LONDON-A mass extinction that wiped out more than three quarters of all marine life on Earth may have been triggered by an unlikely source, new research into algae suggests.
Experts believe expanding populations of the simple marine plants absorbed vast amounts of carbon dioxide from the atmosphere around 445 million years ago.
Without the presence of the gas, which traps heat from the sun in the atmosphere, the planet rapidly cooled, experts claim.
This cooling triggered the Late Ordovician extinction, the only major global extinction event in geological history to be linked to a cooling of the planet.
Researchers from Harvard University made the discovery while studying ancient ocean sediments unearthed in Nevada.
According to the research, the samples, comprised primarily of shale and limestone, contained compounds derived from chlorophyll, which is produced by algae.
Over a period of just a few million years, the amount of these compounds increased approximately five-fold, the team estimated.
That suggests the algae underwent an explosive period of increasing population size at the time of the Late Ordovician extinction.
This population shift may have triggered rapid cooling, according to Ann Pearson, an environmental scientist at Harvard University and one of the study’s coauthors.
The new study ‘reveals how algal evolution could have been vital in regulating the Earth’s carbon cycle,’ Richard Pancost, a biogeochemist at the University of Bristol in the United Kingdom not involved in the research, told Earth and Space Science News (ESSN).
‘It is a fascinating hypothesis based on some exciting new data.’
The rapid carbon capture would have resulted in more carbon being pulled from the atmosphere and becoming trapped in the sea floor.
This would have had large repercussions for the Earth’s carbon cycle and the temperature of the planet.
According to ESSN, atmospheric carbon dioxide levels would have been halved.
This would have triggered several degrees Celsius of rapid cooling in the space of a few million years, which may have prompted the Late Ordovician glaciation.
The findings were published in the journal Nature Geoscience.