Science / Medicine : Another Dinosaur Theory

The disappearance of tiny organisms floating on ocean surfaces caused temperatures around the globe to rise as much as 20 degrees 65 million years ago, and may have contributed to the extinction of dinosaurs, scientists say.

Geologist Michael Rampino of New York University said calcareous marine plankton are microscopic floating organisms that live on ocean surfaces. Plankton produce a chemical called dimethyl sulfide, which is a key element in the condensation of clouds and the reflection of the sun’s rays back to space.

Rampino’s study suggests that bombardments by meteorites or small planets kicked up enough dust in the Earth’s atmosphere to stop photosynthesis temporarily and kill the plankton on the ocean surface. As a result, the dimethyl sulfide produced by the plankton, which turns into tiny droplets of sulfuric acid and provides a nucleus for condensation of water droplets in clouds, was drastically reduced.

“Most of the cloud condensation is produced by this biological mechanism. So we took this one step further and said, what if you removed most of the plankton from the ocean? In that case, you could infer the dimethyl sulfide would have gone down drastically. There would be less cloud condensation and the type of cloud would change.”