Montshire Minute: Deep Sea Life

Originally aired during the week of January 22, 2001

Monday

We've all seen pictures of the ocean floor, taken from deep-sea submarines. Like film of the wreck of the Titanic, 12,000 feet down. But not so long ago, exploring even a few thousand feet down was considered daring to the point of rashness. The cold, the darkness, and the incredible underwater pressure made undersea exploration a risky business. But that spunky, can-do human spirit of discovery can't be denied. In 1934, naturalist William Beebe and a colleague climbed into a steel ball called a bathysphere and descended 2500 feet into the ocean off the coast of Bermuda. During the two-hour dive, Bebee frantically tried to communicate by telephone the variety of sealife that swam past the craft's small window. Bebee saw life no one had seen before. In the darkness half a mile below the surface, schools of luminescent sealife flashed by like bursts of fireworks in the night sky.

Tuesday

We don't think of the ocean as having a climate, at least in the same way we landlubbers have a climate. But there are big differences in temperature, light, and pressure in underwater worlds. Most familiar communities of plants and animals, like coral reefs, live near the water's surface. Life in the reef depends on solar energy to make photosynthesis happen. But most of the sun's life-giving energy penetrates only a few hundred feet underwater. On land, air pressure is pushing down about 15 pounds per square inch. By contrast, the pressure underwater increases the deeper you go. The water pressure at 3,000 feet down is 15 times the atmospheric pressure on the surface. As you might expect, creatures that can survive the extreme deep-sea climates must have some pretty radical adaptations. Some of them even glow in the dark!

Wednesday

Imagine you are piloting your robot submarine deep into the depths of the ocean. The ocean is pitch black! The temperature is near freezing! If you were to swim outside your sub for even a moment, the pressure would crush you like a paper cup! Sorry, I didn't mean to get carried away. What I'm saying is, this is a pretty extreme environment. But as you look out the window of your craft, you see many creatures have found a way to survive here. C.P. Idyll points out in his book Abyss, you might expect deep-sea fishes to have leathery skin and thick, strong bones to withstand the marine pressure. But the flesh of most fish here is soft and jelly-like. This soft, watery material makes the fish more buoyant and resistant to strong pressure. These animals don't need strong skeletal structures to move in deep water where the currents are weak.

Thursday

Thousands of feet under the ocean's surface is a world inhabited by creatures with names like the vampire squid, the viperfish, and the black angler. Sounds like science fiction, huh? Maybe, but this is totally real. One adaptation of deep-sea fish relates to color. Most take on brown or black hues to hide from predators. Shrimp and some other crustaceans in deep water regions may be reddish in color. But surface waters of the ocean absorb the long wavelengths of red light first. Since none of these waves penetrate the deeper waters, animals with red colors appear black. Many of these fish have also developed enlarged eyes to help them adjust to the darkness. These fish are not always "in the dark"-they sometimes move to upper regions of water to feed or spawn. Eyes are also useful in detecting light that fish manufacture themselves-that is, light produced by fish through chemical reactions.

Friday

Hey, who turned off the lights! Thousands of feet below the ocean's surface there is almost no light to see by. So some of the animals that live here have adapted by making their own light. Creatures use "bioluminescence" to attract prey or to ward off predators. The angler fish is one example. This fish lives in extreme depths, and is about the size of a man's fist. It has a big mouth, with sharp fang-like teeth. Cute huh? Let's just say its nickname is the "black devil." The most amazing thing about the angler fish is its long dorsal spine, tipped with a light-producing organ called a photophore. The fish uses this strange looking lantern, which seems to hang in front of its head, to attract prey. It can flash its light on and off while waving it back and forth. When curious passerby get close enough, the angler grabs at them with its powerful jaws.