Our Changing World

What roles do our ocean ecosystems play in capturing carbon? Kate Evans speaks to iwi Māori working to improve the health of an estuary in the Bay of Plenty, and to scientists studying the fiords of New Zealand's southwest coast. There's potential for huge amounts of carbon to be locked away, if we don't mess it up. 

To avert the worst of the climate crisis we need to reduce our emissions. One way is to phase out fossil fuels, to leave forms of carbon like oil and gas locked up in the ground. But we can also look at ways to lock up more carbon, long term. And some options for this are in our oceans. 

The champ of champs

Between 6-10 metres of rain falls in Fiordland each year. An incredible amount. It's part of what powers the forest-to-fiord carbon storage pump that makes Fiordland exceptionally good at locking away large amounts of carbon long-term. Something scientists are only beginning to understand.      

Return of the wetland

Luckily, National Park status on land and marine protection in part of the sea have meant that Fiordland has remained relatively untouched. 

Not so for some of our other carbon-burying ocean ecosystems. Salt marshes and seagrass meadows in estuaries have taken big hits. But Te Whakapū o Waihī, a collective of local iwi and the Bay of Plenty Regional Council, are fighting back. 

Listen as Kate Evans learns about Fiordland's secrets, the plans to restore Waihī wetlands and estuary, and what this all means for our blue carbon potential. 

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Alison Ballance previously reported on the work of the Cawthron Institute to collect and grow seagrass seeds.
• Justine Murray joined Professor Kura Paul-Burke out on the Waihī estuary mud flats last year to learn about tohu (signs), nana (seagrass) and tuangi (cockles). 
• Parts of the Southern Ocean also acts as a carbon sink, but there are concerns this might change.

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

People and livestock gobble so much fish that the seas soon won't keep up. Is the answer to grow fish on land? Kate Evans meets scientists figuring out the puzzles of how to farm some of New Zealand's iconic ocean creatures.

Many of our fisheries are under pressure. At the same time people are eating more fish. Could farming iconic New Zealand species be the future? And what are the advantages of growing fish on land?

A new lease of life

Ocean Beach used to process lambs, a record of 20 000 in one day, but now it's gullies and troughs run with seawater, not blood. Home to the New Zealand Abalone company and Manaaki Whitebait it's become one the frontiers of New Zealand aquaculture - growing fish indoors. 

Pāua puzzles and whitebait mysteries

It's not an easy task. Growing fish on land means taking responsibility for their needs throughout their life cycle. First you must identify those needs, account for them in an indoor setting, and make the whole process as efficient as possible so you can still turn a profit. It takes trial and error, and patience.

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Seaweed is also being farmed in a specialised warehouse space in Tauranga.
• Recently the green light has been given for an open ocean salmon farm in the Cook Strait

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

Kina numbers are exploding on some of our reefs, decimating seaweed habitats. Could this problem be solved by eating them? Kate Evans investigates the potential of kina-nomics.

The kina are out of control. As many as 40 urchins crowd into a single square metre of rock, devoid of other life.

A kina barren is a symptom of an ecosystem out of balance. Could we eat our way to a solution?

Kina zombies

Kina numbers have exploded as we've eaten too many of their predators - like big snapper and crayfish - that usually keep them in check.

The urchins munch through kelp and seaweed, leaving bare rock and little else. The kina themselves end up suffering too - they persist in these zones as zombies, eating little and barely producing any roe.

Luckily, these barrens can be reversed and kelp forests restored when the kina are removed.

Putting kina on the table

Kina-nomics involves taking starving kina off reefs, fattening them up and selling them to an East Asian market.

But how can the kina be made more consistently tasty? And can economic and conservation goals really align?

Listen to the episode to dive under the water with a kina harvester, taste some kina, and untangle whether a commercial harvest of these spiky taonga can really fix kina barrens.

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Check out another effort to restore kelp forests with the Love Rimurimu project in Wellington, profiled in a recent Our Changing World episode.
• Jesse Mulligan spoke to another researcher studying kina removal in the Marlborough Sounds.

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

Crackle, pop, woof, crunch, click. In the ocean, an undersea orchestra is in full swing. Journalist Kate Evans discovers who's playing in it and why, and what happens when human noise drowns out this symphony in the sea.

Symphony in the sea

Journalist Kate Evans and presenter Claire Concannon discover a world of snapping shrimp, singing whales and barking John Dory.

Researchers Professor Craig Radford and Dr Jenni Stanley are uncovering more about the orchestra harmonising under the waves - who's playing in it, and why they are making these sounds.

Plus, what impact is our human noise - like boats - having on ocean creatures?

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.

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

A collaboration between Our Changing World and New Zealand Geographic, the Voice of Tangaroa series explores the state of our oceans, and the extraordinary variety of life that calls it home. 

93% of New Zealand is covered in salt water. 80% of our biodiversity is in our seas. And yet this is the part of our realm we understand the least and treat the worst. 

A collaboration between Our Changing World and New Zealand Geographic, the Voice of Tangaroa series explores the state of our oceans, and the extraordinary variety of life that calls it home. 

From kina-nomics, to the undersea sound, from growing fish on land, to the debates around our marine reserves - science journalist Kate Evans has been diving into the complexities of how we think about, enjoy, manage and use our oceans, and what this means for the creatures that live in it. 

Now, with production help from RNZ's Our Changing World team, and original music composed by Wellington band Grains, you will be able to hear the voices of the characters involved and experience the sounds of our underwater realm.

Voice of Tangaroa is a joint production between RNZ's Our Changing World and New Zealand Geographic.

Reporting for this series is Public Interest Journalism funded through NZ On Air. You can learn more and read the articles for free at www.nzgeo.com/seas

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

A group of young New Zealanders and two meteorologists travel to South Georgia Island in the southern Atlantic Ocean to collect weather observations - continuing the scientific legacy of early Antarctic explorers like Shackleton.

Clarification: In this episode there is a discussion about comparing notes about icebergs taken by Shackleton's team aboard the Aurora to that of the current expedition. What this fails to clarify is that the Aurora expedition travelled through the Ross Sea, not the Weddell sea, where ice activity is notably different.

It's home to one of Earth's most spectacular gatherings of wildlife, with millions of penguins, seabirds and seals crowding the shores. 

South Georgia, in the far reaches of the Southern Atlantic, is a wild and isolated island. It's also the final resting place of famed Antarctic explorer Ernest Shackleton.

To commemorate the 100th anniversary of Shackleton's last journey, 22 young New Zealanders travelled with the Antarctic Heritage Trust's 9th Inspiring Explorers Expedition to South Georgia.

In the wake of Shackleton

One hundred years ago, Shackleton's untimely death at the age of 47 marked the end of the 'heroic age' of Antarctic exploration. The period left us inspiring stories of courage and survival - as well as an enduring scientific legacy, which continues to be built upon today.

As part of their expedition to South Georgia, the young New Zealanders continued Antarctic explorers' tradition of meticulous data collection, by recording rare weather observations from this remote and seldom-visited destination.

Accompanied by Kelly Davenport and Peter Fisher, two meteorologists from MetService, the Inspiring Explorers science team conducted regular and comprehensive weather reports using the same equipment, terminology and methods that would have been used in Shackleton's time. But they also brought some state-of-the art weather equipment, which can collect more data than a heroic-era meteorologist could ever have dreamed of.

Lots of data is important for weather and climate science today. Data feeds into global weather models - complex simulations of the planet's atmosphere that assist the near-term prediction of weather patterns worldwide. Data collected from remote locations such as South Georgia is particularly impactful, as it helps us fill in the blanks in the map of Earth's weather. 

South Georgia: A barometer for change? …

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An ambitious project to rid the remote Antipodes Island of introduced mice proved successful in 2018. Claire Concannon visits the spectacular subantarctic island to meet the locals - from penguins to megaherbs - and the people studying the wildlife. Plus, we learn about what's at stake in the next island eradication challenge for New Zealand.

Excitement rises on board the expedition yacht Evohe as the largest of the Antipodes Islands appears out of the mist. 

These subantarctic islands are wild and remote - some 860km southeast of Rakiura Stewart Island. Their isolation, in a far-flung corner of the South Pacific, means they're some of the most untouched islands in the world. 

They're also brimming with wildlife. 

A wildlife hotspot

Department of Conservation rangers Jemma Welch and Erin Patterson will soon be landing to meet some of the wildlife and start their task: a whole-island count of the Antipodean albatross. Erin dreams of romping through megaherbs, while Jemma, a self-confessed seabird nerd will be in her element - 21 seabird species breed here.  

It's an incredible landscape. Tussock growing in pillars up to two metres tall, pipits and snipe and parakeets roaming, albatrosses and petrels floating overhead, fur seals and elephant seal pups hauled up in the rocky coves. 

With great biodiversity comes great responsibility

The Antipodes Islands, like the other subantarctic islands, have their own cultural and social history, alongside their incredible natural history. 

In the early 1800s gangs of sealers decimated the fur seal population on these islands. Along the way mice were introduced. Remarkably - and fortunately - rats never established.

But the mice were enough to have a major impact. Their population swelled to huge numbers (an estimated 200,000 across the 21 km2 island). This multitude of mice munched their way through a large portion of the native invertebrates on the island - many of which are endemic, meaning they're not found anywhere else. 

This drop in invertebrates had a knock-on effect: it reduced the amount of food available for insect-loving birds like the pipit and snipe. The mice themselves also disrupted burrowing seabirds. And there was another fear of what might be to come as gruesome footage emerged from other islands where mice had developed the disturbing behaviour of eating live albatross chicks as they sat on the nest.  …

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