An Earth Day celebration wouldn’t be complete without a captivating peek into the mysterious depths of our planet’s most species-rich yet mysterious ecosystem: the ocean.
From alien-like pelagic squid to spooky mantis shrimp, the winners of the 2015 Ocean Art Underwater Photo Contest do not disappoint.
Photographers from across the globe submitted thousands of breathtaking ocean photographs to this prestigious competition, which was developed and produced by the Underwater Photography Guide.
The organisation announced winners of this year’s contest on January 6.
Check out our 40 favourites (chosen from the 75 winning photographs) below. They’re absolutely stunning.
Photographer Christian Gloor lit this tiny mantis shrimp from below to give it a spooky look in the waters of Air Bajo III, Indonesia.
A school of Starry Toado Pufferfish make their way to shelter in the Maroro Bay waters off the coast of Northland New Zealand.
A frisky young California sea lion flirts with the camera in Landing Cove near Santa Barbara Island in California.
This shot of the jellyfish Rhizostoma pulmo in the waters of Forte dei Marmi, Italy snagged first place in the 'Wide-angle' category.
Photographer Brian Christiansen shot this back lit profile of a dolphin while swimming with a giant pod of them in Deshaies, Guadeloupe.
Dolphins and sea birds feast on a school of sardines as the fish migrate along the coast of South Africa.
A male seahorse recovers lost eggs from his pouch, which he will carry for up to 45 days before the babies develop and emerge.
A female striated frogfish releases a raft of eggs for the male to fertilize in Blue Heron Bridge in Lake Worth Lagoon in Florida.
A brilliantly coloured sea slug -- Felimare picta -- rests on the north coast of the Balearic island Minorca in Punta den Siulet.
Francesco Pacienza won first place in the 'Conceptual' category for this image of him 'painting' an Axinella sponge under the waters of Santa Maria al Bagno in Apulia, Italy.
A skeleton shrimp poses for a super close-up photoshoot with photographer So Yat Wai in Tulamben, Indonesia.
A collection of baby clownfish 'look like tiny shards of glass with big eyes,' photographer Lynn Wu says. This image was taken in Anilao, Philippines.
Photographer Jack Berthomier snapped this Tylosorus crocodulis fish chomping on a smaller fish while freediving in Ouemo Bay in Noumea, New Caledonia.
A curious young sea lion gives photographer Stephen Holinski a playful hug before swimming away near Hornby Island in Canada.
Photographer Sarah Teveldal shot this conceptual photograph of an underwater mermaid tea party in a pool 12 feet deep. All props and scenery were anchored down with fishing line and fishing weights.
A pink-eared mantis shrimp carries, protects, and keeps a mass of eggs on her front appendages clean in the waters of Lembeh Strait in Indonesia.
A female humpback whale nears diver Gustavo Verzoni just 24 hours after her calf was hunted and killed by a pair of orcas.
An American crocodile nears the surface to breathe, but not without a smile, in Jardines de la Reina, Cuba.
Photographer Uri Magnus Dotan snapped this conceptual image of a diver finding sunken treasure about 20 feet under the surface of the Red Sea in Eilat, Israel.
A massive sunfish in Crystal Bay, Indonesia floats up from the deep to rid itself of parasites. They do this by inviting fish and birds to snap them off their skin, or by splashing around on the surface to shake them off.
A stingless golden jellyfish floats around The Jellyfish Lake in Palau. They have evolved there for thousands of years.
A pregnant black tip shark swims over photographer Lauric Thiault in La Vallée Blanche, French Polynesia.
A hungry California sea lion is forced to eat a sunfish because warmer waters from El Niño are causing their normal prey to move north.
It took photographer Daniel Copeland an hour to get this calm split shot of the coral-dotted Ras Mohammed National Park in the Egyptian Red Sea.
Giant Australian Cuttlefish aggregate in the shallow waters and rocky outcrops of Whyalla in South Australia to breed and deposit the next generation of cuttlefish.
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