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Distribution of modern dinocysts and pollen in the western Mediterranean Sea (Algerian margin and Gulf of Lion)
The Mediterranean Sea is generally described as an oligotrophic area where primary productivity is limited to a few coastal environments with nutrient-enriched fluvial input. However, several studies have revealed that the hydrology of the western Mediterranean has major seasonal productive patterns linked either to significant riverine input or to seasonal upwelling cells. This study aims to: i) discuss organic microfossils (i.e. pollen and dinoflagellate cyst assemblages, as well as other non-pollen palynomorphs) from two different productive areas of the western Mediterranean Sea, and ii) examine the importance of the interconnections between marine and continental influences responsible for modern palynomorph distributions. Based on 25 samples from the Gulf of Lion (GoL) and Algerian Margin, this study key findings are: i) that GoL marine productivity is driven by the combination of discharge from the Rhone River and seasonal upwelling mechanisms, ii) that the strong pro-ductive pattern of the northern African coast is driven by water density front mixings and related upwelling. These two patterns are discussed in the light of major links that provide a better understanding of the signatures of marine and continental bio-indicators. Typical differences in vegetation across the north-south climate gradient in the western Mediterranean Basin are highlighted by the larger ratio of Euro-Siberian to Mediterra-nean pollen taxa in the northern sector. Synoptic maps also illustrate the complex interactions of environmental drivers determining the distributions of continental and marine palynomorphs in the western Mediterranean Sea.
Keyword(s)
Western Mediterranean Sea, Gulf of Lion, Algerian margin, Dinoflagellate cysts, Productivity, Fluvial discharge, Upwelling cells, Pollen and spores, Vegetation gradients, Non-pollen palynomorphs
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File | Pages | Size | Access | |
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Publisher's official version | 20 | 13 Mo | ||
Author's final draft | 56 | 4 Mo |