Hydrothermal vents are geysers located on the ocean floor in the deep sea. Students will first use National Geographic's Fantastic Journeys: Yellowstone to learn about the processes that drive geysers. They will then see photographs of some hydrothermal vents. Students will discuss the reasons hydrothermal vents occur and learn about some uniquely adapted animals that live near the vents. They will conclude by creating aquarium exhibits showcasing some of these animals and their special adaptations.

Geography

Standard 7: "The physical processes that shape the patterns of Earth's surface"
Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"

Two to three hours

• Computer with Internet access
• Construction paper and drawing materials
• Crafts materials such as scissors, glue, and pipe cleaners (optional)

Students will

• explore the interior of a hot spring and geyser in an online feature;
• view and discuss photographs of hydrothermal vents and compare them to land-based geysers;
• use a plate tectonics map to hypothesize the regions where hydrothermal vents might be most likely to occur;
• read about and view pictures of four creatures that live near hydrothermal vents; and
• create exhibits showcasing these creatures and describing their adaptations.

Have students look at the picture of the geyser and read the text at National Geographic's Fantastic Journeys: Yellowstone. Ask them if they have ever seen a geyser up close or on TV. What did it look like? How long did it last? According to this page, why does a geyser erupt?

From this geyser page, ask students to click on "Plumb the Depths." They will see a photograph of the Grand Prismatic Spring in Yellowstone National Park. Ask them to click on the sentence that begins "Get to the bottom of the strange goings-on..." where they will be taken to an interactive feature that sends them down into the spring.

Tell students that this hot spring is similar to a geyser. Ask students to study the hot spring to get an idea about what happens underground to produce these interesting geological features.

Have students click #5, the bottom level of the "Locator" on the left side of the screen. This will take them to the very bottom of the pool. Ask one student to read the text on the right side of the screen to the class.

Have students move upward through the hot spring by clicking #4, then #3, etc. until they're back at the top. At each level, ask one student to read the text to the class. If you only have one computer in your classroom, have students take turns gathering around the computer to see the picture as a student reads the text out loud.

Explain that what happens deep inside a hot spring is very similar to what happens in a geyser, except that in a geyser, the water gets caught in rocks on the way toward the surface. When it tries to boil, the steam has nowhere to go because there's so much pressure keeping the water and steam inside the rocks. This is similar to what might happen if someone tried to boil a pot full of water with a very tight lid. Once the water began to boil, the lid would pop off the pot because the steam would need a place to go. Likewise, in a geyser, the steam needs a place to go and presses the water forcefully upwards until it bursts out of the ground.

If restricted Internet access makes it logistically difficult for you to do the above steps, an alternative would be to draw a diagram on the board showing the different levels of a hot spring or geyser. Point to each level as you describe what can be found there.

Tell the class that geysers can also be found in the ocean. These geysers are called hydrothermal vents. They are generally found at least 7,000 feet (2,134 meters) below the ocean surface in both the Atlantic and the Pacific Oceans. They spew hot water for the same reasons that land-based geysers do.

Have students look at the pictures of hydrothermal vents at National Geographic's Dawn in the Deep and the National Geographic magazine article Deep Sea Vents: Science at the Extreme. If possible, also have them view the video at the Dawn in the Deep page (there's a link on the right side of the screen). In what ways do these vents look similar to the land-based geysers they've seen? In what ways do they look different?

Have students look at the map of the Earth's plates at Extreme 2000: Voyage to the Deep or in a book. If they have already learned about plate tectonics, briefly review the concept.

If plate tectonics is new to them, introduce this topic by explaining that each of the colors on this map represents a different "plate" that sits at the top layer of the Earth. These plates move very slowly, changing the way the continents look. In the places where two plates meet, there's generally a high level of volcanoes, earthquakes, and sometimes geysers and hydrothermal vents. This is because the hot substances under the Earth's crust are able to (and are often forced to) rise to the surface in these areas.

Ask students to predict, based on the plate tectonics map, where in the Atlantic and Pacific oceans they might find the greatest numbers of hydrothermal vents.

Explain that while the vents emit very hot water (over 700 degrees Fahrenheit), the deep ocean water is close to freezing. Ask students if many forms of life can survive at either of these extreme temperatures. Then tell the class that there's a great deal of life around vents. Why might this be? Ask them to brainstorm this question for a minute or two.

Discuss students' ideas. Then explain that there are two main reasons for the abundance of life near hydrothermal vents. First, some animals have adapted to survive in extremely hot temperatures (they'll read about the Pompeii worm in a few minutes). Second, as one moves away from a vent's opening, the hot water combines with cold water to form a more comfortable water temperature, much as adding hot water to a cold or lukewarm bathtub makes the temperature much more comfortable. This temperature is just right for some species. Thus, there's a variety of species living at different distances from the vent's opening, some of which like very hot water, and some of which like less hot water.

Have students go to Creature Features. It would be best to look at these pages as a class and have students take turns reading the paragraphs so you can help them with any difficult vocabulary. If you're not doing this lesson in a computer lab, you can print out each of the four Creature Feature pages and have students read them as handouts.

Discuss the four creatures students have read about. Ask them to describe some of the special adaptations these animals have made to survive in the hydrothermal vent environment.

Divide the class into groups of three or four. Assign each group one of the four creatures they've read about. Ask groups to make models of their animals, using construction paper and other crafts materials, or have them draw pictures of the animals on large pieces of paper.

Ask each group to create a "plaque" to go with its animal. Their plaques should include the following information:

• why hydrothermal vents exist
• where they exist
• why many types of life forms live near hydrothermal vents
• what special adaptations this animal has made to its life near a hydrothermal vent

Put students' finished products together into an exhibit that you might want to call your Aquarium of Hydrothermal Vent Life. Display the "aquarium" in a prominent part of the classroom.

For grades K-2: Help students navigate through the geyser at National Geographic's Fantastic Journeys: Yellowstone. Tell the class that geysers can also be found under the ocean. Ask students to imagine the types of animals that might be able to live in water near these "geysers"—hydrothermal vents. What types of features might animals need to have in order to be able to survive in very hot temperatures? Have students look at the pictures of animals at the University of Delaware's Voyage of the Deep and describe some of these animals' adaptations. Have them make models of these animals and write simple stories describing how the animals survive in the hot water near hydrothermal vents.

This lesson is made possible by a generous grant from the National Oceanic and Atmospheric Administration National Marine Sanctuary Program.

American Museum of Natural History: Expeditions—Black Smokers
Extreme 2000: Voyage to the Deep
National Geographic Magazine: Deep Sea Vents—Science at the Extreme
National Geographic News
National Geographic: Dawn in the Deep
National Geographic: Fantastic Journeys—Yellowstone