Imagine you are a scientist in a miniature submarine, sinking slowly to the ocean floor. 90 minutes later, you have traveled almost two miles down and the water temperature outside your vessel is now barely above freezing. The bright search lights are turned on and you peer out into the murky water. You don’t expect to find much life here; besides being extremely cold and dark, the pressure at this depth is 275 times that at sea level. As your submarine maneuvers around a rock formation, you see a smoking chimney of dark water rising from the ocean floor. A bizarre community of animals is gathered here — eight-foot-long red worms protruding from milky-white tubes, giant clams, big yellow jellyfish that look like dandelions hanging by strings and blind fish that resemble giant tadpoles.

In 1977, this imaginative journey came to life, as researchers aboard the deep-diving submarine Alvin discovered mysterious chimneys, or vents, and the incredible variety of life around them. Just as warm water is forced up to the earth’s surface in the form of hot springs like “Old Faithful” in Yellowstone Park, these underwater vents are escape points for water trapped below the ocean floor. Heated by underground volcanic activity, this water may reach a temperature of 570 degrees Fahrenheit inside the vent, but then cools quickly when it mixes with the near-freezing water at the ocean floor. The area directly around these vents stays at about 55 degrees Fahrenheit.

Biologists are very curious about the life around deep-sea vents. For example, how do these animals survive in this unusual environment? On earth, all life forms depend on energy from the sun to survive. The animals living near these underwater vents, however, seem to be an exception. Scientists, have discovered that the deep sea vent animals depend on chemicals in the water, rather than sunlight for energy. This process is called chemosynthesis. Research also indicates that the vents are not permanent and may close up 50-100 years after they break open. If they do close, where do the animals go? How do they live? Perhaps these questions will be answered as scientific explorations of the sea continue.

Do it yourself

Make a model of the hot water of a deep sea vent in the cold water of the ocean.


Make your own deep sea vent

  • One large glass container
  • One small bottle
  • Food coloring
  • A piece of string
  • Hot and cold water


  1. Fill the large glass container with very cold water.
  2. Tie one end of the string around the neck of the small bottle.
  3. Fill the small bottle with hot water and add a few drops of food coloring.
  4. Keeping the small bottle upright, carefully lower it into the glass container until it rests on the bottom.
  5. Watch what happens. What does this tell you about deep sea vents?