Our Changing World

Claire learns about honey fingerprinting while Katy Gosset meets a scientist studying the anti-microbial properties of some native plants.

Honey is big business in Aotearoa. An estimated 27,000 tonnes of honey was produced in the 2019/20 season, with the value of honey exports for that time at $425 million. So New Zealand honey is in global demand, but how can you be sure that honey labelled as New Zealand origin was really made here?

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts.

The fingerprint of honey

This is what Dr. Megan Grainger hopes to help address with her latest research. Megan has been investigating the elemental fingerprint of different New Zealand honeys and comparing them across regions and with honey from overseas.

The elemental composition of rocks and soils in different locations is taken up by the plants, represented in the nectar, and subsequently in the honey made from that nectar. By using analytical chemistry techniques and equipment, Megan can profile what elements are in the honey and what concentrations they are found in. By analysing over 200 different samples of honey she has been able to build up a picture of what the elemental fingerprint of honey from different regions in the North Island looks like.

Megan has also identified tiny amounts of so-called 'heavy metal' elements in the honey, things like lead, mercury and cadmium, which are linked to human activity. This has sparked her next avenue of research - figuring out if and how these impact the bee's activities and if they could play a role in declining bee populations and colony health.

Plant powers

When microorganisms get in to the soil from manure spreading or livestock excrement, it can lead to further issues downstream when they get into our water ways and impact water quality.

To figure out how to combat this a team at the Bioprotection Aotearoa research centre have turned to native plants.

After testing 12 native plant species for antimicrobial properties, the team have shown that extracts of some of the species are effective at reducing e.coli contamination in soil in a greenhouse experiment. Extracts from northern rātā and swamp mānuka could reduce e.coli by 90% after 14 days, compared with the 45 days it took to see this level of reduction with a control plant extract.

Katy Gosset finds out more at the Bioprotection Aotearoa Research Centre.

Learn more

Read the Marsden Fund Fast-Start grant summary into Megan's upcoming research.

Megan has her own website where she talks about her research…

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

Claire Concannon joins a meteorite hunt on the South Island's West Coast and learns what these rocks from space can tell us about the early formation of our solar system.

In January 1976 Ted Dowie was looking for gold in a river in the mining district of Dunganville near Greymouth when he came across a black, smooth-topped boulder in a dry creek bed. It rang like a bell when he hit it and was unusually heavy. Intrigued, Dowie rolled the boulder up on the stream bank and sent a small sample he had chipped off to New Zealand Geological Survey. 

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts.

Mr. Dowie had found a 50.2kg iron meteorite, the name we give to rock or other solid debris that has come from outer space and landed on Earth. The Dunganville meteorite is still the largest of the nine recorded in New Zealand to date, and it is the iron core of a protoplanet from four and a half billion years ago when our solar system was forming.

At that time most of the gas and dust left over from an explosion of a massive star came together to form our sun. Some of the remaining material became protoplanets, with some getting big and hot enough to melt so that they separated out into a dense iron core and a lighter mantle. 

A few of these protoplanets went on to become our familiar family of planets, but others got smashed apart before they made it that far. The remnants of these drifted in space, but the odd collision knocked them on a course to land on earth. 

A short time after Mr. Dowie's find a further search of the creek bed turned up 68 pieces of the weathered crust. But what if some was overlooked, or if the boulder was just one in a shower of meteorites? Could there be more out there?

These are the questions on the minds of Associate Professor James Scott and students from the Geology department at the University of Otago. Following in Dowie's footsteps, with metal detectors in hand, the team set out to see if they can find a piece of a core of a four and a half billion year old protoplanet in a river on the South Island's West Coast.

To learn more:

Read the 1984 paper that describes the Dunganville meteor here.

Find out more about the recorded New Zealand meteorite falls and finds on the Te Ara website.

Thanks to GNS Science, Te Pū Ao, for providing fragments of the Dunganville meteorite for XRF testing.

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

The story of titipounamu, New Zealand's smallest bird, on Otago Peninsula, told by Karthic SS, a wildlife film maker and podcast producer based in Dunedin.

From the bustling hot city of Coimbatore in southern India to the rather less bustling, and definitely cooler, south of Te Wai Pounamu in Aotearoa, Karthic SS* has spent most of his life paying close attention to the sounds around him.

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts.

Now based in Ōtepoti, Karthic produces the Tune into Nature podcast, telling stories of New Zealand wildlife and conservation, and encouraging his audience to listen to the sounds of the natural world around them.

In India, that included the odd interaction with elephants. But in Aotearoa it often means birds. Lots of birds.

This week, we play an episode of the Tune into Nature podcast about titipounamu (rifleman) on the Otago Peninsula.

Weighing just 6 grams, the titipounamu is New Zealand's smallest bird.

The Otago Peninsula Biodiversity Group have been taking care of the pairs that live on the Peninsula, including setting up nest boxes for them.

Though one pair famously declined these in favour of nesting in a possum trap!

Join Karthic, Shanta McPherson and Marcia Dale on a forest walk to learn more about titipounamu.

The Tune into Nature podcast is created by Karthic SS. It is supported by Otago Access Radio and the Centre for Science Communication, with funding support from the Otago Regional Council's Ecofund. You can find it on Facebook, Instagram, and on your regular podcast provider. The podcast Karthic created as part of his studies, mentioned in this episode, can be found here.

*Where Karthic comes from it is usual not to use family names - instead the first name followed by the initials of father's or mother's name is used.

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

Summer science continues with a play of a science related episode from RNZ's Voices podcast. In 'To spray or not to spray' we meet Tim Vandervoet as he investigates ways to reduce insecticide use in orchards.

This week on Our Changing World, as part of the Summer Science series, a science related episode from the Voices podcast.

To spray or not to spray - from cotton fields to codling moth

As a Peace Corp volunteer in Malawi, Tim Vandervoet developed a passion for using agriculture and science as a tool for social change - reducing insecticide use through more biological control of pests being one way.

Vandervoet was raised in Arizona where the family business involved the import of agricultural produce from Mexico into the US.

Although slightly removed from his direct area of interest, it was still an important influence from the periphery that steered him to agricultural science and entomology.

The expansive cottonfields of the Southwest in Arizona were where he began as a scientist, working on maximising biological control of whitefly.

After landing a job at Hawkes Bay's Plant and Food Research  Vandervoet focus has now shifted to helping develop more effective biocontrol of the codling moth here.

Each year New Zealand exports apple worth nearly 800 million dollars to European and Asian market - both markets with stringent residue regulations and pest-free standards.

Achieving both these in order to maintain access to these crucial markets means a need for to explore newer and more effective ideas - ideas that help ensure high quality fruit with that ultra-low pesticide residues and pest-free status.

A tactic that has been refined in Hawkes Bay is the air-dropping of sterile codling moths imported from Canada.

These are drone-dropped by the thousands over demarcated orchards and disrupt mating behaviour of the moths and suppress the population.

Covid-19 has disrupted this tactic - with no flights coming in, the import of these moths from Canada has been brought to a standstill for the moment.

So it's back to simple methods. Aside from phermone-laden traps for codling moth,  Vandervoet uses simple cardboard traps for the larvae strapped around the tree-trunks, offering several more data points for studying the pest population in orchards and developing more effective biocontrol strategies around this.

"Lowering toxicity, reducing the use of insecticide is obviously good for growers, the environment land and consumers" says Vandervoet

"I'd take an NZ apple over a US apple any day" Tim laughs - "New Zealand has a very good reputation for very low residue fruit"…

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

Centre for Science Communication student Laura McDonald speaks to Dr. Mike Palin about lead contamination in the environment.

Laura McDonald learns the backstory to the discovery of lead contamination in the environment.

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts

After the incident in Waikouaiti in Otago where toxic lead was found in the towns drinking water, there has been much question as to where the lead is coming from. After talking to geochemist Mike Palin, his findings suggest that the lead is very low in the natural waters indicating that the lead is likely coming from the towns water pipes, which are in the process of being removed and replaced. Lead is toxic, so why is it that it's in the water pipes beneath our towns that deliver our drinking water?

This links to an interesting controversy that started in the 1950's with a geochemist named Clair Patterson. For his PhD, Clair Patterson was tasked with figuring out the age of the earth using lead isotopes in meteorites. However, he came across some difficulties due to the high concentrations of lead in the environment making it impossible to decontaminate and measure the lead in his meteorite samples. After building a clean laboratory Patterson figured out the age of the earth, and his next mission was to address the issue of the lead contamination in the environment.

During this time lead was being used as an additive to petrol as it improved motor performance and was also being used in water pipes, taps, paint and even children's toys. Clair Patterson advocated to the US government to get lead removed from these sources as he claimed that it was contaminating the natural environment. To this, the petroleum companies argued that lead is natural in the environment and that the lead from petrol is hardly contributing to the lead already present in the atmosphere. They also brought a medical doctor on board, Robert Kehoe, who claimed that there was no evidence that lead was toxic to humans. For Clair Patterson to prove that lead was contaminating the environment he collected a range of evidence which included ice cores from Greenland and samples of deep ocean water which proved that lead had only been occurring in such high concentrations since it was added to petrol in the 1920's. After years of work Clair Patterson finally won his battle when the US passed the Clean Air Act in 1970 and when lead was subsequently banned from paint in 1977 and from petrol in 1986.

…

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

Summer science continues with a play of a science related episode from RNZ's Black Sheep podcast. Invasive tells the story of one man who released thousands of invasive fish into New Zealand's rivers, lakes and streams. Programme Code

This week on Our Changing World, as part of the Summer Science series, we bring you one of our favourite conservation related episodes from the Black Sheep podcast.

Invasive: the story of Stewart Smith

Between the 1960s and late 2000s Stewart Smith went on a one-man crusade, releasing thousands of invasive fish into New Zealand's rivers, lakes and streams.

One kind of fish he introduced is now so widespread it's been declared an "acclimatised species", meaning the authorities have basically acknowledged it is impossible to remove it from the wild.

"The amount of damage he did was incalculable," says science journalist Charlie Mitchell, who wrote a feature on Smith for Stuff.co.nz.

"He could be positioned alongside the people who released stoats and weasels and ferrets in New Zealand," says Bryan Winters, who wrote an authorised biography of Smith entitled That Pommie Bastard.

So who was Stewart Smith?

He was a devout communist with a stubborn streak a mile wide, a conspiracy theorist who spent years locked up in a conscientious objectors camp, and an environmental imperialist dedicated to the cause of  "improving" recreational fishing in New Zealand.

Subscribe free to Black Sheep: Apple Podcasts, RadioPublic, Spotify, RadioPublic or Stitcher.

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

Centre for Science Communication student William Bowden speaks to Dr. Mike Joy & Dr. Tim Chambers about the issue of nitrates in New Zealand's waterways.

William Bowden dives into the controversial topic of nitrates in our waterways.

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts

Dr Mike Joy is a freshwater ecologist at Victoria University of Wellington. As a scientist he works in the field, studying freshwater organisms and the complex relationships they have with the aquatic environment. As a science communicator however, Mike has become an active participant in one of New Zealand most controversial issues; the nitrate pollution of New Zealand's freshwater.

On this podcast, Mike discusses the issue in depth, tracing the path of nitrogen from the fertiliser factory, through the industrialised farm and into the river network, highlighting the increasingly detrimental impacts it has on ecosystem health as it accumulates there. However, it is on the subject of setting nitrate limits and enforcement where this issue truly becomes controversial.

As a member of the Science and Technology Advisory Group, set up by the Ministry for the Environment, he and other scientists have recommended nitrate limits for our rivers and drinking water supplies. However, if the nitrate limits recommended by this group of scientists were to be adopted and enforced, it could spell the end for industrial dairy farming in some of New Zealand's largest dairy producing regions. As a result, an unavoidable conflict between protecting the environment and protecting the economy emerges.

What may prove to be non-negotiable however, is human health. The link between nitrate and colorectal cancer is an existing debate within the nitrate issue. However an even newer discovery; the emerging causal relationship between nitrate consumption and birth defects in new born babies, could have the potential to tip the balance of public opinion once and for all. So to discuss these emerging health issues, I interviewed Dr Tim Chambers, a leading public health researcher from the University of Otago.

If you are interested in the freshwater environment, the future direction of New Zealand's economy, and emerging public health issues, then be sure to tune in and listen to the podcast.

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

How to deal with unwelcome visitors. Katy Gosset learns about a native fungus that might help in the battle against wilding pines. And two national research programmes combine on an expedition to protect our oceans from plastics and invasive species.

Invasive species in Aotearoa are the unwelcome guests who have taken over, made a mess, and just won't leave. Plants that smother ecosystems, seaweeds that take over ocean floor habitats, insects, fungi and bacteria that harm native species. Not only that, but others are constantly knocking on the door. This week, stories on keeping them out, and keeping them in check.

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts.

Pine-fighting fungus

New research has shown a native fungus could help slow the spread of invasive wilding pines.

Conservationists estimate that these weeds now cover 1.8 million hectares of land across New Zealand and the Ministry of Primary Industries forecasts that as much as 20 percent of New Zealand could be covered by unwanted conifers in as little as 20 years. The cost? Around $100 million annually in lost productivity, irrigation, hydro-electric power and fire control. And if the wilding pines continue to spread the cost to our economy could reach into the billions.

Katy Gosset meets a Canterbury Masters student who hopes to halt the pines' progress by innoculating the felled trees with armillaria fungus.

Keeping an eye on the oceans

Unwelcome visitors from the ocean include both invasive species and plastic pollution; keeping both at bay is a massive job.

Two national collaborative research programmes are trying to tackle these issues - the AIM2 (Aotearoa Impacts and Mitigation of Microplastics) project and the Marine Biosecurity Toolbox programme. Both involve large teams of scientists from multiple organisations.

In 2021 these research programmes came together on two expeditions coordinated by the Blue Cradle Foundation to gather biosecurity and microplastics data, first in the Hauraki Gulf and then in Fiordland.

Collaboration and data sharing between the two teams is key, as plastic rafts could act as vehicles for invasive species to arrive in the waters around Aotearoa. Scientists across the two projects are working to identify what different organisms tend to interact with different kinds of plastic so that they can make predictions about what threats the marine environment might face.

Listen to how the researchers sample for plastics, and use environmental DNA methods to survey for biosecurity threats in the Hauraki Gulf…

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