Diversity, drivers and dispersal of East Antarctic soil microbiota

• Main Author: Zhang, Eden
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UNSW, Sydney 2021
• Subjects: Antarctica; Soil Microbiome; Microbial Ecology; Climate Change; anzsrc-for: 4106 Soil sciences; anzsrc-for: 310703 Microbial ecology; Antarctic; Vestfold; Vestfold Hills; Windmill Islands; Antarc*
• Online Access: http://hdl.handle.net/1959.4/100134; https://unsworks.unsw.edu.au/bitstreams/8b66f78d-02cb-4f17-bbfc-e76f56b429a4/download; https://doi.org/10.26190/unsworks/2044

Microbes are the life support system of the biosphere. Their metabolic activities have been tightly linked to establishing and maintaining core ecosystem processes around the globe, including the polar deserts of terrestrial Antarctica. Shaped by the continent’s extreme abiotic constraints and physical isolation, core ecosystem processes such as primary production and geochemical cycling often involve unique taxa with novel functional traits thus emphasizing the high conservational value of endemic microbiota. Up till now, microorganisms were rarely considered in Antarctic conservation frameworks despite growing concerns about complex environmental change and our anthropogenic footprint. Major gaps in biodiversity surveys and a general lack of understanding in the basic ecological concepts (niche and neutral) underlying the assemblage of Antarctic soil microbial communities has led to their poor protection status and regional sampling bias. Systematic retrieval of baseline data across the continent is therefore much needed, especially in Eastern Antarctica. In support of bridging this gap, we combined a comprehensive amplicon survey (>700 soil samples) with multivariate analyses and high-end modelling approaches to discern biogeographic patterns of polar soil bacteria, micro-eukarya and archaea throughout two coastal regions in Eastern Antarctica – the Windmill Islands and hyperarid Vestfold Hills. This thesis entails three simple but important mission statements: (1) to unveil the diversity of East Antarctic soil microbiota using a multi-domain approach; (2) to identify key edaphic drivers and threshold tipping points by advancing methods for quantifying multispecies responses to change along environmental gradients; and (3) to explore the influence of wind-driven dispersal as a new initiative for monitoring ecosystem change using a combination of dust samples and particulate trajectory modelling with historical climate data. Soil biodiversity profiles and co-occurrence networks found bacteria, micro-eukarya ...