4 news stories you might have missed last week

Did you hear about the discovery in Morocco of three new pterosaur species? Or that Australia’s Great Barrier Reef has just suffered another mass bleaching – its third in five years?

Amid the ongoing coverage of the COVID-19 pandemic, you may have missed these stories and a few more.

1. New pterosaur fossils unearthed

Scientists have discovered three new species of toothed pterosaur that lived in the Sahara during the Cretaceous period some 100 million years ago.

Though they lived among the dinosaurs and became extinct around the same time, pterosaurs were not dinosaurs. They were flying reptiles.

These pterosaurs had wing spans of three to four metres, lived on a diet of fish and were part of a river ecosystem abundant with fish, crocodiles, turtles and several predatory dinosaurs.

Their fossils, discovered in Morocco and described in a study published in the journal Cretaceous Research, will help researchers to better understand the evolutionary history of Africa during the time of the dinosaurs – an ancient world dominated by predators, including crocodile-like hunters and carnivorous dinosaurs.

"Pterosaur remains are very rare, with most known from Europe, South America and Asia. These new finds are very exciting and provide a window into the world of pterosaurs in Cretaceous Africa," said lead author Megan L Jacobs, a doctoral candidate in geosciences at Baylor University.

2. Mass bleaching hits the Great Barrier Reef

Australia’s Great Barrier Reef has suffered its third mass bleaching in five years.

Accumulation of heat, particularly in February when sea surface temperatures around the reef were the hottest on record, led to widespread bleaching, the Great Barrier Reef Marine Park Authority said.

Ocean warming caused by climate change is threatening the world’s largest coral reef system. The reef spans some 344,000 square kilometres and supports a vast array of life, including 1,500 species of fish and one-third of the world’s soft corals.

In 2016 and 2017, mass bleaching events damaged two-thirds of the reef.

Aerial surveys in March 2020 showed the worst bleaching extended across large areas of the reef, though the severity of the damage varied.

Some southern areas, which had been spared in 2016 and 2017, were badly hit, while key tourist sites suffered only moderate bleaching.

3. Healing ozone layer helps redirect wind flows

Earth’s ozone layer is continuing to recover – and the healing process may be reversing human-made damage to atmospheric circulation, a new study has found.

Before 2000, the mid-latitude jet stream had been gradually shifting towards the South Pole due to ozone depletion, which was affecting rainfall patterns in the Southern Hemisphere. Meanwhile, another hurricane-causing jet stream, the Hadley cell, had been getting wider.

Researchers from the University of Colorado Boulder say both those trends paused and began to reverse after 2000, thanks to the Montreal Protocol in 1987, an international agreement to stop the production of ozone-depleting substances.

Last September, the ozone hole over Antarctica was at its smallest since its discovery in 1982, aided by unusual weather patterns in the stratosphere above the South Pole.

4. Antarctic glacier retreated 5.4km in 22 years

Denman Glacier in East Antarctica has retreated 5.4km in just over two decades, according to a new NASA study.

It is the world's deepest land canyon, at 3,500 metres below sea level, and holds as much ice as half of West Antarctica. If all of it melted, it would result in about 1.5 metres of sea level rise worldwide.

Until recently, scientists thought East Antarctica was more stable than West Antarctica because it wasn't losing as much ice as the western part of the continent.

But it turns out that the shape of the ground beneath the ice sheet makes Denman Glacier especially vulnerable to climate-driven melting.