By Monica Antonio Nov 30, 2016 03:50 AM EST
A team of researchers from the University of Cincinnati has discovered
proof that early life forms that lived on Earth thrived even without
oxygen billions of years ago.
The study, published in the journal Geology of the Geological Society
of America, discovered a 2.52-billion-year-old bacteria that can
oxidize sulfur. The said bacteria is similar to single-celled
organisms in present time that can be found in deepwaters where
amounts of sulfur are high. The smooth-walled spherical bacteria is
larger in size compared to modern bacteria.
The researchers found ancient rocks which hold fossilized evidence of
this bacteria in two locations: one in South Africa and another in the
Northern Cape Province. Andrew Czaja from UC, Nicolas Beukes from the University of Johannesburg and Jeffery Osterhout, a UC master's
graduate, discovered that during the Neoarchean Eon, which dates back
2.8 to 2.5 billion years ago, these sulfur-oxidizing bacteria thrived
in the depths of the ocean.
"These fossils represent the oldest known organisms that lived in a
very dark, deep-water environment. These bacteria existed two billion
years before plants and trees, which evolved about 450 million years
ago. We discovered these microfossils preserved in a layer of hard
silica-rich rock called chert located within the Kaapvaal craton of
South Africa," Czaja told Science Daily.
The researchers noted that the Neoarchean Eon was a time where the
atmosphere only contained one percent oxygen. Because of an extremely
different atmospheric makeup, the researchers believe that a set of
different creatures that did not need sunlight or oxygen lived in deep
waters during that time.
The team used radiometric dating and geochemical isotope analysis to
determine that the fossils they found were during the said time.
During the Neoarchean Era, before the shifting of tectonic plates, the
team said that South Africa and Western Australia belonged to a
supercontinent called Vaalbara.
"These are the oldest reported fossil sulfur bacteria to date. And
this discovery is helping us reveal a diversity of life and ecosystems
that existed just prior to the Great Oxidation Event, a time of major atmospheric evolution," Czaja said.
http://www.natureworldnews.com/articles/33103/20161130/scientists-discover-evidence-ancient-life-earth-before-oxygen-existed.htm
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