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Encyclopedia · Group

Kelp & seaweeds

Kelp are not plants at all but brown algae — and the largest of them are among the fastest-growing organisms on Earth. This group covers the forest-builders (giant kelp, bull kelp, the Southern Ocean’s buoyant Durvillaea), the shade-tolerant understory that lives beneath them, and the edible species humanity has cultivated and cooked for millennia. Everything else in the encyclopedia, in a real sense, is life arranged around what these seaweeds build.

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39 profiles

39 scientific names catalogued

Chain bladder kelp

Stephanocystis osmundacea (syn. Cystoseira osmundacea)

The canopy with a rope of pearls — California’s mid-storey fucoid that keeps reef structure standing when giant kelp thins

9 min read · Kelp & seaweeds

Chilean huiro

Lessonia trabeculata

Builder of Chile’s great subtidal kelp forests — and feedstock of the global alginate trade

9 min read · Kelp & seaweeds

Cochayuyo, Chile’s edible bull kelp

Durvillaea antarctica

Chile’s great market kelp — food and industry today, ocean-going raft for whole communities when it tears free

9 min read · Kelp & seaweeds

Coralline algae

Order Corallinales — many species

The living pink cement — and the settlement call for urchins, abalone and kelp

10 min read · Kelp & seaweeds

Crustose coralline algae (CCA)

Order Corallinales — many encrusting species

The pink cement that welds reefs together — and the settlement cue abalone, urchins and corals grow up waiting for

10 min read · Kelp & seaweeds

Cystoseira canopy algae

Cystoseira sensu lato (now split across several genera)

The Mediterranean’s kelp-forest equivalent — perennial canopy fucoids whose dispersal is so poor that lost stands cannot walk back

9 min read · Kelp & seaweeds

Dead man’s bootlace

Chorda filum

A true kelp disguised as a string — an annual, drifting cord forest that shelters young fish along sheltered shores

8 min read · Kelp & seaweeds

Sunlit eelgrass meadow: bright green blades swaying above pale sand, with the dark edge of a kelp forest in the hazy background.

Eelgrass

Zostera marina

A true flowering plant beside the kelp — nursery, sediment-anchor and blue-carbon meadow

8 min read · Kelp & seaweeds

Southern sea palm

Eisenia arborea

The sea palm of the warm edge — a surf-zone kelp carrying its forest into Baja

9 min read · Kelp & seaweeds

Gelidium (agar weed)

Gelidium spp.

The wild-harvested source of the world’s finest laboratory-grade agar

9 min read · Kelp & seaweeds

Irish moss

Chondrus crispus

The little red alga that thickened a century of kitchens — the original carrageenan seaweed

9 min read · Kelp & seaweeds

Ogonori

Gracilaria spp.

The agar weed — the red alga genus behind agar-agar and much of microbiology’s benchwork

9 min read · Kelp & seaweeds

Ribbon kelp

Alaria marginata

The golden streamer of the surge zone — a seasonal pulse of food and forage at the low shore

7 min read · Kelp & seaweeds

Sargassum horneri

Sargassum horneri (recently reassigned as S. filicinum)

The kelp coast’s floating invader — a fast-spreading canopy competitor that sheds its fertile tops and drifts onward

9 min read · Kelp & seaweeds

Underwater view inside a sea bamboo forest off South Africa's Cape coast, long golden stipes rising from the reef to a sunlit surface canopy of fronds

Sea bamboo, the Cape’s giant kelp

Ecklonia maxima

The forest builder of the Cape — the canopy everything else lives beneath

9 min read · Kelp & seaweeds

Sea cabbage

Hedophyllum sessile

The low shore’s own kelp — first plate for grazers as the tide falls

9 min read · Kelp & seaweeds

Sea lettuce

Ulva lactuca and relatives

The harbour opportunist — a fast green that can turn nutrient runoff into “green tides”

8 min read · Kelp & seaweeds

Sea palm, storm specialist

Postelsia palmaeformis

An annual that only wins where waves hit hardest — the intertidal’s own kelp

8 min read · Kelp & seaweeds

Sea spaghetti

Himanthalia elongata

The Atlantic’s ribbon belt — an edible low-shore canopy that comes back as buttons every year

9 min read · Kelp & seaweeds

Southern bull kelp

Durvillaea spp.

The southern surf specialist — and the ocean’s great rafter of life

9 min read · Kelp & seaweeds

Underwater view of a stalked kelp forest: slender woody stipes rising from pink coralline-encrusted rock, each crowned with brown blades, under shafts of teal sunlight

Stalked kelp, the old growth

Pterygophora californica

The patient one — long-lived understory kelp sheltering life while faster kelps rise and fall around it

9 min read · Kelp & seaweeds

Tangle kelp (cuvie)

Laminaria hyperborea

Europe’s great subtidal forest-former — Norway’s “tare” coasts are built of it

8 min read · Kelp & seaweeds

Turf algae

Mixed turf-forming red, green and brown algae

The resilient under-storey rival — a fuzzy carpet that can block kelp recovery and hold a reef in a degraded state

9 min read · Kelp & seaweeds

Sieve kelp

Agarum clathratum

The holey kelp of the far north — a puzzle of drag and light in cold water

8 min read · Kelp & seaweeds

Winged kelp

Alaria esculenta

The wave-exposure specialist of Atlantic shores — and a mild, edible kelp

8 min read · Kelp & seaweeds

Acid kelp

Desmarestia spp.

A pioneer brown seaweed carrying literal acid in its cells — where Desmarestia stands, grazers tread lightly

8 min read · Kelp & seaweeds

Feather boa kelp

Egregia menziesii

Mid-water drapery whose flotilla of floats shelters a miniature rainforest of small life

7 min read · Kelp & seaweeds

Dulse

Palmaria palmata

Red alga of the kelp understory — and the famous “bacon of the sea”

9 min read · Kelp & seaweeds

Five-ribbed kelp

Costaria costata

The North Pacific’s broad mid-story kelp, bending the swell for smaller life

8 min read · Kelp & seaweeds

Nori

Pyropia and Porphyra species

Red algal cousins of the kelp forest edge; the seaweed of sushi fame

9 min read · Kelp & seaweeds

Elk kelp

Pelagophycus porra

The deep-edge canopy kelp — forest where giant kelp can’t root

7 min read · Kelp & seaweeds

Broad, dark kombu fronds swaying in cold, sunlit water over a rocky reef off Hokkaido

Kombu

Saccharina japonica

A wild forest kelp and the backbone of the dashi tradition

9 min read · Kelp & seaweeds

Wakame

Undaria pinnatifida

A prized edible kelp — and one of the ocean’s most successful travellers

9 min read · Kelp & seaweeds

Golden fronds of giant kelp rising through sunlit blue water toward the surface canopy

Giant kelp

Macrocystis pyrifera

Foundation species — builds the towering forest canopy itself

8 min read · Kelp & seaweeds

Turkish towel

Chondracanthus exasperatus

A rough-skinned red of the low reef — a natural carrageenan carrier

7 min read · Kelp & seaweeds

Oarweed

Laminaria digitata

Habitat-former of the low-shore kelp zone; long harvested for alginates

9 min read · Kelp & seaweeds

Sugar kelp

Saccharina latissima

Fast-growing cold-water kelp; a workhorse species of northern kelp farming

9 min read · Kelp & seaweeds

Golden kelp

Ecklonia radiata

The dominant sub-canopy kelp of the Great Southern Reef and much of New Zealand

9 min read · Kelp & seaweeds

Sunbeams filtering through a bull kelp canopy in clear green water off a rocky Pacific coast, long stipes rising from the reef below.

Bull kelp

Nereocystis luetkeana

Annual canopy-former of exposed coasts; its hollow stipe floats fronds to the light

9 min read · Kelp & seaweeds

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