Controls on microbial activity and tidal flat evolution in Shark Bay, Western Australia

Shark Bay, Western Australia, hosts a unique microbial carbonate system shaped by extreme environmental conditions. The study reveals that microbial deposits, including stromatolites and thrombolitic forms, have evolved over the Holocene in response to sea-level variations and salinity changes. Nilemah tidal flat exhibits the thickest (1.3 m) and most developed microbial sedimentary system, with its deposition predating other flats like Rocky Point and Garden Point. The research identifies filamentous bacteria as dominant in tufted and smooth mats, while coccus bacteria dominate pustular and pavement structures. These microbial communities coexist with diverse organisms, contributing to extensive bioturbation and carbonate precipitation. The findings highlight the evolutionary series preserved within tidal flats, reflecting relative ages and salinity elevation.

Jahnert, R. J., & Collins, L. B. (2013). Controls on microbial activity and tidal flat evolution in Shark Bay, Western Australia. Sedimentology, 60(4), 1071–1099. Portico. https://doi.org/10.1111/sed.12023