Life in the Deep
New research shines a light on undersea creatures
Scholastic Kid Reporter Abi Robinson next to the Ventana, a submersible used to gather underwater specimens. The Ventana has a manipulator arm so strong and precise that it can pick up a dime and fold it in half. (Photo courtesy Abi Robinson)
Drifting through the blackness, a glowing sphere pulsates as it feeds on invisible bacteria. Not far from there, thousands of feathered red stalks form a flowing red carpet over a huge, unidentifiable mass. A giant, eyeless blob with lumpy tubes hanging off it floats away into the darkness.
Though it sounds alien and otherworldly, this strange setting isn’t a scene from a science fiction story—it occurs in Earth’s largest continuous ecosystem, the deep sea.
Miles beneath the ocean surface, where scientists once thought that life could not exist, thousands of species thrive. There are no light or plants and very little oxygen, but there is life. The Monterey Bay Aquarium Research Institute (MBARI) is working to learn more about the mysterious creatures of the Monterey trench, a deep-sea canyon that extends deep underwater but is close to land near Monterey, California. To find water this deep sometimes takes days of travel over water. In Monterey, the trench is easy to get to.
MBARI sends robotic vessels 20,000 feet underwater to gather images of these strange sea creatures. Called submersibles, these vessels are equipped with specialized underwater cameras and 3,000-watt light bulbs. A 3,000-watt bulb is 50 times as bright as an ordinary household light bulb!
One MBARI submersible, the Ventana, has a manipulator arm so strong and precise that it can pick up a dime and fold it in half. Underwater, the manipulator arm is used to gather specimens and place equipment on the sea floor.
The water pressure at these depths is equal to more than 17,000 buckets of water sitting on your head. It’s enough to compress a regular Styrofoam cup into a two-inch-tall miniature. To operate in the deep sea, the $2.5 million submersible is specially constructed, using extra strong and lightweight titanium metal.
The animals that live in the deep sea also have to adapt their parts to survive the dark, cold environment. Most are made almost entirely of solid and liquid matter, with no air pockets anywhere. That’s because water pressure only affects the empty places in the body, places where there is air. For example, when you’re underwater at the bottom of a pool, your ears hurt from the water pressure, but not your arms or legs.
Instead of the air sacs that fish use to control their buoyancy, some deep-sea creatures use chemical changes in their blood. Many creatures have enlarged eyes to help them see in the dark. Some produce their own light, called bioluminescence, to help attract prey or find a mate.
The harsh deep-sea environment also forces deep-sea creatures to be creative when it comes to finding their next meal. Some hunt other deep-sea animals, while others live on “marine snow,” organic waste from above that’s been recycled over and over again and drifts down into the depths.
Unlike almost any other place on Earth, some parts of the deep sea don’t depend on the sun as the energy source for the food cycle. In these areas, the life cycle begins with chemosynthesis—chemicals being eaten by bacteria, then sea creatures eating the bacteria. The chemicals come from “cold seeps,” or ocean floor vents. Chemosynthesis, or the creation of energy from chemicals, replaces photosynthesis in this pitch-black environment.
|See a slideshow of some of the strangest creatures found by the Monterey Bay Research Institute in the trench off the California coast. (Photo: Courtesy MBARI)|
But when a whale carcass falls to the deep-sea floor, the local wildlife take a break from their bacterial diet. Entireecosystems develop around these huge sources of food. The food that creatures can obtain from one “whale fall,” as marine biologists call them, is equal to thousands of years of marine snow. Crabs, sharks, and other scavengers feast on the remains. When the rest of the whale has been consumed by other animals, specialized worms called Osedax, which were first identified by an MBARI scientist, take advantage of the skeleton itself. The Osedax form giant colonies that look like a red shag carpet spread over the bones.
Scientists at MBARI study subjects as tiny as the Osedax and as huge as global climate change. Seemingly small changes in the global climate can have major effects on the ecology of the deep sea.
For example, Atlantic Ocean currents coming from the Bahamas are warm, and they stay near the top of the water. By the time the water reaches Europe it’s cooled off, and the cold water sinks to the deep sea. Since the water’s been near the surface so long, it has the oxygen in it that animals need to live. However, global warming could cause the water to stay warm so long that it might never reach some areas of the deep sea. The creatures living in these areas would die, since no oxygenated water would reach them.
“It’s not just science fiction; it’s happened . . . and it could happen again,” said Robert Vrijenhoek, a senior scientist at MBARI.
We may never know everything about the deep sea, but thanks to the scientists and engineers at MBARI, we’re discovering more and more about the largest continuous ecosystem on the planet. To learn more about MBARI and the otherworldly creatures they are studying, visit their Web site.
Life in the Deep
Find out more about exotic sea life in our special report.
Abigail Robinson is a member of the Scholastic Kids Press Corps.