Scientific name: Cystoseira tamariscifolia
Size: Up to 60cm long
Colour: Green with characteristic blue-green iridescence
Habitat: Found on both rocky and gravel shores, including rockpools.
- Colourful iridescence when in the water – reflections of light that produce colours when viewed at different angles.
- Iridescence produced by oil-based structures within the seaweed.
- This iridescence responds to sunlight; lots of light causes the seaweed to breakdown the crystal structures, meaning less iridescence.