Scientific links of the week »Explorersweb

Passion for the natural world drives many of our adventures. And when we’re not actually out there, 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.

Spix Macaw reintroduced to the Brazilian forest: Since 1995, conservationists have been trying to save the Spix Macaw. This blue-gray parrot is one of the rarest birds in the world. Throughout the 19th century they were hunted for their beautiful plumage. In the 1990s, only one known bird remained in the wild, a male.

The scientists then released a female from a zoo in that area. After two months, the birds had mated. Two weeks later, the female disappeared and a few years later the male died. Many believed that this was the end of the species.

Now the environmentalists are trying again to bring it back. Today they released eight captive Spix Macaws in the forests of Brazil. They plan to release 12 more at the end of the year and more in the future.

“There are very few reintroduction programs around the world that have done something like this, and none with parrots or macaws,” said wildlife biologist Thomas White.

Beautiful, poisonous and destructive

Lionfish spreads to the Caribbean: Lionfish are known for both their beautiful motifs and their venom. Although the fish are not aggressive, their poisonous spines contain a neuromuscular toxin which they use to protect themselves.

Lionfish are native to the Pacific and Indian Oceans but have spread to the Gulf of Mexico and the Caribbean Sea. This is not a good thing. Being an invasive species, they devastate the coral reefs of the Atlantic. A single lionfish can reduce the number of juveniles in its feeding area by 80% in just five weeks.

At the same time, they reproduce very quickly. Females can produce 25,000 eggs every few days. Communities around the Caribbean are trying to save their coral reefs by controlling lionfish populations.

Fernanda the giant tortoise. Photo: Lucas Bustamante / PA

100 years later, the surprise appearance of a turtle

Giant tortoise species believed to be extinct found alive: For over a century, everyone has thought that the Chelonoidis phantasticus giant tortoise species was extinct. The last sighting of this fantastic creature dates back to 1906. Now researchers have found one on Fernandina Island in the western Galapagos.

Fernanda, as she was called, first showed up in 2019. Since then, conservationists have wondered if she was, in fact, a member of this supposedly extinct species. Princeton researchers have been sequencing her and the male’s genomes since 1906. They match. It means Fernanda is different from the other 13 living turtle species in the Galapagos.

Why do ocean predators dive so deep? Researchers tag large marine animals with tracking devices, sensors and tiny cameras to capture life beneath the waves. Their monitoring revealed that nearly all large marine predators dived hundreds and thousands of meters deep. But why?

The likely answer is food, but only one species – the northern elephant seal – has been seen doing this. Fish ecologist Simon Thorrold believes they may also dive to hide from other predators, for navigation purposes or for cooler deep-sea temperatures.

Why do whale sharks and other marine predators dive so deep? Photo: Shutterstock

Magnetic microbes

Strange creatures in the Mariana Trench: In 2018, graduate student Yang Hao collected sediment from the Mariana Trench. Reaching 11km, it is the deepest place in the ocean. Yang was looking for cosmic dust but found something completely unexpected. Attached to the magnetic needle that probed the sediment was a tiny shelled organism.

The tiny creature was a single-celled creature called foraminifera, in particular Resigella bilocularis. There are many foraminifera on the sea floor, but these were different. They are magnetic.

Many animals use magnetic fields for navigation, and some can produce magnetite using the iron around them. But no one knows how or why foraminifera are magnetic. They are the first single-celled magnetic organism found this deep. Researchers suspect R. bilocularis they are creating their own magnetite. The magnetite they produce is different from that of the surrounding sediment.

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