Page 34 - University of Pretoria RESEARCH REVIEW 2018

Microbiomes as
sentinels of global change
Thulani Makhalanyane, Department of Biochemistry, Genetics and Microbiology, and the Centre for Microbial Ecology and Genomics (CMEG)
Approximately 4 billion years ago, marine microorganisms shaped and defined the biosphere, facilitating a shift from anoxic to oxic conditions. This transition has allowed multi-cellular life to evolve from ancient unicellular organisms. Despite their centrality in regulating ecosystem processes, our understanding of the microbiome – that is, microorganisms and their genes – remains relatively poorly developed. Due to their rapid metabolisms and response to perturbations, the members of microbiomes serve as cOrucial sentinels of global change.
ur understanding of roughly the same number of microbial the role played by cells as human cells, estimated at 37 microbiomes has been trillion. Secondly, microbiomes are constrained by several continuously in a state of flux with
factors. Firstly, microbial communities widespread gene exchange, gene
with CMEG researchers and colla- borators, demonstrate the impact
and significance of these thematic studies in understanding the effects of microbiomes on global change.
Marine environments occupy
over 70% of the Earth’s surface
and act as a crucial buffer against climate change. Oceans sequester carbon dioxide produced through human activities, and provide food and other essential ecosystem services. Yet knowledge of the
role played by the microbiome
in key South African regions lags behind our current knowledge of phytoplankton and large marine mammals. In a paper published in Scientific Reports, CMEG researchers revealed important insights into the diversity and functional processes of microbiomes in the Agulhas current system. The study showed, for the first time, that ecologically rare taxa disproportionately drive carbon cycling in these marine environments.
Ice-free regions collectively comprise less than 0,40% of continental
are numerically abundant across all ecosystems. For instance, current studies suggest that we harbour
loss and gene gain, which complicate efforts to clarify the relationship between functional traits and microbial diversity. Lastly, we now know that environmental conditions appear to disproportionately shape microbiomes, leading to substantial variability across local and global scales. Large multidisciplinary teams are required to address these constraints and provide important insights into the ecology of the microbiome.
Dr Thulani Makhalanyane, senior lecturer in the Department Biochemistry, Genetics and Microbiology, and at the Centre for Microbial Ecology and Genomics (CMEG), has recently established several new research themes
aimed at illuminating the role of the microbiome in strategically important marine and terrestrial regions. Two publications in 2018, co-authored
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