Novel combination coccospheres from Helicosphaera spp indicate complex relationships between species

• Published in: Journal of Plankton Research
• Main Authors: Sturm, D, Langer, G, Wheeler, G
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press 2022
• Subjects: Aquaculture; Biology; Ecology and Environment; Marine Sciences; Southern Ocean
• Online Access: http://plymsea.ac.uk/id/eprint/9784/; http://plymsea.ac.uk/id/eprint/9784/1/doi/10.1093/plankt/fbac044/6670720; https://academic.oup.com/plankt/advance-article/doi/10.1093/plankt/fbac044/6670720

Coccolithophores play an important role in global biogeochemical cycling, but many aspects of their ecology remain poorly understood, including their heteromorphic haplo-diplontic life cycle. The presence of combination coccospheres in environmental samples, which represent a transition between the lightly calcified haploid (HOL) and heavily calcified diploid (HET) life phases, provides crucial evidence linking the two life cycle phases of a particular species. Here, we describe combination coccospheres from the Southern Ocean that show a novel association between Helicosphaera hyalina (HET) and Helicosphaera HOL catilliferus type. The ability of Helicosphaera HET and HOL morphospecies to form multiple different combinations indicates a substantial complexity in the relationships between life cycle phases in this group. The findings suggest recent divergence within the Helicosphaera lineage may have resulted in significant inter- and intra-specific variability, with cryptic speciation in one or both life cycle phases contributing to their ability to form multiple HET/HOL associations.