First animals may have oxygenated the oceans

[Moontanman]

It appears the first animals may have had more influence on the oxy levels in the ocean than once thought. By removing organic particles from the ocean, sponges and other filter feeders removed a drain on the oxygen in the ocean allowing oxygen levels to rise and allow for more complex animals to evolve.

 

http://www.sciencedaily.com/releases/2014/03/140309150540.htm

 

First animals oxygenated the ocean

Date:

March 9, 2014

Source:

University of Exeter

Summary:

The evolution of the first animals may have oxygenated the earth's oceans -- contrary to the traditional view that a rise in oxygen triggered their development. New research contests the long held belief that oxygenation of the atmosphere and oceans was a pre-requisite for the evolution of complex life forms. The study builds on the recent work of scientists in Denmark who found that sponges -- the first animals to evolve -- require only small amounts of oxygen.

 

 

 

[Johnny Electriglide]

Very interesting! I would say that both views are true. The cyanobacteria and early sponges worked to increase O2 levels. Of course, the cyanobacteria had been at it for millions of years before the sponges had enough oxygen for life. Then further millions until the O2 level near today's.

In the meantime, from minimal oceanic water O2, the sponges then other animal life began their development. Certainly, sponges did not develop at zero oxygen, because they need a little to live. Taking out the oxygen depleting organic detritus helped, but the cyanobacteria soup was letting off much more O2.

How much each contributed in percentage can only be an educated guess until more sponge areas of that period are discovered. Even then, we are limited to the range of age determined by radioactive isotope dating.

I think a lab experiment with containment and O2 measuring from each of sponges and cyanobacteria (hopefully near the same as the ancient), would be in order.

Replicate various conditions from zero O2 to the present level. That would add weight to the studies.

That is, both atmospheric and dissolved O2 could be measured, until the cyanobacteria kill themselves with their waste O2. Then the sponges would have a smorgasbord, if they were in the same container.

In the article, Prof. Poulton's statement at the end is telling.