分类： science

As climate change continues to push ocean temperatures to record highs, leading coral researchers around the globe are sounding the alarm: a potentially powerful El Nino weather pattern forecast for this year could deliver a fatal blow to reef ecosystems already reeling from repeated mass bleaching.

Meteorological forecasters have grown increasingly confident that the cyclical climate phenomenon, which emerges every two to seven years, will return in 2025 with unusual strength. El Nino disrupts established global weather patterns, triggering severe drought in some regions and catastrophic flooding in others. For coral reefs, the most dangerous impacts stem from El Nino’s tie to elevated ocean temperatures and reduced cloud cover across many tropical basins—two conditions that directly trigger mass bleaching.

“Every single global coral bleaching event in recorded history has coincided with an El Nino year,” noted Clint Oakley, a coral biologist at Victoria University of Wellington. He shared that he feels “dread, though not surprise” at the prospect of a strong event, which he says could prove “serious and devastating for reef systems across the world.”

To understand why warm water poses such an existential threat to corals requires looking at their symbiotic biological relationship: corals rely on tiny algae called zooxanthellae that live within their calcium carbonate structures. The algae use photosynthesis to produce nutrient-rich food for their coral hosts, and in exchange gain a stable habitat and access to the sunlight needed for photosynthesis. The algae are also responsible for the vivid, distinctive colors that make reefs so iconic. When ocean temperatures rise too far above historical averages, however, this delicate partnership breaks down. Researchers have not yet pinpointed the exact biological mechanism that triggers this collapse, but the outcome is consistent: the algae either leave the coral tissue voluntarily or are expelled by the coral itself. Without their algae symbionts, corals are left stark white, a state called bleaching, and slowly starve because they no longer receive the nutrients the algae provide.

If ocean temperatures drop back to safe levels quickly enough, corals can survive on stored energy reserves until the algae return. Even then, surviving bleaching leaves corals weakened, malnourished, far more susceptible to disease, and unable to allocate enough energy to reproduce. If heat stress persists or reaches extreme levels, the coral will starve to death before temperatures cool, explained Jen Matthews, a coral scientist at the University of Technology Sydney.

Occasional localised bleaching is a natural part of reef ecosystem dynamics, and can even help cull weaker corals to make space for hardier individuals. The modern crisis stems from repeated mass global bleaching events, which have become the new normal as climate change drives steady long-term ocean warming. When reefs are hit by bleaching before they have fully recovered and had time to produce new juvenile corals to replace lost individuals, the ecosystem enters an irreversible downward spiral, Oakley said.

The most recent global mass bleaching event was officially declared in 2024, and its impacts have already been devastating. In the Caribbean, multiple key coral species are now classified as functionally extinct, meaning they can no longer reproduce enough to sustain stable populations. Australia’s Great Barrier Reef, the world’s largest reef system and the only living structure visible from space, has already lost between 15 and 40 percent of its total coral cover across different regions since 2024.

A powerful “super El Nino” this year would add new heat stress to ocean temperatures that are already far above the safe threshold for most corals. Oakley pointed out that average global ocean temperatures over the past five years are already equal to the peak temperatures recorded during the 1998 global bleaching event, the first major mass bleaching event in modern history.

While a small subset of coral species and individual colonies have shown natural resilience to warm water, these hardier corals are not abundant enough to replace the massive losses caused by repeated bleaching. Scientists have pursued a range of experimental interventions to protect vulnerable reefs, from nutrient gels that feed starved corals to solar shading that cools reefs during heatwaves, and even genetic engineering to breed more heat-tolerant coral strains. These innovative strategies are important, Matthews said, but ultimately they only “buy time” for reefs rather than solving the core crisis.

Researchers emphasize that key details about this year’s El Nino remain uncertain: while an event is very likely, its exact strength and duration are still unpredictable, said Kimberley Reid, an atmospheric science research fellow at the University of Melbourne. El Nino is just one factor shaping regional ocean conditions, she added, with local ocean temperature anomalies and regional wind patterns also playing major roles in how much heat stress reefs will face.

Even if an unusually strong El Nino does not materialise this year, the long-term outlook for global coral reefs remains grim. Roughly half of the world’s total coral cover has already been lost over the past few decades. These ecosystems are not just tourist attractions: they provide critical spawning and nursery habitat for commercial fish species that feed billions of people around the world, and act as natural sea walls that absorb storm energy and protect coastal communities from flooding and erosion.

Matthews called the current trajectory a sobering reality. “If we don’t get our act together on climate change, then all we’re doing is buying time until our reefs, as we know them, disappear.”

Gibraltar’s famous colony of Barbary macaques, a top draw for international visitors to this British overseas territory on southern Spain’s border, have developed an unexpected adaptive behavior: they deliberately eat soil to counteract gastrointestinal distress caused by consuming large amounts of human junk food, according to groundbreaking new research published by an international team of biologists.

Originating from North Africa, the population of roughly 230 macaques holds a unique status as the only free-ranging colony of wild monkeys in all of Europe, per data from the Gibraltar Ornithological and Natural History Society. For millions of tourists who flock to the territory’s iconic Rock of Gibraltar each year, seeing these charismatic primates is often the highlight of their trip. “We came here specifically for the monkeys, because this is the only place in Europe you can see wild populations of them,” 29-year-old Danish visitor Elish told Agence France-Presse. But the tourist attention comes with a hidden cost: despite repeated warnings, many visitors either feed the macaques directly or leave food waste accessible, and the animals regularly raid snacks from unaware guests.

Local authorities have long enforced a ban on feeding the macaques, with posted warning signs across the territory and fines for violations reaching as high as £4,000 ($5,350). But enforcement remains a major challenge: thousands of tourists visit the Rock daily, and the macaques, which can grow up to 15 kilograms, are bold, independent, and skilled at snatching ice cream, cakes, crisps, chocolate and other processed treats from unguarded bags, picnic baskets and public waste bins. Over time, this steady access to unhealthy human food has drastically altered the macaques’ natural diet, which originally consists of wild fruits, leafy vegetables, seeds and native vegetation.

The new study, conducted by researchers from the Universities of Oxford, Cambridge, Paris-Sorbonne and Gibraltar’s local environment department between August 2022 and April 2024, documents this soil-eating behavior — formally called geophagy — for the first time in this Gibraltar macaque population. The research team found that geophagy occurs at far higher rates among this colony than it does among other macaque populations around the world, and that the behavior spikes in summer, when tourist numbers to Gibraltar reach their annual peak. Critically, the behavior was not observed at all in a separate group of Gibraltar macaques that have no regular contact with tourists and do not access human junk food.

“That is a strong argument for the direct association between soil-eating and the consumption of human food,” explained Sylvain Lemoine, co-author of the study and assistant professor of biological anthropology at the University of Cambridge. Lemoine noted that the processed junk food the macaques consume is extremely high in sugar, salt and dairy — ingredients that the primates’ digestive systems are not evolved to process properly, leading to frequent stomach discomfort and disrupted gut microbiomes.

The research team classifies the behavior as an early form of self-medication. They hypothesize that the soil the macaques consume carries beneficial microfungi and natural microorganisms that help rebalance the disordered gut microbiome after a junk food binge, in addition to absorbing toxins to reduce gastrointestinal distress. Bethany Maxwell, technical officer at the Gibraltar Botanic Gardens, pointed out that while primate geophagy is already well-documented in scientific literature, the link to excess junk food consumption from human tourism is an entirely new finding. “We already know primates eat soil mostly to detoxify or to supplement missing nutrients, but this study shows that this behavior is also being driven here by eating too much unhealthy human food — that’s something quite novel,” Maxwell said.

For most modern urban residents, feral pigeons are little more than uninvited pests: filthy birds that leave droppings on building facades, spread disease, and are repelled by ubiquitous anti-perching spikes across city skylines. But this dismissive reputation hides a thousands-year-long partnership between humans and rock doves that shaped both species, and new archaeological research is rewriting the timeline of that shared history.

Published Thursday in the journal *Antiquity*, the study led by a team of Dutch researchers confirms that domestic pigeons were integrated into human societies as early as 3,500 years ago – nearly 1,000 years earlier than the previous scholarly consensus.

Lead author Anderson Carter, a bioarchaeologist at the University of Groningen, told AFP that humans’ widespread rejection of pigeons is a remarkably recent development in the long arc of human-animal coexistence. For millennia, pigeons were far more than urban strays: they served as a reliable food source, delivered messages across impossible distances, produced fertilizer for crops, and held deep meaning as religious symbols across multiple cultures. Even into the 19th and 20th centuries, pigeons remained critical to human society, most notably carrying vital military messages during times of war.

That centuries-long utility ended abruptly with the explosion of communications technology. “When the telegraph and then the telephone were invented, pigeons were out of a job,” Carter explained. But thousands of years of selective breeding and conditioning had left the birds adapted to live alongside humans, so they did not leave human settlements. It was not until the Industrial Revolution created large, dense modern cities that the narrative around pigeons shifted, framing them as dirty, unwanted pests that spread illness.

To unpack the origins of this relationship, the research team traveled to the Hala Sultan Tekke archaeological site on the shores of Larnaca Salt Lake in southeast Cyprus. There, they analyzed 159 ancient pigeon bones recovered from Bronze Age excavation layers, using biometric, isotopic and collagen analysis to trace the birds’ diet and identify signs of human influence.

Dating placed the remains between the 13th and 14th centuries BC, or roughly 3,500 years before the present. When researchers compared the nitrogen and carbon isotope ratios from the pigeon collagen to isotope data from contemporary human remains found at other Bronze Age Cypriot sites, they discovered a near-perfect overlap, indicating the pigeons shared a very similar diet to humans living in the same region. This overlap is strong evidence the birds were already domesticated, or well on their way to domestication, by that time.

Prior to this finding, the earliest confirmed evidence of pigeon domestication dated back to around 300 BC, from large purpose-built stone nesting structures discovered in Greece. The new finding pushes the timeline of domestication back by almost a millennium.

Genomic analysis also confirms that modern feral city pigeons are genetically closely linked to wild rock doves from the Mediterranean and Middle East, matching the archaeological evidence from Cyprus. For the research team, the broader goal of the work is to reframe public perception of the most common urban bird. Carter notes that pigeons’ evolutionary story is inextricably woven into human history: “Their story is also our story.”

Marine biologists have announced an extraordinary discovery that rewrites our understanding of humpback whale migration: two individual humpbacks have completed unprecedented transoceanic journeys between Brazil and Australia, setting new world records for the longest recorded travel distance in the species. The international research team, whose findings are published in *Royal Society Open Science*, pieced together the whales’ multi-decade odysseys using unique identifying markings on their tail flukes, with contributions from both professional scientists and recreational amateur photographers who snapped photos decades apart. The study’s lead author, Cristina Castro, a marine biologist with the Pacific Whale Foundation based in Ecuador, shared that these open-ocean crossings are entirely unlike any movement previously documented for the species. While individual whales have occasionally been spotted straying slightly outside their established migratory paths, the scale of these journeys far exceeds any previously recorded deviation, Castro explained.

What makes this tracking possible is the fact that every humpback whale bears a one-of-a-kind pigment pattern on the underside of its tail fluke, a natural marker as distinct as a human fingerprint that allows researchers to identify individual animals across decades and vast distances. To trace the two whales’ paths, the team analyzed more than 19,000 photos collected between 1984 and 2005 from locations across eastern Australia and Latin America, running the images through a custom image recognition algorithm to find potential matches, then manually verifying each candidate to confirm the identities of the wandering whales. The first of the two record-breaking whales was first photographed and documented in 2007 in Hervey Bay, a well-known humpback habitat on Queensland’s east coast, and spotted again at the same location in 2013. Six years after that second sighting, the same whale was photographed off the coast of São Paulo, Brazil’s most populous coastal state. The straight-line distance between the Australian and Brazilian sighting points measures approximately 14,200 kilometers, or 8,800 miles; researchers note that the whale’s actual total travel distance is likely even longer, as its exact route between the two points remains unknown. The second whale took the reverse route across the South Pacific: it was first photographed swimming alongside eight other adult humpbacks off the coast of Bahia, Brazil in 2003. Nearly 25 years later, in 2025, the same whale was spotted and confirmed in Hervey Bay, Australia, with a straight-line distance of 15,100 kilometers between the two sightings. This journey surpasses the previous record for the longest recorded humpback migration, which was set by a whale that traveled more than 13,000 kilometers from Colombia’s Pacific coast to Zanzibar off the eastern coast of Africa.

For Southern Hemisphere humpback whales, migratory routes are deeply entrenched cultural behaviors. Most populations live in distinct, well-separated pods and follow the same fixed route year after year, moving between cold, nutrient-rich feeding grounds in polar waters and warm tropical breeding grounds where they give birth and mate. Castro notes that these routes are passed down socially: mother humpbacks teach the traditional migratory paths to their calves when they are young, cementing the patterns across generations. That makes these extraordinary deviations all the more surprising, and researchers are now exploring multiple potential explanations for why the two whales strayed so far from their expected paths. One leading hypothesis ties the unusual movement to human-driven climate change, which is altering ocean conditions, food availability, and traditional migration corridors in ways that are still not fully understood. Castro explains that increasing environmental pressure or disturbance to the whales’ original feeding and breeding habitats could push more individual animals to venture far beyond their traditional ranges in search of more suitable conditions, while changes in the distribution of their prey could also encourage long-distance exploration.

Beyond rewriting what we know about humpback migration capacity, these long-distance crossings also carry ecological benefits for the species. After being hunted to the brink of extinction by commercial whaling in the 20th century, humpback whale populations have made a remarkable rebound across much of their global range over the past 50 years. When whales travel between previously isolated breeding populations, they introduce new genetic material that boosts overall genetic diversity, strengthening the long-term resilience of the species. The wandering whales may also drive cultural exchange among humpback populations: male humpback whales are famous for their long, complex songs, which spread rapidly through populations as individuals copy new melodies. If a male from one isolated breeding population travels to a new region and sings his native song, he can introduce entirely new musical themes that spread through the local population, creating a lasting cultural shift. Researchers say the discovery highlights the value of long-term photo identification projects that combine scientific data with contributions from citizen scientists, to reveal unexpected behaviors in one of the ocean’s most iconic inhabitants.

Two individual humpback whales have completed the longest documented transoceanic journeys ever recorded for their species, traveling thousands of kilometers between breeding grounds off Australia and Brazil, according to new research published Wednesday by an international team of marine scientists.

The research team relied on a massive dataset of more than 30,000 photographs of distinct humpback whale tail flukes, a unique identifying marker for every individual, to confirm the two massive mammals had been sighted on opposite sides of the South Atlantic Ocean. The first whale was first photographed off the coast of Queensland, Australia in 2007, and was spotted again near São Paulo, Brazil in 2019 — covering a straight-line distance of 14,200 kilometers, or roughly 8,823 miles. The second individual was observed off Brazil’s Bahia coast, before being re-sighted 22 years later in Australia’s Hervey Bay, a journey of 15,100 kilometers. Researchers confirmed these crossings set a new record for the longest distance between verified sightings of a single humpback whale.

Growing up to 17 meters long and weighing as much as 40 tons, humpback whales are already famous for long annual migrations between Antarctic feeding grounds and tropical breeding areas, but these transoceanic crossings between separate breeding regions are extraordinarily rare, the study authors noted.

Despite their infrequency, these cross-regional journeys play a critical role in supporting the long-term resilience and health of global humpback whale populations, explained Stephanie Stack, a PhD researcher at Australia’s Griffith University and co-author of the study. When individual whales move between geographically distant breeding populations, they introduce new genetic material that maintains overall genetic diversity, a key factor in helping populations adapt to long-term environmental change. Stack added that traveling whales may also carry new humpback whale song patterns between regions — a striking parallel to how music trends spread through human cultures, since humpback songs are a socially learned cultural trait that spreads across entire ocean basins.

The new findings also add further empirical support for a longstanding ecological hypothesis called the Southern Ocean Exchange. This theory proposes that after humpback whales gather to feed in the shared feeding grounds of the Southern Ocean around Antarctica, some individuals do not return to their original breeding grounds, instead settling into an entirely new breeding region on a different continent.

Researchers from Griffith University noted that climate change is altering the Southern Ocean ecosystem in ways that may make these long-distance crossings more common in coming decades. Shifts in sea ice coverage and changes to the distribution of Antarctic krill — the tiny shrimp-like crustaceans that are the primary food source for humpback whales during their feeding season — may push more whales to seek out new breeding routes and areas after feeding, leading to more frequent cross-ocean exchanges.

Nestled in a lot behind an abandoned gas station at the foot of Appalachia’s rolling mountains in West Virginia, a dozen apiarists gather around veteran commercial beekeeper Roy Funkhouser, the air thick with the low buzz of thousands of honeybees. What began as a regular monthly meeting for the group — a mix of casual hobbyists and full-time commercial operators — has shifted from a skill-sharing workshop to a forum for growing anxiety: as U.S. bee populations collapse to historic levels, a looming federal funding cut threatens to shutter the nation’s oldest bee research lab, a 100-year-old institution that has led global efforts to combat the threats facing honeybees.

For Funkhouser, the crisis is not an abstract policy debate — it is a devastating collapse of the livelihood he has built over decades. Where he once tended roughly 1,200 hives, fewer than 200 remain active this year. “It’s a real struggle,” he told Agence France-Presse. “The parasites that we’ve got now, the mites and everything — more viruses and more pesticide exposures, more chemical exposures — everything is just more of a struggle today than what it was in the past.”

Funkhouser’s experience is far from unique. The latest data from Apiary Inspectors of America shows that U.S. beekeepers lost more than half of all their managed colonies in the 12-month period ending April 2025, marking the worst annual loss rate since the organization began tracking colony health decades ago.

At the top of the list of threats facing colonies is *Varroa destructor*, a tiny 1.5-millimeter parasitic mite that the U.S. Department of Agriculture (USDA) recognizes as the single most damaging honeybee pest in the country, inflicting higher economic damage than all other apicultural diseases combined. The crab-like parasites feed on honeybee tissue and fat stores, and spread a debilitating, wing-deforming virus that can wipe out entire colonies in months. Beyond threatening apiculture, the mites put critical agricultural pollination at risk: commercial beekeepers like Funkhouser truck their colonies across the country to pollinate high-value crops, from California’s vast almond orchards to fruit farms across the Midwest. Without sufficient healthy bee populations, crop yields drop sharply, threatening food supplies and raising prices for consumers.

For years, Funkhouser and his fellow beekeepers have turned to researchers at the USDA’s Beltsville Agricultural Research Center (BARC) — home to the nation’s oldest bee lab — for evidence-based guidance to fight the mite crisis. Zac Lamas, one of the lead entomologists at the BARC bee lab, has worked directly with West Virginia beekeepers to sample colonies, test for genetic markers of disease and pesticide exposure, and develop tailored mitigation strategies.

“It’s not that we’re working with one beekeeper,” Lamas explained during a field training session with beekeepers. “We might be working with several million dollars’ worth of colonies, or several million dollars’ worth of pollination services that won’t exist because these colonies are at risk.”

But that support is now at risk of disappearing entirely. As part of a cost-cutting plan driven by congressional funding cuts that reduced USDA agricultural research budgets by more than $32 million in key priority areas, the agency is moving forward with plans to close the entire BARC facility. While some research programs will be redistributed to other federal facilities across the country, the fate of the iconic bee lab remains unclear, and the USDA has not responded to questions about where or if bee research operations will be reestablished.

Lamas, who has already accepted a new position at a local university after facing layoff from the lab, argues that the closure is a short-sighted decision that undermines decades of progress. The entire bee lab program costs just $3.2 million annually, he says, a tiny fraction of the $600 million in annual economic losses that bee colony collapse currently inflicts on U.S. agriculture. “The idea that we’re redundant and expensive isn’t a good way to generalize the value of this lab or the cost of this lab,” he noted.

Beyond the direct funding gap, Lamas warns that breaking up the lab will erase irreplaceable institutional knowledge. For a century, BARC has assembled a team of specialists with overlapping skills focused entirely on protecting bee health and supporting national food security. “When we have a new problem, multiple people with complementary skills can work on it quickly,” he said. That collaborative capacity will be lost if the team is scattered, he added.

For beekeepers already grappling with record losses, the impending closure comes as a devastating blow. Just as researchers are beginning to untangle the complex mix of parasites, viruses, and environmental stressors driving colony collapse, the cut threatens to halt progress. “We’ve got results from a lot of our testing and figured out a lot of the things that are going wrong,” Funkhouser said. “The unfortunate thing is, it seems like when you figure out one thing the next year, it’s something else. Without the lab, we’ll be flying blind.”