A composite image of M51 with X-rays from Chandra and optical light from NASA's Hubble Space Telescope contains a box that marks the location of the possible planet candidate. Image Credit: X-ray: NASA/CXC/SAO/R. DiStefano, et al.; Optical: NASA/ESA/STScI/Grendler

The exoplanet candidate is about the size of Saturn and located in a Whirlpool galaxy system 28 million light-years from Earth.

In a first, astronomers find a potential planet outside the Milky Way

Echo, a scent detection dog, alerts to a locus of human cremains scent in the former home of Marc Pandone. Image Credit: Lynne Engelbert

With cremation on the rise, more Americans are keeping cremains of loved ones in their homes. As larger and fiercer wildfires destroy communities in the West, archaeologists are teaming up with scent detection dogs to find ashes among the ashes.

Dogs sniff out cremation ashes amid wildfire destruction

Stanley Andrisse holds an MBA and Ph.D. His nonprofit organization From Prison Cells to PhD offers education counseling, mentoring, and support to 100+ currently and formerly incarcerated people annually. Image Credit: Tchad at Free Star Media

New programs aim to help formerly incarcerated people enter careers in science, technology, engineering, and mathematics.

Meet the scientists building a prison-to-STEM pipeline

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NOVA Next is NOVA’s award-winning digital publication that provides answers from the cutting edge of science and technology. Launched in 2012, we feature in-depth articles and commentaries from some of the most respected journalists, scientists, and engineers. NOVA Next explores the ideas that are changing the future, from the frontiers of synthetic biology to the politics of personalized medicine.Let us know what you think. We’re listening on <a href="http://www.facebook.com/NOVAonline">Facebook</a>, <a href="http://twitter.com/novapbs">Twitter</a>, and email.If you’re a journalist and have an idea for a story, send it our way.

NOVA Next is NOVA’s award-winning digital publication that provides answers from the cutting edge of science and technology.

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NOVA Next is NOVA’s award-winning digital publication that provides answers from the cutting edge of science and technology.

6 stinking cool facts about dog noses

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Did you know that dogs can use their cold, wet (and cute!) noses to sense sources of heat and thermal radiation? That discovery, via a <a href="https://www.science.org/content/article/new-sense-discovered-dog-noses-ability-detect-heat">2020 study from Sweden</a> that challenged dogs to choose between a warm and cool object across a room, makes them only the second mammal known to possess that superpower. (The other is a vampire bat.)And that’s not all dogs' noses can do. Read on for six reasons why dog noses are among nature’s most amazingly engineered instruments—instruments whose power humans are <a href="https://www.pbs.org/wgbh/nova/video/electronic-nose-imitate-dog-nose/">now trying to recreate</a>: 1. Dogs' <a href="https://www.pbs.org/wgbh/nova/article/dogs-sense-of-smell/">sense of smell</a> is between 10,000 and 100,000 times as potent as humans’. This power comes in part from the up to 300 million olfactory receptors dogs carry around in their noses, compared to our mere 6 million. And the part of the canine brain that is dedicated to smells is 40 times larger than ours, proportionally speaking. 2. Dogs can smell continuously, even while they’re breathing in and out. In contrast, when a human smells a scent (sniffs a rose, for example) we inhale that odor and breathe in oxygen through the same passage. But if a dog smells the same flower, air “splits into two different flow paths, one for olfaction and one for respiration," Brent Craven, a Pennsylvania State University bioengineer who has modeled <a href="https://anatomypubs.onlinelibrary.wiley.com/doi/full/10.1002/ar.20592">canine olfaction anatomy</a> using high-resolution MRIs, <a href="https://www.pbs.org/wgbh/nova/article/dogs-sense-of-smell/">told NOVA</a>.Craven and his colleagues found that a portion of the air dogs inhale gets ushered into a specialized area at the back of the canine nose reserved for odor detection, while the rest of it continues rushing toward the lungs. And when dogs exhale, that air departs through nose slits in a unique aerodynamic pattern that also guides new air in, creating a cycle of breath that continuously supplies the in-house laboratory in the back of the canine nose with new material. In <a href="https://pubmed.ncbi.nlm.nih.gov/8735662/">one study from the University of Oslo</a>, a dog on a hunt sniffed continuously for a full 40 seconds, across 30 respiratory cycles!<h4>Watch: This Device Smells Diseases by Imitating a Dog's Nose</h4>
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3. Dogs can <a href="https://vcahospitals.com/know-your-pet/how-dogs-use-smell-to-perceive-the-world">wiggle their nostrils independently</a>, which helps them figure out which direction a scent is coming from. Humans can only wiggle their nostrils simultaneously. (Try it. We’ll wait.)4. Dogs are great at interpreting all the information coming in through their noses in fine detail. In her book “Inside of a Dog,” canine cognition researcher Alexandra Horowitz writes that humans might taste a teaspoon of sugar added to a cup of coffee. But a dog could detect the same teaspoon of sugar in a million gallons of water—enough to fill two Olympic-sized pools.And to take the sugar metaphor further, “if we humans walk into a bakery, we can say, ‘someone’s baking a pie in here,’” canine search specialist Lynne Engelbert <a href="https://www.pbs.org/wgbh/nova/article/cremation-ashes-sniffing-dogs-california-wildfire/">told NOVA</a>. “A dog would walk in and say, ‘Oh, someone’s baking a pie in here, and it has apples, and butter, and cinnamon, and nutmeg.”
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5. Dogs can connect a human with the scent they leave behind with exceptional precision—and even help diagnose sick humans with a variety of diseases. Forensic chemist Ken Furton, who has studied dog olfaction for more than 25 years, once blew up a car with colleagues and then asked detection dogs to pick out human scent from the resulting debris. The dogs were able to sniff the small amount of shrapnel and correctly identify the people who had been in contact with the bomb pre-explosion 82% of the time.More recently, Furton and his colleagues looked at whether dogs might be trained to identify COVID-19 patients—and found they could do so with 97.5% accuracy. “I was shocked,” he told NOVA. And <a href="https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.2019.33.1_supplement.635.10">one 2019 study</a> indicated humans’ best friends can sniff out cancer with a similarly high 97% accuracy rate.<h4>Watch: Cannabis-Sniffing K-9's: Out of a Job?</h4>
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 6. Dogs can not only identify human remains–they can sniff out already cremated remains from among other ashes. Dogs in the American West are now being trained to <a href="https://www.pbs.org/wgbh/nova/article/cremation-ashes-sniffing-dogs-california-wildfire/">look for the cremated remains</a> of homeowners’ loved ones when those homes are lost to the region's increasingly fierce wildfires. The non-profit Alta Heritage Foundation brings specially trained search dogs and archaeologists to the site of a house destroyed by fire, using canine colleagues to narrow down where the lost ashes might be buried and then archeological techniques to excavate them. The ashes are often the only thing his clients want to recover from their houses, Alta Heritage founder Alex DeGeorgey told NOVA. So being able to find their loved ones’ ashes within the ashes of a house is both powerful and continually surprising. “I’ve done this hundreds of times,” DeGeorgey says of cremation ash recovery, “and I still marvel that we’re able to do it.”
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Dogs can sniff out disease and analyze new odors even as they exhale. But how?

Human fossil footprints at White Sands National Park in New Mexico. Image Credit: Courtesy of the National Park Service

Human tracks may be earliest evidence of people in North America

In southern New Mexico lies the Tularosa Basin, an oblong bowl that’s home to a natural sandbox: White Sands National Park.In 2005, David Bustos came to White Sands to work as a National Park Service biologist. The following year, he took notice of odd animal footprints that would appear only when the ground was wet. (The first of these footprints was reported in the 1930s.) The markings, which would disappear as the earth dried up, became known as ghost tracks.Then in 2009, Bustos came across tracks he thought belonged to ancient humans walking alongside mammoths. But few scientists agreed, he says, rebutting with “No, no, those are the prints of camels that were slipping in the mud,” referring to now-extinct North American camels. And the tracks would disappear with changes in the weather. Heavy rainfall drowned them; periods of drought dried them up. It would take more than a decade—and cooperative weather—for scientists to agree that the tracks belonged to humans. Then, says U.S. Geological Survey (USGS) Research Geologist Kathleen Springer, “What everyone was asking is, ‘How old are these things, really?’”
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In September 2021, Bustos, Springer, and a group of other researchers published their findings in the journal Science: The team identified 61 human tracks within multiple levels of earth belowground, and between layers of these tracks were seeds from an ancient aquatic plant. Analyses of these seeds—and the footprints they were embedded within—are now challenging scientists’ understanding of when and how people arrived in the Americas.Archaeologist Joe Watkins, who was not involved in the study, believes the findings have potentially massive implications. “I think, outside the next big migration of going to the Moon or Mars, the migration to the Americas was the last great migration humanity had,” he says. Upending the timeline of this journey could have implications for both science and Native American cultures, Watkins, who is a member of the Choctaw Nation of Oklahoma, believes.<h3>Visiting the tracks</h3>At first light on a cold January morning in 2020, Bustos set out with Springer and her USGS colleague Jeff Pigati on all-terrain vehicles to visit White Sands’ ancient tracks. The team wore parkas to keep warm amid a prevailing wind. Springer recalls the hour-and-a-half journey through the dunes being like a “Disney ride.” It was the “funnest thing in the world,” she says. “Just being out there is surreal.”Eventually, after passing through a large swath of national park that borders the site of the first atomic bomb test, Springer, Pigati, and Bustos fell upon thousands of tracks. They belonged to packs of dire wolves, giant sloths, 13-foot-tall mammoths, and other animals. And, Springer says, “there’s a person track right smack dab in the middle of them.”
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<img alt="White Sands National Park dunes" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/White_Sands_Dunes.width-990_kjxnoic.jpg"/>
<figcaption>Gypsum sand dunes at White Sands National Park, New Mexico. Image Credit: NOVA/GBH
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“When Dave showed us these things and we had our eyes trained on them, we were almost afraid to step down,” Pigati says. “It looks like a painting in some places.”Bustos recalls the conditions that day being perfect for identifying tracks. The trio saw human footprints going underneath the sediment in places, illustrating that there was more than a surface layer of them. “We were seeing seed layers popping out all over the place,” Bustos says. To determine how old the footprints were, Springer and Pigati’s team would collect these ancient seeds from different layers of footprints. The overwhelming evidence of ancient plant life excited Bustos.About 36,000 to 19,000 years ago, lakes filled the Tularosa Basin. The largest of these was Lake Otero, which fluctuated in size and activity based on rainfall. Plants like spiral ditchgrass (Ruppia cirrhosa), whose seeds are now embedded in layers of earth, grew along Otero’s edges. About 23,000 years ago, the southwestern U.S. became drier and the lake shrank. This exposed a large area of land that was once underwater, whose clays and silts became overtopped by gypsum sand and silt. People began walking around these surfaces, which “were kind of squishy in some areas,” Springer explains. And the people weren’t alone: The impressions from mammoths, ground sloths, and camels, sit alongside—and sometimes right on top of—human prints. “This can only happen if they are in the area at the same time,” Pigati said in an email. “Exactly how they may have interacted in the vicinity of our [research site] is unknown, but there is definitive evidence that humans were harassing or stalking a giant ground sloth on the west side of the basin.”In many other cases, interactions between humans and animals seem peaceful. “What’s interesting to me,” Bustos says, “is it’s not just a mammoth and a hunter. It’s families. You see a baby mammoth turning around and spinning. We have the juvenile and adult megafauna prints with the babies and adult [humans].”
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<img alt="" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Sloth_Footprint.width-990_j4t67Wp.jpg"/>
<figcaption>A footprint from a Harlan's ground sloth at White Sands National Park. Image Credit: Courtesy of the National Parks Service
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Having about 10 hours of daylight, the team got to work “trenching” the human footprints, Springer says. With ground-penetrating radar, they were able to determine that footprints were present within layers of sediment. They then dug a trench to view the layers in cross-section. If Springer and Pigati’s cross-section was a sandwich, the footprints would be the filling and the dateable material around the footprints would be the bread. Dating tracks only at the surface would yield inaccurate results, Pigati explains. “You can look in every direction and there are trackways everywhere in every horizon,” he says. But if you calculate the age of these footprints on the surface layer of earth only, you’ll just find that they’re younger than the ground they’re upon, he says. By looking at layers of sediment below the surface, the team set out to document how many layers contained footprints and find datable material above and below each layer. Each of these layers would contain footprints from a unique time period, the team posited. “The footprints are imprinted at the top of a given layer of sediment—they don’t really pass through the layers,” Pigati wrote in an email.As the sun rose higher in the sky, the white sand reflected a near-blinding light, and the day quickly grew warm. The researchers shedded their parkas and worked in t-shirts until the January sun fizzled and it was time to ride back through the dunes, chunks of sediment layers in hand.The team later extracted 40 to 60 ditchgrass seeds from every level of footprints in every sample. In a USGS lab in Golden, Colorado, they cleaned each set of seeds with a chemical treatment and began combusting them.  The combustion process, automated by a machine in the lab, didn’t obliterate the seeds but turned them into a gas. From this gas, a machine turned the once-seeds back into solids: graphite pellets about the size of a pencil tip. This technology of making “graphite targets” dates back to the 80s, Pigati says. “Every lab does it the same way in the world.”The team then took these pellets, tapped them down into cartridges, and sent them off to a lab to measure the amount of a radioactive isotope of carbon, called carbon-14, they contained. Then they waited for results.<h3>What the tracks mean</h3>Months later, they came. The seeds revealed that the footprints they were embedded within are between 21,000 and 23,000 years old—thousands of years older than what scientists generally consider to be the earliest evidence of people in the Americas.“For forever, people thought Clovis were the first people to cross over [the Bering Strait] about 13,000 years ago,” Pigati says, referring to the commonly-held view among archaeologists. As the story goes, ice sheets in what is now Canada blocked passage between what is now Alaska and the rest of the Americas. Once these ice sheets began retreating, people came south through an ice-free corridor, Pigati explains. His team’s findings now challenge this belief. Carbon dating of the seeds within the White Sands footprints suggest that people were in the Americas while ice sheets still covered much of northern North America. “A lot earlier” than previously thought, Pigati says. “When we got the final dates back, it was very…” Springer pauses over Zoom, choosing her words carefully. “The arrows were going to start flying. We knew we needed an [evidence-supported] explanation why these findings were really robust.”
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Archaeologist Joe Watkins says that if the dating of the seeds, and therefore footprints, is correct, “it puts us at 20% older than the dates we have from the rest of America.” Therefore, ages of other important archaeological sites like Meadowcroft Rockshelter in Pennsylvania, where scientists have found 16,000-year-old evidence of human life, may need to be reconsidered. (In 2014, Nikhil Swaminathan <a href="https://www.archaeology.org/issues/145-1409/features/2369-peopling-the-americas-meadowcroft-rockshelter">wrote for Archaeology Magazine</a> that Meadowcroft Rockshelter is “the longest-occupied site in the Americas.”)Watkins first heard about the White Sands tracks years ago while working in Washington D.C. as the chief of the Tribal Relations and American Cultures Program of the National Park Service. But he didn’t see them until after he’d retired, visiting White Sands during a NOVA shoot for the film “<a href="https://www.pbs.org/wgbh/nova/video/ice-age-footprints/">Ice Age Footprints</a>.” Seeing human footprints intermingling with those of ground sloths was overwhelming and “tremendously exhilarating,” he says.
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<img alt="Archaeologist Joe Watkins holds a clovis point" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Joe_Watkins.width-990_4i0j7w4.jpg"/>
<figcaption>Watkins pictured with a replica Clovis point. His interest in archaeology was piqued at 10 years old when he found an archaic point on his family’s Oklahoma homestead. Watkins, who’s now 71, showed the point to his grandmother. The artifact didn’t come from modern Choctaw, but was much older, she explained in her native language. From that moment, Watkins became “more interested in looking into the unwritten past,” and, with his grandmother’s support, began pursuing a career in archaeology, a field he recognizes isn’t always “in advantage to the Native American community,” he says. Image Credit: NOVA/GBH
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But Watkins cautions that, with no other aspects of culture present but footprints, scientists like him can only speculate how ancient humans were using the land. “Were they just walking? Were they hunting? Did they have a camp nearby?” he asks. Archaeology may not hold all the answers to these questions: “I do think it’s important for American Indians to be involved so they can offer their insights so we can better understand who these people were,” Watkins says, reflecting on his own Choctaw roots.As Native American identity is tied to the land, Watkins believes, “the Native peoples will say we’ve always been here,” he says. “I usually say [the first Americans] weren’t Native Americans. They weren’t Siberians. They were whatever they called themselves.” Combining this philosophy with science is a way to integrate belief systems, he says.
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The White Sands findings, Watkins says, “forced us to reconsider the most cherished ideas of the people of North America.”
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Watkins recites his people’s story about two stiff-legged bears that meet in a black-loam prairie and have a battle. Only one survives; it becomes the last of its species. “Some Choctaw interpret ‘stiff-legged bear’ as being a mammoth,” Watkins says. If humans did once walk alongside mammoths in New Mexico’s Tularosa Basin 20,000 years ago, he adds, there’s a chance these people gave birth “to any number of tribal people across the U.S.” <h3>Racing against time</h3>Bustos, Springer, Pigati, and fellow researchers visited the ghost tracks again in January and April 2022. They extended their trench, identifying more footprints from potentially before and after the original set they excavated. To bolster their findings, Bustos explains, the team won’t rely solely on dating seeds. They’ll date pollen, too. “This work is not done,” Pigati says. “We have a window from 21,000 to 23,000 [years]. We don’t know if people were here before then.” But the clock is ticking. Erosion in White Sands is exposing and destroying the tracks, Springer says. Though the Tularosa Basin has been eroding for nearly 12,000 years, climate change is likely exacerbating erosion today, she explains. “The layers, they’re finite,” Bustos adds. “We’re losing thousands of tracks to erosion. It’s a race to document them before they’re gone.”Already, some tracks reveal clues about ancient daily life in the Tularosa Basin.“There’s something about the children,” Bustos says. “You see these toddlers running and jumping, and the story really comes alive.” Watkins agrees. “When we look at the tracks of children playing in perhaps puddled water surrounded by ground sloths,” he says, “it takes us back to childhood memories of children playing in puddles all around the world.”
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Footprints in New Mexico’s White Sands National Park challenge scientists’ timeline of when humans first came to North America.

The second-ever direct image of a black hole features Sagittarius A*, the supermassive black hole at the center of our galaxy. Image Credit: Event Horizon Telescope collaboration

Scientists capture first-ever image of our galaxy’s supermassive black hole

On Thursday morning, an international team of astrophysicists and other researchers released the world’s first image of the supermassive black hole at the center of our galaxy, 27,000 light-years from Earth. The event marks “the dawn of a new era of black hole physics,” the team<a href="https://twitter.com/ehtelescope/status/1524737908892049408"> announced on Twitter</a>.More than 4 million times the mass of our sun, the black hole, named Sagittarius A* (or Sgr A*, pronounced “sadge ay star,” for short) is so dense and massive that no light can escape its gravity. The visible light in the new image comes from bright stars, gas, and other space matter swarming around the black hole itself.
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The image is the first visual evidence of Sgr A*’s existence; the black hole was previously only indirectly confirmed by observations of stars in orbit around it. The image comes from the Event Horizon Telescope’s (EHT) international consortium. A group of more than 300 scientists helped with the effort to capture it, “compiling information from radio observatories around the world,” Bill Chappell <a href="https://www.npr.org/2022/05/12/1098472567/image-black-hole-milky-way">reports for NPR</a>. (The EHT, named for the event horizon, or “point of no return” from a black hole, consists of eight radio telescopes scattered across the globe.)In 2019, the EHT team compiled an <a href="https://www.pbs.org/wgbh/nova/article/first-black-hole-image/">image of Pōwehi</a>, a supermassive black hole 55 million light-years away in the galaxy Messier 87. Similar in appearance to Sgr A* but much more massive, Pōwehi is 6.5 billion times the mass of our sun.The much smaller Sgr A* proved difficult for scientists to visually capture: It’s a “dynamic environment” full of burbling and gurgling, Feryal Özel, a professor of astronomy and physics at the University of Arizona, told NPR. And the necessity to look through both the Earth’s atmosphere, gas clouds, and interstellar dust near the Milky Way’s center added to the challenge, Özel said. “It took several years to refine our image and confirm what we had, but we prevailed," Özel told NPR. And, despite its meager distance from Earth compared to Pōwehi, Sgr A* is far enough away to appear “to us to have about the same size in the sky as a donut on the Moon,” the EHT team stated <a href="https://eventhorizontelescope.org/blog/astronomers-reveal-first-image-black-hole-heart-our-galaxy">in a press release.</a>Hot gas whirling around Sgr A* at nearly the speed of light made capturing an image of this black hole considerably more difficult than Pōwehi, the EHT team said in the press release. “The brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT was observing it,” EHT scientist Chi-Kwan Chan said in the press release.
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Images of Pōwehi captured by astronomers across the EHT were visually similar to one another, allowing scientists to compile a sharp composite image of Messier 87’s black hole. “That was not the case for Sgr A*,” the EHT team said in the press release. But despite these initial inconsistencies, the scientists were eventually able to compile an image of Sgr A*.Now, having images of such differently sized black holes provides a better look into the behavior of swirling gas around supermassive black holes, a phenomenon that’s not yet fully understood, but thought to play a key role in how galaxies, like our own, came to be. "Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works," EHT scientist Keiichi Asada said in the press release. 
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The Event Horizon Telescope team has captured the first image of Sagittarius A*, the black hole at the center of the Milky Way.

Russian spacewalkers explore the spherical Prichal docking module, which is attached to the Nauka multipurpose laboratory module of the International Space Station. Image credit: NASA Johnson, Flickr

Daily life on the International Space Station: A Q&A with a space archaeologist

Soon after photos started arriving from the International Space Station (ISS), Justin Walsh spotted something unexpected: frosting. Tucked into a plastic bag hanging off the station wall, near a can opener and bottle of ketchup, were telltale red, yellow, and green tubes. Walsh was mystified. “What does frosting imply? Baking,” he said recently over Zoom. But baking in space is pretty much impossible. 
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He got his resolution when astronaut Kayla Barron <a href="https://www.instagram.com/reel/CZmgSeupMuq/?utm_source=ig_web_copy_link">posted on Instagram</a> that she’d made a birthday cake for a colleague. “They did it by cutting the tops off of muffins and gluing them together with honey, then covering the whole thing with icing and frosting,” Walsh says. To Walsh, an art historian and archaeologist at Chapman University, the frosting was physical proof of something less concrete: astronauts’ bond with one another. Cooking and eating “is not only about sustenance; it's about social relations,” he says—even 250 miles above Earth. He, fellow space archaeologist Alice Gorman, and their colleagues received the frosting photo as part of the Sampling Quadrangle Assemblages Research Experiment, known as SQuARE. The ISS, which is administered by multiple space agencies, is essentially a <a href="https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-the-iss-58.html">network of modules</a> for cooking, sleeping, science research, and other uses that’s slightly larger than a six-bedroom house. Between January and March, astronauts on board took daily photos of six carefully chosen sites around their temporary home first at the same time each day, then at random times. The project was an interstellar version of the archaeological technique known as quick testing, in which archaeologists divide a new site into a grid of one-meter squares and dig “test pits” that provide a basic sense of what they might find. In SQuARE, those “pits” are one-square-meter areas marked off with tape, scattered across the American, European, and Japanese modules of the ISS in areas used for work, science experiments, cooking, and hygiene. The team will analyze the resulting photos in hopes of understanding how each area is used over time and, from there, identify opportunities to improve space habitat design. NOVA talked with Walsh about the challenges of space archaeology and why astronauts eat so many tortillas. 
Alissa Greenberg: Usually, archaeologists excavate sites because it’s the only way to learn about life in those places—all the people are long dead. But we can talk to these astronauts. Why not do that?Justin Walsh: It's true that, for the most part, archaeologists do study the distant past. Contemporary archaeology developed starting in the 1970s. The first example of it was a project called the Tucson Garbage Project by a guy named William Rathje at the University of Arizona. He got the City of Tucson sanitation department to drop off samples of neighborhood garbage on a regular basis, and he and his graduate students went through it to understand the patterns of usage of different items.What's really fascinating about it is that they then went and interviewed people from the neighborhood about their consumption habits. So first of all, he found that people were throwing out lots of meat that they weren't using. So he was able to show that people were being wasteful with this particular commodity. But then he went to talk to people about these things, and he found out some interesting facts. Such as when you ask people questions, the way sociologists and anthropologists often do, they are not necessarily really good at articulating the realities of their lives—or they don't want to. Which is also perfectly fair and understandable! I would not blame them for that. But what it shows is that what archaeology can do is provide additional insights into human practices and that those insights don't have to be about the distant past.So, you can say, “Well why don't you just talk to the crew and ask?” or “Doesn't NASA document all that stuff?” Okay, we can absolutely do that, but that doesn't always work well—especially for astronauts, who are 100% good at staying on message and will not say anything to jeopardize their next flight to space. And as for the space agency, they don't do any forensic work on what's happened on the space station before. They're in the present and the future—and the past is gone. They're not thinking about what they can learn.
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<img alt="Mesh bags full of condiments and food items hang from a space station wall" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/iss066e130191_1.width-990_qW6eQSP.jpg"/>
<figcaption>One of the SQuARE sample locations, in a U.S. module galley area, marked by yellow tape at each corner. On the wall, mesh bags hold ketchup, Sriracha sauce, chocolate, and other food items. In the upper right corner are plastic bags holding tubes of frosting, which indicated that a kind of “space cooking” activity was happening in this location. Image courtesy of Justin Walsh
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AG: Why do you find space culture so compelling?JW: Because humans are doing things there in an environment that we are 100% not adapted for. We literally cannot survive. So, we have to come up with all these technologies that allow us to survive in that environment, living in microgravity. And on top of that, there's the other issues of confinement and isolation: the bad food, the distance from family and friends. How do they work together and live together? One of the phrases that I like is that a crewed spacecraft is “<a href="https://nap.nationalacademies.org/read/12387/chapter/1">a microsociety in a miniworld</a>.” You have the transmission of culture and traditions—"this is how we do things, this is how this is laid out”— being handed down almost from generation to generation. For example, on the ISS they have dinner together every Friday. Most of the time it's in the Russian service module; sometimes it's in the American service module. Or on ISS their food is carefully designed, and there are different kinds of traditions associated. Things like there's no bread, because crumbs are bad in space. If you inhale a crumb, that could really be a problem, so instead they use tortillas for everything. Tortillas don't make crumbs.AG: Can you talk about this most recent study? What’s the goal here?JW: We've been doing this study of historic photos that document life on the space station over 21 years. We've got this body of photographs, both published photographs from Flickr and also unpublished photographs that NASA has now given us—thousands and thousands of photographs. We've been working for the last three years to develop machine learning techniques that would allow the automated tagging of people, places, and objects in the photos. But they were taken essentially randomly. They weren't taken at precise intervals. How do we even characterize what the potential problems might be with that? One way is by doing an actually systematic survey of the material culture of the space station over the short term. That's what SQuARE is.
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<img alt="Photo of 3 astronauts with numbers labeling objects and people in the scene" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/iss018e043629_9452806214_o_v3.width-990_xdqMU3n.jpg"/>
<figcaption>A NASA astronaut, a JAXA astronaut, and a Hungarian-American space tourist pose in the Russian service module Zvezda in 2008. The wall behind them is decorated with items including flags, mission patches, portraits of Soviet space heroes, and Russian Orthodox religious objects such as painted icons. Image courtesy of Justin Walsh
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In archaeology, we take soil that’s all the same type, same color, same consistency, and different from what's above it and what's below it or what's adjacent to it, as a group that reflects a particular period of time. We take all of those items as relating to one another, and therefore they are separate from and need to be interpreted differently from what’s above or below. So we're treating each photo that way, because it is a slice of time, separate from the next day or the previous day.The fact that we're doing this one picture a day for each of six squares for 60 days, 360 images that were taken systematically at precisely defined locations, will allow us to better understand what the historic photos are all about. And likewise, what's happening in the historic photos—because there's so many of them and such a variety of things going on in them—will help us to interpret what we're seeing in the systematically recorded images.
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AG: What have you found so far?JW: We thought that the two experimental areas that we selected probably were not going to show very much change over time because they're basically just racks with scientific equipment. In fact, we were asked, “Are you sure you want to use those areas? Don’t you want to see where more activity is happening?” We had to say no because archaeology is not a treasure hunt. We want to actually see the full range. How would we be able to tell the difference between low activity and high activity if we’re only looking at high-activity areas?It turns out that one of those areas is seeing hardly any change. But in one of the other areas, we actually have seen a lot of things moving around. Things are being stored there, like laptops and a video camera. It seems to be kind of a staging area for what's happening next door, a veggie experiment. So that's really interesting, because that shows that when things aren't happening in the location, it can be repurposed.Another thing we’ve been seeing in the eating area is books. In one case there's been an actual physical book on the wall, just kind of stuck there for the time being—somebody put it down. But we've also seen an iPad with an e-book that was on. So, in a leisure moment, when you're eating by yourself, maybe you read a book or a magazine.The way it works right now is that there's this kind of plate hooked to an adjustable arm. And the plate has some Velcro on the front of it, so that the back of the iPad that has Velcro on it can be stuck to it. And that's fine, maybe that's a good enough solution. But now we have evidence of a different way in which the space is being used. And in future space habitat designs you might want to accommodate it in order to make a better experience. If nobody had evidence that this is how this is being done, we wouldn't even be able to think of solutions.
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<img alt="Two astronauts take a photo of themselves in a small mirror hanging on a cluttered wall of the space station" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/iss066e146542.width-990_gLFl5hC.jpg"/>
<figcaption>In an image of a SQuARE sample in a U.S. hygiene area, NASA astronauts Mark Vande Hei and Kayla Barron take a self-portrait in the mirror. Image courtesy of Justin Walsh
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Another aspect of the photo study—we placed a <a href="https://osf.io/preprints/socarxiv/ra4c3/">preprint of this on SocArXiv</a>—is we had all these images from Flickr, 8,000 of them, and helpfully NASA has captioned all of them. We were able to scrape them and peel out particular words: the names of the crew members and the locations. Just with those two pieces of data from each item, for the first time it's possible to map out where men and women are across the International Space Station by module. And if we look at nationality by module, it does seem like there are some real results. In the Russian segment, unsurprisingly, Russians make up the majority of people. And unsurprisingly, in the U.S. segment Americans make up the majority of people who are in those modules. So this indicates that in what claims to be an international space station, there are national zones. That's not something anybody has ever been able to show data for. Again, anecdotally you might have expected that to be the case. But we're able to show the reality. And this is because of the way the ISS is managed. Those are official designations. Each agency decides what happens in its own module and what their own crew do. So as a result, you end up with inefficiencies.AG: You’ve mentioned the future design of space habitats. Do you know if people doing that are watching your project? What kind of questions are they hoping you’ll answer?JW: The ISS is maybe the most expensive building project humans have ever undertaken. A staggering amount of money for one piece of architecture, and $3 billion or $4 billion on NASA alone to maintain it each year. I think that we're looking to be able to give more accurate and more precise descriptions of the functions of different areas and how that relates to what the originally designed and planned functions of those spaces are. It's really important to be able to understand whether people are using spaces the way they're intended. If they're not, how are they being used?We have at the moment four different commercial organizations that are planning, designing, building their own space stations, partly funded by NASA. And NASA and the other space agencies in ISS—except for the Russians—are currently already building a new space station that's going to go into orbit around the moon: Lunar Gateway. There are key problems that they're already focused on sorting out. But also, how do astronauts and designers create the conditions that mimic, or are as my colleague Alice says, are surrogates for, gravity? That is to say, handrails, bungee cords, Velcro, resealable bags. Where do we see Velcro building up over time? Those are areas where it might not have been foreseen, where it ended up that the crew realized that they were going to need more “gravity.” First of all, we have to identify those areas. And, second of all, then we have to understand why those areas are requiring “gravity,” because of the kinds of activities that are going on there. And then third, how do we anticipate that for future designs? Those kinds of questions, the space station companies really want to know that. Even when they have astronauts on their staff or in their executive boardroom, they still realize that there's a difference between anecdotes and data. So the really amazing thing about this is that, as (terrible pun) out of this world as this project is, it's the rare archaeological project that can actually have concrete and practical implications for the future.This interview has been edited for length and clarity.Correction: Due to a punctuation error, a previous version of this article indicated that the Russian space agency was building Lunar Gateway. It is actually a project of the four non-Russian ISS space agencies.
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Archaeologists are working to understand how astronauts really use their space on the ISS—and help improve space habitats of the future.

Quinn Brett hikes with her Bomber off-road handcycle on Walter's Wiggles, a steep trail named for its many switchbacks, in Zion National Park. Image Courtesy of Quinn Brett

Adapting national parks for wheelchair hiking

The trails through our public lands weren’t designed for wheelchairs, but new wheelchairs are designed for those trails. National Park Service accessibility specialist Quinn Brett wants parks to catch up with wheelchair technology, increasing access to American wilderness.

A long exposure shows insects drawn to a halogen street light in the city of Mazatlán, Mexico. Image Credit: Matt Mawson, Getty Images

Why light pollution is a solvable environmental crisis

It’s not easy to make street lights exciting, but Kelly Beatty is trying. Holding court over Zoom on a spring evening in 2021, he warns citizens of Nantucket island in Massachusetts that the decisions they’ll soon make about their lights are choices they’re “going to have to live with for a long time.” Beatty often helps advise communities like Nantucket as they transition their streetlights from traditional bulbs to more energy-efficient LEDs, or light-emitting diodes. As communications officer of the Massachusetts chapter of the <a href="https://www.darksky.org">International Dark-Sky Association</a> (IDA), he’s well aware of the stakes. As this process has been repeated in towns across the world, it has led to a new and preventable environmental problem. LED lights can last 20 years or more, he reminds the group. “It’s important to get it right when you have a chance.”
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The IDA defines light pollution as the inappropriate or excessive use of artificial light, with variations including glare (excessive brightness that causes visual discomfort), skyglow (brightening of sky over inhabited areas) and light trespass (light that falls where it isn’t intended or needed). Already a growing problem, light pollution has intensified with the rise of LEDs, which produce blue-intense light in shorter wavelengths that are more susceptible to scatter and thus travel farther. An estimated 99% of U.S. and European populations now live under light-polluted skies, and one third of humanity is unable to see the Milky Way at night. From marine life and plants to birds and insects, the loss of darkness has left deep scars in our ecosystems.Twenty-five miles off the coast of Massachusetts, Nantucket is one of the darkest places left on the Eastern Seaboard—but even its skies are lightening. As they fight for their darkness, many Nantucketers taking up the cause see light pollution as the rare environmental threat where individual people can make a real difference. “It’s easier to solve than many of the other serious problems we have on Nantucket,” like erosion or affordable housing, says Gail Walker, founder of the local activist organization <a href="https://nantucketlights.org">Nantucket Lights</a>. “If we can educate people and help them understand the problems, most people are going to get on board.”
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<img alt="Silhouette of tree at night with city light behind and Milky Way in the sky" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Nantucket_tree_at_night.width-990_CwescF7.jpg"/>
<figcaption>The night sky as seen from the Middle Moors on Nantucket. Image Credit: Bill Hoenk Photography
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The problem of light pollution started in earnest with the widespread installation of streetlights, which coincided with the rise of highways in the 1950s and 60s. “Think about society then: Everything closed at 8 or 9, and they rolled up the sidewalks,” Beatty says. “We did not have a 24/7 society like we have now.” With highways came all-night gas stations, drug stores, and grocery stores. And, above all, streetlights by the tens of millions. Then, in recent decades, lightbulbs made with LEDs arrived, a revolution in energy efficiency with seemingly little downside. After all, an LED bulb <a href="https://www.energy.gov/energysaver/led-lighting">converts some 90%</a> of the electricity it uses into light, whereas a conventional incandescent bulb only converts about 10%. And LED bulbs are touted as lasting up to 25 times longer.But the physics of LEDs make them fundamentally different from incandescents. While those traditional bulbs put out warm white light made of all colors mixed together, LEDs filter blue-rich light through a specialized phosphor material, producing light that appears white to the human eye but is still more blue-intense than incandescents’ light.But blue light is also the most disruptive to our nighttime environment because it mimics daylight, disrupting the hormone production and sleep cycles of both animals and humans. Melatonin, one of those hormones, helps the immune system destroy renegade cells dividing out of control. That can lead to other health issues, including heightened rates of cancer. And, “we’re not the only ones who produce melatonin,” says Mario Motta, a cardiologist and trustee of the American Medical Association. “Even amoebae produce melatonin”—meaning even amoebae might be vulnerable to light at night. 
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<img alt="Two geckos inside a lit up street lamp at night" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/GettyImages-1287021220_I8ybJf2.width-990_QaqcLnK.jpg"/>
<figcaption>Two geckos in an outdoor lamp in Córdoba, Spain. Studies indicate that insect predators like bats, lizards, and toads will station themselves near artificial lights, where they can easily pick off prey. Image Credit: Clemente Crisci / EyeEm, Getty Images
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The impacts of light pollution are evident everywhere from human health to astronomy research, but they come into particular focus in the recent phenomenon of global species die-offs. Between 100 million and a billion birds die every year due to light pollution, according to Massachusetts IDA chapter president James Lowenthal. New York City recently dealt with a huge die-off, “with flocks of migratory birds slamming into buildings,” says Sarah Bois, an ecologist at the island’s <a href="https://llnf.org">Linda Loring Nature Foundation</a> and a member of Nantucket Lights. “They’re attracted to light.” A 2015 study at New York’s 9/11 “Tribute in Light'' installation showed an increase from 500 birds within half a kilometer of the light beams before they were turned on to 15,700 just minutes after.The issue is a double whammy for birds because they rely on insects for food—and those populations are plummeting, with <a href="https://www.smithsonianmag.com/smart-news/light-pollution-contributes-insect-apocalypse-180973642/">light pollution contributing</a> significantly to the so-called “insect apocalypse.” By some estimates, one third of insects attracted to light sources at night die before morning, either due to exhaustion or because they get eaten. And according to a study in Germany, the number of insects in that country alone that die after being attracted to lights can number 100 billion or more in a single summer. Some starve to death searching for food that should appear bluer at twilight but is lit up amber under streetlights, says insect conservationist Avalon Owens, a doctoral candidate at Tufts University. Some are thrown off by light just the way we are, because of their circadian rhythms. Pollinators whose schedules are altered by artificial light miss the flowers they’re evolutionarily paired with, if the flowers naturally close and open with the warmth of the sun. And insects that rely on circadian rhythms for their yearly development don’t hibernate in time for winter and freeze to death.On Nantucket, these phenomena are of particular concern because the island is home to a remarkably healthy population of northern long-eared bats, which are endangered. Like many birds, the bats rely on insects for food and are easily dazzled by light, putting them in increasing jeopardy. Jack Dubinsky, director of the Maria Mitchell Aquarium on Nantucket, says he’s concerned that adding increasingly lit-up nights to the challenges of climate change, water quality, and ecosystem collapse could put huge pressure on some already struggling species. “The more curveballs we throw, the less likely they’ll be able to find their way,” he says.
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<img alt="Satellite image of U.S. at night, cities lit up" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Light_pollution_US_map.width-990_FtftHWY.jpg"/>
<figcaption>A composite of nighttime images taken by the Suomi National Polar-orbiting Partnership satellite in 2012 shows light pollution in the contiguous United States. Image Credit: NASA Earth Observatory
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For Beatty, the first step in addressing the issues wrought by light pollution—and LEDs in particular—is to look at color temperature, which is measured in kelvins. Lower temperatures like 2,000 K correspond to warm reddish or yellowish light (think candlelight) while higher color temperatures like 4,500 K and up correspond to harsher, bluer light (think blue sky). “When LEDs started getting rolled out for streetlights, the most common ones were very close to this native, blue-rich light,” since they were also the most energy efficient, Beatty says.But because the white light of most LED bulbs is produced by coating a blue-intense LED in phosphor material, it’s possible to switch out that phosphor for one that absorbs and re-radiates the light to be less blue and look warmer, using the same technology already common in fluorescent bulbs. A new wave of LEDs, known as PC Amber, have color temperatures as low as 2,200 K and are gaining popularity.Beatty also points to another solution built into LED technology. Beyond being highly efficient, LED bulbs “can be controlled in amazing ways, programmed with central computers,” he says. Cities like Cambridge, Massachusetts, have programmed their LED streetlights to reduce to 50% power at various points during the night, depending on the street. A few towns in Europe have opted for motion-sensing lights that turn on and off as needed. Older-style lighting worked best if left on continuously through the night, Beatty says. But “LEDs don’t mind being turned on and off or dimmed up, down sideways, multiple times per second,” he says. “You can do anything you want to them.”
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In 2012, the American Medical Association <a href="https://www.mariomottamd.com/wp-content/uploads/AMA-Health-Effects-Light-at-Night.pdf">declared light at night carcinogenic</a>, which has helped drive policy change in cities across the country. New York City drew criticism from the IDA when it began replacing its streetlights with LED bulbs, some at color temperatures as high as 4,000 K, but changed tack when residents complained, citing the <a href="https://www.mariomottamd.com/wp-content/uploads/CSAPH_Report_02-A-16.pdf">AMA guidance</a>. (It helps that high-color-temperature lights are “universally hated,” Beatty says.) Since then, initiatives like Audubon’s Lights Out New York have also convinced managers of major structures like the Chrysler Building to go dark from midnight to dawn during the fall bird migration season. And the city has <a href="https://gothamist.com/arts-entertainment/how-nyc-audubon-helps-birds-disoriented-tribute-light-911">reached an agreement</a> to turn off for short periods the 9/11 memorial lights that were leading to so many avian deaths, allowing the trapped birds to continue their journey.In Chicago, which was famous in light pollution circles as the most over-lit city in the country, the city has been gradually replacing its streetlights with 3,000 K LEDs, which it  touted as saving the same energy as taking 2,400 cars off the road. Tucson, Arizona, reduced its lighting emissions by 60%, in part by switching to 3,000 K LEDs and programming them to dim late at night. And in fall 2021, Pittsburgh passed the nation’s first <a href="https://skyandtelescope.org/astronomy-news/pittsburgh-goes-dark-could-this-new-dark-sky-ordinance-begin-a-trend/">dark sky ordinance</a> that will involve replacing both its older-model conventional streetlights and more recently installed high-color-temperature LEDs with warmer, fully shielded lights equipped with motion sensors.
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<img alt="Teh city of phoenix glows yellow under a night sky" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/GettyImages-200547640-001.width-990_eBLDkCh.jpg"/>
<figcaption>Phoenix, Arizona, illuminated at night. In 1988, two astronomers noticed the brightening glow of nearby Tucson, Arizona, was threatening the dark skies at Kitt Peak National Observatory. They were "the first ones to raise the alarm about light pollution,” Kelly Beatty says. Image Credit: Andy Ryan, Getty Images
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Beatty encourages concerned citizens to get involved with local conversations about light at night—both about streetlights and policies around new construction. “The time to be proactive is when developments are being proposed,” he says, since it’s much easier to convince developers to make changes to their lighting plans when the buildings aren’t already set in literal stone. “Most times people install bad lighting because they don’t know any better,” he says. “It just takes one person to say ‘Hey, there’s another way to do this.’” That’s one reason he came to Nantucket’s meeting about streetlights.“We find the people most concerned about light pollution are not big cities but in rural areas,” he adds. And in that observation he sees a powerful advantage in the fight for dark skies. Since the causes of light pollution are hyperlocal, changes made by individuals and small groups can make a quick and observable difference, which empowers them to continue that work. “Every place where we can energize and educate local citizens is a victory, however small,” he says. “There are hundreds of people like me across the U.S. who are advocates for this, who insert themselves into local situations where education is desperately needed.”Gail Walker had already been watching Nantucket’s brightening skies when she learned about the IDA and its mission. The vivid stars over empty, windswept beaches had always been one of her favorite things about the island, and she wanted to preserve that experience for her grandchildren. Walker has earned a reputation locally as a go-getter, a retired attorney with a knack for bringing people around to her point of view. After coordinating the March 2021 forum on light pollution with Beatty, she began work in earnest with Nantucket Lights, bringing together concerned citizens to raise awareness and shape the community’s response.From there, conversations on the island evolved quickly. Walker began advising homeowners associations about their lighting policies, connecting local groups with lighting experts, and helping assess citizen complaints about lighting issues. She is also shepherding the community’s planned application to become an official International Dark-Sky Community.To be fair, Nantucket has a few key factors that give it an advantage in these efforts: a law governing outdoor lighting already on the books, an affluent community with an interest in maintaining a certain ambience on the island, and officials who see the benefit of that ambience for tourism. But to Walker, a significant part of her success so far is that light pollution “is a solvable problem.” Unlike other issues, which might seem too big, complex or intractable, she says, “there’s kind of an easy fix.”  Motta and Beatty suggest starting with the <a href="https://www.darksky.org/our-work/lighting/lighting-principles/">five principles</a> the IDA has established toward what Motta calls “sane outdoor lighting,” guidelines that individuals can follow to make better lighting choices in their own homes. Those guidelines include an emphasis on light that is useful, or toward a purpose; and targeted, or directed only where it's needed and otherwise properly shielded. Lights should also be no brighter than necessary. And it’s best to avoid high-color temperature, bluer light as much as possible. “That’s it,” Motta says. “Follow those simple rules, and we’ll have a much better world.”Owens, the entomologist, agrees. When it comes to adjusting our night light to help insects, “The most important thing is to ask, ‘Are you using the light?’” she says. “ If not, don’t have it.” She’s a proponent of flashlights, motion detectors, and timers, all the gadgets that might help keep light inside a building. “Automated curtain technology is the next big thing,” she jokes. “Who’s against closing your curtains? Nobody, but it’s hard to remember.”
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<img alt="The Milky Way extends straight up above an observatory dome" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/MilkyDome2.width-990_MGZpnNG.jpg"/>
<figcaption>The Milky Way stretches above the Maria Mitchell Association's Loines Observatory in Nantucket, Massachusetts. Image Credit: Charity Grace Mofsen
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On a breezy fall evening with a nip in the air, Nantucket’s <a href="https://www.mariamitchell.org">Maria Mitchell Association</a> is hosting about 50 visitors on the small platform between the domes of its observatory’s two telescopes—both currently trained on Jupiter to allow observers to admire its stripes. Overhead, clouds glide by soundlessly, reflecting a glow from the north that marks a grocery store and cluster of brightly lit schools. “You can see how they’re reflected up above, leaking up into the sky,” association Director of Astronomy Regina Jorgenson says, pointing. The distant light from Cape Cod is even visible occasionally, she says, on humid nights when moisture in the atmosphere scatters light farther.Still, in breaks in the mist, she’s able to point out the sugary trail of the Milky Way. The upturned faces of tonight’s crowd reflect awe at the sight. Many island visitors have never seen the Milky Way before. “The first time they see it, it’s a transformative experience for them,” she says.Jorgenson has been involved with the observatory since her internship here in 1997 and, along with her astronomy research, is dedicated to preserving the legacy of Maria Mitchell. Mitchell, America’s first professional woman astronomer, was born on the island in 1818. She gained fame for discovering a comet and became the first woman to be inducted into the American Academy of Arts and Sciences. Almost a century later, an NSF-funded internship at the observatory has become a key source of support for female astronomers in the U.S. Jorgenson is determined to protect that resource—and the dark sky that makes it possible. Watching the night grow inexorably brighter over the decades from her observatory perch outside town has been “scary” she says, but she remains hopeful. Nantucket’s geography, history, and culture makes so many things possible, she says. “We’re a small enough community that we have power to make a quick and effective change.” Correction: Nantucket is roughly 25 miles off the coast of Cape Cod, not 12 miles as previously stated.
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Excessive outdoor lighting is deadly to animals and takes a toll on human health and wellbeing, too. But when it comes to large-scale environmental problems, this one may be a relatively easy fix.

Animal Care Supervisor Lisa Dijenno bottle-feeds a manatee named Tober. Image courtesy of ZooTampa

A day at a Florida manatee hospital

On December 7, 2021, NOVA Digital Editor Alissa Greenberg visited ZooTampa’s David A. Straz, Jr. Manatee Critical Care Center to see up close how rescued manatees are recovering and regaining strength amid an ecological crisis and widespread starvation.10:15 a.m. It’s feeding time at the manatee critical care center at ZooTampa, and the calves are ready and waiting. Even before the staff brings bottles of thick formula over to the pool where they are swimming, four sets of fuzzy nostrils break the surface, whiskers wiggling. “As you can see, they know it’s time,” says Animal Care Associate Kelcey Innes. The calves, which are all smaller than a duffel bag but may someday weigh close to 1,000 pounds, suck down the formula, then chew on the bottles’ rubber nipples playfully. 
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There will be more food soon enough—calves at the center are fed every four hours around the clock. But for now, Innes and coworker Sabrina Sauseda have a different task: watch for manatee farts, proof of digestive systems in working order. After a few minutes, Sauseda spots telltale bubbles. “Calliope had gas!” she announces.The center keeps up this intensive feeding schedule because if the calves were still nursing with their mothers, they would be gaining at least a pound a day. But these calves are orphans, part of an ongoing manatee crisis in Florida. Manatees are in trouble all over the state—particularly on its Atlantic (east) coast, they are starving. Last year was the <a href="https://www.tampabay.com/news/environment/2022/01/10/a-record-1101-florida-manatees-died-in-2021-when-will-it-end/">deadliest on record</a>, with more than 1,100 manatees dead, close to 15% of the state’s population. The reason is seagrass: The Florida coast is home to what were once two of the largest undersea meadows in North America, and the plant makes up much of the manatee diet. But <a href="https://news.mongabay.com/2021/09/manatee-deaths-in-florida-point-to-a-global-decline-in-seagrass-ecosystems/">Florida's seagrass</a> ecosystems are collapsing, due largely to fertilizer and development runoff. In the Indian River Lagoon, once one of the continent's most productive estuaries, seagrass has declined an estimated 95% in the last 10 years.As one of four manatee critical care centers in the country, ZooTampa is caring for 23 <a href="https://www.mmc.gov/priority-topics/species-of-concern/florida-manatee/">manatees</a> on this December morning, double its historic capacity. A mother manatee may feed her calf until she starves, so the facility has also taken on an unprecedented number of calves in the past year, left alone after their parents perished. As their state attempts to clean up its waterways, the staff at ZooTampa are working overtime to save the animals that mean so much to the soul of Florida.
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<img alt="A woman bottle feeding two manatee calves in a pool" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Animal_Care_Professional_Sabrina_Sauseda_bottl.width-990_eTRwlCm.jpg"/>
<figcaption>Animal Care Professional Sabrina Sauseda bottle-feeds orphaned mantee calves at ZooTampa. Image courtesy of ZooTampa
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10:35 a.m. It’s also time for morning tube feeding. Two new residents have arrived within the last week, along with the early winter chill. Both were suffering from cold stress; one had a fresh boat propeller injury across his face. And they both need to eat while they convalesce.When a new manatee comes to the center after rescue by the Department of Fish and Wildlife, Animal Care Supervisor Jaime Vaccaro and her staff check its blood levels, respiration, and measurements. Then they set the new resident up in one of three medical pools that make up the hospital’s intensive care area. Each of these interconnected pools is equipped with its own heater, a vertical gate that can be lowered to cut off access, and a hydraulic floor that can be raised and lowered. This feature allows the staff to both customize the environment and raise the manatees out of the water for medical care.Last week’s adult arrival, Corduroy, is in too much distress to eat. After they use the hydraulics to lift him out of the pool, Vaccaro and Innes take some of Corduroy’s blood, then gingerly thread a length of plastic tubing down his throat. His tail flaps a little, but he calms and accepts the liquid quietly. Manatees’ complicated digestive systems are especially sensitive, so the staff tube-feed Corduroy multiple times a day to make sure he stays hydrated and maintains his weight until he’s ready to eat on his own—a process that could take months. Manatee digestion is “like the engine of a car,” Vaccaro says. “If they've been sitting for a while, they might not start back up right away.” Director of Conservation, Research, and Behavior Tiffany Burns connects the increasing number of manatee patients with Florida’s persistent water quality problems. “They look big and full of blubber, but they’re very muscular,” she says. “A lot of that body is intestines.” Without much insulation, manatees are very sensitive to temperature. If they swim in too-cold water long enough (anything under 68 F) they develop cold stress, which manifests outwardly in a frostbite-like icing of white, peeling tissue visible on the flippers and muzzles of many of the animals here. And if they stay even longer, they may develop pneumonia, hypothermia, and organ failure. Manatees typically migrate to warmer water during winter months, but those areas that could once support many manatees in a cold snap no longer have enough seagrass to feed them.
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<img alt="Manatee lies on plank floor and a person holds a tube near his face for feeding" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/tube-feeding_Corduroy.width-990_OFyYUuH.jpg"/>
<figcaption>Newly arrived adult manatee Corduroy is tube-fed at ZooTampa. Image courtesy of ZooTampa
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10:45 a.m. It’s feeding time (again) for the general manatee population housed at the front of the center in two broad pools backed by fake rock walls frequented by very real snowy egrets and great blue herons. Here, meals start at 7:30 a.m. and snacking continues almost without pause all day.On the path between the pools, Intern Olivia Callitsis is unloading heads of endive, escarole, and romaine lettuce from a pallet and stuffing them into a length of PVC pipe with a long hole in the side, so the greens spill out like a planter. A manatee consumes 10%-15% of its body weight daily, and occupants of the two main pools eat through some 1,200 pounds of produce a day. That makes the manatees the most expensive animals to feed at the zoo, costing some $40,000 a month. Burns says the money mostly comes from gate fees and private donors.With a gentle push, Callitsis launches the pipe into the pool, where it bobs gently before sinking. “You can throw it on the surface,” she says of the lettuce, “but this really mimics the natural environment. They have to dive down, work for it a little.” Soon, the surface is broken here and there by smooth gray backs and broad tails, then wrinkly, whiskery snouts munching intently.The inhabitants of the general population pools are mostly at the end of their stay here, with durations that average five months for adults and two years for calves. Because the goal is release, Vaccaro and her colleagues do not engage in the typical zoo enrichment activities, instead switching the manatees between pools frequently so they don’t get too used to their surroundings. And as soon as the calves are stable enough, Vaccaro buddies them up so they learn natural behaviors.
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<img alt="A woman drops a large pipe with protruding lettuce into a manatee pool" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Animal_Care_Professional_Leesa_Whittlef_places.width-990_CV9i266.jpg"/>
<figcaption>Animal Care Professional Leesa Whittlef places a feeder full of lettuce into a critical-care manatee pool at ZooTampa. Image courtesy of ZooTampa
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2:00 p.m. It’s time for the second bottle feeding of the day. Innes and Sauseda carry bottles with a mix of vitamins, baby formula and oils like red palm fruit and macadamia to the medical pools. They lean over and slap the surface to get the calves’ attention and let them know where the goodies are. Small snouts appear and latch onto the bottles, clouds of formula spreading in the water.Burns is aware of the appeal of manatee calves in particular. “Everybody loves manatees and wants to help,” she says of the zoo’s visitors, but they don’t always connect their decisions at home with the fate of the animals they love. “Everyone wants that big, beautiful green lawn, perfectly manicured. But it comes at a cost.”She’s referring to the role nitrates from fertilizers play in <a href="https://www.pbs.org/wgbh/nova/article/florida-red-tide-gulf-coast/">fueling algae blooms</a>, which can block out the sunlight seagrass needs to survive. Similarly, pollution from agricultural runoff, construction, and sewer outflow can cloud coastal waters, starving out seagrass. Sick and dying grass can no longer stabilize the sea floor, which means even more sediment floats up into the water—compounding the situation and giving algae the upper hand, says Lead Biologist Ryan Brushwood of aquatic restoration company Sea &amp; Shoreline. What started as a little algae quickly grows, and ultimately the system hits an inflection point.  
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Some 70 miles north of Tampa, the community of Crystal River saw exactly what that looks like when, in the 1990s, an area that had once hosted some of the state’s largest seagrass meadows was overcome by muck and an algae called Lyngbya wollei. “There was no grass whatsoever,” remembers Lisa Moore, president of the non-profit Save Crystal River. “There were huge plumes of algae growing everywhere.” The water stank; dogs that swam in it got sick. And the population of manatees that had long flocked to the area for its warm springs found little food. In 2015, Save Crystal River hired Sea &amp; Shoreline for a multiyear project: sucking up millions of pounds of muck and water and treating it with a polymer that binds with particles suspended in the water so they become heavier and settle out. The leftover muck is taken to farms to use as fertilizer. Then, Brushwood and his colleagues plant new grass, which they keep in underwater cages to protect it from nibbling manatees until it is well established.Since the plant grows in rhizomes, underground shoots that extend long lateral stems in all directions, it can cover a lot of ground quickly. So far, Save Crystal River has replanted 300,000 plants covering 54 acres out of a planned 92—and those 54 acres have naturally expanded to over 200. The water is clearer, fish and crabs have returned—and so have manatees, in abundance. Save Crystal River hopes its model can be repeated elsewhere in Florida, perhaps including the Indian River Lagoon.  
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<img alt="A woman holds up a funnel and feeding tube that another woman uses to feed a manatee" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Animal_Care_Supervisor_Jaime_Vaccaro_and_Anima.width-990_vLprW02.jpg"/>
<figcaption>Jaime Vaccaro and Sabrina Sauseda tube-feed manatee Kristoff, who has been lifted out of a medical pool with a hydrulic floor for feeding. Image courtesy of ZooTampa
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3:15 p.m. Vaccaro begins shifting manatees around in the medical pools, opening and closing the vertical gates to make space for Pebbles, a mostly-recovered adult who’s been at the center for close to a year. She was in critical condition when she was rescued, with cold stress and propeller wounds that weren’t healing. But she’s made a remarkable recovery and moved into the general population pool not long ago.Pebbles’ bloodwork has recently shown that she might have a brewing infection, though, so she’s receiving antibiotic injections. But after a few days of shots around the same time, Pebbles has figured out the pattern. Vaccaro slips into the water to try to isolate her into medical pool 3 but, in a flash, Pebbles breaks free, using the full force of her tail to twist through the open gate and into the shallow canal that connects the medical and general population pools. Vaccaro radios for help. “She knows she’s going to get an injection, and no one likes those,” Innes says. Instead, Pebbles plays a watery game of cat and mouse. Whenever Vaccaro moves toward her, she glides powerfully to the other side.After half an hour, the staff is on the verge of giving up, aware that Pebbles is stronger than they are. “We try not to force them to do anything they don’t want to do,” Innes says. “But these treatments save their lives, so we have to find that line of when to intervene.”4:25 p.m. As the winter sun starts to dip lower, Vaccaro prepares for the night, loading up PVC pipes full of lettuce and letting whole escarole heads thwap on the surface of medical pool 3 until it’s silty and bobbing with leaves. The buffet of greenery is enough to keep several hungry manatees fed into the wee hours, she reasons—plus, it might tempt Pebbles back into the pool on her own.4:30 p.m. To Vaccaro’s surprise, the tactic works. She moves quickly to drop the gate and hem Pebbles inside. 4:40 p.m. With the floor of medical pool 3 raised all the way up, the heads of lettuce are suddenly beached—and so is Pebbles. Vaccaro and a colleague cover her with a heavy mat, at times using their bodies to keep her steady. The first needle breaks, and Pebbles squirms away, but a second attempt to inject her succeeds. Vaccaro heaves a sigh of relief as Pebbles is lowered back into the pool.
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<img alt="A team loads a large blue sling containing a manatee into a truck" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Loading_Chandler_for_release.width-990_NYhrGgJ.jpg"/>
<figcaption>A manatee named Chandler is loaded for release into the wild in January 2022. Chandler spent a year at ZooTampa's manatee critical care center after being brought in as a juvenile suffering from cold stress. Image courtesy of ZooTampa.
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4:55 p.m. The zoo is closing, but the center’s day never really ends. Vaccaro moves from her antibiotic triumph to mixing up formula for the calves in a cramped office behind the pools, then uses the waning light to tube-feed all three adult manatees in the medical pools in quick succession.When it’s recovering adult Flapjack’s turn, he lies quietly as the slurry of romaine lettuce and formula slips down his throat. He’s gained 70 pounds since he arrived, Sauseda says, showing a photo from the day he arrived with ribs protruding and belly sunken. The difference is still obvious between Flapjack and the other manatees, especially in the definition of his head and the slightness of his torso. But when Vaccaro and Sauseda finish feeding him, his eyes look somehow brighter.Florida made headlines this winter when it went ahead with a controversial program to <a href="https://www.palmbeachpost.com/story/weather/2021/12/08/fwc-oversee-feeding-plan-manatees-starving-death/8887866002/">feed wild manatees</a> in the Indian River Lagoon, in part with the hope of <a href="https://www.mysuncoast.com/2022/03/24/officials-florida-manatees-eat-every-scrap-food-trial/">helping individuals</a> like Flapjack so they don’t need to be treated at places like the center. In Burns’ mind, the most urgent question is how to stop the same thing that’s happened on the state’s Atlantic coast from repeating around Tampa, on the Gulf side. “Let’s learn from this,” she says. “We don’t want to wait for another largest death toll in a year. Let’s get ahead of it and make sure our animals have clean water.” State funds made available for water cleanup are a start, and education is a big part of any solution, she says. But such an urgent and entrenched problem needs a multipronged approach. “You can’t rely solely on education, on rehab, on laws—people break laws all the time. People have to work together in multiple ways to try to solve these problems.”As Flapjack returns to the water, Vaccaro pauses to make sure all her charges are breathing and swimming well after their feeding. She’s also made sure that every manatee has appropriate company overnight—no “busybody” animals that will annoy their poolmates, no males and females that might cause trouble together. Then she walks back to the office for final evening preparations and, eventually, to head home. The center finally lies calm in the half-dark, silent but for the lap of water and occasional hiss of a manatee’s breath. But someone will be back at 10 p.m to feed the calves.
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As Florida’s seagrass beds die off, manatees are starving. Can the seagrass–and the manatees–make a comeback?

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