Scientists Investigating Patches of Ocean With Otherworldly Glow
The nocturnal phenomenon has haunted and mystified sailors for centuries. But they're incredibly rare, and scientists have struggled to determine what causes them. The milky seas are believed to be produced by some form of bioluminescence, but by what creature?
To learn more, researchers have created a database of every recorded sighting over the past 400 years, in the hope of predicting when and where the next display will pop up. As detailed in a new paper published in the journal Earth and Space Science, by teasing out an underlying pattern to the phenomenon, the effort could provide scientists a chance to observe the milky seas and collect samples that have so far eluded them.
"It is really hard to study something if you have no data about it," study lead author Justin Hudson, an atmospheric scientist at Colorado State University, said in a statement about the work. "To this point, there is only one known photograph at sea level that came from a chance encounter by a yacht in 2019."
The serendipitous photo was taken off the coast of Indonesia and was published in a 2022 paper led by Steven Miller, Hudson's colleague at CSU. Along with the photo, the other sacred piece of evidence is a water sample collected by a research vessel's chance encounter in 1985 near the Yemeni island of Socotra, which was found to contain the bacteria Vibrio harveyi.
Today, the strain, which is known to be bioluminescent, remains the prime suspect. But it's far from conclusive evidence. Perhaps it doesn't act alone — and regardless, there are other nagging questions. For one, it remains unclear what role milky seas play in the ocean ecosystem, or how they fit into the carbon cycle. Stretching for tens of thousands of square miles and glowing for up to months at a time, their influence could be incalculably vast.
"It seems possible that milky seas represent an understudied aspect of the large-scale movement of carbon and nutrients through the Earth system," Hudson said.
Based on insights gleaned from modern satellite imagery, combined with mapping hundreds of years of accounts, it appears the milky seas are concentrated around the Arabian Sea and Southeast Asian waters. Intriguingly, the work revealed that the timing of the sightings are statistically related to the Indian Ocean Dipole and the El Niño Southern Oscillation, recurring climate patterns that involve changes to the temperature of the waters. Perhaps the milky seas are the result of a biological response by the bacteria, but it's anyone's guess if it's a healthy sign or a bad one.
"The regions where this happens the most are around the northwest Indian Ocean near Somalia and Socotra, Yemen, with nearly 60 percent of all known events occurring there," Hudson explained. "At the same time, we know the Indian monsoon's phases drive biological activity in the region through changes in wind patterns and currents."
Whatever the cause, Miller, who authored the 2022 paper and contributed to this latest one, is confident they're onto something big.
"Milky seas are incredible expressions of our biosphere whose significance in nature we have not yet fully determined," Miller said in the statement. "Their very existence points to unexplored connections between the surface and the sky, and between microscopic to the global scale roles of bacteria in the Earth system.
More on the ocean: Iceberg Breaks Off Antarctica, Revealing Tentacled Creatures Beneath
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National Geographic
6 days ago
- National Geographic
How 600-lb. megafish became a collector's item in Thailand
The huge fish are dwindling in the wild, but thriving in private homes. Scientists see an opportunity for their recovery. In Thailand, some threatened megafish, like this giant barb photographed at Gilham's Fishing Resort in Khao Thong, can be found in government hatcheries, temples, farms, and backyard ponds. Bangkok, Thailand — When a 200-pound Mekong giant catfish turned up at a flooded train station in the Thai city of Chiang Mai last year, it stopped people in their tracks. Seeing a six-to-seven-foot long fish trapped outside a ticket booth was a surreal sight—and it raised an obvious question: Where did it come from? It certainly did not come from its natural habitat—the Mekong River, which runs through several Southeast Asian countries. The critically endangered species is one of the world's largest freshwater fish and has become vanishingly rare in the wild in Thailand. Instead, the train station fish was surely raised in captivity—possibly escaping from a private pond, temple pool, or stocked reservoir after floodwaters had breached containment. The incident provided a rare glimpse of a hidden world: Across Thailand, megafish like the Mekong giant catfish (Pangasianodon gigas) and the similarly threatened giant barb (Catlocarpio siamensis) are being bred in large numbers in captivity. Government hatcheries, commercial farms, and private owners raise them for fishing ponds, religious purposes, or ornamental displays. Altogether, these captive fish form a vast and largely undocumented population of endangered fish that dwarfs what's likely left in the wild. Now, scientists are beginning to ask a pivotal question: Could these captive stocks play a role in reversing the decline of megafish populations in the wild? 'Captive stocks could be more than just a fallback,' says Zeb Hogan, a biologist at the University of Nevada, Reno, who has studied Mekong megafish for decades. 'With the right science and conservation efforts, they might help bolster wild populations and keep these iconic fish from disappearing altogether.' (Meet the world's largest freshwater fish.) Fish farming is common in the Mekong Delta, and catfish (like these pictured in 2008) are popular. Their larger brethren, Mekong giant catfish, also seem to do well in captivity. Photograph By Justin Mott/Redux Megafish have a sacred status Mekong giant catfish can grow over 600 pounds, and they were once plentiful, caught for food and revered for their size. Thai fishers recorded annual catches in the hundreds in the early 1900s and later dozens. 'I would go to take a bath in the river and catch a fish for dinner at the same time,' recalls 79-year-old Boonrian Jinarat, who spent decades fishing in the town of Chiang Khong. Where guests are guardians But those days are gone. While no exact wild population numbers exist, Thailand hasn't seen wild catches in years. Today, a massive golden catfish statue stands downstream from Chiang Khong where the giant fish once swam—a monument to what's been lost in the wild. Recognizing the threats to the giant catfish, the Thai government launched a breeding program aimed at preservation in the early 1980s. The species, it turned out, adapted well to hatchery techniques, and populations steadily grew in government facilities. Over time, these giants found their way into private hands, with collectors, temple caretakers, and fish farmers raising giant catfish alongside other iconic species such as the giant barb, the world's largest carp, and the striking but rare seven-striped barb. 'Their large size gives them a sacred status that is often linked to religious beliefs,' says Chaiwut Grudpan, a fish biologist at Ubon Ratchathani University. The fish also appeal to the nostalgia of some collectors. Sittitam Ruengcharungpong grew up in Bangkok surrounded by fish his father raised as a hobby. Today, he breeds dragon fish and arapaima commercially but keeps several Thai megafish species in his two home ponds. 'I want to grow them to full size, like the ones I saw when I was young, and be able to show my children how big they can get,' he says. This gold catfish statue at a Buddhist temple, known as Wat Pla Buek, in the northern Thai town of Chiang Khong commemorates the Mekong giant. Photograph By amnat, Almay For Jirawat 'Organ' Sangphoo, Thailand's fascination with giant fish has become a thriving business. Outside Bangkok, he rents a former shrimp farm the size of a football field, where he keeps hundreds of fish ranging from exotic imports to native megafish. His customers include private collectors, aquariums, and fishing parks, and business is steadily growing. The most prized fish, he says, is the giant barb—also known as the Siamese carp—a slow-growing species native to the Mekong and Chao Phraya river basins that is widely considered a symbol of prosperity and good luck. 'Organ' once sold a single specimen weighing 266 pounds (121 kilograms) to a fishing park for 1.7 million baht, or about $52,000. Given their value and the short time he handles them, he says, 'I take care of the fish as if they're my pets.' Avoiding a genetic bottleneck Researchers first need to know how many captive fish there are, where they're being kept, and how genetically diverse they are. Tools like environmental DNA could help detect the presence of megafish in backyard ponds and fish farms. Hogan and his colleagues hope to track the origins of captive megafish and sample the gene pool beginning with a study of Mekong giant catfish. (Read more about scientists' efforts to save the world's largest freshwater fish.) An exact count of Thailand's captive population may not be possible, but Hogan, who leads the Wonders of the Mekong research project, speculates there are more than a million Mekong giant catfish in captivity throughout the country, at least a thousand times more than remain in the wild. That staggering number exists largely because the Mekong giant catfish has proven so resilient in captivity. 'You put this huge fish in a little pond and it does just fine,' says Hogan, who is also a National Geographic Explorer. By comparison, other freshwater giants have struggled to survive outside their natural habitats. The Chinese paddlefish—a native of China's Yangtze River and once one of the world's largest freshwater species—couldn't survive in captivity and is now believed to have gone extinct in the wild in the early 2000s. With enough food and space, Thailand's other megafish might fare better, but getting them to reproduce in captivity could be another challenge. Mekong giant catfish are among the largest freshwater fish in the world. In the early 1900s, fishermen would catch hundreds of fish annually, but today, wild catches are extremely rare. Photograph By Fargriv, Shutterstock Adapting to captivity alone isn't the only hurdle; a central concern is genetics. Decades of artificial selection and inbreeding in closed systems can lead to genetic drift and bottlenecks, weakening traits critical for survival in the wild. Fish like the Mekong giant catfish produce thousands of offspring per spawn, but in hatcheries, a single pair can generate tens of thousands of fish. Without careful tracking, this narrows the gene pool, heightening inbreeding risks and undermining long-term survival. 'Releasing these fish could dilute the genetic diversity of wild populations, making them less resilient to diseases, environmental changes, or new threats,' says Apinun Suvarnaraksha, a fisheries lecturer at Maejo University in Chiang Mai. Compounding the issue, captive fish don't face the same challenges as their wild counterparts. In controlled environments, they often develop traits—like tameness or dependency on hand-feeding—that reduce their ability to survive in the wild. 'To rebuild wild populations, it's not enough to have fish,' says Hogan. 'We need to ensure they're genetically strong enough to survive.' In Cambodia, fishers still sometimes see Mekong giant catfish in the wild. Here Cambodian officials release one back into the wild. Part of a last-ditch effort The role of private collectors in conservation is contentious. Critics say it risks normalizing wildlife ownership, while others see it as a last resort for species with nowhere else to go. For some collectors, being part of the conservation effort is part of the appeal. Nantarika Chansue, a veterinarian at Chulalongkorn University in Bangkok and a leading Thai expert in aquatic animal health, keeps around 20 Mekong giant catfish in a lily-covered pond at her home outside the city. She also cares for two dozen giant freshwater stingrays, many of them rescued from fishermen. 'It makes me proud to care for species that are so rare in the world,' she says. In Vientiane, the capital of neighboring Laos, one individual has taken matters into his own hands. A businessman—who requested anonymity out of concern for provoking the government—has built a custom tank to house a handful of critically endangered wolf barbs (Luciocyprinus striolatus), also known as monkey-eating fish. He rescued them from a Mekong tributary that may be their last refuge but is now threatened by a dam under construction. 'When the dam is finished, the wolf barb will disappear from the wild,' he says. Watching the fish—sleek and fast as they dart through the water—he calls his effort 'the last option.' 'There is no manual for this,' he adds. 'I'm just trying to save the species.' (Rivers and lakes are the most degraded ecosystems in the world. Can we save them?) A river to return to An even bigger challenge awaits beyond the ponds. Reintroducing animals that thrive in captivity back into the wild is notoriously difficult, especially for large freshwater fish. Mekong's megafish face relentless pressures from dam construction, overfishing, and increasingly climate change. Many, like the giant catfish, are long-distance migrators that depend on connected, healthy river systems. While Thailand has released hatchery-raised fingerlings into reservoirs, efforts to reintroduce them into the Mekong itself have struggled. 'The focus must shift towards a more holistic approach, which includes not only breeding and release but also habitat protection and restoration,' says Suvarnaraksha. 'That means controlling illegal fishing, addressing dam impacts, and working closely with local communities.' Thailand may not have seen wild catches of the Mekong giant catfish in years, but it can look to Cambodia, where the river system is healthiest, as a sign of what's still possible. Late last year, Cambodian fishers caught and released 17 Mekong giant catfish in the Tonle Sap and Mekong rivers, the highest number recorded in more than two decades. Several exceeded 200 pounds, and the fish spanned multiple age classes, indicating natural reproduction is still occurring. Whatever role megafish in private collections might end up playing, Thailand's rivers would need to both support fish survival and reproduction. 'It's not the solution, but it's not the problem either,' says Hogan. 'It only becomes a problem when people think having the fish in captivity is enough. It's not. Real conservation means giving them a river to return to.'
CNN
31-07-2025
- CNN
4,000-year-old teeth reveal the earliest use of this psychoactive substance
For the first time, archaeologists have used advanced scientific techniques on 4,000-year-old dental plaque to confirm traces of betel nut chewing in ancient Thai communities. Betel nuts are usually chewed as 'quids,' a mix of slaked lime and ground betel nuts—which contain psychoactive compounds that boost energy, alertness, euphoria, and relaxation—wrapped in a betel leaf. The stimulant, which can leave a red, brown or black stain on the teeth, is thought to be the world's fourth most commonly used psychoactive substance, after caffeine, alcohol, and nicotine, with hundreds of millions of users globally. In the past, betel nuts have been identified at archaeological sites via plant fragments or stained teeth, offering circumstantial evidence that its use goes back at least 8,000 years. But using advanced scientific techniques, an international team of researchers has identified betel nut chewing in an individual with no dental discoloration. The study, published Thursday in Frontiers in Environmental Archaeology, provides the earliest direct biochemical proof of betel nut consumption in Southeast Asia, predating previous evidence by at least 1,000 years, said author Piyawit Moonkham, an archaeologist at Chiang Mai University in Thailand. The discovery of 'invisible' traces of betel nut chewing in the molars demonstrates that for some prehistoric practices, 'the visible evidence that we have might not tell us the whole story,' Moonkham said. Highly sensitive and minimally invasive, the method requires only tiny samples of plaque and offers a 'fascinating' way of finding more clues about the past, said Thanik Lertcharnrit, an associate professor at Silpakorn University in Bangkok, Thailand, and an expert in Southeast Asian archaeology, who was not involved in the study. 'In terms of methodology, we have very few, if any, archaeologists using that kind of scientific technique, the residue analysis, to infer the life, the tradition, the culture of the (prehistoric) people,' said Lertcharnrit. 'This paper represents a pioneer; it's state of the art in terms of archaeological research in mainland South Asia, particularly in Thailand.' Researchers began collecting ancient dental plaque, known as calculus, from Nong Ratchawat, a Neolithic burial site in central Thailand, in 2021. The team removed tiny, five-milligram scrapes of plaque from 36 dental samples, taken from six individuals. The method, called liquid chromatography-mass spectrometry (LC-MS), extracts, separates, and identifies chemical compounds by measuring how heavy the molecule is compared with its electrical charge. But before testing the ancient samples, the team needed a control sample — something they could compare the results with and demonstrate what traces of betel nut liquid might look like. 'We tried to mimic the culture of chewing,' said Moonkham, adding that in addition to the core ingredients of dried betel nut, red limestone paste, and piper betel leaves, they included catechu bark and tobacco in some of their control samples, and ground the ingredients together with human saliva. The modern control samples were tested first to validate the method before the dental samples were analyzed. They detected trace plant alkaloids – including betel nut's main psychoactive compounds, arecoline and arecaidine – in three samples from one individual known as 'Burial 11,' likely a woman aged around 25. Researchers say the benefit of the technique is that it doesn't destroy the original samples, leaving the remains intact for future study. LC-MS is currently used in a variety of fields, including pharmaceuticals, food safety, and environmental testing. But its use in archaeology so far has been limited, said Dr. Melandri Vlok, bioarchaeologist and a lecturer in anatomy and physiology at Charles Sturt University in Australia. 'A lot of the work that's been done using this (method) is looking for proteins in dental calculus for dietary reasons. So, using it to pick up these compounds that get trapped in the dental plaque, that's what's really innovative here. Nobody has done this before,' said Vlok. There's a reason it isn't common: the method requires expensive machinery—such as an Orbitrap, one of the most advanced mass spectrometers on the market, which identifies molecules by measuring the mass-to-charge ratio—that many researchers don't have access to, she added. 'It's starting to be used more routinely by some of the bigger labs, like Harvard and Max Planck — which makes this research even more amazing, because this is a paper with a Thai first-author, which is great,' she said. 'Seeing this research come from within the region is actually the thing that excites me the most.' The team on this paper included researchers from eight institutions across three continents, and the chemical residue analysis was conducted at Washington State University, where Moonkham studied for his PhD. The study's control samples, which created a 'standard' to test against, are another novelty, and future studies could refine this even further by considering how the compounds degrade over thousands of years, said Vlok. 'This is a method that I can definitely see being used quite frequently from now on in the region,' she added. While betel nuts have long been linked to hospitality and religious rituals, much of the research in recent years has focused on its classification as a carcinogen and the correlation between betel quid use and oral cancers. 'Betel nut chewing has significant implications for people's health,' said Vlok. 'It's something that affects millions of people in tropical Asia-Pacific today, but we don't really know how long people have been doing this for.' Better understanding where the tradition comes from, and how and why people are using it, could help address some of these concerns, she added. In Thailand, Moonkham says the practice has been strongly discouraged by the government since the 1940s, and while it's still popular in rural areas, it's now uncommon in cities and with younger generations. Although he recognizes the potential health hazards, Moonkham believes the practice has been overly 'demonized' and hopes research like this can show the long history of betel nuts in Thailand, and their importance in society. He has a personal attachment to the practice, too: he has childhood memories of his grandparents often chewing betel quids, usually while gossiping with friends or relaxing after a family meal. 'I asked my grandmother once, 'Why do you chew it?' And she responded, because it cleans the teeth and it helps me relax,' Moonkham recalled. 'When she chewed it, she tended to share with a friend, family, or colleagues. I think it's significant in the way it creates a social bond.' Researchers are still exploring possible reasons for the absence of tooth stains in the individual they examined, which they speculate could be due to different chewing methods, cleaning habits, or decay over the thousands of years since. Further research could help narrow down the possibilities. The team plans to analyze more individuals from the Nong Ratchawat site, where a further 150 individuals could be tested for signs of betel nut use, and Moonkham intends to dig deeper into the social, religious and medicinal roles of betel nut in ancient societies in future projects. The technique could also be applied to a wide range of plant and food residues, opening new avenues for understanding ancient practices. 'I think people tend to neglect the social and cultural aspect of plants,' said Moonkham. 'It's important to understand the whole perspective.'
Newsweek
25-07-2025
- Newsweek
Map Shows Where 100-Year Floods Have Hit Across the US Over Past Year
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. The term "100-year flood" implies that the event is a rare occurrence; however, dozens of such storms have inundated the United States over the past year alone, prompting concern that they are occurring more frequently as the Earth's climate continues to warm. Why It Matters Flooding is the second-deadliest weather hazard in the U.S., next to extreme heat. Devastating flood events have made headlines numerous times this year, including a 1,000-year atmospheric river event that hit the Midwest and South in April and the deadly floods that inundated Central Texas over the July 4th weekend. The frequency of such flooding rainstorms, which often go hand-in-hand with death and destruction, is alarming. What's even more concerning is that AccuWeather meteorologist Alex DaSilva told Newsweek that these events are happening more frequently. What To Know In 2024, dozens of 100-year rainstorms struck the U.S. Each point is marked on the map below, created by Colorado State University. The points marking each event are widespread, with only a few states escaping unscathed. Last year wasn't a one-time occurrence, either. This year is also "shaping up to be one of the most flood-impacted summers on record in the United States," AccuWeather reported. A map from Colorado State University shows where 100-year rainstorm events were documented in 2024. A map from Colorado State University shows where 100-year rainstorm events were documented in 2024. Colorado State University What Is a 100-Year Flood? The United States Geological Service (USGS) describes the term "100-year flood" as an attempt "to simplify the definition of a flood that statistically has a 1-percent chance of occurring in any given year." Where Did 100-Year Rainstorms Hit in 2024? On the CSU map, countless points pepper the Eastern Seaboard around North Carolina and South Carolina after Hurricane Helene struck in September. Others show the devastating impact of the summer monsoon season in New Mexico, which caused deserts to flood and cars to become stranded as water washed over a highway. Vermont faced catastrophic floods in late July. Central Texas, known as Flash Flood Alley, experienced several 100-year rainstorms last year, as did Florida, with a scattershot of points dated as occurring during the Atlantic hurricane season. There was also an onslaught of precipitation that hit South Dakota in June 2024, as well as a similar storm that measured as a 100-year event at several locations in Missouri in November, among others. Only a few states emerged unscathed, including Iowa, Wisconsin, Oregon, Washington, and Massachusetts, but most of the U.S. experienced some form of severe flooding precipitation last year. Why Are 100-Year Floods Occurring More Frequently? The map's creator, Russ Schumacher, a professor of atmospheric sciences at CSU and a CSU climatologist, told Newsweek that improved technology, such as radar, provides better access to data, which can make it seem as if the flood events are happening more frequently. However, he also stressed the impact of climate change. "The physics of climate change tells us that we should see these extreme events more frequently," he said. As the atmosphere grows warmer through global warming, its ability to hold moisture increases, DaSilva told Newsweek. "This is why in the wintertime, we typically don't see too much flash flooding in the wintertime," DaSilva said. "It's too cold, and there's snow, of course, but it's hard to get the moisture content you need for heavy rain events in the wintertime because it's cooler out. In the summertime obviously the temperature is above freezing, but the atmosphere can hold more water content. There's more moisture to squeeze out." Which States Have Increased Flood Risk? As the atmosphere's ability to hold moisture increases, DaSilva told Newsweek that states in the Ohio and Tennessee valleys are becoming wetter, while areas like California are becoming drier. What People Are Saying AccuWeather meteorologist Alex DaSilva told Newsweek: "When the atmosphere is getting warmer as a what it's doing is making summer warmer and the shoulder seasons warmer as well. What's happening is those seasons, especially in the summertime, the [atmosphere's] ability to hold more moisture is going up as well." DaSilva added: "It doesn't guarantee we will see more rain over a certain area, it rains, it's going to rain heavier." The USGS in a webpage about 100-year flood events: "In other words, over the course of 1 million years, these events would be expected to occur 10,000 times. But, just because it rained 10 inches in one day last year doesn't mean it can't rain 10 inches in one day again this year." What Happens Next As the probability of heavy rain events increases, people are advised to have a flood plan in place before such an event occurs in their area. People should also never drive on a flooded roadway, as most flood-related deaths occur in vehicles.
