C3 Seminar: Dr Brendan Burns
Never judge a microbial mat by its cover: the secret of what lies beneath
Microbial mats are geobiological ecosystems produced by the metabolic activity of complex microbial communities. Biomarkers in ancient mats are a proof of life, and recent work has demonstrated these systems emerged as far back as 3.7 billion years.
The key to understanding the past is to study the present, and living mats are excellent model systems to address fundamental evolutionary questions. The traditional tree of life is in flux and new discoveries in mats of novel organisms and pathways is affording a dynamic and holistic view of these ecosystems and the complex network of processes occurring through space and time.
Shark Bay in Western Australia – a World Heritage site - holds one of the best examples of modern microbial mats in an extreme environment. The aim of this talk is to synthesize my group’s recent efforts in this field at multiple levels, relevant to a wide range of areas including microbial evolution, geobiology, paleobiology, computational biology, and biotechnology. The functional metagenomic potential of Shark Bay microbial mats were examined for the first time at a millimeter scale, employing shotgun sequencing of communities in conjunction with defined chemical analyses.
A detailed functional metagenomic profile has elucidated key pathways and facilitated inference of critical microbial interactions. In addition, 87 medium to high quality metagenome-assembled genomes were assembled, including potentially novel bins under the deep-branching archaeal Asgard group (Thorarchaetoa and Lokiarchaeota). Pathways of environmental adaptation (UV, hypersalinity, oxidative stress, heavy metal resistance) were also delineated, as well as putative viral defensive mechanisms (core genes of the CRISPR, BREX, and DISARM systems).
The optical properties and light-harvesting potential of the mats were also ascertained and correlated with pigment distribution via HPLC analyses. The finding of an abundance of anaerobic microorganisms enriched at the surface where oxygen levels were highest, coupled with peak methane production in the oxic zone, suggests putative surface anoxic niches in these microbial mats. Our work provides new metagenome-based models into how biogeochemical cycles and adaptive responses may be partitioned in the microbial mats of Shark Bay. In addition, the impact of extreme stressors on microbial communities and critical pathways in threatened mat systems are being assessed and critical to ascertain before any irreversible ecosystem tipping points are reached.
Light refreshments provided after talk - All are welcome!
About the speaker
Dr Brendan Burns – Senior Lecturer, School of Biotechnology and Biomolecular Sciences, The University of New South Wales
Brendan Burns completed his PhD in microbiology at The University of New South Wales in 1999. From here, he was awarded a highly prestigious Alexander von Humboldt Fellowship and conducted a post-doc in Munich, Germany from 2000-2001. He was then awarded an ARC Australian Post-doctoral Fellowship to return to UNSW in 2002. Since then he has led research on modern microbial mats and stromatolites - complex geomicrobial communities that are analogues of the very earliest evidence of life on Earth. Using these ancient life forms as blueprints, Brendan has also consulted with NASA to better focus efforts on the search for signals that may help in the detection of life on other planets.
Nationally, his research has been recognised with the award of the 2005 Eureka Prize for Interdisciplinary Scientific Research, Australia's premier science awards and an extremely prestigious honour. Other awards include Kanagawa Museum of Natural History Award (2003), Japan Society for the Promotion of Science Invitation Fellowship (2004), and an Australia Institute of Political Science Tall Poppy Award (2005). Brendan has also demonstrated a real commitment to communicating science to the general public with numerous radio and print articles, involvement in film projects (a 3D IMAX movie directed by James Cameron), and appearances in court as an expert witness.