Japan Geoscience Union Meeting 2023

Presentation information

[E] Online Poster

B (Biogeosciences ) » B-CG Complex & General

[B-CG05] Diversity and ecology of marine protists -from past to present

Thu. May 25, 2023 1:45 PM - 3:15 PM Online Poster Zoom Room (12) (Online Poster)

convener:Rie Hori, S.(Department of Earth Science, Faculty of Science, Ehime University), Yasuhide Nakamura(Estuary Research Center, Shimane University), Tristan Biard(UMR8187)


On-site poster schedule(2023/5/26 17:15-18:45)

1:45 PM - 3:15 PM

[BCG05-P03] Genetic insights into ecology and evolution of the deep-sea foraminifer Chilostomella ovoidea and its endobiotic plastid

*Iines Sandra Salonen1, Filip Husnik2, Yoshiyuki Ishitani1, Julien Richirt1, Hidetaka Nomaki1 (1.SUGAR, X-star, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2.Husnik Unit, Okinawa Institute of Science and Technology (OIST))

Keywords:Foraminifera, Plastid, Symbiont, Sediment

Foraminifera are single-celled eukaryotes abundant in marine benthic environments, where they play key roles in variety of biogeochemical cycles such as those of carbon and nitrogen. They are a diverse group widespread in world’s oceans, some species being able to even thrive in hypoxic conditions. To do so, they show different ecological strategies, for example some of them harbor symbiotic bacteria, and others collect and retain chloroplasts, highlighting their various ways of adaptation. However, despite their abundance and importance to the benthic ecosystem, the ecology and evolution of many species as well as their symbionts remains poorly understood.

Chilostomella ovoidea is a foraminiferal species commonly found in bathyal deep-sea sediments. It is able to tolerate hypoxic conditions and inhabit sediment layers deeper than the oxygen penetration depth. Previous research has indicated that C. ovoidea has several unique traits that are not encountered in other foraminiferal species. Those characteristics include, for example, unique carbon isotopic compositions of its lipids and abundant chitinous structures in its cytoplasm. The microbiome of C. ovoidea is also notably distinctive, containing a low diversity of potentially symbiotic bacteria. In addition, C. ovoidea harbors a unique plastid, of which the function and origin have been unresolved.

Genomic and transcriptomic analyses have emerged as a potential tool to provide new insights into the ecology and evolution of foraminifers and their potential symbionts. Here, we utilized transcriptomics to investigate the metabolic pathways of C. ovoidea and single-cell genomics to analyze the identity and function of its intracellular plastid. Preliminary results indicate that the plastid associated with C. ovoidea is unlike those that have been described in foraminifers before, suggesting a potentially unique co-evolution between this species and its plastid. These findings indicate that C. ovoidea manifests a completely different ecological strategy from other foraminiferal species thriving in oxygen depleted environments and may help us to better understand how foraminifers adapt to such adverse conditions.