Giant kelp is disappearing from Wellington Harbour. Love Rimurimu is aiming to restore lush underwater kelp forests with an ambitious and collaborative replanting effort. Claire Concannon dives in to the wonderful world of seaweeds.

The aquarium room at NIWA is awash with sound. A pump system hums, clicks and splashes as it circulates water through large tanks like the Wellington bucket fountain.

Inside, tiny seaweed fronds tied onto rocks dance in the currents.

Growing kelp

These fronds might be small - a few centimetres at most - but they can grow into lush forests. Giant kelp (Macrocystis pyrifera) starts out in a lab as microscopic spores, before it is coaxed through each phase of its life cycle by staff from the Love Rimurimu project and phycologist Dr Roberta D'Archino.

After growing a few more centimetres, the kelp will be returned to the wild, part of an ambitious effort to restore the seaweed ecosystems of Wellington harbour.

Love Rimurimu

Love Rimurimu began as an educational programme delivered by Mountains to Sea Wellington, says project lead Zoe Studd. Local rangatahi were encouraged to learn more about seaweed, to get into the ocean and have a look around, and to learn about why kelp was disappearing.

But when students from Kura Kaupapa Māori o Ngā Mokopuna suggested that they should be actively growing kelp to plant back out, Love Rimurimu took on a new direction.

Now, the project is piloting plant-outs to help regenerate the giant kelp forests that are so vital to a healthy underwater ecosystem, working with Taranaki Wānui ki Te Upoko o Te Ika, NIWA, Victoria University of Wellington, the kura, and the local community.

Listen to the episode to learn about the stressors impacting kelp, to hear how giant kelp is grown in a lab, and to meet some of the Love Rimurimu team who have been planting out kelp in their blue backyard. …

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