Scientific links of the week »Explorersweb

Passion for the natural world drives many of our adventures. And when we’re not out, we love delving into discoveries about the places we live and travel. Here are some of the best natural history links we found this week.

Rays make sounds: Naturalists have long thought that rays were silent, but new research shows that two species of rays actively produce sounds.

The researchers analyzed videos from three different locations. From these videos, they identified an adult and juvenile mangrove whip breed on the Great Barrier Reef and an adult coastal stingray near the Australian island of Heron, which was making noises.

“I couldn’t believe my ears when I first heard this loud click, clearly coming from the mangrove whip I saw in the video. I started delving into the published literature and couldn’t find anything describing this behavior, so I knew it was something unique, “said marine scientist Joni Pini-Fitzsimmons. The research team would like anyone to have seen or heard something. like it made contact.

Ancient mine

In search of the crystal hunters: Archaeologists are exploring a mine in the Swiss Alps that was first used in 8,000 BC It is the only known prehistoric crystal mining site in the region.

In the Stone Age, hunter-gatherers searched the Alps for crystals to be transformed into tools. In 2020, an audience member came across several crystal shards, two horn pieces, and a few pieces of wood. It might not seem like much, but the person made the discovery at 2,831m in the Alps, a rise where there are very few animals or plants.

Historian Marcel Cornelissen has been studying these crystal mines for years and has been leading research in the Alps since September 2020. Cornelissen has dated the horns to 6000 BC and researchers believe ancient humans used them to mine quartz crystal.

The crystal mining project will finish in December 2022. They are currently filling sacks with rock samples from the top five centimeters of their excavation sites. “This is what people have left. That’s what they didn’t want, and that’s what we’re getting. It’s not a tool or anything. It’s garbage, leftovers from the manufacturing process, ”Cornelissen said.

Bright oceans

The mysterious glow of the “milky sea” captured by the camera: For centuries we have been talking about the sea that turns white at night. Amid the darkness of the ocean, the sections seem to light up. The “milky sea” phenomenon is thought to occur only a few times a year.

Scientists have never been able to study this phenomenon due to its sporadic nature, but for the first time it was captured on camera. “It is a truly huge and mysterious answer in our biosphere. We would like to know how it works and how it could change in a changing climate, ”said atmospheric scientist Steve Miller.

Miller has chased the mysterious glow for decades. Researchers believe that bioluminescent bacteria cause the phenomenon. But why they ignite is unknown. Miller collected satellite images and first-hand reports to find out more. In 2021, you posted images from NOAA satellites showing images of milky seas south of Java, Indonesia. A crew member of a boat in the area saw this and got in touch. He had been there at the time and said it was “like stickers that glow in the dark”.

A satellite image shows a 100,000 km² bioluminescent milky sea south of Java, Indonesia. Photos: Steven Miller, Leon Schommer (photographer) and Naomi McKinnon, Australian National University, Canberra

A Herp Murder Mystery

Thousands of frogs are dying in Australia: Across Australia, people are finding thousands of dead frogs. “It’s a really complicated murder mystery,” says herpetologist Jodi Rowley. So far, no one knows why this is happening.

Frogs are more likely to be found dead in the winter from the cold, but this event goes far beyond normal mortality rates. Frogs usually hunker down during the winter to protect their immune systems. Now they are coming out and dying en masse. The team received over 1,600 reports from the public.

The reports detailed dozens of dead frogs appearing in homes, and the public found over 40 species of frogs. The phenomenon stopped during the summer, but with the arrival of winter it started again.

“They’re cryptic and hiding, but they’re out there in really huge numbers. If their populations change, there will be ripples throughout the food chain, ”explained Karrie Rose of the Taronga Conservation Society.

Small amphibians are indicators of ecosystem health, and this is not a good sign. Scientists are collaborating to try to solve the mystery.

Shipwrecked horses?

The oldest DNA of American horses relates to folklore: Wild horses have lived on Assateague Island for hundreds of years. How they got to the island off the coast of Maryland is a mystery.

Folk stories describe horses washing there after a Spanish galleon was wrecked, and new evidence suggests this may be true. Nicolas Desol was analyzing DNA from fossilized cow teeth from an abandoned Caribbean colony on the island of Hispaniola. One of the examples of him was completely different. It was a fragment of an ancient horse tooth.

Researchers excavated the tooth from one of the first Spanish colonial settlements on the island. The Spaniards founded Puerto Real in 1507, but it became a piracy center and the residents left in 1578. Cow remains are quite common there, but horse remains are not. Desol compared the ancient horse DNA to that of modern horses. He expected it to be very similar to those of the Iberian Peninsula, but their closest relatives are the wild horses of the island of Assateague.

This new DNA evidence suggests that Spanish explorers may have been the source of the horses on Assateague.

The wild horses of Assateague. Photo: National Park Services

Ancient footprints found during dinner

Footprints of the largest dinosaurs in the world discovered in a Chinese restaurant: Paleontologists found the footprints of two sauropod dinosaurs in the outer courtyard of a restaurant in China. Scientists have announced that they were created from the largest terrestrial species ever to exist.

A restaurant customer saw dents in the ground and contacted the researchers. A team of paleontologists studied the site and 3D scans showed it to be footprints of brontosaurs, a species that lived during the Cretaceous period.

The size of the footprints suggests that the sauropods would have been around eight meters long. This is the first time dinosaur footprints have been discovered in Leshan, southwestern China.

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