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