Biogenic Flux: characterization and quantification of the sediment trap samples collected at 150 m depth in the Canary basin, Spain

Abstract

Aeolian Saharan dust is transported from the Saharan desert to the Atlantic Ocean surface, starting then a sinking process. It is interesting to observe this process in the oceanic-climatic scenario because its iron minerals content (hematite and goethite mainly) that acts as a natural ocean fertilizer. The objective of this work was to study the biogenic particles of the filters collected with a sediment trap on April 2011 in the Canary Basin at 150 m depth and 11.5 miles from the north Coast of Gran Canaria Island (LUCIFER project) and the possible relation of the biogenic flux with the Saharan dust events. The analyzed plume dust was generated in Western Sahara and North of Mauritania. The nocturnal samples especially that of the night of April 4 are those that presented more biogenic material. The main components founded in the samples were foraminifera (calcite), copepods (chitin), gastropods (aragonite) and transparent exopolymer particles. The mean flux of chitin was 25.2 mg m-2 12h-1 and 1.1 mg m-2 12h-1 for foraminiferal flux. If we compare our results with other parameters analyzed in a priori studies, they all show a similar trend. This study helps to quantify the effect of Saharan dust episodes in the biogenic particulate oceanic fluxes.