New Revelations of Sea Animals' World
MICHELE NORRIS, host:
Scientists studying the ocean tend to look near the surface or at the sea bottom. What lies in between, the vast midwaters, have barely been explored. That's why scientists keep finding surprises there. NPR's Christopher Joyce tells us about two new discoveries made off the coast of California in Monterey Bay.
CHRISTOPHER JOYCE reporting:
For a long time, the best scientists could do to find out what lived in the deep ocean was to look in fishing nets or along beaches for animal corpses. Anything delicate, like the jellyfish, wasn't likely to make it that far. Then robot submarines came along, and now scientists are awash in bizarre animals, such as siphonophores. These are like jellyfish, but long and skinny. Marine biologist Steven Haddock says you can think of a siphonophore as one animal or a colony.
Mr. STEVEN HADDOCK (Marine Biologist): The siphonophore, itself, is a strange organism. It has sort of like a tube. And hanging down from that tube are a series of stomachs and tentacles and reproductive structures in this repeating series all along the chain, so they grow just by adding those units.
JOYCE: Some species keep adding units until they're over a hundred feet long.
Mr. HADDOCK: You know, it's only the size of a broom handle around, but it just stretches on and on and on, and it just keeps going and going, and they're the ones that have these tentacles maybe hang out for a meter or two down below, and so they form this curtain.
JOYCE: A drifting curtain of six-foot-long deadly tentacles. The species Haddock found was somewhat shorter, only about two feet. But size isn't the point here. It's chemistry. Haddock noticed that attached to some tentacles was a glowing red bulb, something like a lure.
Mr. HADDOCK: It's almost like a Tootsie Pop. There's a stalk. And suspended at the end of the stalk is this lure, and it glows red.
JOYCE: Lots of jellyfish glow with a blue or green light when provoked; it's a form of chemically created luminescence, and usually serves as a warning. But red light is extremely rare in sea creatures. Haddock suspects some fish in the deep sea may be lured by the red light and to the siphonophore's tentacles. Haddock's expedition by the Monterey Bay Aquarium Research Institute is described in the journal Science.
Another recent Science paper appears to solve a long-standing mystery about carbon in the deep sea. It also came about from an expedition by institute scientists. They were looking at larvaceans. They're two-inch-long sea squirts that drift through the deep sea inside a sort of house, each one built out of mucus. Biologist Kim Reisenbichler says the weblike house is a strange sight drifting into the beam of an underwater spotlight.
Mr. KIM REISENBICHLER (Biologist): I guess a sort of almost a transparent hot-air balloon with particles stuck on the side of it: small pieces of marine snow, fecal pellets. Small critters also live on it.
JOYCE: Scientists knew about these animals, but didn't realize how many there were until they started counting the dead ones.
Mr. REISENBICHLER: We'd see them all the way to the bottom, and then going to the bottom, we would see them lying on the bottom, hanging on the canyon walls at densities as high as one per meter.
JOYCE: And here's the mystery part. Microscopic animals on the seafloor depend on carbon. Most comes from marine snow: dead animals and fecal material that rain down from above. But scientists have measured marine snow, and there isn't enough to explain all the carbon on the bottom. So where was the extra coming from? Apparently from innumerable dead sea squirts drifting down to hungry mouths on the seafloor. Christopher Joyce, NPR News.
ROBERT SIEGEL (Host): You're listening to ALL THINGS CONSIDERED from NPR News.
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