Our Changing World

Chemical isotope analysis is a powerful technique - Dr. Charlotte King explains to Claire how she uses it to reconstruct past lives of forgotten people from the Otago gold rush.

Our skeleton, our nails, our tissues, are all made from basic chemical elements. These elements pass from the soil, to growing plants, to the food we eat and into our bodies. By following this pathway backwards, one researcher is learning about the lives of some forgotten people of the Otago gold rush.

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In a small lab in the Department of Anatomy at the University of Otago, research fellow Dr. Charlotte King is carefully photographing a piece of bone, teeth and some hair. She is documenting them before she takes a small section to do her research - chemical isotope analysis.

Charlotte is part of the Southern Cemeteries Archaeology project - a group of researchers working with local communities who were concerned about unmarked graves related to the gold fields of central Otago.

The project has run over several years and has involved excavations of unmarked graves at several cemetery sites in Milton, Lawrence and Drybread. Once human remains are recovered, many lines of evidence are used by the team to reconstruct where these people came from and how they lived.

The aim is to learn about them, and their lives in the Otago gold fields, before they are reburied in marked sites.

Charlotte is investigating the ratios of isotopes of different chemical elements in the human tissues recovered. Because different chemical isotope signatures are present in different rocks, soils and food, Charlotte can use this to uncover clues as to where the people were from and what kinds of food they ate at different times during their lives.

Learn more:

A previous Our Changing World episode was recorded at the archaeological dig in Milton.

The Drybread cemetery dig was reported on with several interviews at the time:

On Nights, before the excavation

Morning report

Checkpoint

The project's website contains further information about their findings

The Southern Cemeteries Archaeology project is co-lead by Prof. Hallie Buckley and Dr. Peter Petchey. The excavations at Drybread cemetery were done in consultation with, and permissions from, the Drybread Cemetery Trust and Leslie and Maisie Wong of the Otago-Southland Chinese association.

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Sci Fi / Sci Fact is a new podcast series in which scientists from New Zealand's MacDiarmid Institute talk to RNZ host Bryan Crump about whether some of science-fiction's most popular concepts could actually come true.

Sci Fi / Sci Fact is a new podcast series in which scientists from New Zealand's MacDiarmid Institute talk to RNZ host Bryan Crump about whether some of science-fiction's most popular concepts could actually come true.

Follow Sci Fi / Sci Fact on Apple Podcasts, Spotify, iHeart Radio, Google Podcasts, Stitcher or wherever you listen to podcasts.

Taken from the popular Materials: Fact or Fiction segment which runs on Nights with Bryan Crump, this podcast series delves into the mines of Moria in Middle Earth to find out what Frodo's mithril vest might be made from.

It travels into deep space with the crew of the Starship Enterprise to find out if dilithium crystals are real and if they really could separate matter and anti-matter.

And don't miss the episode looking at what aspects of quantum physics could explain just how Santa manages to deliver all those presents on Christmas Eve.

Go to this episode on rnz.co.nz for more details

Two stories on keeping an eye on river flow - helping fish to migrate back upstream, and development of a national river flow forecasting tool.

Fish friendly flow

For thousands of years several species of New Zealand's native freshwater fish have been making journeys from the rivers, down streams, to the ocean, and back upstream again, as part of their natural lifecycle. Until we started putting things in the way.

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Look out into the fields and ditches of New Zealand, along the roadside and down on the farms, and you'll see them - culverts. Structures designed to channel water past an obstacle or under structures, such as roads. Often made of steel, plastic or concrete in either a box or pipe design, many in Aotearoa have been designed with water flow considerations in mind, but not the needs of migratory fish.

Changing the bottom of a stream into a uniform flat piece of concrete can mean very fast and uniform water flow. But native juvenile fish, on their return from their ocean phase of their lifecycle, just can't swim upstream against these flows. They're too fast. Plus, many culverts have steep drop-offs that some fish can't climb up and over.

Different solutions to this problem have been proposed - including remediation of the existing culverts - that is, installing devices to make them more fish friendly. Because if these fish can't make it back upstream, we lose the next generation, and most of these migratory species are already classified by the Department of Conservation as threatened with extinction or at risk of becoming so.

Claire Concannon catches up with Stephanie Patchett, an engineering master's student from the University of Canterbury, as she begins her research testing some of these devices in real world settings. In collaboration with a team of scientists from the Department of Conservation, the study will look at fish numbers up and downstream of each culvert before and after the devices have been installed to figure out which devices work best in different situations.

Forecasting the flow

It rains a lot here in New Zealand. A lot.

Between 600-1600mm falls here every year. For context, Australia gets around 400mm annually, although a more apt comparison might be with the United Kingdom, which records around 900mm every year.

Westerly winds scream in from the roaring forties, hit our high mountain chain and then rain falls, in vast quantities, sometimes very quickly…

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A team of scientists are installing an array of seismic sensors along the South Island's Alpine Fault. Claire Concannon joins them to find out how and why.

Standing in the last back field of a deer farm near Whataroa on the South Island's West Coast, orange high-vis vest on, shovel in hand, Professor John Townend is looking for the perfect spot - not too wet, not too stony, with a good view of the sun. A good space to dig a hole and bury something that may help us learn what is to come in the next big earthquake.

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This is to be the site of one of the South Island Long Skinny Array (SALSA) seismic sensors - a string of 55 sensors spaced 10km apart along 450km of the Alpine Fault between Maruia and Milford Sound.

The Alpine Fault is the on-land boundary between the Pacific and Australian plates, running almost the length of the South Island. Paleoseismology research has shown that the fault has a remarkably regular history of producing large earthquakes; one about every 300 years. The last large earthquake was in 1717 - 304 years ago, making it likely that the next severe earthquake on the Alpine Fault will occur within our lifetimes.

The aim of SALSA is to increase our understanding of what will happen as a result of that earthquake. The seismic sensors John and his team are using are able to detect a wide range of frequencies of seismic waves, including the background hum, or ambient seismic noise, that is produced when ocean waves hit the land.

Previously, scientists would have deleted this 'noise' from their data, or avoided capturing it in the first place. However, recent advances have shown that collecting this type of data over a long period and running analysis on it can give insight into how seismic waves will move along the fault and affect ground shaking further afield. It allows scientists to create 'virtual' earthquakes - they can model how the energy will transfer without having to wait for an actual earthquake to occur.

First though the sensors have to be installed, a mammoth task in itself as the team must contend with the challenges that the Southern Alps present - different terrain, difficult access and changeable weather. The full team of 11 people are working together over two and a half weeks to fit as many sensors as possible. Claire Concannon joins a group as they install one sensor to learn all about how and why they are doing it.

Listen to more episodes about earthquakes and earthquake science by visiting our collection.

https://www.youtube.com/watch?v=bU_O6Qe6Knk…

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Katy Gosset speaks to a PhD student designing new tech to catch predators and Claire Concannon meets the team who are working to restore a unique landscape on the South Island's West Coast.

Whistles, song, calls, booms, rustling in the undergrowth, hooting at night. How busy the bush of Aotearoa must have been, this land of birds, before human-introduced predators and tree clearance. Today, two stories of people committed to the restoration of our forests, taking steps towards returning some of this former glory.

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New lure technology

The battle to save our native birds is heating up with Predator Free 2050 spending $2.4m to enlist fresh scientific talent to the cause.

Department of Conservation figures show 4000 native species are currently under threat, with about a quarter of them in serious danger of extinction.

Predator Free 2050 has now funded six young scientists to come up with new solutions to the problem.

Katy Gosset meets one University of Canterbury student whose intelligent lure system will make it easier to trap predators. Ben McEwen hopes his work will play a role in returning native bird song to the bush.

Planting the polje

Dramatic forest-clad limestone cliffs surround a flat expanse with snakes of gravel - a clue that sometimes water flows through there - the Bullock Creek area just north of Punakaiki is unique in Aotearoa.

This wetland valley of flat ground with steep walls is known as a polje, having formed when a giant cave of series of caverns collapsed. The soft, dissolvable limestone results in unusual hydrology - at times the Bullock flows underground, before resurfacing, and the area is subject to flash flooding. This makes it far from ideal for the farming purpose it was once cleared for.

Conservation Volunteers New Zealand began replanting some of this area in 2020 using Te Uru Rākau, One Billion Trees programme support and are continuing with funding from Jobs for Nature, Mahi mō te Taiao.

Claire Concannon visits the team on the West Coast to learn about this special landscape and find out how the restoration work is going.

Go to this episode on rnz.co.nz for more details

On the 100th anniversary of radio in Aotearoa, Claire Concannon learns about the very first broadcast, explores how radio works, and finds out about current research into communicating using light.

How are you reading this? On a computer, laptop, mobile phone? Connected to the internet by a cable or wirelessly through the use of radiowaves? Instantaneous round-the-world communication is now an everyday - almost essential - part of life. And this week, radio celebrates a major milestone.

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A century ago, on the 17th November 1921, Professor Robert Jack of the Physics department in the University of Otago completed New Zealand's first successful radio broadcast using equipment he had assembled in his lab. It was the beginning of radio stations in Aotearoa New Zealand.

That equipment sits in Tōitu Otago Settlers Museum in Dunedin today, to help tell the story of that broadcast. But Professor Jack was tapping in to technology that had already been explored by others across the world, and which can be traced back to the mid-1880s when physicist Heinrich Hertz was the first to deliberately produce radio waves.

Hertz was experimenting to prove the existence of electromagnetic waves - synchronised oscillations of electric and magnetic fields, waves of energy that can move through space. These electromagnetic waves exist on a spectrum from waves with a very long wavelengths (time between peaks) and low frequencies (number of wave oscillations per second) to those with very short wavelengths and high frequencies.

By understanding the different properties and behaviours of waves along this spectrum, from radiowaves to microwaves, infrared, visible and UV light, X-rays and gamma rays, we have been able to harness their power.

Listen to the episode to hear Tōitu Otago Settlers Museum curator Pete Read talks about the background to that first broadcast by Professor Robert Jack. Then Associate Professor Harald Schwefel of the University of Otago explains how radio works and talks about his latest cutting edge research into improving communication via light.

Thanks to Ngā Taonga Sound and Vision for their help with archival audio. This episode also contains two sound files from NASA: Chorus Radio Waves within Earth's Atmosphere and Kepler: Star KIC7671081B Light Curve Waves to Sound.

Go to this episode on rnz.co.nz for more details

Claire visits the team at K9 Medical Detection Charitable Trust to learn how their dogs are being trained to detect bowel and prostate cancer.

Levi loves what he does. He gets picked up each morning at 8:30am, happy and excited to go to work. He spends his time investigating samples, figuring out whether they contain cancer or not. His payment - toys and play time.    

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Levi is a German Shephard with a finely tuned olfactory system - a nose perfectly adapted to smelling, around 225 million scent receptors and a large part of the brain designated to distinguishing smells.

He is part of the K9 Medical Detection Charitable Trust team based at AgResearch in Invermay. Alongside his colleagues Wētā, Frieda, Magic and puppy Ace, Levi has been training to do one job extremely well - sniff out bowel cancer. 

Trainer Courtney Moore works with the dogs - helping them to 'imprint' on the cancer scent from an early stage. It is unclear exactly what the dogs are sniffing out - it is likely to be metabolites or volatile organic compounds released by the cancer cells into the solutions they are in - but the dogs are able to distinguish a unique cancer 'scent'. The imprinting is part of the first 'proof of concept' phase, a validation step that the dogs must pass through where they show they can selectively pick which of the saline samples contain the cancer cells, and ignore those that contain healthy cells.

Levi has already passed this validation step with flying colours with regards detecting bowel cancer, and the team hope that Wētā will soon follow. Frieda has recently passed for prostate cancer detection with 100% selectively and specificity. The next phase is a test of diagnostic accuracy, says director Pauline Blomfield. This would involve the dogs investigating urine samples from patients.

The goal is to provide a non-invasive, value-added tool to existing cancer screening methods. In addition, identifying the volatile organic compounds the dogs are detecting could provide a further opportunity to develop specific and selective diagnostic tests based on these molecules, says Professor Sarah Young of the University of Sydney, one of the scientists who work with K9 Medical Detection.

While it is still relatively early days in terms of the dogs providing help with cancer diagnoses, the dogs have achieved good results so far and the team have faith in their strong work ethic and amazing noses. Levi is just happy to do something he loves each day.

Learn more: …

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Claire Concannon hits the Central Otago hills with Botany PhD student Ben Teele to imagine the landscape as it use to be, and to follow the clues to find leftover pockets of tōtara trees.

The hillsides of Central Otago are known for their golden grass and tussock slopes with scattered low-lying shrubs. But once this landscape was covered in tōtara forest. Now only a few trees remain, cryptic and scattered across the large region, and Ben Teele is on the hunt for as many of them as he can find.

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University of Otago Botany PhD student Ben Teele is mapping and 'health-checking' the remaining tōtara tree populations. Some large, some small, some regenerating well, but others struggling.

Clues are key to him finding the trees in this vast landscape, and he finds them in all kinds of nooks and crannies - tōtara sightings from geologists, botanists or hill walkers, environmental reports to local authorities and even historical gold mining records describing where tōtara grew.

Ben is looking for the thin-barked tōtara species well adapted to this semi-arid environment. Once widespread, they are now restricted to rocky bluffs high on the hills, which helped them survive the fires that swept across the region after human arrival.

Ben wants to collect the seeds and grow some cuttings from these Central Otago survivors to ensure good genetic diversity, and to figure out what the optimal conditions might be to help them regenerate, and spread back down the hills to the lowers slopes they once inhabited. His research is funded by the Ministry for Primary Industries One Billion Trees programme, with the aim of planning one billion trees across Aotearoa by 2028. Ben hopes that at least some of those trees planted will be thin-barked tōtara in Central Otago and imagines a future where this landscape could look very different.

Go to this episode on rnz.co.nz for more details

Claire Concannon hears how the the New Zealand Plant Conservation Network's favourite plant competition is shaping up, while Katy Gosset learns about research to improve the quality and growth efficiency of grapevines.

If you had to choose, what would your favourite plant be? Something beautiful and flashy like kōwhai or pōhutukawa? Or maybe something subtle like a native moss or grass? Or perhaps you would go with something that produces delicious fruit like a cherry or peach tree? This week, we pick favourites.

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The dwarf plant with long odds

From a childhood exploring shrub-filled gorges around Taranaki, through a career learning about and looking after threatened native plants with DOC, John Barkla has never lost his love of plants. Currently John is the president of the New Zealand Plant Conservation Network - an organisation dedicated to advocating for plant conservation and sharing information about Aotearoa's native flora.

On a stroll through Dunedin's town belt John speaks to Claire about the threat status of native plants and the issues they are facing, as well as introducing her to some of the locals. Plus he puts his vote behind a dark horse, outside contender for the Favourite Plant competition - korthalsella lindsayi - the dwarf mistletoe.

Perfecting the pinot

A plant native to Burgundy in France, the Pinot Noir grape has found a home in New Zealand, and is a favourite tipple for many both here and abroad.

But keeping the quality consistent while ensuring yield for the years to come is a balancing act for wine makers.

Katy Gosset meets Minoo Mohajer, a PhD student at Lincoln University, who has found a way to help, using focused grapevine management to control yield while ensuring the favourite drop still tastes just as good.

Listen to more

- Learn more about the life of mistletoe and its vine cousins in Epiphytes - high-rise plants

- It's not just plants that are important in brewing wine - in the episode Using local yeasts to make distinctive NZ beers & wine Peter Griffin learns how New Zealand scientists are looking for native yeasts to give local brews a unique flavour.

Go to this episode on rnz.co.nz for more details

This week on Our Changing World, Aotearoa Science Agency's Damian Christie speaks to three scientists about the world of data.

As we approach the end of our second year dealing with Covid-19, it's notable how many of us are now familiar with the basic concepts of epidemiology. Social conversations are no longer about house prices and sports results, but debates over elimination versus suppression, the stringency of our lockdown measures, and the current R-value as our daily cases creep higher.

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We have become armchair experts in looking at data, searching for meaning - and hope - among the numbers. What does the latest study say about the best gap between vaccines? What do ICU admissions tell us about our level of protection? What proof do we have against the deniers?

For scientists, making sense of the data is all part of the job. Damian Christie speaks to two scientists who work with respectively some of the the largest and smallest data sets there are - from the mindblowing amount of information collected every single hour that helps researchers make sense of our changing climate, to a marine scientist tasked with tracking the mere dozens of māui dolphins remaining in Aotearoa. They discuss how their own research journeys, and how they have watched as the public interest in using data for decision making has grown during the pandemic.

https://youtu.be/I6MTGfOjCu8

Thanks to Professor James Renwick, Dr Andrew Chen and Associate Professor Rochelle Constantine for their contributions to this episode.

You can read more about Associate Professor Rochelle Constantine and the MAUI63 drone project here: https://www.maui63.org/

Go to this episode on rnz.co.nz for more details