Joanna Klein

Spanning up to 25 feet from wing to wing, manta rays look like UFO's from below. If you ever get a chance to dive with them, look up. Lights won’t beam down and abduct you, but something about their bellies may surprise you. Most are white, but some are splattered with unique black blotches.

This trait, known as melanism, is seen with some frequency on land. For many terrestrial animals, having a black coat seems to offer an evolutionary advantage. It helps some pocket mice hide out, some snakes regulate their body temperature and some insects resist diseases.

But underwater, melanism is far less common. Of the hundreds of species of cartilaginous fish in the ocean, only two — the two known species of manta rays — exhibit this trait, and then only in some populations. The reason for this dark pigmentation has long been unknown.

The mystery of the melanistic mantas remains unsolved. But in a study published Tuesday in Proceedings of the Royal Society B, researchers confirmed that some manta ray populations have more melanistic individuals than others, and at least one possible explanation was definitively eliminated. For the moment, the team hypothesizes that an evolutionary process that is neutral, and not related to predation, might be at play. And their work demonstrates that some scientific questions don’t have black-or-white answers.

“There are a lot of things that we don’t understand about why animals are the way they are and how they have evolved,” said Stephanie Venables, a graduate student at the University of Western Australia and lead author of the study.

To study the manta-ray enigma, the researchers looked at the frequency of melanism in thousands of photos uploaded by divers, dive operators and underwater photographers between 2003 and 2018 in different locations in and around the Indian and Pacific oceans.

They found that melanism varied from place to place. In Indonesia’s Raja Ampat islands, for example, 40% of the reef manta population was melanistic, but in others, it was hard to find even two melanistic mantas. This suggested that some evolutionary advantage could be selecting for this trait in these populations, but what?

Mantas have few predators, in part because of their size. They also tend to have white bellies, which enable them to blend in with contrasting light from the surface and avoid being seen from below. Presumably a black belly would make them more conspicuous, and more prone to predation. The researchers tested that idea by following a few individual animals through years of photos, then determining whether coloration influenced the animals’ survival.

The results, described in the new paper, showed no difference in the survivorship of white and melanistic rays. Whatever the role of those dark blotches, they weren’t making the rays more visible to predators.

One potential explanation for why some manta populations may have more melanism than others, they say, is that the trait may spread at random when different groups meet. Or perhaps the trait is passed down among individuals in populations that have become isolated.

Genetics are complex, and in future research Venables and her colleagues hope to identify the genes responsible for melanism in mantas, which could be linked to other traits that are important for survival.

Venables also hopes that by expanding their investigations globally, they may gain a better understanding of how different groups of manta rays are connected. That might improve efforts to protect vulnerable populations.

“Divers and snorkelers will fly around the world to spend a bit of time with them,” she said. “But they’re also threatened, and conservation efforts are needed to make sure they’re around in the future.”

This article originally appeared in

(Trilobites)

The Mystery of the Melanistic Manta Rays

In 2013, a mutual friend brought Kat Vollinger and Nathan Richman together as rock climbing partners. Within a few years, they were married, and their shared love of climbing led them on adventures around the world. That’s how, in March 2018, they found themselves scaling Castleton Tower, a nearly 400-foot sandstone spire near Moab, Utah, with a seismometer in tow.

They helped scientists measure, for the first time, how Castleton Tower taps into the earth’s natural vibrations, finding that it pulsates at about the rate of a human heartbeat.

Castleton Tower is one of many culturally significant desert rock formations that Jeff Moore, a geologist, and his team at the Geohazards research group at the University of Utah have been monitoring with audio recordings. Like a doctor listening to the beating of a human heart, they hope to learn about the structural health of these arches, bridges and towers and how their environments affect them.

Formed over tens of thousands of years, these structures have withstood earthquakes and heavy winds. But human-made sounds and vibrations — from helicopters, for instance, or highway traffic — may be challenging their endurance. As some of the most well-known and photographed arches in Arches National Park have collapsed over the past two decades, scientists, climbers, Native Americans and the National Park Service have been left to wonder: Is this normal? How much can a rock take?

In their study, published last month in the Bulletin of the Seismological Society of America, Moore’s team found that Castleton Tower can withstand quite a bit. They had predicted that such a large structure would vibrate at a lower frequency than a smaller one, much as a thicker guitar string has a lower pitch than a thinner one. Their research suggests that smaller formations that vibrate at a higher frequency may not be as resilient as Castleton appears to be.

Their work also offers a new perspective on nature: Even seemingly sturdy rock formations move and change.

“We like to think of it as a voice,” Moore said. “It’s sort of alive with this vibrational energy.”

One of the world’s largest free-standing rock towers, Castleton sways like a skyscraper in response to deep vibrations in the earth. But while engineers rely on abundant research to understand how buildings respond to such stressors, little is known about how rock structures do.

To assess how Castleton manages, Moore taught Vollinger and Richman to use a seismometer.

They placed one seismometer at the tower’s base and then carried a second to the top, scaling its flat northern face. Placing a seismometer at each location allowed the researchers to distinguish between vibrations coming from the swaying of the tower and the ground around it.

They found that the tower registered pitches of 0.8 and 1 hertz. It vibrates in a sort of trembling cross, with movement in perpendicular directions, simultaneously. The vibrations measured at the top were 70 times stronger than those at the base.

“It was really interesting to learn that they move like that, but I can’t say it was a revelation to learn that the mountains and hills breathe,” Richman said. “If you spend enough time there, you can see they are moving things.”

And if your ears were sensitive enough, you could hear their endless drone, gaining strength from wind, earthquakes, passing cars and other sounds, said Paul Geimer, a doctoral student who worked on the project. But the pitch is always the same. If researchers were to measure a different pitch in future recordings, it could be an indication that the rock is weakening or that its properties had changed.

But it would take a massive earthquake or a long time for Castleton to crumble, Moore said. Vibrations from mild and medium seismic events and traffic, both rare here, as well as wind, rock climbers and helicopters, are too small to disturb Castleton. Still, while one helicopter may not do much damage, the team wants to know what cumulative effects human sounds might have over time.

“A lot of people have the sense that rock is rock, and rock is strong, and people don’t affect that,” Moore said. “These rocks are buzzing with physical energy, and they respond to what we do.”

Taking the Pulse of a Sandstone Tower in Utah

In the capital of Zimbabwe, a building called Eastgate Centre holds nearly 350,000 square feet of office space and shops. It uses 90 percent less energy than a similar sized building next door.

What’s Eastgate Centre’s secret? Termites.

In the 1990s, Mick Pearce, the building’s architect, took his inspiration from mounds built by fungus-farming termites he saw on a nature show. The insects created their own air conditioning systems that circulated hot and cool air between the mound and the outside.

As architects and builders seek new and improved ways to cool buildings without using more energy in a warming world, a study of another type of termite mound suggests that Pearce won’t be the last human to take design tips from these cockroach cousins.

“We think humans are the best designers, but this is not really true,” said Kamaljit Singh, an engineer at Imperial College London and an author on the study, published Friday in the journal Science Advances. “We can learn from small animals.”

Singh and his colleagues used high-resolution scanning technology and computer and physical simulations to examine the microscopic structure of the external walls of African termite nests. In slabs that look solid to the naked eye, the team found a network of tiny, interconnected pores. Through principles of basic physics, these pores regulate ventilation, humidity and possibly temperature, within the mound and nest. These natural structures may offer inspiration for engineers and builders, emphasizing how comfort can be achieved through structure alone.

There are around 2,600 species of termites, and only about two dozen infest and destroy buildings. Many more are highly social builders aiming to protect their queens and ensure the survival of their colonies.

Carbon dioxide must exit so they don’t suffocate in their underground nests, and oxygen must enter. The mounds termites build above nests are the lungs that make this breathing possible.

But there are different types of mounds. Termites that farm fungus build structures with chimneys and openings that work like windows. The structures of nonfarming termites, like the ones the researchers collected in Senegal and Guinea, have no apparent openings. To the naked eye, “everything looks blocked,” Singh said.

But the pores are there, because the mounds are made from stacking pellets of sand mixed with spit and soil. Small spaces form inside these pellets and larger spaces, between them. Previous work with CT scans showed the small pores in the outer walls of these nests.

But with micro-CT scanners, the team saw deeper inside, with greater resolution and revealed the connections between smaller pores and bigger ones. That this microstructure was practically the same regardless of whether it was built of sand in dry Senegal or clay in wet Guinea suggested structure, not material, might be the key to ventilation.

When the team mimicked strong winds in simulations, structures without the larger pores couldn’t breathe as well and accumulated more carbon dioxide. The researchers also drenched mound walls in water to mimic heavy rain. The big-pore-small-pore structure dried out faster.

Scott Turner, a physiologist who was not involved in the study, said Singh’s research revealed how these pores help manage gas flow and drainage.

“If you look at the physics of gas exchange in the lung, it’s very much the same way as the termite mound is organized,” Turner said.

Stirring from wind, much like a muscle contraction, allows gases to mix and reach important places like a termite nest or human blood. “If you think about what the mound is,” he said, “it’s literally an organ in physiology that’s constructed out of dirt by a bunch of little termites.”

The team also thinks the pores may help regulate temperature. But Turner says in other nests soil does this; more research is needed.

It’s also unclear how the termites work together to build these structures. They could coordinate actions through synergy, a kind of indirect communication system where the termites respond to chemical traces left behind by others, said Guy Theraulaz, a French biologist who also worked on the study. It’s believed that a pheromone, or chemical signal, in the spit on the pellets tells the blind termites when to build.

“They don’t have to really think,” he said. They follow rules that result from evolutionary forces and function kind of like an artificial intelligence program.

“I personally wish that more people could be like termites and be comfortable with natural ventilation,” said Maki San Miguel Paulson, an architect who consults on building envelopes — the outer layers that keep air sealed inside buildings. Termites, she said, “don’t want an airtight environment. They want the air to flow through their building.”

Builders typically focus on mechanical ventilation — fans, heating and cooling — that uses fuel and is easier to control. Eco-friendly buildings are typically smaller scale, because human comfort is difficult to achieve in systems dependent on varying climates. “Wouldn’t it be nice if people could do a building that does both?” she said.

Singh and his colleagues hope future studies of nests from other termite species will reveal general design principles that can be scaled up for humans. And as Eastgate Centre shows, buildings inspired by termites don’t have to look like termites built them.

“There is a danger to see beautiful forms and shapes in nature and simply copy them,” Pearce said. “We’re not copying forms. We’re copying the process that made the form.”

This article originally appeared in <a href="https://www.nytimes.com/2019/03/26/science/termite-nest-ventilation.html" id="c5140e27-5a1c-35e2-a725-6e7f0e801360">The New York Times</a>.

What Termites Can Teach Us About Cooling Our Buildings

The Oregon Department of Agriculture later determined that a pesticide used against aphids had poisoned the bees. They banned its use on lindens. But still more reports surfaced of mass bumblebee deaths around Oregon. Explaining them wasn’t as simple.

“It’s not your classic story of, oh, the pesticides kill the bees,” said Sujaya Rao, an entomologist who studied the bee deaths while at Oregon State University.

“Not every dead bee could be because of a pesticide,” she added. “There are strange phenomena in nature that lead to things like this.”

For centuries, people have noticed similar mysterious incidents around the United States, Europe and Britain. In a study published last month in PLOS ONE, Rao and other researchers proposed an explanation: If it’s too cold, and the bees are too weak, and the trees are enticing but don’t produce enough nectar — all that may tip bumblebees over the edge.

“Not all bee death is related to humans,” said Claire Lande, a co-author of the study who also runs an apiary in Minnesota. “Sometimes it just happens.”

To examine the other alleged death-by-linden cases in Oregon, Rao, now at the University of Minnesota, assembled a team of bee detectives who followed leads to various sites for observation and collection of actively foraging and dying bumblebees, and then drew connections between the cases.

After many dead ends, a pattern emerged: Deaths seemed to occur on cooler mornings, late in the blooming season, when trees start running out of nectar. So what did it mean?

Bumblebees are warm-blooded. To fly and forage, their thoraxes — where their wings and flight muscles are — must reach a temperature of 86 degrees Fahrenheit. To generate that, they shiver. But the cooler it is outside, the more energy the bee needs to do it.

In crawling bees near death, the team found compounds related to energy processing that were different from those in active and foraging bees, suggesting the dying bees didn’t have enough energy.

As the floral blooming season progresses, the linden tree runs out of nectar. Why, then, would the bees keep returning if they are able to detect nectar levels?

Alkaloids, like caffeine, can boost how rewarding bees find linden nectar. The team found an alkaloid called trigonelline that they think may attract bees.

They haven’t tested the idea, but they speculate that trigonelline could boost bees’ loyalty to linden even as nectar runs out. But when they visit on cool mornings without enough energy to heat up for a return flight to their nests, they fall to the ground, crawl around and die.

“It’s like you have a favorite Starbucks, and you keep going there,” said Rao. “And one time they’re out of coffee, and then you don’t have enough gas to go to the next Starbucks. And so you’re stranded.”

Hauke Koch, a biologist who was not involved in the new study, said the story is plausible. He previously led a team at Royal Botanic Gardens, Kew, in England, that identified a few ways these mass deaths can occur, and also suggested that bumblebees may become so loyal to linden trees that they would endure starvation.

But Koch wonders what direct tests of the new study’s hypotheses will reveal, or what would happen to the bees if other flowering plants were available.

The authors stress their findings don’t mean we should stop planting linden trees. Instead, they call for planting flowers alongside to supplement bees throughout the season. Even when these bees die, many more survive and carry on their colonies’ legacy.

This article originally appeared in <a href="https://www.nytimes.com/2019/08/03/science/dead-bumblebees-linden-trees.html" id="394e8f4c-2d18-33b1-a588-db7b45d6323c">The New York Times</a>.

Seeking a Culprit When Bumblebee Carcasses Pile Up

In June 2013, in a Target parking lot in Wilsonville, Oregon, an estimated 50,000 bumblebees dropped dead. Shoppers reported bees falling from branches and crawling on the ground. Piles of carcasses scattered beneath dozens of linden trees marked the largest mass bee kill ever recorded.

In a rainforest near Auckland, New Zealand, a leafless kauri tree stump rises a few feet off the ground. These trees can become giants: The country’s biggest, Tāne Mahuta, or the “Lord of the Forest,” has grown 168 feet high, with a 115-foot canopy.

But this stump is just a stump, so unassuming most would pass it by.

One day, two ecologists from Auckland University of Technology spotted it on a hike.

“A normal person would just think it’s dead. It looks dead to a point, but if you look a bit closer, you can see living tissue,” said Sebastian Leuzinger. “We both said to each other, ‘It’s clearly not dead. How does it live?’”

Naturalists have observed living tree stumps in New Jersey, the Sierra Nevada, British Columbia and elsewhere. But for more than 150 years, how the stumps survived without leaves for photosynthesis was a mystery.

Leuzinger and Martin Bader discovered that the kauri stump lives by sharing water with neighboring trees. Most likely, they’re connected through an underground plumbing system formed when their roots naturally fused, or grafted, together, the researchers reported in a study published Thursday in the journal iScience.

These types of relationships may be more common among trees in forests than once thought, adding evidence to the notion that while trees may appear solitary aboveground, they’re intimately connected underground.

Most trees communicate through subterranean networks of symbiotic fungi referred to as the “wood wide web,” sharing nutrients, carbon and other information. But a tree needs roots for water, and leaves to sustain itself.

During photosynthesis, plants open pores on their leaves to allow carbon dioxide to flow in. Open pores also allow water the plant has not used to be released into the atmosphere. This process, called transpiration, draws water up from the roots so the plant does not wilt.

But a leafless stump needs another way to circulate water.

To figure out how it was surviving, Leuzinger and Bader measured water moving in the stump as well as in a neighboring tree. They found that when the tree transpired on sunny days, it took in water, but the stump did not.

But during rainy days and at night, the stump drank and the tree shut down. The stump had somehow rerouted its circulatory system, and it seemed to take turns with the tree.

To confirm their hypothesis, the scientists will need to clear away soil to expose the roots. But their early finding strongly suggests the stump received and circulated water through grafted roots.

Why would a tree support a stump that cannot reproduce or make its own food? And for the stump, why bother?

“It’s a bit unlikely that the tree dies, and goes and knocks on the other trees’ doors and says, ‘Hey, can I get a little carbon you? I’m dead,’” said Leuzinger.

The stump may be an oddball that got lucky from a connection formed before it became a stump. And that could mean such connections are quite common, he suggested.

Natural root grafts have been reported in some 150 tree species. But how the roots fuse and the evolutionary reason for these grafts are buried mysteries.

Scientists think grafting could have developed between trees because it’s cheap and easy. Trees may not sense death, recognize dying connections or spend energy cutting off little stumps with small appetites. A stump’s extra roots may also add stability to other trees.

And Camille Defrenne, who studies tree communication at the Oak Ridge National Laboratory in Tennessee, thinks exploring potential root grafts and fungal connections could reveal more: Perhaps a tree supports a stump to maintain its symbiotic relationships with helpful fungi.

The researchers also say their results have implications for how forests respond to disease and drought. In New Zealand, a root fungus thought to spread through human foot traffic is killing off kauris, which are among the largest trees in the world. But changing our view of forest ecology to include root grafts will take years of follow-up.

“We probably know more about the surface of the moon than how a tree internally functions,” said Leuzinger.

This article originally appeared in <a href="https://www.nytimes.com/2019/07/25/science/tree-stump-alive.html" id="6aa61249-494e-3708-a087-2952b5970533">The New York Times</a>.

Tree Stumps Are Dead, Right? This One Was Alive

The silver spinyfin, or little dori, inhabits a layer of the deep sea, where the Twilight Zone’s blue fades to black, often half a mile below the surface. Down there, they may see the world like no other animal known to science.

Scientists have generally understood that color vision wasn’t necessary in the deep sea. It’s too far for sunbeams to penetrate, and so there’s no light to give way to color. But in a study published Thursday in Science, researchers interested in the evolution of color vision analyzed the genomes of 101 different fishes. They discovered that one, the silver spinyfin, has more genes for discriminating dull light than any other vertebrate on the planet. These genes make it possible to see the whole range of residual daylight and the full spectrum of bioluminescence in the deep sea. Other fishes may have this ability to detect color in the deep sea, too.

“In vertebrate fishes, nothing has been seen like this before,” said Megan Porter, who studies how vision evolved at the University of Hawaii at Mānoa and was not involved in the research. “This goes against what we understood as how visual systems evolved in the deep sea, which means we have to question how visual systems work and function in the dim light.”

The basics of vision start when light hits our retinas, which contain photoreceptor cells called rods and cones that are sensitive to particular wavelengths. Inside these cells, photopigments, or proteins called visual opsins help translate light into signals our bodies can understand.

Typically vertebrates have up to four cone photoreceptors, and one rod photoreceptor. Most humans, for instance, see color input from three cones — red, green and blue. Cones help us see colors in bright light, but in dim light, we’re generally colorblind, and see only intensity based on input from a single rod.

But some deep sea fish appear to see their world in a very different way.

Zuzana Musilová, an evolutionary biologist at Charles University in Prague who led the study, and her team first noticed these fish had lost the genes other fish had for making cone cells and opsins that could detect red and ultraviolet parts of the spectrum. This wasn’t surprising: These wavelengths don’t penetrate the deep sea. But then they found some deep sea fishes had extra copies of genes to make rods.

Looking more closely at 101 genomes, they found that three different lineages of deep sea fish had extra copies of genes for seeing in dim light. Among these, the silver spinyfin took the cake. It had genes for two cone opsins and 38 rod opsins — more abundant and sensitive to more blue than any known vertebrate.

“We were quite, let’s say, astonished by this finding itself because that’s very unique,” Musilová said.

But more astonishing was that silver spinyfins still used up to 14 of these rod-opsin-making genes (adults in deeper water expressed more rod genes than their larvae living in shallower water). And each opsin is tuned to a slightly different wavelength of green or blue.

These fish may use their extra genes for detecting subtle differences and see the world in shades of blue and green we can’t even imagine.

It’s also possible that these fish may not utilize all this extra visual power. Scientists previously studied mantis shrimp, which have complex eyes with more than a dozen color-receptive cones and a visual processing system like no other animal on the planet. Sure, they can detect more colors, but further research showed that mantis shrimp are no better than humans at discerning subtle differences in colors when they had to associate them with treats.

“The mantis shrimp is a case study about how wrong we were about how they were using all their different receptors,” Porter said. It’s possible these fish use rods to see color, but what would that world look like? “I’m not even willing to hazard a guess, just because it’s so unlike anything else we ever have seen,” she added.

Most scientists thought that as creatures moved into and adapted to the deep sea, they shed expensive, unnecessary features, like vision, particularly genes used for seeing color. So what’s the benefit of copying and keeping rod opsin-making genes?

Silver spinyfins, which aren’t bioluminescent, may be able to better detect bioluminescent signals from predators and prey that use them in the deep. Their vision could also help them see better as they migrate between different depths during development.

“Either there’s some difference ecologically that’s driving this, or have we just not looked at enough things yet to see the same pattern in other marine species?” Porter said. “There’s still a lot we don’t know about the deep sea.”

This article originally appeared in <a href="https://www.nytimes.com/2019/05/10/science/fish-deep-ocean-eyes.html" id="0cd977c4-59dc-3861-a052-9bfb54770847">The New York Times</a>.

How Fish May See Color in the Deep Ocean's Darkness

Sea spiders are abundant in waters across the globe, and most are so small that you could hold one on the tip of your pinkie. But in the swirling waters around our planet’s icy poles, these spiders are giants. If you held the largest of these creatures, its gangly legs would just dangle off the palm of your hand.

Antarctic sea spiders got so big because some 30 million years ago, the Southern Ocean got cooler. This trait, known as polar gigantism, is thought to be essential to why they and many other cold-dwelling invertebrates of unusual size managed to survive.

Researchers wondered what allowed animals like these to reach such gigantic sizes. They also want to know what will happen as the waters they inhabit continue to get warmer, because it’s thought that extremely cold water marine animals can tolerate only a tiny range in temperature, making them particularly vulnerable to global warming.

In a study published Wednesday in Proceedings of the Royal Society B, a team of scientists challenged giant sea spiders collected in Antarctic waters to exercise to exhaustion in a kind of aquatic crossfit class.

Observing how many times they could make the spiders flip over before giving up in water with increasing temperatures and decreasing oxygen, they discovered that the key was in their swiss-cheese-like skin. As the spiders grow bigger, their skin gets holier, allowing them to fuel their larger bodies by absorbing the abundant oxygen packed into cold waters. It turns out this helps them get oxygen during hot workout sessions, too, suggesting they might find a way to survive as their habitats heat up.

“We thought the giant spiders are going to be the first to disappear from the Antarctic Ocean,” said Caitlin Shoshido, a doctorate student at the University of Hawaii at Mānoa who led the study.

But “they may actually be OK as these oceans warm,” she added: “It’s like Jurassic Park: ‘Life finds a way.’”

Sea spiders, a kind of marine arthropod called a pycnogonida, are bizarre. They have no lungs, no gills — no organs for breathing at all. They get oxygen by just sitting there, allowing it to pass through the pores of their shell-like skin, called the cuticle.

Oxygen supply and demand limits the size of most animals. But in cold water, where oxygen is packed more tightly together and animals have slower metabolisms, abundant fuel allows them to grow big — with leg spans of more than 2 feet.

Shoshido and her colleagues thought giant sea spiders wouldn’t be able to handle really warm waters as well as smaller ones, because their oxygen demands would use up all their supply. But in tests, bigger sea spiders performed just as well as smaller ones of the same species. Used to living at temperatures below the freezing point of fresh water, surprisingly, some giant sea spiders were still flipping at almost 50 degrees Fahrenheit.

Their cuticles made it possible: “These guys have found a way around this oxygen limitation by basically making themselves more holey or more Swiss cheesy,” Shoshido said.

In the future, she hopes to find out just how holey the skin can get before it becomes structurally unsound — and if the holes are present, or even more abundant, in more active species that need more oxygen. She also wants to know if they can acclimate to gradual temperature increases or react to extended periods of warming in a longer term experiment.

“Nobody really works on them, and they’re just really weird creatures,” she said. “You don’t want them to disappear yet because we just don’t know much about them, and they could be really important.”

This article originally appeared in <a href="https://www.nytimes.com/2019/04/14/science/sea-spiders-antarctica.html" id="249b4f39-d299-3b1f-a7ab-a1f8158d0234">The New York Times</a>.

How Giant Sea Spiders May Survive in Warming Oceans

This shark is going where many thought no sharks would go: on a daytime swim through a kelp forest to chase seals she wants to eat. As the seals evade her, the shark charges deeper into the forest.

She zigzags through gnarled seascape that eventually snags the camera from her fin — and then the footage stops.

We’re used to the idea of sharks as predators in the open ocean, not creatures that stalk seals through tangles of sea grass.

“People would anecdotally say the sharks won’t swim into the kelp, not the great whites,” said Oliver Jewell, a doctoral student at Murdoch University in Australia.

Great white sharks typically hunt at dusk or dawn, near the ocean’s surface, and will jump out of the water to snag cape fur seals — just like on TV. But in the middle of the day, cage divers and researchers near Dyer Island Marine Reserve, off South Africa’s west coast, had noticed sharks lurking in areas close to the island’s cape fur seal colonies, which are surrounded by kelp forests.

They assumed the sharks, too big to maneuver through the dense vegetation, avoided the kelp forests where seals hide. But this footage reveals there’s more to a sharks’ predatory strategy than previously known.

“We kind of thought they would wait for the seals to come out of the kelp but no, they’re not that patient,” said Jewell, who led the research that captured this footage, which was published Wednesday in Biology Letters. “They want to go in and find them.”

In other well-studied white shark populations in South African waters, sharks aren’t found near kelp, because there isn’t much kelp. But here, mixing oceans stir up nutrients so kelp — and the animals it feeds — thrive.

When Jewell worked in this area in the past, he could only see sharks at the surface or track their movements by following the ping of an acoustic tag. Near kelp forests, he almost always lost the signal. So to find out what the sharks truly were doing during lunchtime, he and his team attached sensors and cameras to their dorsal fins.

Clamping a camera onto a shark fin is about as easy as suctioning one to a whale’s back — and bloodier, with more teeth.

In a small boat, one person stirred up chum in the water to lure in the shark. Jewell stood at the boat’s side, dangling a fish head from a rope. If they were lucky, this brought a shark close enough to a third person who was laying on his belly, holding a long pole with the tag on a spring clamp that he attached to the shark.

After that, the team hoped for a tag that stayed on, as well as some visibility and an interesting shark. Then they hoped to retrieve the tag. After three years they finally captured this footage and more from a total of eight sharks.

“It was just relief,” said Jewell.

Researchers can now better understand how sharks use these environments for hunting and find new ways to conserve this rare and vulnerable apex predator. And Jewell hopes this footage will change people’s Hollywood perception of the Great White.

“People think sharks are mindless killing machines,” but that’s not how they behave in the wild, he said. “They’re very calm and they’re also curious animals, and they’re just there doing their own thing.”

They were spotted 10 minutes later and never seen again. Perhaps they got away, but you’d have to ask the shark.

This article originally appeared in <a href="https://www.nytimes.com/2019/04/05/science/shark-kelp-video.html" id="5fb99dda-d45b-3b0f-a8ca-85a5ac6131a3">The New York Times</a>.

Watch a Great White Shark Hunt Through a Kelp Forest for Its Next Meal

The Southern Ocean around Antarctica was once warmer. Then about 30 million years ago, the temperature dropped. Few fish could survive temperatures that were just above seawater’s freezing point, and they either migrated to warmer waters or went extinct.

One bottom-dweller held on. Through the power of natural selection, its descendants developed traits that let them survive these unlikely conditions. Today, the Antarctic blackfin icefish, or Chaenocephalus aceratus, thrives in these frigid waters with no scales, blood as clear as water, and bones so thin, you can see its brain through its skull.

How this creature — no longer a bottom-dweller — can live in such a hostile environment has long fascinated scientists, who have mapped its genome and continued exploring its unusual traits. In a paper published Monday in Nature Ecology and Evolution, a team of scientists compared the genome of the Antarctic blackfin icefish to those of its close relatives. They found that, across these genomic maps, and tens of millions of years of evolution, gene families had shrunken or expanded, giving rise to some of the icefish’s most unusual features. In addition to revealing how the icefish managed to adapt to extreme Antarctic conditions, the team’s findings provide a new way to look at the genetics behind human diseases such as anemia and osteoporosis.

“A trait that’s maladaptive in one environment can be adaptive in another,” said H. William Detrich, a marine scientist at Northeastern University who has been studying icefish for decades and helped lead the study. He added that “we can learn a lot about human physiology and medicine by studying these evolutionary outliers.”

The icefish first surprised science with its clear blood after a Norwegian zoologist caught one in the early 20th century. The species no longer makes red blood cells and hemoglobin to carry oxygen through its body. Those traits are essential to the survival of other vertebrate species, all 60-some-thousand of us.

Now, why would the icefish go and do a thing like that?

Becoming the modern icefish required millions of years of natural gene hacking. Parts of their genomes that, in adults, were dedicated to making antifreeze for blood were greatly expanded. More genome space became dedicated to making ice-preventing proteins in the shell-like casings that surround icefish embryos.

Frigid water holds more gasses, including oxygen, than warmer water does. But in water so cold, red blood becomes gunky, hard to pump and more likely to freeze. So the fish basically “evolved a therapy for anemia,” said John Postlethwait, a developmental biologist at the University of Oregon who also worked on the paper. It developed supersize gills and lost its scales, which enabled it to absorb the water’s plentiful oxygen through its skin. It also expanded its circulatory system with extra vasculature and a heart four times the size of closely related, red-blooded species.

Over evolutionary time, the icefish accumulated lipids, or fats, which, like oil, float in water. It also developed floppy bones that were less mineralized than those of their ancestors. This allowed the icefish to rise in the water column, like spaghetti in boiling water, and eat krill and other creatures that couldn’t be found near the sea floor.

The research team is still working to understand how these adaptations in bone density are reflected in the icefish genome. That may lead to insights into how humans lose bone density and develop osteoporosis with age, the researchers said.

Similarly, by looking at how the icefish gets by with severe anemia, scientists may learn something about why humans don’t.

Creatures such as the icefish are what Charles Darwin called “wrecks of ancient life,” because they lost important traits of their ancestors, like red blood cells and dense bones. Postlethwait calls them “evolutionary mutant models,” because their genomes could help explain why some physiological traits can be adaptive for one animal but disease states in another.

The icefish may be a wreck of ancient life, but it’s a wonderful wreck.

This article originally appeared in <a href="https://www.nytimes.com/2019/02/28/science/antarctic-blackfin-icefish-genome.html" id="02256293-3714-3057-a613-a4abe33924b5">The New York Times</a>.

How the Icefish Got Its Transparent Blood and See-Through Skull

Romeo was made for love, as all animals are. But for years he couldn’t find it. It’s not like there was anything wrong with Romeo. Sure he’s shy, eats worms, lacks eyelashes and is 10 years old, at least. But he’s aged well, and he’s kind of a special guy.

Romeo is a Sehuencas water frog, once thought to be the last one on the planet. He lives alone in a tank at the Museo de Historia Natural Alcide d’Orbigny in Bolivia.

A deadly fungal disease threatens his species and other frogs in the cloud forest where he was found a decade ago. When researchers brought him to the museum’s conservation breeding center, they expected to find another frog he could mate with and save the species from extinction. But they searched stream after stream, and nothing.

Romeo, called the “World’s Loneliest Frog,” started sharing his feelings on Twitter. Things got desperate.

He needed a match before he croaked, so last year conservation groups partnered to create a Match.com profile for him. People related to Romeo’s romantic struggles, and on Valentine’s Day last year, the company and his fans raised $25,000 to send an expedition team out to the cloud forest to find his Juliet.

Well, Juliet has been found, and Romeo soon will be a bachelor no more. From this story of star-crossed science and love, conservationists have great hopes. If all goes well when the two meet, their offspring will return to the wild. From there, time will tell if their habitat is preserved, the frogs avoid disease and their legacy continues.

And for all the lonely lovers searching for that special someone, Teresa Camacho Badani, a herpetologist at the museum who found Juliet, has another message: “Never give up searching for that happy ending.”

When the expedition team set out last year, historical records provided little help. Sehuencas, a region in Bolivia and the species’ namesake, was gone, replaced by a massive dam. Local guides took the team to pristine streams, but habitats that once hosted dozens of frog species were now frogless. And Romeo’s species is particularly elusive, living under rocks at high elevations and never leaving the water.

The search was cold, wet and taxing in the misty, overgrown forest. Near the end of one long day, the researchers were ready to give up, but rallied to search one last stream. That’s when Camacho Badani spotted a frog leaping from a waterfall into a pond.

She hustled to the spot where it landed, reached down and pulled up a Sehuencas water frog. This was Juliet.

“Oh my God, I found it!” Camacho Badani screamed. The team later found four more specimens, a female and three males.

Although Juliet looks healthy, she is in quarantine for disease testing before she meets Romeo. “We don’t want Romeo to get sick on the first date,” Camacho Badani said.

The two make a typical opposites-attract couple. Juliet is wild, energetic and doesn’t mind cameras that Romeo avoids. But they both like worms.

If the chemistry is there, the team hopes to reintroduce baby Romeos and Juliets to the wild. But first the researchers must keep the frogs healthy, learn more about how the pair combat the fatal fungus, better understand their habitat and build local support to protect them.

And before Juliet commits, Romeo will take down his dating profile, said Robin Moore, the team’s photographer, and communications director at Global Wildlife Conservation.

“It would have been easy to have given up and said that this frog was gone and lost,” Moore said. “Rather than telling this story, we could have been telling the story that Romeo’s the last of his kind.”

This article originally appeared in <a href="https://www.nytimes.com/2019/01/17/science/romeo-loneliest-frog-mate.html" id="ee5020fb-a1ff-3224-acb5-18cc849796c7">The New York Times</a>.

Romeo the Frog Finds His Juliet. Their Courtship May Save a Species.

Scientists first reported finding it in 1992: a giant mushroom that weighed as much as a blue whale and sprawled across more than 30 acres of forest in Michigan’s upper peninsula. It wasn’t some Alice-in-Wonderland-type toadstool but a 1,500-year-old parasitic mold, with growing tentacles that foraged beneath the soil for roots and decaying wood to devour.

More than 30 years later, the same scientists — using new technology for genetic analysis — wanted to know whether they had properly measured this unusual example of fungal life.

“We made this outlandish prediction that the fungus is more than 1,000 years old,” said James Anderson, now a retired mycologist and emeritus professor at the University of Toronto. “And so an obvious outcome of that, is after three decades, it ought still be there, and if not, we’d have some explaining to do.”

Recently they published what they uncovered in Proceedings of the Royal Society B: Biological Sciences. Their original humongous fungus, Armillaria gallica, is even older and bigger than first estimated: the 2,500-year-old parasite spreads across 180 acres of forest. And its genome harbors a mysterious survival strategy: an extremely low mutation rate.

From 2015 through 2017, Anderson and his colleagues tested soil from nearly 250 sites on the peninsula. They connected dots on a forestwide canvas and painted an impressionist portrait of this monster beneath the dirt.

And it had some surprising features.

First, it covered more space than first measured.

Second, based on observations of how much it grew over a season, the scientists figured the fungus had to be 1,000 years older than they had originally estimated.

And when they began considering that age against their genetic analysis, something seemed strange.

As an organism grows and cells start splitting and copying DNA during mitosis — which is how they make new, identical body cells — you expect to see mutations emerge in copies that are passed on from one generation to the next. But this old beast harbored only about 160 mutations, orders of magnitude lower than expected.

More than two millenniums was plenty of time for cells to divide, copy and paste their DNA and send it — mistakes and all — from one generation to the next. But to get so few mutations, the fungus must have had very few cell divisions, which is crazy for a giant fungus made of microscopic cells. The researchers couldn’t measure how many cell divisions separate the bits of fungus spanning the length of nine football fields side by side, and so they couldn’t measure the mutation rate directly. It should have been huge, but it wasn’t.

“I think it’s a really interesting result with cutting-edge technology, and it opens up new questions about how organisms can remain stable over that length of time,” said Tom Bruns, a fungal ecologist at the University of California, Berkeley who reviewed the study.

But he and Anderson agree that it’s still unclear how the fungus genome ended up this way.

Their paper offers some speculation. The infecting tips of the fungi’s rhizomes could have low rates of cell division. Or the fungus could be really good at repairing damage inside its cells, passing healthy traits onto the next generation. Even more bizarrely, the cells may be selective about which copies of DNA they send on to the next generation. Maybe it’s a combination of these factors — or something else entirely, Anderson said.

Bruns said it was also possible that the analysis missed some mutations. When they do show up within a big pool of cells, they’re so rare, they’re presumed to be errors.

But if this extremely low mutation rate is indeed the case — and it seems to be, according to Bruns, it poses other interesting questions.

How widespread among fungi and other life is this low mutation rate? What can it tell us about cancer, which seems to be on the opposite end of the genetic stability spectrum? And if this thing is so good at living, who wins in an apocalypse: the cockroach or Armillaria?

“I’ll bet on Armillaria,” Bruns said.

Joanna Klein

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