What are the benefits of rimurimu or kelp for skin?

Fucoidan is a sulfated polysaccharide found in the cell walls of brown seaweeds with anti-inflammatory and antioxidant properties. Fucoidan helps reduce chronic inflammation and oxidative stress.

Kelp often contains high concentrations of iodine, known for its exfoliating and detoxifying effect. It is good for skin prone to clogged pores and bacterial infection.

With a high concentration of natural polysaccharides, sea kelp acts as a humectant, drawing in moisture.

The vitamins and minerals found in kelp, including Calcium, Vitamin C and Vitamin E, support collagen production.

Is kelp an algae?

Kelp and all seaweeds are a marine algae. They belong to the Kingdom of Life known as Protista. They are not plants.

What they share in common with plants is the ability to photosynthesise, meaning they create their own food from carbon dioxide and water, using the energy of sunlight, through organs called chloroplasts. Chloroplasts contain the green chemical chlorophyll, which absorbs sunlight and catalyses the reaction.

 

How does a kelp organism function and what is its structure?

The photosynthetic capacity of kelp is in the green blades or fronds. They contain chlorophyll which absorbs sunlight and creates food for the plant.

Kelp fronds often possess high buoyancy through gas-filled, balloon-like bladders called pneumatocysts. This buoyancy allows them to maximise sunlight exposure for photosynthesis.

The photosynthesising blades are connected to a stipe, which is a stem-like, often flexible stalk. Kelp do not have roots that draw in water. However, they do have a root-like “holdfast,” which anchors them to the rocks. The stipe can carry nutrients and flex with the rush in and out of the waves and swells. It also often contains pneumatocysts to keep the blades near the surface, where they absorb maximum sunlight.

While kelp normally grows on subsurface rocks or the seafloor in kelp forests, it can also be passively mobile in the ocean.

Because kelp is not reliant on roots for critical nutrients, like plants are, it can continue photosynthesising even after being ripped from the seafloor or rocky shore.

Giant kelp and bull kelp can act as passively mobile ocean rafts that transport marine organisms across oceans. Kelp are sturdy enough to travel between continents in this way. An entire ecosystem of worms, crabs and other small organisms may inhabit a floating kelp for hundreds of kilometres before the kelp raft breaks down.

Kelp thrives in cold water, between 5 and 20 degrees Celsius, with high nutrient availability and strong sunlight. Darker coloured kelp is more nutrient-rich and typically is found in colder parts of the ocean.

Macrocystis pyrifera or giant kelp is the fastest-growing organism on earth, able to grow up to 50-60 cm per day in cold, nutrient-rich coastal waters.

Large specimens of kelp can reach up to 60 metres in length.

What role does rimurimu play in Aotearoa New Zealand?

Rimurimu is a vital underwater species and ecosystem anchor in Aotearoa. Kelp forests are found around New Zealand’s shorelines, where it provides a habitat, food source and carbon sink. A healthy kelp forest is usually a thriving diverse ecosystem of marine life. It also can act as a buffer against ocean swells to protect the shoreline geologically and ecologically. By absorbing CO2, kelp not only provides a carbon sink but also deacidifies the ocean.

What does the Māori name rimurimu have to do with rimu (the tree)?

Rimu is one of New Zealand’s most well-known trees, one of the ngahere’s rakau rangatira, its chiefly trees, which grace the canopy of the bush, attaining great height. Distinguished from other rakau rangatira, such as the tōtara, mātai, miro and kauri by its droopy branches, this name shares a meaning with rimurimu, which has a spread of blades that droop in the water like the branches of a rimu.

Sometimes rimurimu is called rimu o te moana (rimu of the sea) to distinguish it from rimu (the tree).

New Zealand Folk Song Rimu-rimu

Rimu-rimu, tere tere

E rere ki te moana.

E tere ana ki te ripo

I waho e.

Tirohia i waho rā

E marino ana e.

Kei roto i ahau

E marangai ana e.

Kei te tio te huka

I runga o ngā hiwi.

Kei te moe koromeke

Te wairua e.

Rite tonu tō hanga

Ki te tīrairaka e

Waihoki tō hanga

Te wairangi e.

Kelp, drifting, drifting,

Floating out at sea.

Drifting on the swirling tides

Out at sea.

Look out there

It is calm.

Inside me,

It is bad weather.

The snow is icy cold

On the ridge tops.

Your spirit is lying
Curled up asleep.

Your spirit is like

The fantail

Your spirit also

unsettles me.

 

The New Zealand folk song Rimurimu was composed by a grieving mother who lost her child and saw a strand of drifting seaweed, which she likened to the spirit of her child returning home to Hawaiki.

The metaphor of the fantail is a comparison between the restless searching nature of the tīrairaka and the search of the spirit of the dead for a berth, a home.