Distribution, sedimentation and fate of pigment biomarkers following thermal stratification in the western Alboran Sea

Abstract

A spring investigation of the phytoplankton was undertaken using chlorophyll and carotenoid biomarkers to characterize the community in the water column and in drifting sediment traps set at 100 and 200 m. Thermal stratification reduced pigment sedimentation into deeper water and confined the phytoplankton to the surface layer, resulting in an increase in chlorophyll biomass. 19'-Hexanoyloxyfucoxanthin and chlorophyll b were the major accessory pigments, while fucoxanthin, alloxanthin and peridinin indicated the presence of diatoms, cryptophytes and dinoflagellates, respectively. Prymnesiophytes, crytophytes and the green alga group collectively accounted for at least 75% in the upper 100 m, emphasizing the importance of the nanophytoplankton. Phaeopigments, dominated by phaeophorbide a2, were the main pigments observed in sediment traps. -from Authors