Scientists have found what might have caused the last extinction on Earth
The new evidence is the Foraminifera. These are tiny plankton that contains fossil records that go back to hundreds of millions of years.
A new study led by Yale University provides a clear picture of the reasons and effects of the mass extinction event that happened around 66 million years ago.
Researchers have found the first direct evidence of the extinction event relating to the drop in pH levels of the oceans. Decreases in pH levels increase the acidity.
What was the previous theory?
According to the lead author, Michael Henehan, the previous theory speculated about sulphuric acid rain caused because of the meteor impact. But, there has been no evidence of that.
The new evidence is the foraminifera. These are tiny plankton that contains fossil records that go back to hundreds of millions of years.
The analysis of the chemical composition of these planktons reflected the change in the behaviour of the marine environment before, during, and after the extinction event. This analysis provided evidence about the acidity of the oceans.
The marine calcifiers:
Ocean animals are responsible for creating shells and skeletons from calcium carbonate. The earlier studies suggested that these calcifiers got wiped out in the mass extinction.
But the new study suggests that the increase in the acidity of the ocean might have prevented them from creating shells. This information is important as these animals play a major role in the marine ecosystem.
Simply put, the new theory suggests that the oceans saw up to 50 per cent loss in productivity after which the marine life started to recover.
It also debunks an earlier theory that suggests that volcanic eruption caused an increase in acidity that led to mass extinction.
"What we can show is that there is no real signal of gradual pH decline in the ocean in the lead-up to K-Pg," Henehan said. "Our results do not support any major role for volcanic activity in priming the world for extinction."