ORCID

Document Type

Article

Abstract

Background: Antarctic marine food webs are expected to be significantly impacted by future climate change. In particular, the recent rapid regional warming in the West Antarctic Peninsula has, and will continue to have, a negative impact on endemic marine biodiversity. However, despite the growing recognition of the role microbial symbionts play in mediating responses to environmental change, microbiome characterisation has been conducted for only a small fraction of the marine invertebrates in the Southern Ocean. Our study examined the effects of feeding guild, seasonality, and experimental warming (6 months at + 2 °C) on the gut microbiome of six species of near-shore marine Antarctic echinoderms sampled from waters off Rothera Research Station, Antarctica. Our study used 16 S rRNA amplicon sequencing of the V3-V4 region, with analyses including measurements of alpha and beta-diversity alongside co-occurrence network analyses. Results: Of the six invertebrate species sampled in winter, peak species diversity values in gut microbiomes were observed in the omnivores, Ophionotus victoriae and Sterechinus neumayeri, with lower values in the scavenger/predator, Odontaster validus, and the suspension feeders, Cucumaria georgiana, Echinopsolus charcoti, and Heterocucumis steineni. In the seasonal experiment, H. steineni bacterial gut species diversity doubled from winter to early summer yet decreased by a similar magnitude during the same period in O. victoriae. Despite these opposing diversity trends, both species displayed similar increases in the relative abundances of Bacteroidota and Bacillota in winter and early summer in their gut microbiomes. Bacterial diversity in the gut microbiome of the sea cucumbers E. charcoti and H. steineni, was not impacted by six-months at + 2 ˚C above ambient, although C. georgiana displayed a decrease in observed ASVs following this treatment. Conclusions: These results suggest a strong influence of feeding guild and seasonality on the gut microbiomes of these invertebrates. There appeared to be little effect of warming (+ 2 °C) on the taxonomic composition of the gut microbiomes of the three holothurians. This highlights the need to examine the functional significance of experimental warming treatments using metabolomics and transcriptomics alongside microbial species diversity analyses to understand whether gut microbiomes can aid resilience under future climate change.

Publication Date

2026-05-12

Publication Title

BMC Microbiology

Volume

26

Issue

1

Acceptance Date

2026-04-29

Deposit Date

2026-10-06

Funding

This work and KH were supported by the Natural Environment Research Council (NERC) and ARIES Doctoral Training Partnership, grant reference: NE/S007334/1; UK Research and Innovation (UKRI)/NERC core funding to BAS (MSC and LSP); GGJ is supported by the South African Medical Research Council (MRC), with funds received from the South African National Department of Health, and the United Kingdom MRC, with funds received from the UK Government’s Newton Fund (awarded to MU). The work between SS and KH was funded by a departmental grant awarded by the University of Cambridge, Department of Veterinary Medicine.

Keywords

Brittle star, Diet, Gut microbiome, Holothurian, Invertebrate, Marine, Metabarcoding, Sea star, Sea urchin, Season, Antarctic Regions, Bacteria/classification, RNA, Ribosomal, 16S/genetics, Feeding Behavior, Biodiversity, Echinodermata/microbiology, Food Chain, Animals, Climate Change, Gastrointestinal Microbiome/genetics, Seasons

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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