Ms. Black, what fascinates you about the last days of dinosaurs that you wrote a book about it too?
The asteroid impact is a well-documented event. We all know the direct consequences of the impact, for example the extinction of dinosaurs with the exception of birds. In my book, I devote myself more to the small, less well-known details, for example how some animals survived the impact or how life came back to earth. There have been many exciting research results on this in recent years.
Some researchers believe that the era of dinosaurs ended before the impact. What was the status of the dinosaurs shortly before the impact?
In my view, 66 million years ago there was no mass extinction in the air. The fossil finds always show us only a small part of the real diversity of species and ecosystems. We will never find traces of the vast majority of dinosaurs because they lived and died in deserts, on mountains or in dry steppes. So it’s difficult to say what the global biodiversity of dinosaurs was like. There were certainly still very successful species like the T-Rex or duck-billed dinosaurs that lived in large numbers on earth. Large dinosaurs still flew and swam in the seas and in the air. Added to this is the adaptability of the dinosaurs. They have survived a variety of climate changes, tectonic plate movements and many volcanic eruptions and have not become extinct for 180 million years.
Riley Black, US science editor, has been a big fan of fossils and dinosaurs since she was a child. She is the author of several non-fiction and children’s books on primeval phenomena and has published in various print and online magazines, including National Geographic, Slate and Scientific American. She lives in Salt Lake City/Utah – in the middle of dinosaur country.
© Source: Riley Black
That changed abruptly 66 million years ago. What were the consequences of the impact?
Our earth was hit by a rock the size of a mountain with tremendous speed and unimaginable force. To this day, the impact crater can be seen off the coast of Mexico. It is 10 kilometers deep and 180 kilometers in diameter. The impact kicked up tons of white dust and tiny rocks. We find these little rocks on every continent. The tiny rocks were thrown high into the atmosphere and burned up on their way back to earth.
So it got hotter on earth than in an oven. forests burned. There were also huge tidal waves and earthquakes. In the days, weeks and years that followed, things remained uncomfortable on earth. The dust from the impact darkened the sky, and the sun had not shone for years. Temperatures dropped by up to 25 degrees and winter came suddenly. All of this cost the lives of more than three quarters of all living things on earth. The special thing about it is the speed, all other mass extinctions took place over many hundreds of thousands of years.
What can we learn about impacts from fossils?
For example, there was a recent study of primeval fish that were killed in the asteroid impact 66 million years ago and fossilized almost unharmed. These fish are related to modern-day sturgeons. It is known that in spring they are still in the middle of the growth phase. These fish fossils were not fully grown either. So the asteroid hit the northern hemisphere in the spring. This was bad timing for most animals. Spring is mating season and some animals have already nested. Unfortunately, we don’t yet know very much about what happened in the southern hemisphere and whether it helped the animals that autumn had already arrived there.
How were some animals able to survive this impact?
Almost 75 percent of all living things on earth died on or shortly after the impact. But no animal group disappeared completely, none was completely spared. From the dinosaurs, the birds remained. Many surviving mammals were small and adaptable. They lived underground and could feed on roots as well as small insects or lizards. Our ancestors were among these animals. The chances of survival were also good in freshwater ecosystems such as ponds or lakes. Many frogs, fish, turtles and crocodiles also survived the catastrophe there.
So having a layer of water or earth over your head wasn’t a bad strategy for survival.
In her book, The Last Days of the Dinosaurs, there are individual chapters about what the world looked like 100 years, 100,000 years, and even 1 million years after the impact. How did the world change during this time?
100 years after the impact, the sudden winter was over and the sun was shining again. The surviving animals spread again. Insects and small mammals were on the rise again. The plants and trees, on the other hand, still have difficulties regaining their old size. So there are no large, dense forests yet.
100,000 years after the impact, the world has already become significantly greener. For example, we find pollen from ferns at many fossil sites. These plants cope very well with difficult environmental conditions and by this time had already grown back to their old size.
After a million years, biodiversity had also made immense leaps. The earth’s climate became warmer again. Early primates lived in the trees of the partly tropical forests. The mammals also became significantly larger again, the largest being about the size of a shepherd dog. And more importantly, they are occupying more and more niches and competing for top positions in the food chain. However, almost ten million years passed before all gaps and tasks in the ecosystems were completely filled with large predators and important players.
What are remaining research questions about the last days of dinosaurs?
What science still lacks is a global picture of the catastrophe. Fossil finds from this period are patchy and have not yet been found on every continent. It is therefore difficult for us to draw comparisons between different regions. We also don’t know whether certain species of dinosaurs or large marine dinosaurs survived longer and perhaps only became extinct in the years after the impact. We can also say little about possible migrations of animals. To answer such global questions, we simply need more fossil sites from the time of the impact. However, I am firmly convinced that we will soon find more and that our picture of this catastrophe will become even more complete over the next few years.
The last days of the dinosaurs: why their end was our beginning and what an asteroid has to do with it. by Riley Black. gold man ISBN: 978-3-442-31674-8. Price: 24.00 euros.
© Source: Riley Black
Can we learn anything from this mass extinction event for the future and biodiversity loss today?
NASA researchers are looking for ways to prevent another large asteroid from impacting Earth. It was therefore recently tested whether the trajectory of such a celestial body could be deflected by letting a satellite fly into it at high speed. On the other hand, the mass extinction 66 million ago is really a big accident. Direct conclusions about today’s loss of biodiversity are therefore difficult. Except perhaps that, unlike an asteroid, we can still change direction and prevent a real catastrophe.