Our Changing World

Off the coast of New Zealand, deep underwater, the seafloor shifts in landslides and slow-motion earthquakes. Claire Concannon meets two researchers investigating geological phenomena that could pose a tsunami risk to Aotearoa New Zealand.

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Underwater landslides: out of sight, but not out of mind

One million years ago something triggered an underwater landslide in the Tasman Sea off the coast of Taranaki. A massive amount of sediment, 32 times the volume of Mount Ruapehu, thundered down a slope. 

But if the land slides underwater and there's nobody there to see it, does it have an impact? 

Early modelling suggests yes - it's likely to have caused a large tsunami that would have hit the west coast of Aotearoa. 

So today, with our populated coastlines and our underwater communication cables, what's the likelihood of it happening again? 

That's what GNS senior marine geohazard researcher Dr Suzanne Bull is keen to answer. 

Figuring out the where and why

Just like on land, any sloped area under the sea has the potential to slide - but underwater landslides tend to be far more massive. 

Understanding what triggers them is tricky, says Suzanne, because you can't easily survey after an event. 

For example, in the aftermath of Cyclone Gabrielle more than 140,000 landslides have been documented from on-the-ground reports and aerial imagery, but doing a similar assessment underwater is far more expensive and time consuming. 

Earthquakes could be another potential trigger. One natural disaster that woke scientists up to the potential hazard of such landslides was when a 7.0 magnitude earthquake off Papua New Guinea in 1998 resulted in an unexpected tsunami. Investigations indicated that it was caused not by the earthquake itself, but by a large underwater landslide.  

Listen to the episode to hear Suzanne explain how she and her colleagues have been investigating a group of large landslides in the Tasman Sea in the hopes of learning more about the potential risks to Aotearoa.  

Homing in on the zone

Of course, Aoteaoroa is also at risk from tsunamis generated in the more 'classic' way: large earthquakes occurring underwater. 

Off the North Island's East Coast, the Pacific Plate dives under the Australian Plate in an area known as the Hikurangi subduction zone.  …

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Go behind the scenes at the National Geohazard Monitoring Centre, where a team of analysts are on alert 24/7 for earthquakes, volcanic activity, tsunamis and landslides. What happens when a natural disaster strikes?

It could be the headquarters for a rocket launch, or the control centre for a highly coordinated operation. One wall is full of large monitors, information updating in real time. Cameras, maps of the Pacific, incoming streams of data. A room that never sleeps, that's always on alert. 

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24/7 operation

This is the National Geohazard Monitoring Centre (NGMC). Based at GNS Science in Lower Hutt in Wellington, it's part of GeoNet - the programme tasked with New Zealand's geohazard monitoring and response, operated in partnership with Toka Tū Ake EQC, Toitū Te Whenua Land Information New Zealand and GNS Science

Kimberly Presow has worked here for five years, since this new 24/7 version of the centre opened in 2018. She's a shift leader now, responsible for one of the teams of geohazard analysts that constantly scan the monitors for any changes that might indicate a significant geohazard event. 

Four main geohazards

While keeping an eye out for earthquakes is the bread and butter of the NGMC, they are also on alert for three other geohazards: landslides, tsunamis and volcanic activity. A network of seismometers, underwater pressure sensors, coastal gauges, cameras and international monitoring stations constantly feed data into this room, where the geohazard analysts are wary to any changes in the patterns. 

A pager will sound for anything greater than a magnitude six earthquake, but the geohazard analysts will be on alert for any change they see in the incoming data. And once something is identified, they will work quickly to assess and update the information, sometimes correcting errors in the automatic system - which may, for example, see one earthquake when there were two. 

Coordinating the response

When a large event occurs the NGMC goes into response mode. 

The analysts alert civil defence, and the on-call duty scientist will be looped in to give their assessment. From there, depending on the scale of the hazard, an entire panel of expert scientists might be assembled. In the meantime, the incoming data is being constantly assessed and updated, to fine-tune the information about the location, scale and repercussions of the event, to further inform civil defence.  …

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Mohua are bright yellow forest birds - but despite their eye-catching plumage, they can be tricky to spot flitting high in the forest canopy. Claire Concannon visits the Makarora mohua population, where a team of conservationists and scientists are testing acoustic machine learning to identify individual birds.

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A 'rat plague' has come to the beech forest near Makarora, and Jo Tilson is worried for the little population of mohua who call this area home. 

The 'bush canary'

In the 1800s mohua were one of the most abundant forest birds, found in different forest types. Their bright yellow heads (hence their common English name, yellowhead) and yellow-feathered bellies led them to being dubbed the 'bush canary' by European settlers. 

But - and you know this story - forest clearance and introduced predators reduced their population and range significantly. These little songbird insectivores nest in holes in trees, and so are vulnerable to stoats and ship rats. Some mohua have been transferred to predator-free offshore islands where they are doing well, but on mainland New Zealand there remains just a few small, scattered populations living in South Island beech forest. 

One of these can be found just north of Makarora, near Cameron Flat, in the silver beech forest that lines the west side of the Makarora River as it runs alongside State Highway 6 through the Haast Pass. 

It takes a village

Jo works as a biodiversity coordinator for Southern Lakes Sanctuary, focused on species and predator monitoring for the Mātukituki and Makarora hubs. Southern Lakes Sanctuary is essentially an umbrella organisation that has wrapped around existing conservation groups to enable a regionwide effort. 

In this area, that includes a highly motivated group of 60 or so trapping volunteers from the Central Otago Lakes Branch of Forest & Bird. With the first trap lines established in 1998, the group has been "sustainably harvesting predators," as volunteer Mo Turnbull puts it, for more than 25 years, to help the local mohua population hold on. 

But it's not about dead rats, Mo says, it's about live mohua. So how are they doing? 

Cryptic in the canopy

Transects run by the Department of Conservation and the sanctuary across the years indicate that the mohua numbers in the area are declining. But without a complete census it's hard to have the full picture of what's going on.  …

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Varroa mite parasites cause major problems for honey bees - and beekeepers. Now, New Zealand researchers are investigating a new type of RNA-based treatment that could make treating varroa mite infestations easier, as well as better for the bees and the environment.

Varroa destructor mites are bad news for honey bees. 

Not only do they attack the bees by chewing on a vital organ called the fat body, but they also introduce problematic viruses to the hive - such as deformed wing virus, which does exactly what it says on the tin. 

Beekeepers worldwide must treat for varroa mites several times a year just to keep their numbers in check. They mostly use pesticides, which can have damaging effects on the bees and environment. The mites are also beginning to develop resistance to pesticides, but a new treatment method may be just on the horizon.  

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RNA interference

This is what PhD candidates Zoe Smeele and Rose McGruddy have been researching. Under the supervision of Professor Phil Lester, they've been working with US biotechnology company Greenlight Biosciences to investigate how their new treatment for varroa mites works. 

The treatment is based on a technique called RNA interference. An interesting bio-hack that researchers have figured out is how they turn a natural virus defence mechanism in the cell against one of the mite's vital proteins. 

Greenlight Biosciences were able to identify a working treatment that reduced mite numbers in field trials in the states but turned to the New Zealand researchers for help in uncovering exactly how it works. 

Mini-hive experiments

In one of the research labs in the School of Biological Sciences at Te Herenga Waka Victoria University of Wellington, Zoe and Rose have been conducting mini-hive experiments. Their participants are larval stage bees taken from the hives on the roof of the building, infected with varroa mites.  

The nurse bees that feed the larvae are given plastic pouches full of sugar water with the RNA interference treatment inside. What the team has discovered is that instead of killing the mites, what the treatment does is severely impact the mites' reproduction. 

But what about real beehives?

Initial field trials with New Zealand beekeepers have showed some promise, but also highlighted that there's much to learn in terms of the dosage per bee. A next round of trials is just getting underway, and this will also include RFID tagging of bees to monitor any impacts at the individual bee level.  …

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New video series: A turning point in the fight to preserve Aotearoa's natural environment.

If you enjoy listening to Our Changing World, we reckon that you might be keen on a new video series just released on RNZ.

The Turning Point is about the new generation of kaitiaki across Aotearoa taking on the challenge of protecting and restoring our natural environment, paving the way to a more hopeful future.

Each of the six episodes follows one person, giving a glimpse into the communities they work with and telling the story of their journey into conservation. They look at how they got to where they are now, what their day-to-day jobs look like, the challenges facing the affected species and the impact of their work.

Caring for penguins, growing native plants, battling wilding pines, protecting kōkako, helping migratory fish and bridging the gap between science and mātauranga Māori - these young conservationists are making a positive change for te taiao.

Watch the The Turning Point on the RNZ website, or on the RNZ YouTube channel.

To learn more:

The Turning Point focuses on conservation roles funded under the Covid-19 Jobs for Nature fund. Our Changing World has told several stories of projects also supported by this fund - such as creating a home for inanga outside Hokitika and replanting near Pūnakaiki.

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Claire Concannon meets GERALDINE, the Gigantic and Extremely Radical Atmosphere-Lacking Device for Interesting and Novel Experimentation. Plus, a team of scientists and engineers designing plasma rocket thrusters for space travel with super-conducting magnets.

GERALDINE loiters at one end of the giant lab space. Metal, shiny, round and very large, she's been purposely built to help scientists and engineers test plasma rocket thrusters in the vacuum environment of space. 

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New frontiers

As senior scientist Dr Ben Mallett explains, GERALDINE's full name is the Gigantic and Extremely Radical Atmosphere-Lacking Device for Interesting and Novel Experimentation. And you can't really get more novel than the current project he is working on. It's the Paihau - Robinson Research Institute's first foray into space, and they are looking to test a brand-new superconducting magnet and flux pump design to see if it can make the plasma rockets more efficient. 

Plasma rockets

Actually, the full and correct name is 'applied-field magneto plasma dynamic thrusters'. These kinds of rockets don't produce a huge amount of force - for some, the thrust they produce is equal to the weight of a piece of paper on your hand. However, they are extremely efficient. In the frictionless vacuum of space, over time, they can help spacecrafts build up great speeds and travel long distances. 

Plasma is charged gas, and in these kinds of electric space thruster, electromagnets are used to direct the plasma so that it fires out the back and pushes the rocket forward. But the weight and power requirements of current magnets used in these thrusters is a barrier. 

Enter Paihau - Robinson, known for their work with high-temperature superconducting magnets. Superconducting materials conduct electrical current with no resistance, so they can create very powerful electro-magnets when a current is passed through them. They do come with baggage though - a cryocooler to keep the magnet at -200oC and a flux pump to send current through the magnet to power it up. All of these parts need to be carefully designed and then tested.

But space is tricky....

There's a lot to think about when making equipment to be used in space. There's the shaking of everything as it gets launched through the atmosphere and then there's the lack of atmosphere once it's up there - the vacuum, the radiation, the different temperature effects - all have to be considered.   …

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A Moriori musician, an ethnomusicologist and the Hokotehi Moriori Trust are part of a team helping to revitalise Moriori culture with 3D-printed replicas of traditional bone flutes from Rēkohu the Chatham Islands. Claire Concannon finds out more about the Moriori, music and manawa project.

A born and bred Chatham Islander, from the largest island, Rēkohu, musician Ajay Peni says the wildness, the ocean, the ruralness all feeds into his music. Through his nan's side Ajay can trace his hokopapa, his genealogy, back to indigenous Moriori who first settled these islands. 

Today he is playing his part in the revitalisation of Moriori culture, by bringing traditional Moriori songs, rongo, into contemporary times. 

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Rongo

Through collaboration with the Hokotehi Moriori Trust Ajay has already been part of the creation of two collections of rongo - Hokotehi Me Rongo - featuring Ta Rē Moriori lyrics long ago recorded by Alexander Shand and Hirawanu Tapu. 

He is currently working on another collection of rongo with the Trust, and alongside this, creating music for the Moriori, music and manawa project based at the University of Otago, with fellow musician Alistair Fraser. 

Two remaining Moriori bone flutes

Dr Jennifer Cattermole is one of the co-leads of this project. An ethnomusicologist, she studies music in its social and cultural contexts. After scouring different sources of information, two remaining Moriori bone flutes were identified: one in the Canterbury Museum in Christchurch, the other in the Bishop Museum in Hawai'i. 

But careful preservation of these mīheke oro (treasured musical instruments) in museums means that no one can touch them with their hands or play them. So how can they be used as part of the Moriori cultural revitalisation that has been happening for many years now? 

Enter modern technology. 

Careful CT scanning the two flutes meant that the tiny, nuanced details of their carving could be captured in digital form, and then translated into a 3D print design. As well as allowing experimentation of different materials to recreate the look, feel and sound of the flutes, the 3D-printed versions were used to guide a carving wānanga, where copies of the flute were made from what was likely the original material - albatross or hopo bone. 

Multi-sensory exhibition  …

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In the last week, Hurricane Otis hit southern Mexico with little warning, and Cyclone Lola set a record for the earliest category five cyclone in the southern hemisphere. Climate change is making work tricky for weather forecasters. What might be in store for our upcoming El Niño summer?

Last week in southern Mexico Hurricane Otis made landfall near the city of Acapulco as a category five hurricane. With wind speeds estimated at around 266 kph (165 mph) it caused huge amounts of damage and loss of life. 

In part because there was so little warning.

Just 24 hours beforehand the US National Hurricane Centre modelling of then tropical storm Otis predicted max winds of about 112 kph (70 mph).

But the rapid and unexpected intensification of Otis caught everyone off guard, including the weather models. 

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Is the forecasting game changing? 

"You can never really attribute, you know, one single weather event to climate change. It's very difficult to do that," says NIWA meteorologist Tristan Meyers. But, he says, different recent extreme weather events in New Zealand do have the "fingerprints of climate change" all over them. 

As part of his job, Tristan works on a number of different forecasts: from on demand 'now-casts' to look a few hours ahead - maybe to help Fire and Emergency New Zealand deal with spreading fires - through to seasonal forecasts across a few months to help those dependent on the weather for their livelihoods prepare for what's to come. 

But the impacts of climate change are making his job trickier. 

El Niño is here

There's a large patch of ocean in the Eastern Pacific along the equator where sea surface temperatures are monitored closely. Think of it as extending out from Ecuador in South America, into the middle of the Pacific. 

When this patch of ocean is warmer than normal, and the air above the ocean responds, that's when the El Niño Southern Oscillation is in effect. Wind and ocean currents change, and when these changes spread out across the Pacific, it generally means more westerly winds for Aotearoa. 

With El Niño officially declared as an important climate driver for this summer season, we can look at past seasons to forecast what might be coming: westerly winds that bring rain to the west coast but a drier outlook for the east of the country.  

Overlapping climate drivers …

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Could your burger one day come with a plankton patty? Alison Ballance visits the Cawthron Institute's collection of more than 750 different strains of microalgae, where scientists are investigating these teeny organisms for new food ingredients and powerful painkillers.

Imagine a future where your burger comes with a plankton patty.

Or where you are prepped for a hospital operation with an algal anaesthetic.

If Cawthron Institute researchers have their way, this microalgae-themed future for food and pharmaceuticals could be just around the corner.

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The Cawthron Institute research is based on a culture collection of microalgae, also known as phytoplankton. The collection goes back more than three decades, and now contains more than 750 isolates or different strains of microalgae, collected from New Zealand, Antarctica and the Pacific. It includes marine and freshwater species.

The collection differs from Aotearoa's other significant national biological collections - think herbariums containing dried specimens of plants, for example - in that it is a living collection.

Curator Sarah Challenger has the job of keeping the collection alive and healthy. The microalgae require light of the right wavelengths, nutrients, and a suitable temperature to survive. Every three weeks Sarah carefully replaces the water and nutrients in the small plastic pottles in which the living samples are maintained.

Sarah says it is a much easier job to care for some of the freshwater microalgae, which can survive cryopreservation - or freezing - to very low temperatures and be brought back to life later as needed.

The Cawthron Institute's Chief Science Officer, Dr Cath McLeod, says the collection began with a monitoring programme for toxic phytoplankton blooms in the Marlborough Sounds that were having an impact on shellfish farms. The collection grew as the researchers realised that phytoplankton was a vast untapped resource which could potentially provide ingredients for food and pharmaceutical products.

Developing new food and drugs

Andy Selwood and Dr Matt Miller are currently screening about a hundred of the different strains to identify which ones might produce useful bioactive compounds. They grow each strain in a series of one-litre bioreactors, exposed to slightly different combinations of light and nutrients. This allows the researchers to identify optimum growth conditions and work out which strains are producing what kinds of bioactives and in what quantities. …

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In the ever-shifting streams and channels of a braided river, creatures must adapt to change. Claire Concannon joins a researcher on the spectacular Cass River near Tekapo for a spot of electrofishing and bird counting - part of a project seeking to understand this complex ecosystem and the threats it faces.

It's a blue-sky spring day in the Canterbury high country. The sun beams and the wind is whipping down the wide gravel plains of the braided Cass River. 

To the left is the Gamack Range. To the right, the vivid turquoise of Lake Tekapo. Black-fronted terns call out as they drift above the weaving and winding water channels, on the hunt for fish to deliver as gifts as part of their courtship. 

And standing in the middle of one of the streams, water up to her knees and a heart-shaped metal wand stuck into the fast-flowing water, is University of Canterbury PhD candidate Holly Harris. She is electrofishing.  

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Changing channels

Braided rivers are rare worldwide. In New Zealand they are classed as naturally rare habitats, but we are lucky in comparison to other countries. There are a few in the south of the North Island, but most can be found in Te Waipounamu. 

If you've flown over the South Island you'll have seen them in all their glory -  silver snaking braids of water in wide gravel floodplains making their way from the Southern Alps to the ocean. 

They are complex and dynamic ecosystems. There are springs that feed side streams, and water can flow through the gravel under the surface to pop up in other places. As the seasons change, floods wash out main braids and give life to side braids. The gravel shifts and the channels can change course. It's an intricate dance that the creatures that live here have learned to adapt to. 

Life and death

As in every ecosystem, in braided rivers there is an interconnected web of things eating other things. The freshwater invertebrates eat the algae that grows on settled river stones. The fish eat the invertebrates. The birds eat the fish, lizards and terrestrial invertebrates.

As part of Holly's PhD she wants to better understand the elaborate interplay between life in the river: how it is interconnected, and how it can move and adapt to the changing channels. She uses isotopic analysis of different species to investigate this.  …

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