Colombia’s rainforest looks Sixty-six million years ago, things were very different. Currently, the moist and biologically diverse ecosystem is crowded with plants and covered by thick, light-blocking leaves and branches. It is worth noting that there are no dinosaurs. However, before the disappearance of the dinosaurs due to the Chicxulub impact, marking the end of the Cretaceous era, the situation was very different. The plant cover in this area is relatively sparse, and a cluster of conifers is called “home”.
A team of researchers used plant fossil remains to study the past of tropical rainforests and how asteroids led to tropical rainforests today.The research was published in science On April 1
Mónica Carvalho, the first author and postdoctoral co-researcher of STRI and the University of Rosario in Colombia, said in an interview: “The forest has disappeared due to ecological disasters… Then, the returned vegetation is mainly flowering Plants.” Ars.
The research began 20 years ago, when members of the team collected and analyzed 6,000 leaves and 50,000 pollen fossils from Colombia. By observing these fossils, the team can understand the types of plants that existed before and after the asteroid hit the Earth. This sequence represents the biodiversity of the region from 72 million to 58 million years ago, covering both before and after the impact. Carvalho told Ars: “It took us a long time to collect enough data so that we can clearly understand what happened during the extinction.”
Carvalho said that although the study involves fossils in Colombia, researchers can have a clear understanding of what is happening in the rainforests of other parts of Central and South America, although the impact of asteroid impacts varies from region to region. “It’s a bit variable. We still don’t know why some places are more affected than others,” she said.
After the asteroid hit the earth, almost half of Colombia’s plant species became extinct, and the pollen fossils of these species ceased to appear. Rain forests are beginning to be replaced by ferns and flowering plants, and despite their early effects, they are not as common as they are today. In contrast, conifers are actually extinct.
Except for the existence of conifers, the rain forests of the past may be sparser than modern rain forests. The current tropical rain forests have dense canopies and plants in them are arranged closely together, which means that more and more plants are infiltrating water into the atmosphere. This leads to higher humidity and cloud coverage. According to Carvalho, the relative lack of humidity in earlier forests means that the productivity of the area may be much lower than it is today.
However, until the asteroid impact, low-productivity forests still existed. She said: “Only after being affected can we see the forest change its structure.”
Researchers have some assumptions about how this change occurs. The first is that the extinction of the dinosaurs has resulted in denser forests-there may be fewer animals consuming plants or stepping on bushes, allowing leaves to grow relatively unrestricted. The second idea is that shortly after the collision between the asteroid and the planet, the conifers in the tropics are selectively extinct, and their impact may be much better than their peers after the impact.
The third is that the consequences of the disaster may make the soil fertile. The tsunami event that occurred after the impact may have carried debris and sediments from nearby carbon-rich, shallow sea areas. Burning wildfires may release ashes into the atmosphere, and when the ashes finally fall on the ground, it may act as a fertilizer. Carvalho said that in high-nutrient soils, flowering plants tend to grow better than conifers. She also pointed out that all these assumptions or any two of them may be true at the same time.