We all know that a massive asteroid smashed into Earth around 66 million years ago, giving dinosaurs a very bad day and destroying 75% of life on the planet.
But scientists have now discovered that just ten years later, life had returned to the crater left by the impact and there was a thriving ecosystem there within just 30,000 years.
“We found life in the crater within a few years of impact, which is really fast, surprisingly fast,” said Chris Lowery, a postdoctoral researcher at the University of Texas Institute for Geophysics (UTIG), in a statement. “It shows that there’s not a lot of predictability of recovery in general.”
The researchers found the first evidence for life, including burrows made by small shrimp or worms, just two to three years after the extinction-level event. By 30,000 years later, blooming phytoplankton plants were supporting a diverse ecosystem of creatures large and small in surface waters and on the seafloor. On the other side of the world, there were areas that took up to 300,000 years to recover to that level.
It should have taken a really long time for life to find a way at the crash site, because of the environmental contaminants released by the explosive impact. When an asteroid hammers a planet, the theory goes that it would release lots of detrimental substances, like toxic metals, that would hamper the return of living organisms.
But this research suggests that recovery around the world from the dinosaur-ending asteroid was more influenced by local factors than anything else, which could have implications for environments suffering destructive influences like climate change today.
Lowery’s team, including researchers from UTIG and a team of international scientists, found the evidence of life in microfossils like those of algae and plankton and the remains of burrows of larger animals uncovered during scientific drilling conducted jointly by the International Ocean Discovery Program and International Continental Drilling Program.
“Microfossils let you get at this complete community picture of what’s going on,” Lowery said. “You get a chunk of rock and there’s thousands of microfossils there, so we can look at changes in the population with a really high degree of confidence… and we can use that as kind of a proxy for the larger scale organisms.”
The team were able to narrow the timeline down for the study in Nature because they found a unique core section with more than 130 metres of material. Normally, the core sections found hold only millimetres of material deposited just after impact.