NOV 22, 2015 2:27 PM PST

Fresh Air, Courtesy of Cyanobacteria

WRITTEN BY: Kerry Evans
Researchers at the University of Waterloo think cyanobacteria contributed to the “Great Oxidation Event” (GOE).  The GOE was the biological introduction of oxygen (O2) into the atmosphere, about 2.3 billion years ago.  It is the point at which organic and inorganic matter could no longer absorb oxygen, and it built up in the atmosphere.

Cyanobacteria are photosynthetic bacteria that appeared on Earth about 200 million years before the GOE.  They are often referred to as blue-green algae (although they are, in fact, bacteria).  Like modern plants, they use chlorophyll for photosynthesis, and there is evidence that chloroplasts are the remnants of symbiotic cyanobacteria.
 
Cyanobacteria contribute to the early atmosphere.

According to study author Brian Kendall, “the onset of Earth’s surface oxygenation was likely a complex process characterized by multiple whiffs of oxygen until a tipping point was crossed … until now, we haven't been able to tell whether oxygen concentrations 2.5 billion years ago were stable or not. These new data provide a much more conclusive answer to that question”.

The group found evidence of oxygen “whiffs” in black shale deposits that are part of an ancient ocean in Western Australia.  They looked for two osmium isotopes in the shale deposits, 187Os and 188Os.  The ratio of these isotopes tells scientists whether the deposits were exposed to atmospheric oxygen.  The group concluded that the levels of atmospheric oxygen fluctuated for some time after the rise of photosynthetic organisms leading up to the GOE.

While the GOE was good news for future oxygen-breathing humans, it was catastrophic for many organisms.  Since oxygen is toxic to obligate anaerobes, cyanobacteria may have been responsible for their extinction.  

Sources: Science Daily, Genome Biology, Wikipedia, UC Berkeley
 
 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
MAR 30, 2021
Microbiology
A Marburg Virus Treatment Approach is Identified
MAR 30, 2021
A Marburg Virus Treatment Approach is Identified
Marburg virus causes severe hemorrhagic fever; its fatality ratio can be as high as 88 percent. Researchers may have now ...
APR 27, 2021
Immunology
Breakthrough Malaria Vaccine Is a Ray of Hope
APR 27, 2021
Breakthrough Malaria Vaccine Is a Ray of Hope
University of Oxford scientists have developed a vaccine against malaria, which they describe as having “unprecede ...
APR 25, 2021
Microbiology
Plant-Eating Microbes Expand the Tree of Life
APR 25, 2021
Plant-Eating Microbes Expand the Tree of Life
After microbes called archaea were discovered in the 1970s, a branch was added to the tree of life after some debate, wh ...
MAY 13, 2021
Microbiology
The Gut Microbiome Was More Diverse in Ancient People
MAY 13, 2021
The Gut Microbiome Was More Diverse in Ancient People
What can we learn from a specimen of ancient poo? A lot, it turns out. Scientists have now reported their findings from ...
MAY 28, 2021
Genetics & Genomics
Some Biofilms Seem to Activate Cancer Genes
MAY 28, 2021
Some Biofilms Seem to Activate Cancer Genes
New research assessed bacterial and fungal biofilms, tenacious microbial communities that are tougher than small groups ...
JUN 04, 2021
Cell & Molecular Biology
Even When They're Outside the Brain, Infections Worsen Alzheimer's
JUN 04, 2021
Even When They're Outside the Brain, Infections Worsen Alzheimer's
It's thought that inflammation is closely connected to cognitive decline, and neuroinflammation plays a role role in the ...
Loading Comments...