Another victim: of Hurricane Irma: Florida’s sea turtle nests
News and notes about science
In addition to wiping out homes and businesses, Hurricane Irma swept away a large number of sea turtle nests as it tore across Florida last month.
The state is a center of sea turtle nesting, and this year was developing into a very encouraging year for the endangered leatherback turtles, the threatened loggerheads and green turtles, said Kate Mansfield, a marine scientist and sea turtle biologist at the University of Central Florida. The hurricane suddenly dashed those hopes.
At the Archie Carr National Wildlife Refuge, just south of Cape Canaveral on the east coast of the state, more than half of the green turtle nests laid this season and a quarter of the loggerheads were lost as the storm tore up beaches.
Along two stretches of beach south of Cape Canaveral, more than 90 percent of incubating loggerhead nests were destroyed by the storm, representing about 25 percent of the season’s total.
Although the losses this year are significant, sea turtle populations will survive as long as the hits don’t keep coming, Mansfield said.
— Karen Weintraub
A stick insect. A tree lobster. Whatever you call it, it’s not extinct.
The tree lobster, one of the rarest insects on Earth, has lived a rather twisted life story.
Scientifically known as Dryococelus australis, this 6-inchlong stick bug with a lobster-esque exoskeleton once occupied Lord Howe Island in the Tasman Sea, between Australia and New Zealand.
In 1918, rats escaping a capsized steamship swam ashore. The tree lobsters became rat chow. Two years later, all tree lobsters seemed to have vanished, and by 1960 they were declared extinct.
But in the latest chapter for what has also been called the Lord Howe stick insect, scientists compared the genomes of living stick bugs from a small island nearby to those of museum specimens, revealing that they are indeed the same species. The resulting paper, published Oct. 5 in Current Biology, resolves an identity question that has impeded conservation efforts for years, and sets the scale to effectively resurrect the insect.
“This allows us a second chance to bring it back to the island,” said Alexander Mikheyev, an ecologist at the Okinawa Institute of Science and Technology who led the study.
Not long after the insects were believed extinct, climbers found dead tree lobsters on Ball’s Pyramid, a sheer rock cliff of an island separated from Lord Howe by 12 miles of water. In 2001, nearly four decades later, scientists scaled the rock, a third of a mile high, and discovered a small group of living tree lobsters dining on tea tree at night.
But some scientists worried these tree lobsters might be a distinct species because they looked different from the preserved Lord Howe tree lobsters.
Mikheyev and his colleagues managed to show that the genetic differences between Lorde Howe and Ball’s Pyramid insects were within the range of the same species. This meant that they had to make sense of stick bugs’ massive genome — about a quarter bigger than the human genome.
— Joanna Klein
Yearly 9/11 tribute shows light pollution’s effects on birds
Scientists have long known that artificial light can attract and disorient birds at night, causing collisions and wreaking mischief with their migratory path. Now, the annual September 11 “Tribute in Light Memorial” in Manhattan has provided a unique opportunity to study and quantify the effect.
The multiyear study, published in the Proceedings of the National Academy of Sciences, found that birds gathered in greater densities, flew repeatedly in circles and vocalized loudly when the memorial’s powerful beams were illuminated.
However, when the lights were turned off for brief periods, the birds were quick to resume their normal flight paths and behaviors. Although the researchers were not calling for any changes to the annual event, their findings suggest a simple fix for ongoing light pollution in other places.
“Wherever we can turn lights off at night, we should be doing it,” said Andrew Farnsworth, an ornithologist with Cornell University and an author of the study, which claims to be the first to quantify bird responses to urban nighttime light.
Researchers from Cornell and the New York City Audubon Society have been monitoring the memorial, which consists of two pillars of 44 spotlights aimed directly upward to simulate the fallen Twin Towers, since it was first presented in 2002. In 2008, the team began using radar and acoustic sensors to track how many birds the light was attracting and how it affected their behavior.
In 2010, the beams attracted so many birds that the researchers persuaded the memorial’s operators to turn off the lights for 20-minute intervals, which presented “a unique opportunity” to study “behavior in birds when these incredibly powerful lights were on versus when they were off,” Farnsworth said. The lights were briefly extinguished again in 2012, 2013, 2015 and 2016.
Compiling data from seven nonconsecutive years, the researchers found that bird density near the installation was 20 times greater than surrounding areas.
— Douglas Quenqua
Rosetta’s lost picture from moments before it struck a comet
Nearly a year after it crashed into a comet, the Rosetta spacecraft has given scientists a gift from beyond the grave: the final image of its resting place on Comet 67P/churyumov-gerasimenko.
Researchers from the European Space Agency thought they had collected every picture beamed back by the probe during the two years it spent investigating the rubber-ducky shaped comet. But on Sept. 28 they announced the discovery of one more hidden image in Rosetta’s final transmission.
Grainy and blurry, it shows Comet 67P’s cold, rocky surface from about 60 feet above and covers about 10 square feet. The craft’s previous “last image” was taken from about 80 feet above. Together, they show the final moments of humanity’s first visit to a comet.
As the spacecraft deliberately dived toward Comet 67P, Rosetta split this final image into six packets — or units — of data before attempting to send it to Earth. But the transmission was interrupted, and only three data packets made it back to Earth.
When the scientists went back later and reanalyzed the transmission, they stumbled upon the data fragments, which they hoped might be salvageable.
“We found a few telemetry packets on our server and thought, wow, that could be another image,” said Holger Sierks, principal investigator for the spacecraft’s OSIRIS camera at the Max Planck Institute for Solar System Research in Göttingen, Germany, in an ESA statement.
While Rosetta will never again transmit images and data from the surface of the comet, scientists are studying the information collected by the spacecraft in hopes of learning more about how Comet 67P formed and how its creation fits into the evolution of the solar system.
— Nicholas St. Fleur
The elusive giant coconut-cracking rat of the Solomon Islands
Locals living on the island of Vangunu in the Solomon Islands sing songs about vika, a giant, tree-dwelling rat that can crack open coconuts with its teeth. But scientists had never seen it.
Tyrone Lavery, a conservation ecologist at The University of Queensland and The Field Museum of Natural History in Chicago, searched for this rat for years. But the closest he got was a mysterious dropping found on the forest floor that contained the hair of some unidentified species of rodent.
Now the Vanganu Giant Rat is no longer legend, but scientific fact. Hikuna Judge, a ranger at the Zaira Resource Management Area on the island, found an injured specimen scampering away from a felled tree. He and Lavery reported this new species, Uromys vika, in the Journal of Mammalogy on Sept. 27. It’s the first new rat species discovered on the islands in about 80 years.
Uromys vika can weigh more than 2 pounds and stretch up to a foot and a half from nose to tail. Its ears are small, and its feet are wide, to help it maneuver among the branches in the forest canopy where it lives. The rat’s smooth tail is particularly special, covered in tiny scales surrounded by large areas of flesh. Think opossum, or squirrel, but more rat, and very, very, rare.
They get to the meat inside the ngali nut by drilling a hole in the shell with their teeth. Knowing this detail now, scientists can track rats using their leftover shells like breadcrumbs.
The rare species will begin its scientific life listed as critically endangered because the island is losing rain forest habitat to logging.
“Now that we know it definitely exists,” Lavery said, “we can work out ways to conserve it.”
— Joanna Klein
Electric honeycombs form when nature gets out of balance
An electric honeycomb is what happens when certain kinds of electrically charged particles travel between a pointy electrode and a flat one, but bump into a puddle of oil along the way.
This visualization reveals fundamental principles about how electricity moves through fluids that engineers can use to develop technology for printing, heating or biomedicine. But it also reminds us that humans aren’t the only ones seeking stability in an unstable world. Even tiny, unconscious objects need balance. You can see similar patterns in wax honeycombs, fly’s eyes and soap bubbles.
Physicists knew of this phenomenon decades before Muhammad Shaheer Niazi, a 17-year-old high school student from Pakistan met the electric honeycomb. In 2016, as one of the first Pakistani participants in the International Young Physicists’ Tournament, he replicated the phenomenon and presented his work as any professional scientist would. But he also developed photographic evidence of charged ions creating the honeycomb, and published his work Oct. 4 in the journal Royal Society Open Science.
An electric honeycomb behaves like a capacitor, which store electricity, a bit like a battery. The top electrode is a needle that delivers high voltage to the air just a few centimeters above a thin layer of oil on the other flat, grounded surface electrode.
The high voltage strips molecules in the air of their electrons, and pours these ions onto the surface of the oil. Just as lightning strives to strike the ground, these ions want to hit their ground electrode. But because oil is an inefficient conductor, they can’t get through it.
The ions start accumulating on top of the oil until their force is too much. They sink, forming a dimple in the oil that exposes the bottom electrode, allowing them to find their ground.
But now, the surface of the oil is no longer even. Within milliseconds, dozens of hexagonal shapes form in the layer that help maintain the equilibrium nature demands. The polygons keep the amount of energy flowing into and out of the system equal, and balance two forces — gravity, which keeps the oil’s surface horizontal, and the electric field pushing down on top of it.
To prove that the ions were moving, Niazi photographed images of the shadows formed by their wind as they exited the needle and recorded the heat presumed to come from the friction of their travel through the oil.
— Joanna Klein
Who’s eating jellyfish? Penguins, that’s who
There are not many jellyvores in the world, or so scientists have long thought.
Gelatinous sea animals, like jellyfish and ctenophores, have traditionally been regarded as “dead ends” in food webs. Because they are so low in calories (jellyfish are about 95 percent water), it was thought that most predators would not benefit from eating them. But a recent study has identified a new, unexpected jelly-eater: penguins.
Like other warm-blooded animals, penguins have high caloric demands and typically seek energy-dense foods, like fish and krill. In a paper published in Frontiers in Ecology and the Environment, however, an international consortium of scientists has reported that an assortment of penguin species frequently attack jellies as food, a behavior that had not been documented before.
In the new study, led by Jean-baptiste Thiebot, a postdoctoral researcher at the National Institute of Polar Research in Japan, teams from five countries monitored four penguin species: Magellanic penguins in Argentina, Adélie penguins in Antarctica, little penguins in Australia and yellow-eyed penguins in New Zealand.
Strapping miniature video cameras to the penguins, the scientists documented nearly 200 strikes on jellies at seven sites.
“We were amazed to realize that all teams observed the same phenomenon,” Thiebot said.
The researchers estimated that jellies provide only 1 to 2 percent of penguins’ daily energy needs. This begs an interesting question, said Nina Karnovsky, an associate professor of biology at Pomona College who did not participate in the research: Why would penguins expend the energy to catch and digest jellies for such low return?
One possible clue comes from the fact Thiebot and his collaborators saw penguins eating only carnivorous jellies, not herbivorous ones, like salps. It’s possible that the penguins are gaining nutrients from the food eaten by carnivorous jellies, which include crustaceans that are too small for the penguins to target themselves, Thiebot said.
— Steph Yin