Characteristics, distribution and morphogenesis of subtidal microbial systems in Shark Bay, Australia

Extensive subtidal microbial deposits, covering approximately 300 km² of Hamelin Pool in Shark Bay, Australia, have been mapped and analyzed for the first time. These deposits, dominated by aragonite with distinctive isotopic signatures (δ13C +4.46 to +5.88; δ18O +3.06 to +3.88), reveal a subtidal microbial habitat 10 times larger than previously known intertidal areas. The study highlights two depositional stages, with growth rates ranging from <0.1 mm/year to 0.5 mm/year, and provides evidence of late Holocene sea-level changes through fabric sequences. Distinct microbial communities and lateral fabric relations were identified, emphasizing the geoscientific significance of Hamelin Pool for early life studies and ancient environmental interpretations.

Jahnert, R. J., & Collins, L. B. (2012). Characteristics, distribution and morphogenesis of subtidal microbial systems in Shark Bay, Australia. Marine Geology, 303-306, 115–136. https://doi.org/10.1016/j.margeo.2012.02.009