Coccolithophore life-cycle dynamics in a coastal Mediterranean ecosystem: seasonality and species-specific patterns

• Published in: Journal of plankton research Vol. 38; no. 5; pp. 1178 - 1193
• Main Authors: Šupraha, Luka, Ljubešić, Zrinka, Mihanović, Hrvoje, Henderiks, Jorijntje
• Format: Journal Article
• Language: English
• Published: 01.09.2016
• ISSN: 0142-7873; 1464-3774; 1464-3774
• DOI: 10.1093/plankt/fbw061

Coccolithophores (calcifying haptophyte algae) commonly exhibit a heteromorphic life cycle, alternating between morphologically distinct heterococcolith (diploid) and holococcolith (haploid) phases. The prevalence of each life phase in a coccolithophore community defines its overall ecological and biogeochemical performance due to differences in physiology, biomass and calcification. The main drivers of life-cycle dynamics and ecological preferences of the two life-phases are still unclear and field data of high taxonomic resolution are needed. We investigated the distribution and abundance patterns of the life-phases of 14 coccolithophore species. The study was conducted along the strong environmental gradients of the Krka River estuary (Eastern Adriatic Sea) during winter (February) and summer (July) 2013. The results reveal characteristic life-phase seasonality with an overall dominance of the heterococcolith phase during winter and a holococcolith phase during summer. However, we also detected exceptions to the strictly seasonal patterns as well as species-specific ecological preferences. Our findings provide new insights into coccolithophore life-phase dynamics in the Mediterranean Sea that will further advance the understanding of ecology and evolution of the group.