Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats

Microbial mats in Shark Bay, Australia, exhibit distinct niche differentiation at millimeter scales, offering insights into early Earth ecosystems. The study revealed that smooth and pustular mat types harbor unique bacterial communities, with Cyanobacteria dominating the surface layers while deeper anoxic zones are dominated by Chloroflexi (smooth mats) or Alphaproteobacteria (pustular mats). High-throughput sequencing of 8.26 million 16S rRNA gene sequences identified 58 bacterial and candidate phyla, alongside biogeochemical measurements that showed smooth mats have steeper oxygen and hydrogen sulfide gradients, higher oxygen production, and sulfate reduction rates. Specific elements like molybdenum, magnesium, manganese, iron, vanadium, and phosphorus correlated with mat types and phylogenetic groups, suggesting surface anoxic niches, differential nitrogen fixation, and methane metabolism interactions.

Wong, H. L., Smith, D.-L., Visscher, P. T., & Burns, B. P. (2015). Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats. Scientific Reports, 5(1). https://doi.org/10.1038/srep15607