Novel combination coccospheres from Helicosphaera spp indicate complex relationships between species

• Published in: Journal of Plankton Research
• Main Authors: Sturm, Daniela, Langer, Gerald, Wheeler, Glen
• Other Authors: National Research Council
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2022
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Southern Ocean
• Online Access: http://dx.doi.org/10.1093/plankt/fbac044; https://academic.oup.com/plankt/article-pdf/44/6/838/47210089/fbac044.pdf

Abstract 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.