Microbial mat

Metagenomics has been a hot topic at JAMS in 2011. Playing to this popular theme, Thomas Jeffries of the University of Technology, Sydney opened the final meeting for the year with his metagenomic analysis of taxonomic and functional patterns in South Australia's hypersaline Coorong Lagoon. Thomas and colleagues found shifts in the abundance of cyanobacteria and Archaea linked to a salinity and nutrient gradient along the lagoon, as well as a shift in the abundance of genes related to salinity tolerance and photosynthesis. Surprisingly, despite the extreme range of environmental factors within Coorong, they found these patterns were dwarfed when the lagoon samples were placed in a global context, which showed substrate - in this case, solid or fluid - had a greater influence on taxonomic profiles. Thomas's work shows the importance of scale in the relationship between a microbial community and its environment.

Event Date: 
Wednesday, November 30, 2011 - 19:15 - 20:00

Rocking the cradle of life: Functional complexity of modern stromatolites.

One of the major challenges in science is to identify modern living systems that present unique opportunities to address fundamental questions in diverse fields ranging from microbiology, geology, evolution, chemical biology, functional genomics, and biotechnology. The living stromatolites of Shark Bay on the western coast of Australia represent such a system. The overarching aim of our research program is to comprehensively characterise the functional complexity of modern stromatolites, in particular the diversity, biogeochemistry, and key interactions of the microorganisms forming the Shark Bay stromatolites. Understanding modern stromatolite systems is of fundamental significance to shed light on the evolution of early microbial life and the impacts of these ecosystems on both past and present global nutrient cycling.

Shark Bay is notable for its living marine stromatolites, and is listed as a World Heritage Site. In addition to their established evolutionary significance, these stromatolites, located in a hypersaline environment, are an ideal biological system for studying survival strategies of microorganisms to a range of stresses and their metabolic cooperation with other microorganisms. To further our understanding of these geobiological structures, detailed analyses of associated microbial communities and their functional characteristics are crucial.

This presentation will summarise the platform of our work over the last several years, focusing on recent discoveries and how these have led to new research directions employing a range of cutting edge technologies. This includes a comprehensive study elucidating major microbial populations, novel organism characterisation, signature lipid profiles, adaptive mechanisms of novel stromatolite isolates, creating a detailed biogeochemical profile of living stromatolites, whole genome analyses, and mechanisms of communication in these systems.

Finally, from an educational perspective, an interactive virtual field trip is being developed that will be an invaluable tool for both future research and conservation. Through the application of a rational and integrated approach, this research has provided valuable insights into these evolutionally significant biological systems. We now know who the key microbial players are, and can use this knowledge to examine specific functional characteristics to take the research to the next level, utilising the new suite of techniques now revolutionising the field of environmental microbiology.

  1. Allen MA, et al. (2010) Lipid biomarkers in Hamelin Pool microbial mats and stromatolites. Org Geochem 41, 1207-1218.
  2. Leuko S, et al. (2011) Molecular assessment of UVC radiation-induced DNA damage repair in the stromatolitic halophilic archaeon, Halococcus hamelinensis. J Photochem Photobiol B: Biology 102, 140–145.
  3. Goh F, et al. (2011) Osmoadaptive strategies of the archaeon Halococcus hamelinensis isolated from a hypersaline stromatolite environment. Astrobiology 11, 529-536.
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