"The Beasts of the Benthos—Scary Sancturary"
It is autumn; the Earth slowly turns its face from the sun’s resplendence and toward the ever-darkening sky. Creatures of land and the air respond to this transition, and we humans, too: with fire festivals such as Samhain and Halloween, to ward off the spirits of darkness. But to animals living in the sea’s depths, each day brings eternal midnight. This month, NOAA scientists will encounter many of them as we explore the sea floor and adjacent waters - the benthos - off Point Arena and the Sonoma Coast. Who knows what curious, mysterious, even frightening creatures lurk in these night-bound kingdoms?
CHIMAERA, or Ghost Shark: This denizen of the deep’s bulbous head appears stitched together, like a briny Frankenstein’s Monster. Named after the mythical part-lion, part goat-part snake beast, the chimaera is neither shark nor spirit, but a cartilaginous fish found in oceans worldwide at depths to 8,500+ feet. Sharks are their closest living relatives, but diverged evolutionarily nearly 400 million years ago. Reaching five or six feet in length, most chimaeras have a defensive venomous spine at their dorsal fin. On the snout are tiny pores which lead to electroreceptor cells to detect electrical fields of their fish prey, a sharky “sixth sense.”
SLIME STAR (Pteraster tesselatus): This pudgy six-inch sea star has five stumpy arms and a smooth skin that gives it a pillowy shape; it may be orange, red, tan, gray or brown. It preys on sponges and other marine invertebrates. When threatened, it produces copious amounts of clear mucous, a sticky, suffocating defense weapon to repel attacks by other, fiercer members of its family like the many-armed sunflower star. Rows of spines add to its armory. Off the west coast of North America, it favors rocky habitats, from Alaska’s Bering Sea southward to central California, and across the North Pacific Basin to depths of 3,120 ft.
SHRIMP: Several shrimp and krill species are equipped with photophores – light-producing organs that may appears as luminous spots. Some are as complex as the human eye, with lenses, shutters, reflectors, color filters. In shallow waters, they can emit light that helps them blend in with the sunlit sea. But in the blackness of the abyss, these chemical “lamps” can be used to attract unwary prey. Some shrimp species have an additional method of using light: when threatened, they can spew glowing bioluminescent clouds from their mouths for predatory defense to startle their enemies and conceal themselves as they flee.
VAMPIRE SQUID: The vampire squid, Vampyroteuthis infernalis, or "the vampire squid from Hell," isn’t your ordinary cephalopod (head-footed marine invertebrate): it shares characteristics with both the true squid and the octopus. It has adapted to tremendous pressure at over 3,000-foot depths, and low-oxygen conditions that would kill many other sea creatures.
In form, the Vamp lives up to its name: blood-red, its skin is almost covered by light-producing photophores. Its eyes shine fierce red, or cold blue. But its ominous aspect is betrayed by its small size, about that of a football. Surprisingly, this imposter does not feed on blood! Its sticky tentacles capture plant and animal matter floating in the water column. A web of skin – its vampire “cloak” – connects eight glow-tipped arms and is blackish on the inside. When a predator approaches, it inverts the cloak over itself, displaying a formidable array of spines.
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COMING UP SOON, NOAA GOING DEEP! From October 4 to 11, in cooperation with NOAA’s Greater Farallones and Cordell Bank national marine sanctuaries, the Ocean Exploration Trust’s ship E/V Nautilus will explore the benthos off the Redwood Coast. Hear scientists discuss their discoveries via live stream video, 24/7. http://www.nautiluslive.org. Note: For live dive updates follow along on social media at http://www.facebook.com/nautiluslive and @evnautilus on Twitter. And check out Instagram @nautiluslive.
