En este trabajo se estudió la distribución de cocolitos en muestras de sedimentos superficiales del margen ibérico mediterráneo. Se calculó la abundancia total y se representó en un mapa de distribución. La mayor abundancia de cocolitos se registró en tres muestras situadas en los alrededores de las islas Baleares y se relacionó con los aportes de las aguas atlánticas modificadas más modernas (Modified Atlantic Water, MAW). La menor abundancia total se registró cerca de la costa, en el área de acción de la corriente del Norte (NC) y del frente Catalán y se ha relacionado principalmente con los aportes terrígenos del río Ebro. Las abundancias relativas muestran que los pequeños placolitos (Emiliania huxleyi, Gephyrocapsa aperta y Gephyrocapsa ericsonii) son las formas dominantes de la asociación de cocolitos en el Mediterráneo occidental, disminuyendo su abundancia con la distancia a la costa y relacionándolas con concentraciones de nutrientes. La distribución de Gephyrocapsa oceanica y Gephyrocapsa muellerae parece estar relacionada con la MAW de las proximidades del estrecho de Gibraltar y con alguno de los remolinos costeros generados por la corriente de Argelia (AC), respectivamente. Syracosphaera spp. y Helicosphaera spp. también alcanzan una abundancia significativa mostrando una distribución concéntrica en el mar Catalano-Balear. La distribución de Florisphaera profunda, que mostró algunos valores más altos al sur del delta del Ebro, también puede ser de interés biogeográfico.
The distribution of coccoliths in surface sediments from the Mediterranean Iberian Margin is shown in the present study. Total abundance was recorded and represented in a distribution map. Higher abundance was recorded in three samples located in the surroundings of the Balearic Islands related to the contribution of the recent Modified Atlantic Waters (MAW). The lowest total abundance was recorded close to the Iberian shoreline under the influence of the Northern Current (NC) and the Catalan Front and mainly related to the terrigenous runoff of the Ebro River. Relative abundance reveals that the small placoliths (Emiliania huxleyi, Gephyrocapsa aperta and Gephyrocapsa ericsonii) are the dominant group in the Western Mediterranean; decreasing in percentage with distance from the coast and related to nutrient concentrations. Gephyrocapsa oceanica and Gephyrocapsa muellerae distributions seem to be related to the recent MAW close to the Strait of Gibraltar and to some of the coastal eddies generated from the Algerian Current (AC), respectively. Syracosphaera spp. and Helicosphaera spp. also reach significant abundances, having a concentric distribution in the Catalano- Balearic Sea. The distribution of Florisphaera profunda, which has higher values to the south of the Ebro Delta, may also be of biogeographic interest.
Coccolithophore biogeography in the Mediterranean Iberian margin
AMORE F;
2010-01-01
Abstract
The distribution of coccoliths in surface sediments from the Mediterranean Iberian Margin is shown in the present study. Total abundance was recorded and represented in a distribution map. Higher abundance was recorded in three samples located in the surroundings of the Balearic Islands related to the contribution of the recent Modified Atlantic Waters (MAW). The lowest total abundance was recorded close to the Iberian shoreline under the influence of the Northern Current (NC) and the Catalan Front and mainly related to the terrigenous runoff of the Ebro River. Relative abundance reveals that the small placoliths (Emiliania huxleyi, Gephyrocapsa aperta and Gephyrocapsa ericsonii) are the dominant group in the Western Mediterranean; decreasing in percentage with distance from the coast and related to nutrient concentrations. Gephyrocapsa oceanica and Gephyrocapsa muellerae distributions seem to be related to the recent MAW close to the Strait of Gibraltar and to some of the coastal eddies generated from the Algerian Current (AC), respectively. Syracosphaera spp. and Helicosphaera spp. also reach significant abundances, having a concentric distribution in the Catalano- Balearic Sea. The distribution of Florisphaera profunda, which has higher values to the south of the Ebro Delta, may also be of biogeographic interest.File | Dimensione | Formato | |
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