High coccolithophore biodiversity in the NW Mediterranean

Abstract

Coccolithophores are one of the main groups of calcifying organisms on Earth today. The NW Mediterranean, from where more than 150 coccolithophore taxa have been described, represents a biodiversity hot-spot for these calcifying organisms. In addition, coccolithophores present life cycle phases with different morphologies and ecological strategies, enabling each taxon to occupy various environmental niches. This communication presents a study of coccolithophore samples obtained during three cruises (Famoso project) carried out in deep convection region of the NW Mediterranean, in mid-March, April-May and September 2009, covering the seasonal changes between the diatom-dominated winter-spring bloom (mid-March), the post-bloom period (April-May) and the stratification period (September). In general, there was a high coccolithophore biodiversity, with a marked increasing trend from mid-March to September, in parallel with a decrease of the relative abundance of Emiliania huxleyi. Our results suggest a general preference of most coccolithophore taxa for relatively oligotrophic waters and confirm the ecological importance of this phytoplankton group in the open NW Mediterranean Sea