“Earth lungs, Amazon… created by an asteroid impact that exterminated dinosaurs”

Research has shown that an asteroid impact that extinct dinosaurs in the past gave birth to the Earth’s rainforest.

The researchers used fossil pollen and leaves collected from Colombia to investigate how the asteroid impact affected tropical forests in South America.

And after about 66 million years ago, a 12-kilometer-wide cosmic rock collided with Earth, it was discovered that the types of plant ecosystems that make up the forest have changed dramatically.

The results of this study were published in the international academic journal’Science’.

“For this study, we analyzed more than 50,000 fossil pollen records and 6,000 leaf fossils that occurred before and after the asteroid impact,” said Dr. Monica Cavallo of the Parmana Smithsonian Tropical Research Institute (STRI), co-author of the paper.

According to the researchers, the Yucatan Peninsula, now in Mexico, was rich in conifers and ferns before the asteroid impact, but vegetation diversity declined by about 45% after the impact.

In particular, it has been shown that a wide range of extinctions have occurred, mainly in plants with seeds.

After that, it took 6 million years for the forest to recover, and in the meantime, flowering plants became the dominant species in the region.

The structure of the rainforest has also undergone major changes.

In the late Cretaceous period when dinosaurs lived, the width of the trees making up the forest widened, and thanks to the fact that the treetops did not overlap, there was a lot of space for sunlight on the forest floor.

However, after the asteroid impact, the forest developed into a thick canopy, and the amount of sunlight entering the ground was much less.

Then, how did asteroid impact transform the dinosaur-era rainforest, which was rich in conifers, into today’s tall trees and a variety of flowers?

The researchers explained three hypotheses based on the analysis of fossil pollen and leaves:

First, it is an analysis that in the past, dinosaurs would have lowered the density of the rainforest by eating plants growing in the lower part of the forest and walking on the floor of the forest.

Second, it is explained that the ashes from the asteroid impact enrich the soil in tropical regions, and the flowering plants will have favorable conditions.

Third, it is hypothesized that the selective extinction of coniferous species gives the flowering plants an opportunity to take over the forest.

However, since these hypotheses are not mutually exclusive, these factors may have a combination of influences on the current rainforest appearance.

“The lesson we can learn here is that in the process of rapid change, tropical ecosystems are not simply restored, but replaced, and the process takes a very long time,” said Dr. Cavallo.