Investigating the dynamics of kelp-associated bacterial microbiomes in Antarctic and sub-Antarctic environments

Host-associated microbiomes (i.e. the community of microbes living on or within a given organism), play crucial roles in shaping physiological processes within their host organisms, influencing immunity, metabolism, and growth. In marine ecosystems, these microbial communities are particularly exposed to environmental influences, with changing climates and extreme weather events potentially driving shifts in microbial community composition.

While Antarctica has long been considered isolated, kelp rafts originating from populations further north are known to reach Antarctic shores. Despite the inability of permanent kelp populations to establish in Antarctic environments thus far, climate change may facilitate colonisation in the future. The successful establishment of kelp populations in Antarctica hinges not only on the suitability of local climatic conditions, but also on the persistence or adaptation of their microbiomes, without which the health of the plant is likely to deteriorate.

Our study aims to characterise and compare the bacterial microbiomes associated with macroalgae (Durvillaea antarctica and Macrocystis pyrifera) across various sites throughout the Southern Ocean. Through the collection of kelp swab and tissue samples from sub-Antarctic islands and Antarctia, we seek to compare and track bacterial community composition between these sites using 16S amplicon sequencing and host genomics. Additionally, we will determine the influence of the environment on kelp microbiomes using concurrently collected environmental samples. By doing so, we aim to provide insights into the stability of bacterial communities associated with kelp and the potential for kelp rafts to transport or adapt their microbial communities for new locations.

Our findings hold significance for understanding potential future changes in Antarctic ecosystems resulting from climate change and shed light on the mechanisms underlying microbial community dynamics in marine environments.