Our Changing World

This week, an underwater mystery connecting New Zealand and Ireland - the puzzle of the disappearing sponges of Lough Hyne. In the late 1990s/early 2000s James Bell was doing PhD research on the sponge communities that coated the underwater cliffs of this small sea inlet in West Cork. When he returned 15 years later, they had vanished. Why did they disappear, are they starting to recover, and can they be helped to return? Now a Professor at Victoria University of Wellington, these are the key questions that James, and PhD candidates from his lab, have been working to answer. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more. See more photos on the webpage for this story. In this episode:00:00 – Divers return, introduction to Lough Hyne and its scientific history.02:50 – James Bell on his early research at Lough Hyne and the surprising disappearance of sponge communities.05:15 – Gabi Wood and Kea Witting get ready to dive at Whirlpool Cliffs.06:30 – James Bell explains the unique tidal regime of Lough Hyne that means it has many diverse habitats.09:00 – Gabi Wood is collecting water samples to study sponge feeding and nutrient levels.11:00 – What caused the sponges to disappear.14:00 – Kea Witting is investigating sponge community recovery.21:00 – Experiments to help the sponges return…Go to this episode on rnz.co.nz for more details

Need a nature fix? RNZ now has a podcast feed dedicated to our beautifully produced series telling stories from te taiao nature. Check out the Wild Sounds feed – now playing Voices from Antarctica, featuring Alison Ballance reporting from the frozen deep south.Find and follow Wild Sounds on your favourite podcast platform, or listen on RNZGo to this episode on rnz.co.nz for more details

In March 2024, a satellite built to detect the potent greenhouse gas methane launched into orbit – backed by New Zealand to a final total of $32 million. MethaneSAT aimed to pinpoint large leaks from oil and gas fields, since plugging these is considered an easy climate win. But an add-on mission was investigating whether the satellite could pick up the smaller, more diffuse methane emissions from agriculture. Our Changing World joined the New Zealand-based team testing this capability – before disaster struck. With MethaneSAT uncontactable and lost in space, what did the mission deliver? Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.In this episode:00:00 – 03:08: Introduction03:08 – 05:38: A methane-measuring device takes off from the airfield05:38 – 16:32: Ground-based methane measurements with the EM-2716:32 – 25:29: What went wrong, and what data MethaneSAT did collect…Go to this episode on rnz.co.nz for more details

In March 2024, a rocket launched from Florida carrying New Zealand’s first science payload to the International Space Station. The small cube, named Lucy, is a protein crystallisation lab developed by Dr Sarah Kessans from the University of Canterbury. Protein crystallisation is often the key first step in figuring out a protein structure, and the unique fluid conditions of microgravity in low Earth orbit helps the process. Working with several collaborators, Sarah is trying to develop a commercially viable crystallisation lab in space. Plus, Dr Brian Russell is creating AI tools to help space companies make critical decisions around astronaut health and safety. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Associate Professor Sarah Kessans, University of CanterburyDr Brian Russell, Auckland Bioengineering Institute and AUTLearn more:Read more: New Zealand in the low Earth orbit economy.Researchers in the Paihau Robinson Research institute are also working on developing plasma rockets for travel in space. They launched a superconducting magnet for testing on board the ISS yesterday. In 2017, the same year that RocketLab did their first ‘It’s a test’ launch, William Ray had a look at New Zealand in space.Listen to Dr Sarah Kessans on Morning Report in 2023.Go to this episode on rnz.co.nz for more details

An elaborate game of carbon ‘I spy’ is happening on the streets of Wellington. With their brand-new mobile carbon lab, Earth Sciences New Zealand (formerly GNS) can detect things like carbon dioxide and methane as they drive around. This allows them to pinpoint where emissions are coming from. Plus, with radiocarbon measurements, they can understand what amount of the carbon they detect is coming from fossil fuels. It all helps to ground-truth our estimates of what’s happening in our urban environments.Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Jocelyn Turnbull, Earth Sciences New ZealandHayden Young, Earth Sciences New ZealandLearn more:Read this week's article: Playing 'I-spy' with urban emissions.Carbon Watch NZ is an ongoing project to measure how much carbon is being produced across New Zealand. Alison Ballance covered this project in 2020, including learning about Baring Head atmospheric research station, and about a project also by Dr Jocelyn Turnbull using grass to measure urban emissions.The mobile carbon lab uses glass-blown flasks to collect radiocarbon. Learn about scientific glassblowing in this 2010 OCW episode.The People, Cities and Nature project is investigating how to return biodiversity to our towns and cities, such as the gullies in Kirikiriroa Hamilton. Such green areas would act as urban carbon sinks. Go to this episode on rnz.co.nz for more details

Takahē were believed to be extinct not once, but twice. Today their population is just over 500 – still not a huge number, but big enough that new homes are needed for these flightless manu. The latest area to welcome takahē is the upper Whakatipu – in particular, the stunning Rees Valley. But threats remain and keeping on top of predator numbers is key for this comeback bird to survive and thrive in their new home.Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Chrissy Becker-Fifield, Southern Lakes Sanctuary.Additional thanks to Glen Greaves of DOC’s takahē recovery programme for background information.Also mentioned: the Routeburn Dart Wildlife Trust.Learn more:Read this episode's article: Backcountry takahē make a comeback.November 2023 marked the 75th anniversary of the second time takahē were ‘rediscovered’. We spoke to Alison Ballance about her book about takahē, and her years of reporting on these birds. RNZ reported on DOC’s efforts to catch the stoat culprits that killed a number of takahē in the Greenstone valley.After decades of careful monitoring, DOC are stepping back from the Murchison Mountain’s population of takahē.Takahē have been spotted by trampers around the Shelter Rock hut deep in the Rees valley.Go to this episode on rnz.co.nz for more details

Gas shortages, a reversal of the ban of offshore oil and gas exploration, and a government plan to double geothermal energy in the next 15 years… There’s been a lot in the news recently about New Zealand’s energy supply now and in the future. Claire Concannon speaks to researcher Dr Jen Purdie about our ongoing electrification of industry and transport, about our ‘dry year problem’, and what the future of supply and demand might look like in a changing climate.*This episode was updated with some additional clarifications on 15th September 2025Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Jen Purdie, Senior Research Fellow, Centre for Sustainability, University of Otago.Kirsty Johnston, RNZ In-Depth journalistLearn more:Could nuclear fusion-generated energy be a way to help us power the future? Learn how New Zealand company OpenStar Technologies are trying to crack this.Read or listen to Kirsty’s recent reporting about what has changed in climate policies underpinning the Zero Carbon Act 2019. The coalition government has stated they want to use New Zealand’s Emissions Trading Scheme (rather than the GIDI fund) to help drive the transition from fossil fuels to other forms of energy, but as climate change journalist Eloise Gibson reports, there are issues with this plan.ReferencesThe 2025 Energy in New Zealand report came out in August 2025.Go to this episode on rnz.co.nz for more details

New Zealand’s youth vaping rates are among the highest in the world. How did we get here and what will this mean for the future of our rangatahi? A 2018 court case paved the way for a loose regulatory start for vaping in New Zealand, and rapid uptake by those aged 14–24 in the years since has led to concerns that a new generation is now addicted to nicotine. New Zealand researchers are investigating how vaping affects our lungs, and the harms young people are experiencing in terms of social connections and mental health. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.…Go to this episode on rnz.co.nz for more details

More and more of us are reaching for low or no-alcohol beers. As the market grows, the options are also expanding – but brewing beer without alcohol fermentation presents a tricky puzzle. In traditional beer brewing the conversion of sugars into ethanol and carbon dioxide through yeast fermentation is a key part of the process. How can you get the same flavour into beer without it? A team at Victoria University of Wellington, including the head of research and development at Garage Project, have begun an interdisciplinary research project to address this. They’re hoping to develop a brand-new yeast strain, one that will recreate delicious beer flavours, but without the alcohol.Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.…Go to this episode on rnz.co.nz for more details

Project Tongariro was established as a living memorial for five people who died in a tragic helicopter accident. Last November, the project turned 40 years old. Over those four decades, activities have expanded beyond Tongariro National Park and into the wider area, including urban restoration through tree planting and predator trapping. Claire Concannon visits the Taupō-based projects that Project Tongariro is supporting as they prepare for Greening Taupō Day – their biggest planting day of the year.Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Kiri Te Wano, CEO Project TongariroRobyn Ellis, Greening Taupō and Predator Free TaupōRachel Thompson, Kids Greening TaupōHeidi Pritchard, Kids Greening TaupōCelia Bocket, Wicked WeedersZara, Jack, Taylor and Emily, students of Taupō Intermediate SchoolLearn more:Read the article that accompanies this episode: 40 years of Project TongariroProject Tongariro are also involved in a number of restoration projects near Tūrangi, including removing willows from a wetland area.In Kirikiriroa Hamilton, a team are also focused on urban greening as part of the People, Nature and Cities project.Just outside Dunedin, the Halo Project has been working to provide a safe space for birds around the Orokonui fenced ecosanctuary, as the Country Life team learned last year.Go to this episode on rnz.co.nz for more details

The battle on the frontlines of conservation continues around the motu. This week we head to the central North Island to join some of the staff and volunteers of Project Tongariro. Ecologist Nick Singers is coordinating the fight against the invasive grey willow that’s taking over a wetland area, while Shirley Potter is applying a ‘let’s get it done’ attitude to reforesting a patch of public conservation land near her home in Tauranga-Taupō. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Kiri Te Wano, CEO of Project TongariroShirley PotterNick SingersLearn more:Read the article that accompanies this episode: 40 years of Project TongariroWillow is an issue in many wetland areas where it binds up waterways and transforms the land. Just outside Dunedin, a team are using drone spraying to combat it near the Te Nohoaka o Tukiauau wetland complex.In the Rotopiko wetland complex, near Hamilton, the pest battle is a bit unusual: conservationists are concerned about the half a million sparrows and starlings that roost at night.The fight for the forest also continues on multiple pest fronts in the Catlins area in Otago.Go to this episode on rnz.co.nz for more details

During World War II, sonar operators discovered a ‘false seabed’ that appeared to move upwards during the nighttime. In fact, the sound waves were bouncing off huge numbers of small critters. This daily movement is the largest animal migration on the planet, consisting of deep-water animals that hide in the ocean’s twilight then move to the surface after sunset to feed. By far the most abundant fish in this crowd are the lanternfishes. New Zealand researchers are investigating what impact lanternfish migration has on the life cycle of fish we like to eat, and how it may also play a huge role in the Earth’s carbon cycle. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Professor Jeff Shima, Victoria University of WellingtonAlisha Gill, Victoria University of WellingtonNiamh Smith, Victoria University of WellingtonLearn more:Read the article for this episode: Lanternfish: small fish, big impactBelow the twilight zone, in the deepest parts of the worlds’ oceans, including in New Zealand waters, scientists continue to discover new critters.The deep ocean makes up the majority of the living space on our planet, where life down there has evolved to cope with the pressure, cold and darkness.The Southern Ocean absorbs a huge amount of carbon, but scientists are concerned that may change as the planet warms.Go to this episode on rnz.co.nz for more details

For a long time, nuclear fusion was viewed as a powerful, but unachievable, energy source, because the technological challenges were just too great. But recent advances, particularly in the development of powerful magnets, have reignited the race to create the world’s first efficient nuclear fusion powerplant. Claire Concannon visits one private company just outside Wellington who have joined the nuclear fusion effort, with a unique approach they believe might be the key. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Ratu Mataira, Founder and CEO of OpenStar TechnologiesEmily Hunter, Lead Engineer Cryogenics and Docking, OpenStarThomas Berry, Deputy Direct of Plasma Science, OpenStarLearn more:Read the article that accompanies this episode: Could a Kiwi company crack nuclear fusion?Kim Hill had a lengthy and fascinating interview with Dr Ratu Mataira in 2023 on RNZ’s Saturday Morning show. He also spoke with Alexa Cook on Morning Report in 2024 after OpenStar achieved ‘first plasma’. In 2023 Our Changing World played an episode of the ABC’s Strange Frontiers that went inside the nuclear fusion reactor ITER.Learn more about the simplest element, Hydrogen, from RNZ’s 2019 Elemental podcast.The Royal Society of New Zealand has a series of videos on Ernest Rutherford’s scientific discoveries including radioactive decay and half-life, and splitting the atom. Go to this episode on rnz.co.nz for more details

In May 2024, 100 strange rocky structures were installed along Tauranga's harbour shoreline. These flower-shaped artificial rockpools, nicknamed 'sea pods', provide prime waterfront real estate for marine life – from colourful sea slugs to sneezing sponges. Justine Murray finds out how 'living sea walls' are bringing back biodiversity to urban harbours around the world, and joins a marine scientist to check out what creatures have moved into Tauranga's sea pods.Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.In this episode:00:49 – What is a sea pod?06:27 – Living sea walls in Sydney with Dr Aria Lee10:25 – Sea pods around the world and in Tauranga13:06 – Monitoring marine life in the sea pods with David Culliford20:50 – Port of Tauranga21:48 – Looking for critters in the sea pods…Go to this episode on rnz.co.nz for more details

Speckled, pencil-thin and sporting an underbite: the lowland longjaw galaxias is New Zealand’s rarest freshwater fish species. With just seven known populations, this species is considered nationally endangered. Join producer Karthic SS at a spring-fed stream in the wild Mackenzie Basin to meet the tiny fish, hear from a researcher studying trout-proof barriers, and chat to a ranger who for 20 years has cared for the little fish he calls 'Jaws'. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dean Nelson, Senior Ranger, Biodiversity, Department of ConservationMartha Jolly, PhD candidate, University of CanterburyLearn more:Read the article that accompanies this episode: Looking after New Zealand's rarest freshwater fish.Otago farmers are looking out for another species of rare non-migratory galaxiid.In Auckland’s Lake Rototoa, introduced perch are the problem for the native kākahi.Karthic produces the Tune Into Nature podcast about New Zealand’s unique wildlife.Go to this episode on rnz.co.nz for more details

Since the 1800s, tuberculosis (TB) has been responsible for an estimated 1 billion deaths. In New Zealand today, we don’t get many cases of TB, but worldwide it is the leading infectious disease killer. In the early 1900s a TB vaccine was developed. Called the BCG vaccine, it’s still used today. While it is the best TB vaccine we have, it’s not actually great at preventing TB infection, only providing some protection for the youngest of patients. However, scientists have discovered that the BCG vaccine can boost people’s immune systems in other ways. Now researchers at the Malaghan Institute in Wellington are investigating these findings further. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Kerry Hilligan, Malaghan InstituteRebecca Palmer, Malaghan InstituteLearn more:In 2017, Alison Ballance reported on the looming antimicrobial resistance crisis, with drug-resistant TB part of the problem.Other Our Changing World episodes about research at the Malaghan Institute include this 2024 episode on a new way to target rising stomach cancer rates, and this 2022 episode on next-generation cancer therapies.In 2021, Claire Concannon covered mRNA vaccine technology.The What if...? Genomics in Aotearoa series explores the different ways genomics is transforming different sectors, including infectious disease medicine.Go to this episode on rnz.co.nz for more details

2020 saw the start of two global pandemics. Covid-19, of course, but also H5N1 bird flu. The latter has swept around the world leaving millions of dead wild birds and marine mammals in its wake. It has reached everywhere – except Australia, New Zealand and the Pacific. Alison Ballance has been finding out why this strain of bird flu is so deadly, and what we are doing to get ready for its possible arrival on our shores. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Kate McInnes, Department of ConservationDr Megan Jolly, Wildbase Hospital, Massey UniversityDr Mary van Andel, Ministry for Primary IndustriesRob Schuckard, Birds New ZealandDavid Melville, Birds New ZealandLearn more:Read the article that accompanies this episode: A deadly bird flu strain is coming. Are we ready?Find out about Biosecurity NZ’s bird flu surveillance work and what New Zealand is doing to prepare for the possible arrival of avian influenza.The Exotic Pest and Disease Hotline for reporting suspected bird flu is 0800 80 99 66.The Department of Conservation is preparing for the possible arrival of H5N1 bird flu in New Zealand.Claire Concannon spoke about viruses, including H5N1 bird flu, with virologist Professor Jemma Geoghegan, winner of the 2024 Prime Minister's Te Puiaki Whakapā Pūtaiao Science Communication Prize.Go to this episode on rnz.co.nz for more details

If you like Our Changing World, you should find and follow Wild Sounds: RNZ's new podcast feed dedicated to incredible natural science stories from New Zealand! Go to this episode on rnz.co.nz for more details

In late 2024 a cluster of sick green sea turtles washed up around the Rangaunu Harbour on the east coast of the Far North. It was just another mystery in a long line of all the things we don’t know about these ocean taonga. But a new telemetry study, using these very turtles, could change all that. The study has officially kicked off with the release of five satellite-tagged honu. Liz Garton finds out what secrets the researchers hope to uncover.From now on Our Changing World will appear on Tuesdays in your podcast feed!Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.Guests:Dr Karen Middlemiss, Department of ConservationDr James Chatterton, Auckland ZooCeline Campana, Auckland ZooKim Evans, SEA LIFE Kelly Tarlton’sLearn more:Read the article that accompanies this episode: Solving green sea turtle mysteries.Find out more about the honu that visit our shores.RNZ’s Peter de Graaf describes the release of the first lot of satellite-tagged turtles in Northland.Learn more about the international effort to protect leatherback turtlesGo to this episode on rnz.co.nz for more details

One from the archives! By the 1990s Chatham Island tūī had all but disappeared from the main island. Slightly different to their mainland counterparts, these songbirds had survived on nearby Pitt and Rangatira islands. So a local conservation group decided to try bring them back. In this episode from 2010, Alison Ballance joins the ‘tūī team’ tasked with moving 40 birds from Rangatira island back to the main island. From now on Our Changing World will arrive in your podcast feed first thing on a Tuesday morning!Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.In this episode:00:00 – 02:30 Introduction and background info02:30 – 12:14 Catching tūī on Rangatira Island12:15 – 12:24 Team has caught 40 birds12:25 – 24:46 Moving the birds to main Chatham Island24:47 – 25:55 Update on the birds…Go to this episode on rnz.co.nz for more details