Food can be scarce in the deep waters off Australia. To clutch its prey, this dragonfish uses sharp rows of teeth that cover even parts of its tongue. The fish is one of thousands of species documented by the Census of Marine Life, a ten-year project that is nearing completion. Across its 25 study sites on all seven continents, the Census has found that fish account for an average of 12 percent of all underwater life. Although waters off Australia's tropical northern coast share many species with the Indo-West Pacific, scientists have found that Australia's more temperate—and isolated—southern waters host species that are found nowhere else. Up to 90 percent of the species are endemic, more than in any other region studied by the Census. However, scientists estimate that only around 10 percent of Australia’s marine species are known today.
The sponge brittle star (Ophiothrix suensonii) lives within or near sponges and soft corals in the ocean. These are not your average starfish—adorned with long, shiny spines on each of their arms, these stars come in a range of colors befitting a sunset. Unlike areas such as Australia, which has a high number of species found only in that region, the enclosed Caribbean has fewer than 2,000 endemic species. And that limited biodiversity has been threatened in recent years by hurricanes, disease, pollution, climate change and overfishing.
The giant Caribbean anemone (Condylactis gigantean) is commonly found in the inner reefs and lagoons of the West Indies and the western Atlantic. It can grow up to 16 inches in diameter and is identifiable by the brightly colored tips of its tentacles. But beware: these eye-catching anemones have venom in their tentacles, which they use to stun and capture their prey.
China is one of the 25 areas targeted by the Census of Marine Life, and its seabeds have the greatest density of different species. The spider conch (Lambis chiragra), a gastropod mollusk with six fingerlike projections sticking out of its shell, is one of these seabed dwellers. Female spider conchs can grow to be up to eight inches larger than males, though the apertures, or openings, of male shells tend to be more brightly colored.
Not only does the Venus flytrap anemone (Actinoscyphia saginata) resemble the well-known carnivorous plant, but it also emulates the plant's behavior. The anemone, an inhabitant of deep-sea reefs, closes its jaws to trap its prey and to protect itself when threatened. Anemones, coral and jellyfish make up approximately 5 percent of all marine life documented in the Census.
The roving Phronima sedentaria, a small crustacean, inhabits the hollowed-out bodies of dead barrel-shaped organisms called salps. The crustacean deposits its young on the salp barrel, in a phenomenon called demarsupiation. This unique creature is part of an imperiled community of aquatic organisms in the Gulf of Mexico, where poor water quality and habitat loss have weakened the ecosystem.
One of 25 species in the deep-water genus Benthoctopus, this cephalopod lives in Gulf of Mexico waters as deep as 13,000 feet. Mollusks—a group that includes squid, octopuses, clams, snails and slugs—are one of 12 different phyla or sub-phyla documented by the Census of Marine Life. The group accounts for 17 percent of all marine species, according to the Census, making mollusks the second most diverse group, after crustaceans.
You won’t spot this striking jellyfish (Atolla wyvillei) anywhere near the ocean’s surface—which is a shame, because this deep-sea inhabitant, which lives at depths as great as 16,000 feet, has its own built-in light show. When caught by a predator, A. wyvillei lights up in a process called bioluminescence. This “burglar alarm,” scientists speculate, is meant to attract the attention of an even bigger creature that might be able to eat the predator and free the jellyfish.
According to an estimate from the Census of Marine Life, more than 70 percent of marine species in Japanese waters have yet to be discovered. In pursuing this abundance of unknown species, researchers may find that whales are an excellent, if unexpected, place to start. When whales die, their sunken bodies become prime habitat for a variety of sea creatures. This gastropod (from the Hydatinidae family) was recently discovered living on a sperm whale carcass in the deep sea near Kagoshima in southern Japan.
The word “osedax,” Latin for “bone-eating,” is an apt description of this whale-carcass dweller; Osedax roseus, known as the zombie worm, inhabits and feeds on whale bones. Each female has dozens of dwarf male zombie worms living inside a gelatinous tube that surrounds her body. Flatworms such as these are just one of the 33,000 known species in Japanese waters.