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Since summer 2013, starfish along both coasts of the United States have been dying in large numbers—and not gracefully. As their tissues collapse, the starfish (also called sea stars) start to look stretched and...
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Tiny plant-like organisms called zooxanthellae live in the tissues of many...
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I have been at the Smithsonian’s National Museum of Natural History since 1966...
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Collect, sort, identify, photograph, sample, record. Repeat a couple thousand...

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A huge colony of brittlestars (likely Ophiacantha rosea ) covers the peak of a seamount in the deep ocean. What’s the attraction? Food! Their arms reach out for tiny food particles carried by the swift Antarctic Circumpolar...
This copepod Calanus hyperboreus (up to 7mm in length) lives in the Arctic...
Deep-sea corals miles away from the source of the Deepwater Horizon oil...

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Jellyfish and comb jellies are gelatinous animals that drift through the ocean's water column around the world. They are...
A veined octopus ( Amphioctopus marginatus ) briefly leaves its hiding spot, a seafloor shell, to devour a crab.
Syllid fireworms are a part of the Syllidae family , which is a type of polychaete worm. Usually these small worms, not getting much bigger than 13 cm, live on the ocean floor. But when the worms...
Nudibranchs are mollusks that have evolved from shelled ancestors. Like the reddish-orange Coryphella verrucosa shown here, they're often noted for their vibrant colors and striking forms. View other...
Two California market squids ( Loligo opalescens ) mate in the waters off of California's Channel Islands. While spawning, the male's arms blush red as he embraces the female, a warning to other...
Hyperiid amphipods are small crustaceans related to sand fleas and distantly related to shrimp. They range in size from very tiny to more than 7 inches long, and are found at all depths of the ocean...
This male giant squid is on display in the Sant Ocean Hall at the Smithsonian’s National Museum of Natural History . It measures about 2.7 meters (9 feet) long and weighs a little more than 45.5...
A blue cod and sea pens , a unique type of cnidarian , speckle the seafloor in New Zealand's Fiordland region.You can see more beautiful underwater photos from Brian Skerry in his image gallery .
Found in the icy waters of the Arctic , Comb Jellies, or ctenophores like this one, of the Aulacoctena genus, are poorly known animals. With extremely fragile bodies, they are difficult to capture...
Throughout their lifecycle, jellyfish take on two different body forms: medusa and polyps. Polyps can reproduce asexually by budding, while medusae spawn eggs and sperm to reproduce sexually. Learn...
A sea star , Hymenaster pellucidus , brought up from a benthic ROV dive. View the “Under Arctic Ice” photo essay to learn more.
The blue-lined octopus may be small, growing to at most 15 cm, but it can be deadly: its venom can cause breathing failure in humans as well as other animals. Turtles can accidentally consume the...
A rockfish finds refuge in a deep-sea coral—a red tree coral of the Primnoidae family in the Olympic Coast National Marine Sanctuary. Learn more about deep-sea coral reef ecosystems in our Deep-sea...
Come one, come all! See the amazing, the astonishing, half-animal, half-plant! Journey to Tampa Bay, Florida, where scientist Skip Pierce and one of his students first made a remarkable discovery...
Claws, spines, spikes, tentacles, and fangs. Aliens, monsters, and ghostly apparitions glowing in the night. Marine life forms have some of the best looks for Halloween—no costumes needed. From...
Ochre seastars ( Pisaster ochraceus ) feed on invertebrates, such as coral and shellfish, like the mussels pictured here. The starfish forces open the shell with suction disks on the underside of its...
A humboldt squid ( Dosidicus gigas )—also known as the jumbo squid—releases a cloud of ink at night in Mexico's Sea of Cortez. These large, carnivorous squids can reach more than 5 feet in length and...
Coral reefs are the most diverse of all marine ecosystems. They teem with life, with perhaps one quarter of all ocean species depending on reefs for food and shelter. This is a remarkable statistic...
Weighing 600 pounds (around 272kg) and having a 30 foot (around 9 meters) arm span, the largest recorded giant pacific octopus was truly enormous. Giant pacific octopuses are powerful predators that...
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