Life in the Water Supply

Resource for Grades 4-8

| Citation

Media Type:
Video

Running Time: 3m 20s
Size: 21.0 MB

Source: Nature: "Springs Eternal: Florida's Fountain of Youth"

Learn more about the Nature film "Springs Eternal: Florida's Fountain of Youth."

Resource Produced by:

In this video from Nature, a team of scientists dives into one Florida town’s water supply, in a series of caves nearly 150 feet below the bedrock of the town itself. They have found life there, living in near darkness with no apparent source of food or energy to create food. On further exploration, they observe a bacteria living on a horizon between fresh and salt water that serves as the basis for all life in the cave.

Permitted use:

Download and Share

Accessibility Features: Transcript

Discussion Questions

Where do you think your drinking water comes from?
Describe the species in the Florida water supply. What makes it possible for them to survive there?
What is one indication that the water quality, in the aquifer, is high?

Print Discussion Questions

Transcript

Narrator: The divers started in the ocean, but they are now within solid bedrock, one hundred fifty feet beneath someone's living room.

They are now swimming in the water supply for the town above. Here they find, as they had hoped, life in the pitch darkness. These are hydroids, small filter-feeding organisms: a species entirely new to science.

Around the hydroids are mussels. Neither of them are found in the springs above. Both are anchored to the rock and live on food that drifts by. But there is no apparent sign of food and no energy to create it. In almost every living system the sun provides fuel for all life - but there is no sunlight here. How are these organisms kept alive?

With such exciting discoveries, the team decides to press on. But time--and air--are finite. Their air is consumed quickly at this depth and each minute they stay will increase the time they must spend decompressing before they can leave the water. The slightest turbulence stirs up sediment - which can render visibility from hundreds of feet to nearly zero.

Then, three thousand feet into the springs, they make an extraordinary discovery - a strange layer of water.

The layer below is saltwater, but clear, fresh water flows above. Where the layers meet, there is a thin cloudy substance that they have never seen before.

Later analysis reveals it to be bacteria. It lives on a microscopic horizon between fresh and salt water. It is this bacteria which provides the basis for all life in the cave. The bacteria metabolizes sulfur from the water, and multiplies. In turn, the bacteria becomes food for the mussels and hydroids downstream. In this cave, lowly bacteria takes the place of sunlight and starts the chain of life.

The divers christen the cave of their discovery "the Dragon's Lair," in honor of its unique, smoky resident.

It's a shock to realize that there is so much life within the town's water supply. But it's probably an indicator of healthy water. If the life here vanishes, maybe then we should worry about the quality of our drinking water.