Love Rimurimu – an ocean of potential for seaweed

We hear a lot about the role of terrestrial forests in climate change, but what about the ocean’s forests? It’s amazing to think that a kelp forest the size of the Amazon rainforest could absorb more CO₂ than humans produce. That’s just one amazing fact about rimurimu (seaweed). Not only does rimurimu absorb more carbon than trees, it also improves water quality and provides habitats for thousands of marine creatures.

These important ecosystem services have inspired Mountains to Sea Wellington (MTSW) to initiate the Love Rimurimu project. The MTSW team worked with Mana College, Scots College, Te Kura Kaupapa Māori o Ngā Mokopuna and Koraunui School to learn about their local underwater forests and how ākonga can help with their conservation. The programme built upon the experiences provided through the national Experiencing Marine Reserves programme.

The Love Rimurimu project is supported by experts and technical advisors from the National Institute of Water and Atmospheric Research (NIWA), Victoria University, Experiencing Marine Reserves, Te Aho Tū Roa and the Wellington Underwater Club.

Wellington harbour and the blue belt has a flourishing ocean forest, cared for by our local communities. Our seaweed forests are valued for their beauty and ecosystem services – absorbing carbon, steadily improving water quality and as a home to an increasing abundance of marine life.
Love Rimurimu vision

Exploration in the classroom and in the field

Love Rimurimu is a year-long inquiry. The initial focus is on seaweed biodiversity and its importance in the marine environment. Observation and mātauranga Māori are interwoven throughout the programme.

Introductory sessions begin in the classroom with information about seaweed structure, ecosystems and habitats and the three different groups of seaweed: parāone (browns), kākāriki (greens) and whero (reds). Learning then moves to shore and water-based experiences, which may include snorkelling sessions. Students use transects and quadrats to observe the biodiversity of the seabed. They also collect seaweed samples for pressing and for photosynthesis experiments to observe and measure seaweed’s ability to absorb CO₂ from the water and produce oxygen.

Armed with knowledge about rimurimu habitats and the ecosystem services they provide, the second term of the inquiry focuses on the human impacts that affect seaweed health. Students learn about risks from pollution, sedimentation, overfishing, ocean acidification and climate change.

Uses for rimurimu

During the third term, the inquiry turns to exploring practical uses for rimurimu. Seaweed is an amazingly versatile product. In 2019, the global commercial seaweed market was over NZ$18 billion! The food and cosmetics industries are interested in seaweed due to its sustainability, health benefits and ecosystem services. The MTSW team held workshops, making seaweed-based products including bath bombs, face masks, fertilisers, bioplastics and kai.

Community engagement

The final part of the inquiry takes place in term 4. Students are encouraged to reflect on their actions, share their knowledge with the wider community and consider how they can support rimurimu conservation. The initial cohort of schools that worked with MTSW in 2020 held workshops, delved more deeply into the sources of pollution affecting their local beaches and joined the Litter Intelligence citizen science project.

Giant kelp, which loves the cold waters of Aotearoa, is the fastest-growing organism in the world as it can lengthen by as much as 60 cm in a day. However this doesn’t apply if the spores can’t develop in the first place – one of the many problems seaweeds are facing today.
Curious Minds

Delving deeper

In addition to experiments that investigate seaweed photosynthesis, ākonga also have the opportunity to harvest rimurimu spores and attempt to germinate them and grow rimurimu in a classroom aquarium. They have found that this isn’t necessarily a straightforward process. During the 2020 season, warm water temperatures meant that giant kelp spores were released sooner than the MTSW team expected. Students who successfully grew spores hope that growing rimurimu and returning it to coastal areas will help restore the habitat and clean up the water.

Love Rimurimu resources

The MTSW team has developed resources to support the Love Rimurimu Project in downloadable PDF format (and one PowerPoint). The resources in te reo Māori are courtesy of Te Aho Tū Roa.