About 66 million years ago, the 10-mile-wide Chicxulub asteroid hit the ground with a bang and the dinosaurs were dead. It is believed that around 75% of all life went extinct from its impact. Apart from dinosaurs, several marine reptiles and vertebrates also could not survive the attack. After Chicxulub, the globe underwent a series of changes, and it profoundly impacted the climate and forest. So, other organisms who were able to survive the attack, died later in the decade as they were not able to adjust to the climatic changes.
Researchers claimed that the changes that occurred due to the impact of the asteroid have shaped the Amazon and other neotropical rainforests. A botanist and paleobiologist at the Smithsonian Tropical Research Institute Monica Carvalho said that the forest as we know it today, as it functions today, began after the extinction had reset the whole ecosystem and allowed flowering plants to take over.
Ferns and Confers – Carvalho said that it’s unclear what exactly happened immediately after Chicxulub hit the Earth. It is believed that photosynthesis would have largely shut down for up to a century as the dust from the impact could have possibly blocked the sunlight. Ashes from various fires also clogged the atmosphere, making it difficult for sunlight to penetrate. Carvalho’s research said that only seeds were able to survive and the tropical plant diversity suffered a 45 per cent loss. The forests took over 7 million years to get back in shape.
Rise of the flowerage – When the recovery commenced, the plants evolving in the neotropical rainforests were mostly flowering plants. Deciduous trees, those which lose their leaves at the end of a growing season, fall under the above category. Carvalho’s research states that the Neotropical forests were dominated by flowering plants and they changed their structure too. Amazon Forest was not dense as trees grew at a distance from each other. But now the forest is filled with closed canopies and comparatively dark floors.
Diversification of new species- The research also claims that the large quantity of fruit produced from the forests may have helped in the diversification of new species families like mammals.
Nitrogen in the air - It is also said that the legumes of the honey locust family become very abundant, which might have led to the nitrogen content of the air. According to Carvalho, “Symbiotic bacteria that live in the roots of honey locust plants remove nitrogen from the air and feed it to the plants.”
Water cycle - Following the impact, the forests were able to cycle water quickly, as it absorbed and released it back into the atmosphere.