Oxygenation by animals?
Nature Geoscience
March 10, 2014
The evolution of large single-celled organisms and simple, sponge-like animals between 750 and 500 million years ago could have led to the oxygenation of the deep oceans, argues a review article published online in Nature Geoscience. This conclusion is at odds with the commonly held suggestion that the oxygenation of the oceans spurred animal evolution.
Until about 550 million years ago, much of the Earth’s deep oceans lacked any appreciable amounts of oxygen, despite the presence of moderate amounts of oxygen at the ocean surface. Timothy Lenton and colleagues suggest that this state arose because of high oxygen usage in the surface waters, primarily from the decomposition of tiny bacteria that rarely sank below the surface. However, once larger cells evolved - particularly amoebae with an organic shell - the dead cells sank below the surface, lowering the surface oxygen demand. The authors suggest that oxygen from the surface could then diffuse and mix downwards. The later evolution of filter-feeding sponges, some tens to hundreds of millions of years later, would have removed even more organic matter from the surface oceans, allowing further oxygen diffusion.
doi: 10.1038/ngeo2108
Research highlights
-
Jul 1
Criminology: Predicting police enforcement bias in major US citiesNature Human Behaviour
-
Jul 1
Evolution: Pandas gave bamboo the thumbs up at least six million years agoScientific Reports
-
Jul 1
Space health: The path of most resistance could help limit bone loss during spaceflightScientific Reports
-
Jun 30
Genomics: Gray wolf genome hints at dual ancestry of dogsNature
-
Jun 30
Evolution: Hawks learn on the fly to swoop up before perchingNature
-
Jun 30
Microbiology: Transmission of gastrointestinal viruses in salivaNature