Using Molecular Tools to Understand Microbial Carbonates

Here we review the application of molecular biological approaches to mineral precipitation in modern marine microbialites. The review focuses on the nearly two decades of nucleotide sequencing studies of the microbialites of Shark Bay, Australia; and The Bahamas. Molecular methods have successfully characterized the overall community composition of mats, pinpointed microbes involved in key metabolisms, and revealed patterns in the distributions of microbial groups and functional genes. Molecular tools have become widely accessible, and we can now aim to establish firmer links between microbes and mineralization. Two promising future directions include zooming in to assess the roles of specific organisms, microbial groups, and surfaces in carbonate biomineralization and zooming out to consider broader spans of space and time. A middle ground between the two can include model systems that contain representatives of important microbial groups, processes, and metabolisms in mats and simplify hypothesis testing. These directions will benefit from expanding reference datasets of marine microbes and enzymes and enrichments of representative microbes from mats. Such applications of molecular tools should improve our ability to interpret ancient and modern microbialites and increase the utility of these rocks as long-term recorders of microbial processes and environmental chemistry.

Automated summary

This review article focuses on the application of molecular biological approaches to the study of mineral precipitation in modern marine microbialites. It highlights the advancements made through nucleotide sequencing studies of microbialites in Shark Bay, Australia, and The Bahamas. Molecular methods have provided valuable insights into the overall community composition, key microbial metabolisms, and distribution patterns of microbial groups and functional genes. Future research directions include zooming in to assess the roles of specific organisms and surfaces in carbonate biomineralization, and zooming out to consider broader spatial and temporal spans. The use of model systems that simplify hypothesis testing and the expansion of reference datasets of marine microbes and enzymes will aid in furthering our understanding of microbial processes and their long-term records in microbialites.