Shane Gross / Two grey triggerfish (Balistes capriscus) fight over a large piece of plastic floating at the surface among sargassum seaweed (Sargassum natans) in the Sargasso Sea, Atlantic Ocean.

Alex Mustard / Portrait of a male short snouted seahorse (Hippocampus hippocampus) in sea oak seaweed (Halidrys siliquosa). Devon, England, United Kingdom. British Isles. English Channel. North East Atlantic Ocean.

Solvin Zankl / Thongweed (Himanthalia elongata) edible plant sold as 'Sea Spaghetti' for human consumption. From Roscoff, France, April. Preserved specimen.

Solvin Zankl / Tiny crab on Broad-toothed Gulfweed (Sargassum fluitans) Sargassum Community. Sargasso Sea, Bermuda

Orsolya Haarberg,Orsolya Haarberg / Brown Algae (Fucus dustuchus) making patterns in snow and sand. Skagsanden beach, Nordland, Norway, February. Highly commended in Plants category of the GDT 2011 competition.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) fish eggs freshly spawned and attached to Sargassum (Sargassum horneri) by a sticky secretion, Japan, Pacific Ocean.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) male tending to fresh eggs which a female has deposited on Sargassum (Sargassum horneri), Japan, Pacific Ocean.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) male tending to fresh eggs which multiple females have deposited on Sargassum (Sargassum horneri), Japan, Pacific Ocean.

Tui De Roy / Galapagos sargassum (Sargassum albemarlense) growing at the heart of the Cromwell Current upwelling, Galapagos, South America, Pacific Ocean.

Tui De Roy / Galapagos sargassum (Sargassum albemarlense) growing at the heart of the Cromwell Current upwelling, Galapagos, South America, Pacific Ocean.

Alex Mustard / Male Fifteen spined stickleback / Sea stickleback (Spinachia spinachia) guarding a nest in Spaghetti seaweed / Thong weed (Himanthalia elongata), Isle of Coll, Inner Hebrides, Scotland, UK, North Atla...

Alex Mustard / Spaghetti seaweed / Thong weed (Himanthalia elongata) growing up to the water surface, Isle of Coll, Inner Hebrides, Scotland, UK, Atlantic Ocean. August.

Alex Mustard / Spaghetti seaweed / Thong weed (Himanthalia elongata) growing up from a bed of seaweed, Isle of Coll, Inner Hebrides, UK, Atlantic Ocean. August.

Alex Mustard / Spaghetti seaweed / Thong weed (Himanthalia elongata) flowing with the current, Inner Hebrides, Scotland, UK, Atlantic Ocean. August.

Alex Mustard / A tangle of Spaghetti seaweed / Thong weed (Himanthalia elongata) growing beneath the straight basalt columns outside Fingal's Cave. Isle of Staffa, Inner Hebrides, Scotland, UK, Atlantic Ocean. Augus...

Alex Mustard / Spaghetti seaweed / Thong weed (Himanthalia elongata) forest reaching up to the surface to absorb sunlight, Isle of Coll, Inner Hebrides, Scotland, UK, Atlantic Ocean. August.

Alex Mustard / Spaghetti seaweed / Thong weed (Himanthalia elongata) forest reaching up to water surface to absorb sunlight, Isle of Coll, Inner Hebrides, Scotland, UK, Atlantic Ocean. August.

Alex Mustard / Spaghetti seaweed (Himanthalia elongata) and Wireweed (Sargassum muticum) reflected in the calm surface of the sea, Cornwall, UK, English Channel.

Alex Mustard / Spaghetti seaweed (Himanthalia elongata), Cornwall, UK. English Channel.

Alex Mustard / Underwater forest of Spaghetti seaweed (Himanthalia elongata) in shallow water, Pendennis Head, Cornwall, UK, English Channel.

Alex Mustard / Spaghetti seaweed (Himanthalia elongata) reaching for the surface, Pendennis Head, Cornwall, UK, English Channel.

Alex Mustard / Juvenile Pollack (Pollachius pollachius) swimming through shallow water rich with seaweed growth: Wireweed (Sargassum muticum and Sea lettuce (Ulva lactuca), Pendennis Head, Cornwall, UK, English Chan...

Alex Mustard / Spider crab / Cornish king crab (Maja brachydactyla) in shallow water amongst Wireweed (Sargassum muticum). Pendennis Head, Cornwall, UK. English Channel.

Alex Mustard / Contrast of lush growth of Egg wrack (Ascophyllum nodosum) underwater and leafless trees on the shore, Loch Carron, Highlands, Scotland, UK. May.

Alex Mustard / Contrast of lush growth of Egg wrack (Ascophyllum nodosum) underwater and leafless trees on the shore, Loch Carron, Highlands, Scotland, UK. May.

Alex Mustard / Bed of Spiral wrack (Fucus spiralis) growing in shallow water reflecting in the surface, Loch Carron, Highlands, Scotland, UK.

Alex Mustard / RF - Spaghetti seaweed (Himanthalia elongata) bending in the current, Isle of Coll, Inner Hebrides, UK, Atlantic Ocean. (This image may be licensed either as rights managed or royalty free.)

Alex Mustard / RF - Spaghetti seaweed (Himanthalia elongata) forest floating up to the surface providing shelter for juvenile Pollack (Pollachius pollachius), Isle of Coll, Inner Hebrides, UK, Atlantic Ocean. (This...

Alex Mustard / RF - Wireweed (Sargassum muticum) and Spaghetti seaweed (Himanthalia elongata) in shallow water, Cornwall, UK, English Channel. (This image may be licensed either as rights managed or royalty free.)

Konrad Wothe / Bladder wrack (Fucus vesiculosus) in intertidal zone, Atlantic Ocean, Ireland. August.

Adrian Davies / Spiral Wrack (Fucus spiralis) Devon, UK. August.

Alex Mustard / Thongweed (Himanthalia elongata) in sun beams surrounded by kelp (Laminaria sp.). This common seaweed has a two stage morphology, seen here is the strap-like reproductive frond, which can reach up to...

Alex Mustard / Shoal of Lesser sandeels (Ammodytes tobianus) swims through thongweed (Himanthalia elongata) and sunbeams. Falmouth, Cornwall, England, United Kingdom. British Isles. North East Atlantic Ocean.

Alex Mustard / Seaweeds in shallow water, with thongweed (Himanthalia elongata) growing over serrated wrack (Fucus serratus). Falmouth, Cornwall, England, United Kingdom. British Isles. North East Atlantic Ocean.

Alex Mustard / Serrated wrack (Fucus serratus) reflected in the surface as it grows in a rockpool. Looe, Cornwall, England, United Kingdom. British Isles. English Channel, North East Atlantic.

Alex Mustard / Dense growth of invasive Wireweed (Sargassum muticum) in shallow water. Looe, Cornwall, England, United Kingdom. British Isles. English Channel, North East Atlantic.

Alex Mustard / Dense growth of Thongweed (Himanthalia elongata) is reflected in the surface of the sea. Looe, Cornwall, England, United Kingdom. British Isles. English Channel, North East Atlantic.

Alex Mustard / Shallow water seaweeds (including sea lettuce: Ulva spp. and serrated wrack: Fucus serratus) carpet the seabed. Looe, Cornwall, England, United Kingdom. British Isles. English Channel, North East Atla...

Franco Banfi / Split image of brown macroalgae (Sargassum sp.) bank drifting on the sea, Dominica, Caribbean Sea, Atlantic Ocean.

Sergio Hanquet / Algae (Treptacantha abies-marina / Cystoseira abies-marina) Canary Islands.

Sergio Hanquet / Algae (Treptacantha abies-marina / Cystoseira abies-marina) Canary Islands.

Sergio Hanquet / Sargassum weed (Sargassum) Tenerife, Canary Islands.

Pal Hermansen / Brown algae (Pelevetia canaliculata) Photograph taken with the Kirlian technique, a technique which allows imaging of electrical coronal discharge.

Alex Mustard / Detail of the fronds of Spiral wrack (Fucus spiralis). Mylor, Falmouth, Cornwall, England, United Kingdom. North East Atlantic Ocean.

Alex Mustard / Seaweed bed with Thongweed (Himanthalia elongata) in shallow water. Falmouth, Cornwall, England, United Kingdom. North East Atlantic Ocean.

Alex Mustard / Split level image of seaweed bed, Thongweed (Himanthalia elongata) and tree covered cliffs. Falmouth, Cornwall, England, United Kingdom. North East Atlantic Ocean.

Alex Mustard / Shoal of lesser sandeels ( Ammodytes tobianus) swims through thongweed (Himanthalia elongata) and sunbeams. Falmouth, Cornwall, England, United Kingdom. North East Atlantic Ocean.

Alex Mustard / Shoal of lesser sandeels (Ammodytes tobianus) swims through thongweed (Himanthalia elongata) and sunbeams. Falmouth, Cornwall, England, United Kingdom. North East Atlantic Ocean.