Microbial mats may have given early animals breathing room
Canadian ponds and Venezuelan lagoons inspire a hypothesis about ancient life
Like exhausted nightclubbers, early animals may have weathered their harsh lifestyle by squirming up to the oxygen bar.
Animals living more than 550 million years ago could have survived inhospitable oceans by associating with dense mounds of cyanobacteria called microbial mats, an international team of researchers argues in a new study. Such clumps of oxygen-producing gunk could have supplied the first mobile animals with food to eat and air to breathe, the group reports online May 15 in Nature Geoscience.
The animal kingdom’s vanguard would have needed all the help it could get. Recent fossil finds show that wriggling animals first emerged at least 555 million years ago, when atmospheric oxygen concentrations may have been about one-tenth what they are today. Yet as creatures moved around more, they needed more oxygen. So how early mobile critters, which probably resembled worms or slugs, eked out a living in these choked environments has been a big puzzle for paleontologists, says study coauthor Murray Gingras. “Biomats provided the oxygen that ironically enabled the animals to better exploit biomats as food,” he says.