Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats.
Modern microbial mats can provide key insights into early Earth ecosystems, and Shark Bay, Australia, holds one of the best examples of these systems. Identifying the spatial distribution of microorganisms with mat depth facilitates a greater understanding of specific niches and potentially novel microbial interactions. High throughput sequencing coupled with elemental analyses and biogeochemical measurements of two distinct mat types (smooth and pustular) at a millimeter scale were undertaken in the present study. A total of 8,263,982 16S rRNA gene sequences were obtained, which were affiliated to 58 bacterial and candidate phyla. The surface of both mats were dominated by Cyanobacteria, accompanied with known or putative members of Alphaproteobacteria and Bacteroidetes. The deeper anoxic layers of smooth mats were dominated by Chloroflexi, while Alphaproteobacteria dominated the lower layers of pustular mats. In situ microelectrode measurements revealed smooth mats have a steeper profile of O2 and H2S concentrations, as well as higher oxygen production, consumption, and sulfate reduction rates. Specific elements (Mo, Mg, Mn, Fe, V, P) could be correlated with specific mat types and putative phylogenetic groups. Models are proposed for these systems suggesting putative surface anoxic niches, differential nitrogen fixing niches, and those coupled with methane metabolism.
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.
Hon Lun
HL
Wong
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.
Daniela-Lee
DL
Smith
Department of Marine Sciences, University of Connecticut, USA.|Australian Centre for Astrobiology, University of New South Wales Sydney, Australia.
Pieter T
PT
Visscher
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.
Brendan P
BP
Burns
D020561:Alphaproteobacteria / Q000235:genetics / Q000302:isolation & purification; D001315:Australia; D041963:Bacteroidetes / Q000235:genetics / Q000302:isolation & purification; D061006:Bays / Q000382:microbiology*; D044822:Biodiversity; D018441:Biofilms; D060833:Cellular Microenvironment / Q000502:physiology*; D041862:Chloroflexi / Q000235:genetics / Q000302:isolation & purification; D000458:Cyanobacteria / Q000235:genetics / Q000302:isolation & purification; D017753:Ecosystem; D019015:Geologic Sediments / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D006862:Hydrogen Sulfide / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D059013:Microbial Consortia / Q000235:genetics*; D056265:Microbial Interactions / Q000502:physiology*; D009586:Nitrogen Fixation / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D008670:Metals; D012336:RNA, Ribosomal, 16S; D010100:Oxygen; D006862:Hydrogen Sulfide