Shrinking to survive: Clownfish adapt to climate change by getting smaller
It is often said that size does not matter… but clownfish prove otherwise. In terms of hierarchy, for example, these fish form small clans – consisting of a breeding pair and a few subordinates – where size determines social rank. "The breeding female is the largest of them all, and she rules over the territory of the anemone [around which the group lives]," said Melissa Versteeg, a researcher at Newcastle University in the United Kingdom. Next comes the breeding male, who is slightly smaller, followed by the subordinates, juvenile fish who would be wise not to outgrow their superiors. "That could disrupt the established hierarchy," added Versteeg. "To minimize the risk of social conflict, a lower-ranking clownfish will therefore maintain a size that is about 80% of that of its immediate superior."
The researcher, who focuses extensively on these questions of size, recently made a surprising discovery: Clownfish can shrink during marine heatwaves, which increases their short-term chances of survival.
To obtain these results, published Thursday, May 22, in Science Advances, the researchers donned their wetsuits to observe breeding pairs of Pacific clownfish living in the coral reefs of Kimbe Bay, Papua New Guinea. At that time, between February and August 2023, a severe global coral bleaching event was underway, during which sea temperatures in the study area exceeded 32°C.
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LeMonde
7 days ago
- LeMonde
Shrinking to survive: Clownfish adapt to climate change by getting smaller
It is often said that size does not matter… but clownfish prove otherwise. In terms of hierarchy, for example, these fish form small clans – consisting of a breeding pair and a few subordinates – where size determines social rank. "The breeding female is the largest of them all, and she rules over the territory of the anemone [around which the group lives]," said Melissa Versteeg, a researcher at Newcastle University in the United Kingdom. Next comes the breeding male, who is slightly smaller, followed by the subordinates, juvenile fish who would be wise not to outgrow their superiors. "That could disrupt the established hierarchy," added Versteeg. "To minimize the risk of social conflict, a lower-ranking clownfish will therefore maintain a size that is about 80% of that of its immediate superior." The researcher, who focuses extensively on these questions of size, recently made a surprising discovery: Clownfish can shrink during marine heatwaves, which increases their short-term chances of survival. To obtain these results, published Thursday, May 22, in Science Advances, the researchers donned their wetsuits to observe breeding pairs of Pacific clownfish living in the coral reefs of Kimbe Bay, Papua New Guinea. At that time, between February and August 2023, a severe global coral bleaching event was underway, during which sea temperatures in the study area exceeded 32°C.
Euronews
22-05-2025
- Euronews
Clownfish shrink to survive heat waves as climate change warms oceans
To survive warming oceans, clownfish cope by shrinking in size. Scientists observed that some of the orange-striped fish shrank their bodies during a heat wave off the coast of Papa New Guinea. Fish that slimmed were more likely to survive. Heat waves are becoming more common and intense underwater due to climate change. Warmer water temperatures can bleach sea anemones that clownfish call home, forcing them to adapt to stay alive. Scientists monitored and measured 134 colorful clownfish in Kimbe Bay during an intense heat wave in 2023 that's still bleaching corals worldwide. They found that 101 clownfish decreased in length on one or more occasions from heat stress. 'We were really shocked at first when we saw that they were shrinking at all,' said study author Morgan Bennett-Smith with Boston University. The findings were published Wednesday in the journal Science Advances. Though scientists don't yet know how clownfish shrink, one idea is that they could be reabsorbing their own bone matter. It's possible the smaller stature may help the clownfish save energy during a stressful scorch since smaller fish need less food. Certain clownfish breeding pairs also synced their shrink to boost their survival odds. The females adjusted their size to stay bigger than their partners, keeping the female-dominated social hierarchy intact, researchers said. Other animals also decrease in size to beat the heat. Marine iguanas get smaller during El Niño events that usher warm waters into the Galapagos. But this coping strategy hadn't yet been spotted in coral reef fish until now. 'This is another tool in the toolbox that fish are going to use to deal with a changing world,' said Simon Thorrold, an ocean ecologist at Woods Hole Oceanographic Institution who was not involved with the new study. The tactic helps clownfish weather heat waves in the short-term, but it's not yet clear how the fish will fare if they have to keep it up in the years to come, Thorrold said. Researchers found the shrinking was temporary. Clownfish possessed the ability to 'catch up' and grow back when their environment got less stressful, showing how living things are staying flexible to keep up with a warming world, said study author Melissa Versteeg with Newcastle University. 'These natural systems really are under stress, but there's a capacity for incredible resilience,' Versteeg said. The creative, cobblestoned Dutch city of Breda has officially become the first National Park City in the European Union. Officially designated by the National Park City Foundation in May, Breda joins London, Adelaide and Chattanooga as the fourth member of a growing global movement to make urban areas greener, healthier and more connected to nature. This new status recognises more than a decade of work to restore wetlands, green its streets and bring residents into the process. It also signals a shift in how cities across Europe redefine their relationship with nature. The National Park City initiative was launched in the UK in 2019 to promote nature-connected, environmentally just urban living. Cities don't need to meet traditional national park criteria. Instead, they must show a city-wide commitment to sustainability, biodiversity and public access to green space. Breda's application caught the attention of assessors with its strong environmental leadership, citizen engagement and urban planning that places nature at its core. 'I absolutely loved exploring Breda and learning about all the things they are doing to make their city greener, healthier and wilder – from restoring a river through the middle of the city to innovative community food growing programmes, tiny forests set up by schools, wildlife-friendly gardens and public art,' says Daniel Raven-Ellison, founder of the National Park City Foundation. 'I am sure that people of all ages and backgrounds in Breda will be inspired by becoming a National Park City and want to explore how they can be part of its growth and story.' Breda is now the fourth city to earn National Park City status, joining London, Adelaide and most recently Chattanooga. Nine other cities are currently working towards it, too. Breda has long prioritised nature-based solutions, from transforming quaysides into biodiverse urban gardens to replacing concrete tiles with grass, flower beds and trees. Today, 60 per cent of Breda is made up of green space, from historic forests like the Mastbos – one of the oldest in the Netherlands – to nature reserves, parks and waterways. By 2030, local leaders aim to make it one of the most nature-rich cities in Europe. But the status also reflects a buy-in from residents. The city has become a leader in green design, using nature-based solutions to improve liveability and manage climate risks. And residents have been active participants in that process, often greening their own streets, installing rooftop gardens and developing green schoolyards, according to Breda Stad in een Park, a grassroots movement that helped to lead the city's efforts to become a National Park City. 'This title is a recognition for the many residents, entrepreneurs and organisations who are committed to greening Breda and an inspiration to continue doing so,' says Joost Barendrecht, chairman of Breda Stad in een Park. 'It's an incentive to make more [people] enthusiastic about getting started with greenery. It doesn't always have to be big. A [simple] garden is a nice contribution.' Across the EU, cities are increasingly stepping in the same direction as Breda. From car-free zones in Paris to flood-proofing efforts in Copenhagen, local leaders are responding to climate change and declining biodiversity with initiatives that aim to make urban settlements greener, more livable and future-ready. For example, access to green space significantly reduces heat-related health risks – a benefit Breda now exemplifies and other European cities might seek to emulate. 'London and Breda are the first National Park Cities in Europe, but there's no shortage of others that want and need to be greener, healthier, wilder, cooler and fairer,' says Raven-Ellison. 'National Park Cities are helping to show the way, forming strong relationships and exchanging optimism, ideas, knowledge and energy.'
Euronews
21-04-2025
- Euronews
Scientists discover new colour ‘olo' - and there's a link to ‘The Wizard of Oz'
ADVERTISEMENT Scientists claim they have discovered a new colour called 'olo'. The snag is that it's only ever been witnessed by five people in the world – and cannot be seen by the naked eye. Indeed, the colour, said to be a saturated shade of blue-green, cannot be seen without the help of stimulation by laser. The researchers from UC Berkeley and the University of Washington had laser pulses fired into their eyes. This Oz Vision System technique, named in homage to the Emerald City in L. Frank Baum's novel 'The Wonderful Wizard of Oz' (and the subsequent 1939 film starring Judy Garland), can allow people to see beyond the normal gamut of colour perception. The study, published in the journal Science Advances , states that when Oz laser signals are intentionally 'jittered' by just a few microns (one millionth of a metre) subjects perceive the stimulating laser's natural colour. The Emerald City in 'The Wizard of Oz' MGM-Warner Bros. There are three types of cone cells in the eye – S (short), L (long) and M (medium) - each one sensitive to different wavelengths of light. By stimulating only M cones, the five participants claim to have witnessed a blue-green colour that scientists have called "olo" - denoting the binary 010. The paper read: 'We name this new color 'olo'. Subjects report that olo in our prototype system appears blue-green of unprecedented saturation, when viewed relative to a neutral grey background. Subjects find that they must desaturate olo by adding white light before they can achieve a colour match with the closest monochromatic light, which lies on the boundary of the gamut, unequivocal proof that olo lies beyond the gamut.' The study's co-author, Professor Ren Ng from the University of California, has described the findings as "jaw-dropping". 'We predicted from the beginning that it would look like an unprecedented colour signal but we didn't know what the brain would do with it,' said Professor Ng. 'It was jaw-dropping. It's incredibly saturated.' Prof Ng told BBC's Radio 4's Today programme that olo was "more saturated than any colour that you can see in the real world". "Let's say you go around your whole life and you see only pink, baby pink, a pastel pink," he said. "And then one day you go to the office and someone's wearing a shirt, and it's the most intense baby pink you've ever seen, and they say it's a new colour and we call it red." While it does not fully capture the colour, the researchers shared an image of a turquoise square to give a sense of the hue: Scientists say olo was best matched by this blue green colour square Science Advances However, they stressed that the colour could only be experienced through laser manipulation of the retina. The claim of a new colour has been contested, however. 'It is not a new colour,' said John Barbur, a vision scientist at City St George's, University of London. 'It's a more saturated green that can only be produced in a subject with normal red-green chromatic mechanism when the only input comes from M cones.' ADVERTISEMENT The work, while a 'technological feat', has 'limited value' according to Barbur. The authors of the study disagree. They believe 'Oz' will help them delve into how the brain creates visual perceptions of the world. As reported by the BBC, it may also allow them to learn more about colour blindness or diseases that affect vision. Well, there's no place like home... Sorry, no colour like olo. Dorothy would be proud. ADVERTISEMENT
