Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

Abstract

The global biogeography of microorganisms remains poorly resolved, which limits the current understanding of microbial resilience toward environmental changes. Using high-throughput 16S rRNA gene amplicon sequencing, we characterized the microbial diversity of terrestrial and lacustrine biofilms from the Arctic, Antarctic and temperate regions. Our analyses suggest that bacterial community compositions at the poles are more similar to each other than they are to geographically closer temperate habitats, with 32% of all operational taxonomic units (OTUs) co-occurring in both polar regions. While specific microbial taxa were confined to distinct regions, representing potentially endemic populations, the percentage of cosmopolitan taxa was higher in Arctic (43%) than in Antarctic samples (36%). The overlap in polar microbial OTUs may be explained by natural or anthropogenically-mediated dispersal in combination with environmental filtering. Current and future changing environmental conditions may enhance microbial invasion, establishment of cosmopolitan genotypes and loss of endemic taxa.

Microbial dispersal limitation to isolated soil habitats in the McMurdo Dry Valleys of Antarctica

“…A global theoretical model for atmospheric aerosols estimated that the rate of airborne microbial exchange to Antarctica may be extremely low, with 90% of aerosols expected to be of local origin 34 . In contrast, empirical studies have claimed circum-polar distribution for some Cyanobacteria, chlorophyte algae, and Fungi 22,30,35 . Antarctica therefore presents a paradox in microbial biogeography with regard to microbial dispersal.…”

“…Antarctica is a focus for microbial ecology research due to its geographic isolation, lack of trophic complexity and human influence 20 and vulnerability of endemic biodiversity to climate change 21 . The extent to which airborne immigration may influence isolated Antarctic terrestrial microbial communities, however, is an enduring enigma in microbial ecology 22–25 . Highly specialised microbial communities display strong allopatric signals 26–29 , yet microbial dispersal is conventionally viewed as occurring across inter-continental distances 22,30 .…”

“…The extent to which airborne immigration may influence isolated Antarctic terrestrial microbial communities, however, is an enduring enigma in microbial ecology 22–25 . Highly specialised microbial communities display strong allopatric signals 26–29 , yet microbial dispersal is conventionally viewed as occurring across inter-continental distances 22,30 . Establishing the extent to which Antarctic communities are connected to the global system via airborne dispersal also has key relevance to predicting potential responses of polar ecosystems to environmental change.…”

Phenotypes Associated with Pathogenicity: Their Expression in Arctic Fungal Isolates

“…Due to their small size, microorganisms generally disperse over large distances, decreasing the impact of geographical barriers [7,8]. At least for some species, a constant exchange of populations between fairly remote habitats is possible [9]. For fungi, and in particular those inhabiting the poles, the main dispersal vector is the air [10].…”

Does size really matter in biogeography? Patterns and drivers of global distribution of marine micro‐ and meiofauna

“…Several well‐defined morphospecies of acanthoecid choanoflagellates isolated from both poles showed very low genetic differences and were very similar regarding their salinity and temperature tolerances (Nitsche & Arndt, ). A high degree of commonality between northern and southern polar communities was demonstrated by next‐generation sequencing (Kleinteich et al, ; Wolf, Kilias, & Metfies, ). Sufficient evidence exists to support the leading role of environmental selection and climatic conditions in particular in structuring flagellate (Lansac‐Tôha, Meira, Segovia, Lansac‐Tôha, & Velho, ) and other microbe communities (Aguilar & Lado, ; Baldwin et al, ; Bates et al, ).…”