This asset was created based on the National Geographic Magazine article that shares the same title. Written by Hillel J. Hoffman, the article offers insights into the author’s interactions with paleontologists and scientists while exploring the Black Triangle and Karoo regions. The primary goal is to uncover a deeper understanding of the Permian extinction and its subsequent consequences.
"Welcome to the Black Triangle," said paleobiologist Cindy Looy. Paleobiologists study ancient life by looking at fossils and old rock layers. Our van slowed to a stop. We were in the gentle hills of the Czech Republic. The Black Triangle gets its name from the coal burned by nearby power plants. Decades of acid rain from emissions have devastated the region's ecosystems.
Permian Extinction Mystery
I was on the trail of the greatest natural disaster in Earth's history. It occurred at the end of the Permian period, about 250 million years ago. Something killed off 90 percent of the planet's species. Nearly all the trees died. Looy had told me that the Black Triangle was the best place today to see what the world would have looked like after the Permian extinction. We saw the first signs of death as we walked into the hills. Hundreds of fallen logs lay in the green grass. No birds called, no insects hummed. Looy is like a detective. "You could say we're working on the greatest murder mystery of all time," she said. Her theory? She believes the Permian extinction was caused by a massive release of volcanic gases.
What Caused 90 Percent Of Life To Disappear?
Looy is one of many scientists on the case. After all, this was the largest of several mass extinctions on the planet. So what was the killer? To understand this extinction, I wanted first to get a sense of its scale. For that, I had to go to South Africa. I joined Roger Smith, a paleontologist at the South African Museum. We drove across a treeless stretch of land. If we had driven here before the Permian extinction, we would have seen a landscape full of many animal species. Most would have belonged to a group known as synapsids. They looked like a cross between a dog and a lizard. Smith slowed, rolled down the window. He pointed to a horizontally banded cliff. He explained that the fossil record here dates from the switch from the Permian to the Triassic periods. The fossils in the rock show that synapsids took a savage hit at the end of the Permian. There are plenty of synapsid fossils on the lower layers. Higher up, though, they grow fewer, then disappear.
The World's Tree Suddenly Died
Plants were also hit by the extinction. I joined a research team led by Henk Visscher in the Italian Alps. We visited fossil beds revealing the transition of the Permian to the Triassic. Here, researchers showed me the evidence. Lower levels of the fossil record come from before the extinction event. They contain a great deal of tree pollen. In rocks from this transition period, though, the pollen has disappeared. It was replaced by fossilized fungi. Looy explained that this may be a wood-decaying fungus. It only grows in the wood of dead trees. Visscher's team has found high levels of these fungal remains in Permo-Triassic rocks from all over the world. Their conclusion: Nearly all the world's trees died suddenly. There is plenty of evidence of the Permian disaster. However, what was the cause? Gregory Retallack is a geologist at the University of Oregon. He points to evidence that the Permian extinction was caused by an asteroid smashing into the Earth. A team of researchers in Australia recently found possible evidence: a 120-kilometer-wide (75-mile-wide) crater. The impact would have sent clouds of particles into the atmosphere, Retallack said. These would have blocked sunlight and cooled the Earth. Then plants and plankton would have died, the base of all food chains. Herbivores would have starved, as would the carnivores that fed on them.
Many Global Disasters?
Other Permian detectives suspect the killer oozed up from the sea. In 1996, English geologists Paul Wignall and Richard Twitchett reported a discovery. They found evidence of decreasing oxygen, or anoxia, in rocks that formed under shallow water at the time of the extinction. Anoxic water could have built up and smothered marine life. yardAnother leading suspect is volcanic activity. Eruptions spread a kilometers (miles) deep layer of lava across Siberia. Volcanic gases poured into the skies and generated acid rain. Particles would have blocked sunlight and cooled the planet. Each scientist I met left me thinking that he or she was close to solving the crime. Yet, as Doug Erwin of the Smithsonian cautioned me, "the truth is sometimes untidy." Erwin suspects there may have been more than one killer. Maybe several global disasters occurred at the same time. Now humanity is causing a new mass extinction, wiping out countless species. Will life bounce back again this time? I think about what I have learned in my research. I conclude that if life can survive the Permian extinction, it can survive anything.
