Alex Mustard / RF - Grey seal (Halichoerus grypus) relaxing in a bed of kelp (Laminaria digitata), with two seals in the background. Farne Islands, Northumberland, England, United Kingdom. British Isles. North Sea....

David Hall / Split level of a Lion's mane Jellyfish (Cyanea capillata) and Feather-boa kelp (Egregia menziesii), Seven-tree Island, Browning Pass, Queen Charlotte Strait, British Columbia, Canada. September.

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.

Claudio Contreras / Californian sea lion (Zalophus californianus) swimming in Southern sea palm (Eisenia arborea) and Giant Kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphe...

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.

Nick Hawkins / Sugar kelp (Sacchinaria latissima) off Nova Scotia, Canada. September

SCOTLAND: The Big Picture / Kelp forest (Laminaria digitata) with small fish, Shetland, Scotland, UK, July.

Franco Banfi / Sugar kelp (Saccharina latissima) and Sea anemones (Actiniaria) on rock near iceberg. Tasiilaq, East Greenland. April.

Franco Banfi / Sugar kelp (Saccharina latissima) near iceberg, view upwards to gap in sea ice. Tasiilaq, East Greenland. April.

Claudio Contreras / Californian Sealion (Zalophus californianus) in kelp (Macrocystis pyrifera) forest, San Benito del Este Island, Baja California Peninsula Pacific Islands Biosphere Reserve, Baja California, Mexico, Ma...

Alex Mustard / RF - Female grey seal (Halichoerus grypus) hovering in gully of kelp (oarweed: laminaria: Laminaria hyperborea). Farne Islands, Northumberland, England, United Kingdom. British Isles. North Sea. (This...

SCOTLAND: The Big Picture / Grey seal (Halichoerus grypus) swimming over kelp forest, Shetland, Scotland, UK, August.

Alex Mustard / California sea lion (Zalophus californianus) resting in the canopy of a forest of giant kelp (Macrocystis pyrifera). Santa Barbara Island, Channel Islands. Los Angeles, California, United States of Am...

Alex Mustard / Young California sea lion (Zalophus californianus) playing in the canopy of a forest of Giant kelp (Macrocystis pyrifera). Santa Barbara Island, Channel Islands. California, USA. North East Pacific Oc...

Solvin Zankl / Kelp forest (Laminaria hyperborea), Atlantic Ocean, North West Norway, March.

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

Juergen Freund / Detail of Giant kelp (Macrocystis pyrifera) gas-filled bladders (pneumatocysts) Vancouver Island, British Columbia, Vancouver Island, Canada.

Pascal Kobeh / Group of California sea lions (Zalophus californianus) in a kelp forest (Macrocystis pyrifera), California, USA. Pacific ocean.

Pascal Kobeh / Group of California sea lions (Zalophus californianus) swimming in kelp forest (Macrocystis pyrifera), California, USA. Pacific ocean.

Brandon Cole / Red Sea Urchins (Stronglyocentrotus franciscanus) and Purple Sea Urchins (Stronglyocentrotus purpuratus) feeding on bottom algae and Giant kelp (Macrocystis pyrifera), Channel Islands National Marine...

Alex Mustard / Scenic view of a bull kelp forest (Nereocystis luetkeana) with sunlight shining through the fronds. Browning Pass, Port Hardy, Vancouver Island, British Columbia. Canada. North East Pacific Ocean.

Chris Gomersall / 2020VISION / European river otter (Lutra lutra) cub amongst kelp on shoreline, Shetland Isles, Scotland, UK, October.

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.

David Fleetham / Giant kelpfish (Heterostichus rostratus) hiding amongst a forest of Giant kelp (Macrocystis pyrifera), off Catalina Island, California, USA, Pacific Ocean.

David Fleetham / Giant kelp (Macrocystis pyrifera) forest, floating on ocean the surface off Catalina Island, California, USA, Pacific Ocean.

David Fleetham / Giant kelp (Macrocystis pyrifera) forest floating on the surface, Catalina Island, California, USA, Pacific Ocean.

Franco Banfi / Scuba diver observing Spiny starfish (Marthasterias glacialis) on forest kelp (Laminaria hyperborea), Trondheimfjord, Norway, Atlantic Ocean. Model released.

Franco Banfi / Spiny starfish (Marthasterias glacialis) on forest kelp (Laminaria hyperborea), Trondheimfjord, Norway, North Atlantic Ocean.

Shane Gross / Brooding anemone (Epiactis lisbethae) attached to Bull kelp (Nereocystis luetkeana), Browning Pass, Queen Charlotte Strait, Vancouver Island, British Columbia, Canada.

Shane Gross / Proliferating anemones (Epiactis prolifera) on Bull kelp (Nereocystis luetkeana), Browning Pass, Queen Charlotte Strait, British Columbia, Canada.

Shane Gross / Reef scene including red soft coral (Gersemia rubiformis), Giant plumose anemone (Metridium senile) and Bull kelp (Nereocystis luetkeana), Vancouver Island, British Columbia, Canada, Pacific Ocean.

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.

David Fleetham / Female California sheephead (Semicossyphus pulcher) and miscellaneous reef fish swimming in a forest of Giant kelp (Macrocystis pyrifera) off Santa Barbara Island, California, USA.

David Fleetham / Sunlight streaming through forest of giant kelp (Macrocystis pyrifera) toward the surface, off Santa Barbara Island, California, USA.

David Fleetham / Air bladders lifting strands of giant kelp (Macrocystis pyrifera) towards the surface, off Santa Barbara Island, California, USA.

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 / Young, female Grey seal (Halichoerus grypus) swimming over a forest of Cuvie kelp (Laminaria hyperborea), 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.