Andy Rouse / Galapagos green turtle (Chelonia mydas agassisi) underwater portrait, being inquisitive, note algae growing on head and shell

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...

SINCLAIR STAMMERS / Timelapse of filaments of Oscillatoria, a type of Blue green algae gliding over each other, filmed using differential interference contrast.

Sue Daly / Furbelows seaweed (Saccorhiza polyschides), with fronds moving in the current, Sark, British Channel Islands, UK, June.

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

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

Andres M. Dominguez / Dove's-foot crane's-bill leaf (Geranium molle) and algae in ice with air bubbles, Sierra de Grazalema Natural Park, southern Spain, February.

Jeff Vanuga / Ephydrid flies (Ephydra sp) that eat microscopic algae and survives during the winter in thermal pools. Biscut Basin, Yellowstone National Park, Wyoming, USA, January.

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.

Richard Herrmann / Yellowfin Tuna (Thunnus albacares) and Blue Marlin (Makaira nigricans) beside floating kelp, Nine Mile Bank, San Diego, California

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.

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.

Juan Carlos Munoz,Juan Carlos Munoz / Lesser flamingo flock (Phoeniconaias) flying over lake with green algae, aerial view, Rift valley, Kenya

Franco Banfi / Bridled parrotfish (Scarus frenatus) clownish grin reveals its power tools: grinding teeth used to scrape algae from rock, Maldives, Indian Ocean. Highly commended in the Underwater World Category of...

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

Graham Eaton / Split level shot of Llyn Idwal and Cwm Idwal, showing freshwater habitat with Green lacustrine algae (Chlorophyceae sp.), Snowdonia NP, Gwynedd, Wales, UK, August

Roberto Rinaldi / Yellow fan coral / Seafan (Paramuricea clavata) amongst mass of invasive algae (Caulerpa taxifolia) with Rainbow wrasse fish (Coris julis), Strait of Messina, Southern Italy

Alex Mustard / 2020VISION / Tufts of seaweed growing on a shallow seabed, Island of Coll, Inner Hebrides, Scotland, UK, June

Alex Mustard / 2020VISION / Meadow of seaweeds in a shallow channel between islands in the Cairns Of Coll, Island of Coll, Inner Hebrides, Scotland, UK, July

Doug Perrine / Green sea turtle (Chelonia mydas) being cleaned of algae by Yellow tangs / surgeonfish (Zebrasoma flavescens), Puako, Kona, Hawaii, USA, June, Endangered species

Doug Perrine / Green sea turtle (Chelonia mydas) cleaned of algae by Yellow tangs / surgeonfish (Zebrasoma flavescens), Puako, Kona, Hawaii, USA, June, Endangered species

Juergen Freund / Mermaid's wineglass algae (Acetabularia calyculus) Batangas, Philippines.

Juergen Freund / Aerial view of a seaweed farmer tending his crop, growing agar-agar for processing into carageenan (gelatinous extracts used as binder for food or product) Philippines, May 2009.

Juergen Freund / Aerial view of a seaweed farmer tending his crop, growing agar-agar for processing into carageenan (gelatinous extracts used as binder for food or product) Philippines, May 2009

Alex Mustard / Female Grey seal (Halichoerus grypus) tangled in a discarded fishing net, Lundy Island, Devon, England, UK, July 2010.

Michel Roggo / Underwater landscape in Spring creek, Saane river tributary, in winter, Gruyre, Fribourg, Switzerland. February

Niall Benvie / Enteromorpha seaweed rooted in sand, exposed by spring tide, Scotland, uk

SINCLAIR STAMMERS / Light photomicrograph of Blue green algae / Cyanobacteria (Nostoc sp) capable of nitrogen fixation, and used for soil enrichment especially with rice cultivation. The long filaments are composed of in...

SINCLAIR STAMMERS / Phase contrast photomicrograph of Blue green alga / Cyanobacteria (Spirulina platensis) each algal filament or Trichome is 5 microns in diameter.

Wild Wonders of Europe / López / Aerial view of saltmarsh exposed at low tide, Baha de Cdiz Natural Park, Cdiz, Andalusia, Spain, March 2008

Alex Hyde / Light micrograph of pond water including single celled algae called desmids {Desmidiaceae sp}

Wild Wonders of Europe / Hermansen / Seaweed, Tory Island, County Donegal, Republic of Ireland, June 2009

Wild Wonders of Europe / O. Haarberg / Algae growing in rock pools on rocky coast, Lngviksskr, Stockholm Archipelago, Sweden, June 2009

Richard Herrmann / Garibaldi (Hypsypops rubicundus) amid kelp, San Clemente Island, Channel Islands, California

Fabio Liverani / European Edible Frog (Rana esculenta) eating a Green eyed hook tailed dragonfly (Onychogomphus forcupatus) amongst pond weed, Grigne Mountains, Lombardia Region, Italy

Kim Taylor / Filamentous green algae {Spirogyra sp} showing cell structure

Kim Taylor / Blue green algae {Oscillatoria sp} floating in lake, UK.

Fred Bavendam / Stromatolites, colonies of blue-green algae, the oldest life form that still exists today fossils dated to over three billion years ago, Hamelin pool, Western Australia

Peter Bassett / Green snow algae. Petermann Island, Antarctic Penninsula, Antarctica

Alex Mustard / Sacoglossan sea slug (Costasiella sp.) tiny <5mm along, on algae. Anilao, Batangas marine protected area, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Alex Mustard / A raft of sargasso weed (Sargassum natans) in open ocean. Off shore, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Franco Banfi / Bladder wrack (Fucus sp) exposed at low tide. Vrangel Bay, Primorsky Krai, Russia. August.

Franco Banfi / Bladder wrack (Fucus sp) exposed at low tide. Vrangel Bay, Primorsky Krai, Russia. August.

Franco Banfi / Bladder wrack (Fucus sp) frond on sand at low tide, Vrangel Bay, Primorsky Krai, Russia. August.

Sergio Hanquet / Emerald wrasse (Symphodus trutta) male making nest of algae where female will deposit eggs. Tenerife, Canary Islands.

David Hall / Ghost pipefish (Solenostomus sp) pair camouflaged amongst green algae. Komodo, Indonesia.

Shane Gross / Stoplight parrotfish (Sparisoma viride) eating algae on coral reef. Eleuthera, Bahamas.

Tony Wu / Korean sandlance (Hypoptychus dybowskii) egg clusters on Sargassum (Sargassum horneri). Fish produce sticky secretion in kidneys that adheres eggs to Sargassum. Hokkaido, Japan. May.

Nick Upton / Common shore crab (Carcinus maenas) hiding among Coralweed (Corallina officinalis) in a rock pool, Cornwall, UK, March.

Gary Bell/ Oceanwide / Kelp, Port Phillip Bay, Mornington Peninsula, Victoria, Australia

Gary Bell/ Oceanwide / Kelp holdfasts, Governor Island Marine Reserve, Bicheno, Tasmania, Australia

Gary Bell/ Oceanwide / Kelp and algae, Western Port Bay, Mornington Peninsula, Victoria, Australia

Gary Bell/ Oceanwide / Sea Lettuce (Ulva australis) and other alga, Hopkins Island, South Australia, Australia

Gary Bell/ Oceanwide / Wine Glass Alga (Acetabularia major), Anilao, Philippines

Theo Bosboom / Detail of a piece of of kelp seaweed (Laminaria hyperborea) with snow and sand, as photographed on Bosta beach, Isle of LewisScotland, UK, February.

Theo Bosboom / Dragon shaped rock with green algae on the Amoreira beach, Aljezur, Alentejo region, Portugal. May 2017.

Alex Mustard / Algae farming white damselfish (Dischistodus perpicillatus) attacks a herbivorous green sea turtle (Chelonia mydas) that is feeding in its territory. Misool, Raja Ampat, West Papua, Indonesia. Ceram S...

Nick Upton / Common pond skater (Gerris lacustris) standing on the surface of a garden pond before skating off at speed, with many colonial Green algae (Volvox) spheres moving below the surface, Wiltshire, England...

Georgette Douwma / Banggai cardinalfish (Pterapogon kauderni) with Green algae (Halimeda copiosa). Lembeh Strait, North Sulawesi, Indonesia.

Nick Hawkins / View of stipe and holdfast of sugar kelp (Saccharina latissima) off Nova Scotia, Canada. September

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

Nick Hawkins / View of kelp forests (Laminaria digitata) off Nova Scotia, Canada. July.

Nick Hawkins / Oarweed kelp (Laminaria digitata) off Nova Scotia, Canada. September

SCOTLAND: The Big Picture / Mysid on algae (Fucus serratus), Shetland Isles, Scotland, UK, June.

SCOTLAND: The Big Picture / Split level view of a Kelp forest (Laminaria hyperbore) at Mousa Broch (iron age tower) Shetland, Scotland, UK, August.

SCOTLAND: The Big Picture / Kelp forest (Laminaria hyperborea) in the clear seas of Scotland, UK, September.

Nick Upton / Duckpool Beach and rock pools at low tide, with a variety of green and brown algae covering rocks, near Bude, Cornwall, UK, September 2018.

Georgette Douwma / Funnelweed (Padina gymnospora) and Green Algae (Halimeda sp.). West Papua, Indonesia. Indo-West Pacific.

Ralph Pace / Pacific Sea Nettle (Chrysaora fuscescens) jellyfish in kelp, Monterey Bay, California

Ralph Pace / Halfmoon (Medialuna californiensis) school under kelp paddy, San Diego, California

Ralph Pace / Halfmoon (Medialuna californiensis) school under kelp paddy, San Diego, California

Ralph Pace / Pelagic Red Crab (Pleuroncodes planipes) group on kelp, indicators of El Nino, California

Ralph Pace / Green Sea Turtle (Chelonia mydas) feeding on seaweed, San Diego, California

Ralph Pace / Green Sea Turtle (Chelonia mydas) feeding on seaweed, San Diego, California

Ralph Pace / Green Sea Turtle (Chelonia mydas) feeding on seaweed, San Diego, California

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.

Franco Banfi / Amphipods (Amphipoda) on Kelp (Laminaria sp). Tasiilaq, East Greenland. April.

Franco Banfi / Robust frond-aeolis (Dendronotus robustus) nudibranch on Kelp. Tasiilaq, East Greenland. April.

John Cancalosi / Snapping turtle (Chelydra serpentina) amongst leaves in blue-green algae (Woronichinia naegeliana). Microcystin produced is toxic to wildlife and humans. Maryland, USA. October 2018.

Nick Hawkins / Galapagos green turtle (Chelonia mydas agassizi) feeding on marine algae on sea floor. Near Isabela Island, Galapagos.

John Cancalosi / Red-eared slider (Trachemys scripta elegans) in blue-green algae (Woronichinia naegeliana). Microcystin produced is toxic to wildlife and humans. Maryland. October 2018.

John Cancalosi / Black-crowned night-heron (Nycticorax nycticorax) juvenile preening whilst standing on log. Toxin forming Blue-green algae (Woronichinia naegeliana) in water behind. Maryland. October 2018.

David Fleetham / California sea lions (Zalophus californianus) playing in a kelp forest off Santa Barbara Island, California, USA.

David Fleetham / California sea lions (Zalophus californianus) playing in a kelp forest off Santa Barbara Island, California, USA.

Alex Mustard / Harbour seal (Phoca vitulina) in the kelp forest (Macrocystis pyrifera). Santa Barbara Island, Channel Islands. Los Angeles, California, United States of America. North East Pacific Ocean.

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...

Kevin Schafer / Common Dolphin (Delphinus delphis) pod, Santa Barbara Channel, Channel Islands National Marine Sanctuary, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) fatally injured in collision with ship and subsequently found by research vessel, Santa Barbara Channel, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) surfacing, Santa Barbara Channel, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) surfacing, Santa Barbara Channel, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) with researcher Bruce Mate on boat attempting to attach satellite tag, Santa Barbara, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) with researcher Bruce Mate on boat attempting to attach satellite tag, Santa Barbara, California

Flip Nicklin / Blue Whale (Balaenoptera musculus) with researcher Bruce Mate attempting to attach satellite tag, Santa Barbara, California