Study cracks question of anciet microbial diet
The University of Western Australia (UWA) has created the first-ever snapshot of primitive organisims devouring each other.
The fossilised remains of 1900 million-year-old micoribial organisms show the ancient microbes in the act of feasting on a cyanobacterium-like fossil, and discarding the leftovers of the early meal.
UWA postdoctoral research fellow and study leader Dr David Wacey said instead of absorbing carbon dioxide, the microbes were eating previously formed organic matter and breaking it down, much as humans do after dinner, in a manner of feeding called hetertrophy.
Dr Wacey and UWA colleagues from the ARC Centre of Excellence in Core to Crust Fluid Systems, the Centre for Microscopy, Characterisation and Analysis and the Centre for Exploration Targeting, and researchers from the University of NSW, Oxford University and Bergen University in Norway, analysed the microscopic fossils, ranging from about 3-15 microns in diameter.
They used a battery of new techniques and found that Gunflintia was more perforated after death than other kinds of fossils, consistent with them having been eaten by bacteria. In some places many of the tiny fossils had been partially or entirely replaced with iron sulfide (‘fool's gold') a waste product of heterotrophic sulfate-reducing bacteria that is also a highly visible marker.