The main reason for the mass extinction of dinosaurs about 66 million years ago was the fall of a meteorite. But the exact mechanisms that linked the fall of the meteorite to the extinction remain unclear. Scientists from McGill University conducted a study and published their results.
To understand how the mass extinction and associated climate change affected specific ecosystems, McGill’s team analyzed microscopic plant remains from the period found in river sediments in southern Saskatchewan.
It turned out that in this area, plant communities and ecosystems have changed. The number of aquatic plants has decreased, the number of terrestrial planets, including trees such as birches and elms, on the contrary, has increased. Researchers speculate that this growth was due to the disappearance of large plant-eating dinosaurs. Also, scientists found changes in rainfall’s nature during the extinction – they were relatively minor and short-lived.
“Many scientists predicted that changes in rainfall would have a profound effect on people and ecosystems during global warming,” explains Peter Douglas, senior author of the study. “At other times of major climatic change in Earth’s history, we find evidence of such changes. The lack of such a signal during the most recent mass extinction is very intriguing. ”
Douglas adds, “Surprisingly, scientists know more about what happened in the oceans at the end of the Cretaceous extinction period than on land. By clarifying the ecological changes during this period, we narrowed down the factors that led to the dinosaurs’ extinction. This study is also an important analog of environmental change caused by human activities and will allow better predicting the likelihood and details of future mass extinctions.”