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Overview:
The Mariana Trench is the deepest location on the entire Earth. If you set Mt. Everest down in the Mariana Trench, there would still be over 7,000 feet of water above it. What's down there? How are we able to explore such deep seas? How might the resources of the deep sea benefit people on land? In this two-part lesson, students explore the From Sea to Shining Sea map (PDF, Adobe Reader required) to learn about the Mariana Trench's location, who has jurisdiction over it, what lives down there and how we can reach it, and why its resources are of value. Then students will learn about the increasing accessibility and vulnerability of deep-sea resources as they consider how the Mariana Trench's natural assets could affect communities worldwide. Although the Trench is a remote and harsh environment, students will come to understand the global value of researching and exploring its varied resources.
Connections to the Curriculum:
Geography, life science
Connections to the National Geography Standards:
Time:
Two to three hours
Materials Required:
Objectives:
Students will
- describe the general characteristics of three ocean light zones;
- use the From Sea to Shining Sea map resources to identify the location and features of the Mariana Trench;
- define the Exclusive Economic Zone (EEZ) and describe how it impacts jurisdiction and stewardship;
- describe the technologies used to explore deep-sea areas;
- research specific resources from the deep seas;
- describe the personal and societal value of such deep-sea resources; and
- develop and convey through a public awareness promotion their own ideas about the value of deep-sea prospecting, and future rules governing such prospecting.
Geographic Skills:
Acquiring Geographic Information
Answering Geographic Questions
Analyzing Geographic Information
S u g g e s t e d P r o c e d u r e
Opening:
Guiding Question: What and where is the Mariana Trench and what is its global significance?
Begin by asking the students, "What is the highest point in the world and where is it located?" (Answer: Mt. Everest at 29,035 feet, located on the borders of Nepal and China.) Then, ask the students where the deepest point of the Earth is (Answer: Mariana Trench). If a student answers correctly (or you can provide it after a few guesses), write "Mariana Trench" across the top of one side of the blackboard. Explain that this is the deepest part of the ocean and the deepest location on earth. It is 36,201 feet—almost 7 miles—deep. Explain that if you placed Mt. Everest at the bottom of the Mariana Trench, the peak would still be 7,000 feet below sea level.
Ask students to imagine what the Mariana Trench is like. Brainstorm what type of living conditions might exist down there and write responses on the board. Student replies may include: cold, dark, little life, scary, vast, etc. Tell students that throughout the lesson, the class can change or add to the list of responses.
Tell students that there are different ways to describe the layers of the ocean. One way to classify the ocean is in zones.
Draw a diagram of the three general light zones on the board such as the one from the Office of Naval Research. Provide the names and definitions for the zones from distributed copies of the Mariana Trench: Key Vocabulary (PDF, Adobe Reader required) or write them on the board or display them on an overhead. Then ask students to think about how the ocean waters might vary from zone to zone.
(Note: There are several ways to divide the ocean into light zones (there are also divisions related to salinity, dissolved oxygen, temperature, etc.). Sometimes the "Aphotic Zone" is subdivided into further zones—the Abyss and the Hadal—thus sometimes research may show the Mariana Trench to be in the "Hadal Zone." There are also various names for the same zones (The "Euphotic Zone" is also known as the "Sunlight Zone" or the "Epipelagic Zone.") Since the point of this lesson is to highlight the Mariana Trench as being without light, with extreme temperatures and under high pressure, a general division of three zones is presented.)
Next, pass out at random the pre-cut Ocean Zone Sentence Strips (PDF, Adobe Reader required) to students. Call on them to read their statement aloud and then come up to the board and place it (by writing it or by attaching it with tape) in the zone where they think it would belong. As they take turns, ask students to identify how they agree or disagree with the other students. Then move on to the next student until the three zones are filled with descriptions. Once all the zones are filled in, ask the class to place the Mariana Trench into the most appropriate zone (Answer: the Aphotic Zone).
Confirm for students that since the Mariana Trench falls into the Aphotic Zone; it does, in fact, have cold temperatures, extreme pressure, and no sunlight, yet it still has some life. In spite of the remote access and harsh environment of the trench, it is being accessed for its deep-sea resources, some of which could have far-reaching benefits. Explain that in the next activity, the class is going to learn more about the Mariana Trench and its unique resources. First, students will find its location. Then they will consider how technology enables researchers to explore deep-sea areas and who, then, has the responsibility for this vast underwater abyss.
Development:
Activity 1: Where is it? Who has jurisdiction over it? How do we get there?
Show students the From Sea to Shining Sea map (PDF, Adobe Reader required) or explore as a class the interactive version of the map. Identify the location of the Mariana Trench in the western North Pacific Ocean (11"21' N. Latitude; 142"12'E. Longitude). Tell students that the Trench is 1,554 miles long and 44 miles wide. Have students note the nearest bodies of land (Guam, Mariana Islands). Add additional facts like length and width and nearest land under the list on the blackboard.
Next, ask students, "Who do you think has jurisdiction, and therefore responsibility, over the resources of the Mariana Trench?" After they respond, explain that according to the Exclusive Economic Zone (EEZ) a country has the rights to all living and non-living resources up to 200 nautical miles from its coastline. (To help students understand this distance in terms they recognize, have them convert the nautical miles to standard miles by multiplying nautical miles by 1.15 to get an answer of 230 standard miles.) Point out that Guam is a territory of the U.S. and the Mariana Islands are a commonwealth of the U.S. So which country has the jurisdiction over the Trench and everything in it? The U.S. does because the Trench falls within 200 nautical miles of a U.S. Territory.
Now ask students how they think researchers know what they do about this area. Have humans actually gone there? Did they send robots? Have students use the Marine Conservation Biology Institute's (MCBI) From Sea to Shining Sea website to learn about the following technologies that assist in these deep water discoveries: vessels, submersibles, Remotely Operated Vehicles (ROVs), observation tools, and diving. As a class watch the three minute long Alvin submersible video to give students a clear picture of the types of vehicles used to explore deep-sea areas and what it feels like that far under water. Ask students to relate this back to the ocean light zones that they learned about in the opening activity.
Activity 2: What does the trench have to offer?
Tell students the class is going to further research the resources of the deep sea and the Mariana Trench. Have students guess what some possible resources of the trench may be and list them on the board. Some possible answers might be large creatures, food products, ingredients for medical or beauty products, bioluminescent fish, or nothing at all.
Next, as a class, discuss the value of deep-sea resources. Begin by having the class read the article "Scientists Seek New Medicines from the Ocean" and then review the Deep-sea Sponges and Coral overhead (PDF, Adobe Reader required).
Discuss the following questions:
- Why are the creatures of the Mariana Trench (and the deep sea in general) of special interest to scientists?
- How may the deep sea help the medical community? Which specific diseases may someday be treated by resources from the deep sea?
- What are some common products that have ingredients derived from the sea?
- How do you think deep-sea life may affect you in your lifetime?
After discussing the resources mentioned in the articles, explain that there is yet another major way that deep-sea waters could affect the global community. Scientists are presently postulating that excess carbon dioxide produced by burning fossil fuels could be injected beneath the deep-sea beds and stored for millions of years. Ask students what they think the importance of this discovery might be. Then have them read "Ocean Floor Could be Greenhouse Gas 'Dump'" and discuss the pros and cons if such a technology came to fruition. How might such a method affect our climate and economy?
Have students do further research into some of the discoveries of the scientific community as it explores the deep seas. Break students into five small groups and assign each group one of the following deep-sea resources to investigate:
- reserves of gas hydrates;
- deep-sea compounds in development for medical use;
- deep-sea ingredients used in cosmetics/health products;
- oil;
- deep-sea mining of mineral resources (such as copper, nickel, gold, zinc, etc.); or
- deep-sea water used for drinking water.
Have groups use the Ocean Resources: Research handout (PDF, Adobe Reader required) to conduct research, beginning with the Exploration and Research section of the MCBI From Sea to Shining Sea website to find answers to the following questions, and then share their findings with the rest of the class in brief group presentations:
- What are some specific examples of the resource?
- How, when, and by whom was the resource discovered?
- What specific technology was utilized to access the resource?
- What is the real or potential value of the resource to society?
- What is the real or potential value of the resource to you personally?
- Are there any challenges or potential drawbacks in mining these resources?
- What do you think should be done with this resource? (What responsibilities do people have in developing and disseminating the resource? What responsibilities do they have to conserve and protect this resource and the surrounding environment?)
After students have shared their findings, tell them that as of now, there is little, if any, regulation governing the exploration of the deep sea. As further discoveries uncover anything from promising anti-cancer drugs to alternative ways to store toxic gas, deep-sea resources are becoming a hot topic in the scientific community. Warnings are being issued regarding the need for international rules to oversee the access and exploitation of these resources. There are currently no guidelines in place to prevent damage to these deep-sea ecosystems or to ensure that benefits are shared globally. Ask students what responsibilities they think should accompany discovery in and jurisdiction over the resources of the deep sea.
Closing:
Go back to the board and review the original list students generated about the Mariana Trench. What new information did students learn? Have each student recount one interesting fact about the Trench.
Write the following quote from the director of the United Nations University Institute for Advanced Studies on the board or overhead:
"Deep-sea ecosystems hold the promise of huge potential contributions to future human well-being, provide our planet with vital climate-related and other ecological services, and have much to teach us about life processes."
Have students apply this thought to their understanding of the Mariana Trench by completing the following sentence: "The Mariana Trench and other deep-sea communities are important because ..."
Suggested Student Assessment:
Have students advocate for the importance of the Mariana Trench and other deep-sea communities by adapting their rephrased sentences into public awareness posters. The posters should demonstrate student understanding about the importance of these communities, as well as human responsibility to be good stewards of them.
You may also wish to administer the Quick Quiz: Mariana Trench—Show what you know! handout (PDF, Adobe Reader required). (Note on adapting the quiz: This assessment can be given verbally to the group or students can work in pairs. It is meant to be a brief (less than 10 minute) assessment. Students could also be offered a "word bank" where possible answers are listed.) Extending the Lesson:
Inquiry Extension
- Have students research online about hydrothermal vents like those found in the Mariana Trench. Refer them to Nova: Into the Abyss to begin their research.
- Explore the trench more in depth. Watch the Marianas Trench Dive Animation. Then follow NOAA Ocean Exploration expeditions to the Mariana Arc. Each expedition includes background content information, daily logs posted from sea, still and video images, virtual tours of Arc features, and educational resources including lesson plans:
2003
2004
2006
Cross-Curricular Extension
- Read the executive summary of the United Nation's University report, "Bioprospecting of Genetic Resources in the Deep Seabed" (page 7) (PDF, Adobe Reader required) and write a student-friendly version of the legal gaps regarding deep-sea exploitation. (Language Arts)
- Research the varied and numerous species of invertebrates and fish that live in the Mariana Trench. Find out how they adapt to the extreme temperatures and pressure and lack of light. (Science)
- Create a timeline of the history of ocean exploration, including exploration of Mariana Trench.
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