title: Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes.
abstract: The role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of putative niches in these systems. In the present study, high throughput amplicon sequencing was undertaken in conjunction with analysis of key biogeochemical properties of two mats (smooth and pustular) from Shark Bay, Australia. One-way analysis of similarity tests indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1%). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Pustular mats were enriched with Halobacteria and Parvarchaeota. Key metabolisms (bacterial and archaeal) were measured, and the rates of oxygen production/consumption and sulfate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic layers and was up to seven-fold higher in smooth than pustular mats. The finding of an abundance of anaerobic methanogens 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.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia.|Australian Centre for Astrobiology, University of New South Wales Sydney, Australia.
authors.forename: Hon Lun
authors.initials: HL
authors.lastname: Wong
authors.affiliation: Department of Marine Sciences, University of Connecticut, USA.|Australian Centre for Astrobiology, University of New South Wales Sydney, Australia.
authors.forename: Pieter T
authors.initials: PT
authors.lastname: Visscher
authors.affiliation: Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Richard Allen
authors.initials: RA
authors.lastname: White
authors.affiliation: School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia.
authors.forename: Daniela-Lee
authors.initials: DL
authors.lastname: Smith
authors.affiliation: Department of Marine Sciences, University of Connecticut, USA.
authors.forename: Molly M
authors.initials: MM
authors.lastname: Patterson
authors.affiliation: School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia.|Australian Centre for Astrobiology, University of New South Wales Sydney, Australia.
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Burns
mesh_terms: D001105:Archaea / Q000502:physiology*; D001315:Australia; D061006:Bays / Q000382:microbiology*; D044822:Biodiversity; D008697:Methane / Q000096:biosynthesis; D056265:Microbial Interactions; D064307:Microbiota
chemical_list: D008697:Methane