Researchers have found that some forms of microscopic marine life — the so called "primary producers," or photosynthetic organisms such as algae and cyanobacteria in the ocean — recovered within about a century after the mass extinction 65 million years ago that killed off the dinosaurs . Previous research had indicated the process might have taken millions of years.
The findings provide observational evidence supporting models suggesting that global darkness after the impact was rather short. "Primary productivity came back quickly, at least in the environment we were studying," says Summons, referring to the near-shore environment represented by the Danish sediments.
"The atmosphere must have cleared up rapidly," he says. "People will have to rethink the recovery of the ecosystems. It can't be just the lack of food supply" that made it take so long to recover. link