.5194/bgd-9-14537-2012 ◽

2012 ◽

Vol 9 (10) ◽

pp. 14537-14558

Author(s):

M. Ribas-Ribas ◽

L. I. Carracedo ◽

E. Anfuso ◽

J. M. Forja

Keyword(s):

Continental Shelf ◽

Dissolved Inorganic Carbon ◽

Gulf Of Cadiz ◽

Diurnal Variability ◽

Guadalquivir Estuary ◽

The North ◽

Total Dissolved Nitrogen ◽

Gulf Of Cádiz ◽

Bay Of Cadiz ◽

Bay Of Cádiz

Abstract. To study the effects of the physical environment on carbon and nutrients cycles dynamics in the north eastern shelf of the Gulf of Cádiz, changes in currents, tides, salinity, temperature, carbon system parameters (fugacity of CO2 (fCO2), dissolved organic carbon, dissolved inorganic carbon and pH) and others related (dissolved oxygen, total dissolved nitrogen, nutrients and suspended particulate matter) were measured in transects across the Guadalquivir Estuary and Bay of Cádiz mouths. Thus, the main objective of this study is to investigate the influence of these inner ecosystems on the carbon and nutrient distributions in the adjacent continental shelf. Three cruises have been undertaken in June 2006, November 2006 and February 2007, each one covering one complete tidal cycle during June, both systems were exporting components to the adjacent continental shelf of the Gulf of Cádiz. In an annual scale, Guadalquivir Estuary exported components while Bay of Cádiz imported them. Diurnal variability of fCO2 could have a potentially important implication on the estimate of air-sea CO2 fluxes. Monthly studies should be undertaken to completely understand this dynamic system.

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