DOI: 10.5281/zenodo.14887660
title: Genbank Accession Numbers of Habitat specificity modulates the bacterial biogeographic patterns in the Southern Ocean

description: This dataset contains the accession numbers of BioSamples and SRA for 54 DNA raw sequences extracted from the microbiome of the sea urchins Abatus cavernosus and Abatus agassizii associated with the BioProject PRJNA1065352. Scientific names, localities, and the latitude/longitude of the hosts are also included.

Scientific name marked as not applicable correspond to external substrate samples.
description: Conceptual biogeographic frameworks have proposed that the relative contribution of environmental and geographical factors on microbial distribution depends on several characteristics of the habitat (e.g. environmental heterogeneity, species diversity, and proportion of specialist/generalist taxa), all of them defining the degree of habitat specificity, but few experimental demonstrations exist. Here, we aimed to determine the effect of habitat specificity on bacterial biogeographic patterns and assembly processes in benthic coastal ecosystems of the Southern Ocean (Patagonia, Falkland/Malvinas, Kerguelen, South Georgia, and King George Islands), using 16S rRNA gene metabarcoding. The gradient of habitat specificity resulted from a ‘natural experimental design’ provided by the Abatus sea urchin model, from the sediment (least specific habitat) to the intestinal tissue (most specific habitat). The phylogenetic composition of the bacterial communities showed a clear differentiation by site, driven by a similar contribution of geographic and environmental distances. However, the strength of this biogeographic pattern decreased with increasing habitat specificity: sediment communities showed stronger geographic and environmental divergence compared to gut tissue. The proportion of stochastic and deterministic processes contributing to bacterial assembly varied according to the geographic scale and the habitat specificity level. For instance, an increased contribution of dispersal limitation was observed in gut tissue habitat. Our results underscore the importance of considering different habitats with contrasting levels of specificity to better understand bacterial biogeography and assembly processes over oceanographic scales.
description: The authors would like to thank the INACH (Instituto Antártico Chileno) staff at Professor Julio Escudero Antarctic Research Station for logistic facilities during sampling campaigns in King George Island, South Shetland Islands. The authors are grateful to the Government of South Georgia and South Sandwich Islands (GSGSSI), South Atlantic Environmental Research Institute (SAERI), Natural History Museum (NHM) London, and the Shallow Marine Surveys Group (SMSG) for organizing the research cruise (Operation Himantothallus, Darwin Plus Marine Biodiversity Research Cruise, Pharos SG-11–2021). The research cruise that went to South Georgia was funded by GSGSSI and a Darwin Plus Grant (DPLUS122) to the N.H.M. This study is a contribution to project #1044 PROTEKER from the French Polar Institute. The authors are indebted to S Motreuil, PY Pascal, and G Marty for sampling in Kerguelen. This research was partially supported by the supercomputing infrastructure of the NLHPC (CCSS210001).