Diversity and Functioning of Antarctic Seaweed Microbiomes

Antarctic macroalgae are important primary producers and habitat-forming species that play fundamental roles in Antarctic coastal habitats and sustain important communities of benthic organisms, including a not well-known microbiota. Anthropogenic pressures, e.g., increasing ocean temperatures and extreme events, have threatened the ecological integrity of several seaweed species and also can modify the range shifts (e.g., introduction of Durvillaea antarctica in King George Island), cause local extinctions, and alter the structure of these associations in their natural habitats. However, understanding and prediction of the responses of seaweeds to changing environment and rapid anthropogenic-driven change cannot be done without considering the associated microbiome. These complex microbial communities are intricately involved in the host health, defense, growth, and development of seaweeds, thus with far-reaching implications for the ecology of the whole coastal ecosystem. For most Antarctic seaweeds, the microbiome comprises a stable core as well as microbes whose presence depends on local conditions and transient microbial associates that are responsive to biotic and abiotic processes across spatial and temporal scales. In this chapter, we will explore the ecological and genetic diversity of microbiomes in Antarctic seaweeds and their functional connections.