Sulphuric acid clouds caused darkness that kills dinosaurs

London (IANS): Millions of years ago, tiny droplets of sulphuric acid formed high up in the air after an asteroid hit the Earth, making it dark and cold for several years and resulted in the extinction of dinosaurs from the planet, a study has revealed.

The study conducted by Potsdam Institute for Climate Impact Research (PIK) in Germany found that the droplets resulted in long lasting cooling, a likely contributor to the death of land-living dinosaurs.

"The long-term cooling caused by the sulfate aerosols was much more important for the mass extinction than the dust that stays in the atmosphere for only a relatively short time," said Georg Feulner from PIK.

It took the climate about 30 years to recover, the scientists found.

"The dinosaurs were used to living in a lush climate. After the asteroid's impact, the annual average temperature was below freezing point for about three years. Evidently, the ice caps expanded.

Even in the tropics, annual mean temperatures went from 27 degrees to mere five degrees," the study added.

According to the study, an additional factor for the dinosaurs' extinction might have been a vigorous mixing of the oceans, caused by the surface
cooling, severely disturbing marine ecosystems.

Scientists built on research showing that sulfur-bearing gases that evaporated from the violent asteroid impact on the Earth's surface were the main factor for blocking the sunlight and cooling Earth down.

"In addition to this, ocean circulation became disturbed. Surface waters cooled down, thereby becoming denser and hence heavier," added the study published in Geophysical Research Letters.

"While these cooler water masses sank into the depths, warmer water from deeper ocean layers rose to the surface, carrying nutrients that likely led to massive blooms of algae which further produced toxic substances, thus affecting life on the coasts," the study explained.