Seaweed glossary
Plain-language definitions of seaweed and cultivation terms: macroalgae, sporophyte, gametophyte, seeded line, seeded twine, holdfast and more.
A plain-language guide to the seaweed and cultivation terms used across this site.
- Macroalgae
- The scientific name for seaweed — large algae visible to the eye, grouped as brown, red and green.
- Sporophyte
- The seaweed generation that produces spores; in kelps it is the large blade you see.
- Gametophyte
- The generation that produces eggs and sperm; in kelps it is microscopic.
- Alternation of generations
- The life cycle in which a seaweed alternates between sporophyte and gametophyte stages.
- Spore
- A tiny reproductive cell that settles and grows into a new plant without fertilisation.
- Zoospore
- A spore that swims using whip-like tails before settling.
- Gamete
- An egg or sperm cell; two gametes fuse at fertilisation.
- Holdfast
- The root-like structure a seaweed uses to grip rock or rope. It anchors but does not feed the plant.
- Stipe
- The stalk between the holdfast and the blade.
- Blade (lamina)
- The broad, leaf-like part of a seaweed where most photosynthesis happens.
- Frond
- A general word for the whole visible body of a seaweed.
- Seedling
- A young seaweed plant raised in the hatchery, ready to grow on at sea.
- Seeded line
- Cultivation rope already carrying seaweed seedlings, ready to deploy.
- Seeded twine
- Fine twine seeded with young seaweed, often wound onto a line or used for direct seeding.
- Direct seeding
- Applying seaweed starting material straight onto a line or substrate at the site, rather than transplanting older plants.
- Gametophyte culture
- A maintained stock of the microscopic gametophyte stage, used to seed new lines on demand.
- Broodstock (mother plants)
- Mature, fertile seaweed collected to supply spores or gametes for cultivation.
- Native strain
- Seaweed originating from local waters and adapted to local conditions.
- Hatchery
- The controlled facility where spores settle and seedlings are grown before going to sea.
- Kelp
- Large brown seaweeds of the groups that include Saccharina and Laminaria.
- Wrack
- Brown seaweeds of the genus Fucus and its relatives, common on rocky shores.
- Biosecurity
- Practices that prevent spreading disease or non-native genetics between sites.
See these ideas in context: how seaweed reproduces and where seaweed grows.
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