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OCEANS: EARTH'S LAST FRONTIER 1 videocassette. . . . . . . . . . . . . . . 25 minutes Copyright MCMXCV Rainbow Educational Media 4540 Preslyn Drive Raleigh, NC 27616-3177 Distributed by: United Learning 1560 Sherman Ave., Suite 100 Evanston, IL. 60201 800-323-9084 www.unitedlearning.com | www.unitedstreaming.com CREDITS Author and Producer: Director of Photography: Graphics and Animation: Production Coordinator: Narrators: Peter Cochran Peter Scheer Roger Meyer Kathy Kavanaugh Richard Cassell Randye Kaye Consultant: Michael Worosz Stock Video: Encyclopaedia Britannica European Space Agency Georgia Dept. of Natural Resources Jason Foundation for Education Kaw Valley Films NASA National Park Service Newport News Shipbuilders Photo Researchers, Inc. Scripps Institution of Oceanography Woods Hole Oceanographic Institution Post-Production: North Country Media Audio Sweetening: Acme Recording Studios Our appreciation to: Coastal Ecology Learning Program (C.E.L.P.) Caumsett State Park Produced for Rainbow Educational Media by Cochran Communications TABLE OF CONTENTS Introduction .......................................................................1 Program Summary ............................................................1 Objectives ..........................................................................4 Review Questions .............................................................5 Activities............................................................................7 Glossary .............................................................................9 Bibliography..................................................................... 12 Related Videos from Rainbow.........................................12 Script ...............................................................................13 INTRODUCTION Covering more than 70% of the earth's surface and containing 95% of its water, the oceans are the dominant feature of our planet. They are also the least explored. For most of human history, we have had little knowledge about what exists below the ocean surface. However, with the development of sophisticated research tools such as submersibles and satellites, we have recently learned a great deal more about the oceans and how they affect the earth's ecology. This video program provides viewers with a tour of the basic features of the oceans; including the topography of the ocean floor, examples of different types of marine life and the properties of waves, currents and tides. The video uses a variety of techniques to be both informative and entertaining. The narration alternates between male and female narrators. Computer graphics clarify key points. Colorful footage provides views of unusual marine life. Portions of the program show students doing a variety of activities and experiments to illustrate important concepts. Many of these experiments and demonstrations students themselves can perform, either in class or at home. In this way, the video promotes active participation in the scientific process. The video is designed to be used by students in grades four through seven, but younger and older students can use it effectively as well. SUMMARY The video states that the earth is unique among the planets because it is covered mostly by water. In spite of the predominance of the oceans, however, they are the earth's last frontier, the part of our world that remains largely unexplored. The program shows how scientists are busy finding out more about what goes on in the oceans, but argues that it is not necessary to be a scientist to explore them. The scene shifts to the schooner Phoenix, part of the Coastal Ecology Learning Program on Long Island Sound. The video shows students aboard the Phoenix measuring the salinity of seawater, and the captain describes the major source of this salt: dissolved solids from rocks, carried by rivers to the sea. Next the program shows the students pulling in a net and examining marine life that lives on the ocean bottom. The video draws distinctions among three types of life found in the oceans: benthos, bottom dwellers; nekton, the free swimmers; and plankton, floaters and drifters. It shows students aboard the Phoenix examining plankton and explains the importance of phytoplankton, which produce the major share of the earth's oxygen. It also describes the importance of plankton as the source of food for many other kinds of life. The next section of the program looks at differences in light, temperature and pressure, at different ocean depths. The top layer gets the most light and heat. For these reasons, it is here that most life in the oceans exists. As you go deeper into the ocean, the temperature drops quickly and there are fewer living things. In the deepest layer, the temperature is uniformly cold and there is no light from the sun. Even here, however, there is some life. The program also talks about how pressure increases with depth. It shows a student doing an experiment that illustrates that. She puts three holes in a milk carton at different levels and then fills the carton with water. Differences in the resulting streams of water coming from the holes indicate differences in pressure. Then the video shows how submersibles like the Alvin are able to resist great pressure, allowing humans to explore depths that were once beyond their reach. The next segment examines the topography of the ocean floor. The shallowest parts of the oceans are the continental shelves that stretch out from the continents in a gentle slope. The video shows students using a net to gather samples of marine life along the continental shelf off Long Island, New York. Graphics show that when the shelf reaches the continental slope, the ocean bottom drops off sharply. In some places, particularly in the Pacific, deep trenches parallel the continental slope. Trenches are formed when plates that form the earth's crust collide and one plate slips under another. The program also shows how mountain ranges, called rifts, form when plates move apart on the ocean floor. Here, magma from deep within the earth seeps out to form new crust. Shots of tube worms that feed on sulfur-eating bacteria on rifts show unusual marine life that are the only known living things that don't directly or indirectly depend on photosynthesis to survive. The video then returns to things about the ocean that we can observe on its surface. It describes how waves form and move. A student performs an experiment that shows that waves move water up and down but not forward. Next, video footage and graphics explain how the moon's gravity causes tides. Finally, the program describes currents and the effects of currents on weather. A brief summary concludes the video. LEARNING OBJECTIVES After viewing the program, students will be able to: 1. describe different geological features of the oceans, including: continental shelf continental slope trenches mid-ocean ridges 2. describe different life forms that exist in different parts of the ocean. 3. explain in simple terms the chemistry of seawater. 4. describe differences in light, temperature and pressure at different ocean depths. 5. explain what waves are and how they move. 6. explain how tides function. 7. explain how different kinds of currents function and the effects of currents on climate. 8. describe how the development of submersibles and other forms of technology has advanced our understanding of the oceans. REVIEW QUESTIONS 1. Why is the earth called "the blue planet"? Because the earth's most distinguishing characteristic is its oceans. 2. How is ocean water different from fresh water? Ocean water contains much more salt, on average about 35 parts per thousand parts of seawater. 3. Why can't you drink ocean water? The salt in ocean water robs your cells of water, causing them to dry out. 4. What are the three main groups of marine life described in the video and how are they different? Give some examples of each. Benthos are things that live on the ocean floor. Horseshoe crabs are the example in the video. Encourage students to think of others. Nekton are things that swim freely through the water. Fish, turtles, whales and dolphins are examples. Plankton are plants and animals that float or drift in the water. Phytoplankton are plant plankton and zooplankton are animal plankton. 5. Why are phytoplankton important to the survival of other things that live on earth? Phytoplankton, through photosynthesis, produce most of the earth's atmospheric oxygen. They are also an important source of food for zooplankton, which in turn are eaten by other living things. 6. What are several ways that the oceans change the deeper you go? As you descend from the surface, light disappears. Pressure increases. It gets colder. 7. What are some of the geological features of the ocean bottom? The continental shelf, the shallowest part of the ocean bottom, slopes gently from the continents. The continental slope, drops off sharply from the continental shelf. Trenches, deep canyons exist where two plates of the earth's crust collide. Mid-ocean ridges, mountain ranges, form where plates move apart and magma from deep within the earth spills out onto the ocean floor. 8. What causes tides? Gravity from the moon causes tides. 9. How do currents affect the earth's weather? Currents such as the Gulf Stream warm the air above it. Water from the oceans evaporates and is carried by winds across the land where it condenses and forms rain. ACTIVITIES 1. A sea is a large body of saltwater that is nearly surrounded by land. Seas are part of the world's oceans. Ask students to locate on a globe or map the earth's major seas: Aegean Sea Coral Sea Sea of Marmara Arabian Sea Irish Sea Red Sea Bismark Sea Sea of Japan White Sea Black Sea Java Sea Yellow Sea 2. Winds are not the only things that cause waves. They can also be caused by underwater disturbances such as earthquakes. Large surface waves caused by such disturbances are called tsunamis. A tsunami can be as high as 32 meters (105 feet) and travel thousands of miles. Ask students to research and report on tsunamis and the damage they cause. 3. Oceanography is the study of the ocean. Historians consider Matthew Maury of the United States Navy the founder of oceanography because of the information he gathered and published on ocean currents, temperatures and winds from 1842 to 1861. From 1872 until 1876, scientists aboard the British ship Challenger were the first to make detailed studies of the ocean bottom. In this century, important contributions have been made as a result of scientists' working aboard surface research vessels like the Glomar Challenger and submersibles like the Alvin. Increasingly, satellites and underwater robots also play an important role in ocean research. Ask students to research and report on the history of oceanography. 4. Students interested in finding out more about careers in oceanography can write to: National Oceanography Association 1900 L Street, N.W. Washington, D.C. 20036 U.S. Naval Oceanographic Society Washington, D.C. 20390 5. If you live near the ocean, there are many organizations that will take students out on excursions to perform investigations similar to those performed aboard the Phoenix in the video. Such trips are most profitable when students prepare beforehand by studying what they will be observing, such as plankton. 6. If you don't live near the ocean, specimens of marine life can be ordered from a variety of sources, including: Carolina Biological Supply Eastern U.S.: 1-800-334-5551 Western U.S: 1-800-547-1733 Science Kit and Boreal Laboratories 1800-828-7777 Wards Natural Science Establishment 1800-962-2660 If you order live specimens, you will need an all-glass saltwater aquarium, filters, an air pump, tubing and other things. Carolina Biological sells a basic tank kit. 7. The video describes how, on average, there are 35 parts of salt in every thousand parts of seawater. If you live near the oceans, obtain a sample of seawater. Then have the students put the seawater in a shallow dish and leave the dish outside or on a window ledge that gets a lot of sun. After the water has evaporated, ask the students to describe what is left in the dish. You can also have students do an experiment where they add salt to tap water in a dish. Have them leave this dish and another dish with plain water in a sunny place. After the water has evaporated from both dishes, have the students describe what they see. 8. Each student can choose a different form of marine life to research and report on. The report should include information about the distinguishing characteristics of the plant or animal, where in the ocean it lives and how it gets its energy. Students could then present their reports orally to the whole class. They could also make posters and other visual displays. GLOSSARY benthos: organisms that live on the ocean bottom bioluminescence: emission of visible light by living organisms chloroplast: chlorophyll-containing organelle in plants where photosynthesis takes place continental shelf: shallow part of ocean floor next to a continent continental slope: steep section of ocean floor that stretches from the continental shelf to the ocean basin current: river of water that flows through an ocean diatom: kind of phytoplankton magma: liquid rock mid-ocean ridge: long, underwater mountain range nekton: marine organisms that can swim freely photosynthesis: process by which plants use energy from the sun, water and carbon dioxide to produce sugar and oxygen phytoplankton: tiny plants that float in the ocean plankton: aquatic organisms that drift, float or swim feebly plates: parts into which the crust of the earth is divided pressure: force acting on something salinity: measure of the amount of salt in seawater, usually given in parts of salt per thousand parts of seawater sea: large body of salt water nearly surrounded by land sonar: system of transmitting underwater sound waves and receiving the reflected waves to determine the depth of ocean floor submersible: research vessel designed to go to deep 10 depths of the oceans tide: rising and falling of water levels along the coast trench: deep valley in ocean floor where two plates collide zooplankton: tiny animals that float, drift or swim feebly in the ocean 11 BIBLIOGRAPHY Carson, Rachel. The Sea Around Us. New York; Oxford University Press, 1961. Doris, Ellen. Marine Biology. New York; Thames and Hudson, 1993. ReVelle, Penelope and ReVelle, Charles. The Environment: Issues and Choices for Society. Boston; Jones and Bartlett Publishers, 1988. Ronan, Colin A., General Editor. Science Explained. New York; Henry Holt and Company, 1993. The Ocean Unfolds. New York; Van Dam Publishers, Inc. Thorndike, Joseph J., Jr., ed. Mysteries of the Deep. New York; American Heritage Publishing Co., 1980. Weiner, Jonathan. Planet Earth. New York; Bantam Books, 1986. Whipple, A.B.C. Restless Oceans. Alexandria, VA.; Time-Life Books, 1983. Williams, Brian. The Sea. New York; Kingfisher Books, 1991. RELATED VIDEOS FROM RAINBOW Continents Adrift: An Introduction to Continental Drift & Plate Tectonics Earthquakes: Our Restless Planet Our Changing Earth Source of Life: Water in Our Environment Volcanoes: Mountains of Fire What's Inside The Earth?: An Introduction to The Earth's Interior, Crust and Mineral Resources 12 SCRIPT Male Narrator: There are places on earth where mountain ranges stretch much farther than the Rockies, and where there are trenches several times deeper than the Grand Canyon. There are places never seen by human eyes where lava spills out of cracks in the earth's crust, and where there are animals, only recently discovered, as strange and wonderful as any found in a zoo. We know more about the surface and features of the moon than we do about most of these places, because they remain largely unexplored - under the surface of the oceans, the earth's last frontier. Title: Oceans: Earth's Last Frontier Female Narrator: The earth is often called the blue planet because its most distinguishing characteristic is not its continents but its oceans. One ocean alone, the Pacific, could fit all the continents within its borders and still have room to spare. 13 Besides the Pacific, there are four other oceans - the Atlantic, the Indian, the Arctic and the Antarctic. Together, these oceans and some smaller seas form one huge body of water that covers over 70% of our planet's surface and contains 97% of its water. Yet, for much of human history people viewed the oceans as mainly boundaries marking the edges of the continents. For the most part, people could only imagine what secrets were contained in the ocean depths. Male Narrator: Today, the oceans are revealing many of their secrets as scientists use sophisticated tools to explore below the ocean surface, to analyze the properties of waves and currents, and to find out more about what kinds of life live in the oceans. But you don't have to be a scientist to explore the oceans. Each summer, for example, thousands of students from New York and Connecticut have a chance to study Long Island Sound aboard the schooner Phoenix. The Phoenix belongs to a program called C.E.L.P., or Coastal Ecology Learning Program. Under captain Dennis Watson and his crew, students per- 14 form a variety of activities that help them learn more about ocean ecology. One thing they investigate is the chemistry of ocean water and how it is different from fresh water. A student lowers a probe that measures the salinity, or salt content, of the Sound's water. Instructor: Turn this to where it says salinity... and read the red numbers. Male Narrator (contd.) On average, there are 35 parts of salt per thousand parts of ocean water. That may not seem like much, but it is enough to make this water undrinkable for humans. Captain Watson explains why. Captain Watson: Salt water is something the fish like, but we can't drink it. If you drink salt water, you actually get thirstier. It's a dehydrating agent that will actually rob water from the cells of your body, making the situation worse. You will die quicker drinking salty water than if you don't drink water at all. Salt water came into the ocean from the land. As water runs over the rocks it actually leaches out salt and miner- 15 ah from the rocks thereby depositing it in solution in the ocean. Female Narrator: Animals and plants that live in the ocean either have special cells that aren't affected by salt or have ways of ridding their bodies of salt. To see some things that live in the ocean, the Phoenix drags a net along the bottom of Long Island Sound. The students then help pull in the net. Students: Horseshoe crab! Instructor: O.K. Everybody agree it's a horseshoe crab? It's got two names - horseshoe crab, known also as a king crab. He's really feisty, this guy. There's no stinger on the tail or anything, but say you were walking along the bottom and accidentally stepped on him. Look at these burrs on his carapace - that would feel like a sting, wouldn't it? Also on the tail, look how the burrs go up. So, if you were to step down, you'd end up with a nice laceration. Female Narrator (contd.) Horseshoe crabs and all other kinds of animals that live on the ocean bottom are members of a group called benthos. 16 The bottom is called the benthic layer of the ocean. Another group of marine organisms are called nekton. These swim freely through the water. Among the nekton are thousands of different species of fish, sea turtles, and mammals like whales and dolphin. Male Narrator: A third group that lives in the oceans are plankton, living things that simply float or drift wherever the waves or currents take them. Many kinds of plankton are plants and animals, too small to be seen by the naked eye. But they can be gathered using special plankton nets. This jar of water contains thousands of plankton. With the help of a microscope, you can see an incredible diversity of these tiny ocean-dwellers. Some are called phytoplankton. Phytoplankton are plant plankton. The most abundant are diatoms whose unusual shapes come from the glass boxes in which their cells are encased. Looking like Christmas ornaments, diatoms come in a variety of shapes. 17 Phytoplankton get their green color from structures inside their cells called chloroplasts. Chloroplasts are responsible for photosynthesis, the process by which plants produce oxygen. Phytoplankton produce more oxygen than all the earth's trees and forests combined. In fact, over half the oxygen in the earth's atmosphere was made by phytoplankton floating on or near the surface of the oceans. Without this oxygen, life as we know it couldn't exist. Phytoplankton are important for other reasons. They are the main food for animal plankton, or zooplankton. The zooplankton in turn are eaten by many other kinds of marine animals, from tiny fish to baleen whales. Without plankton, most kinds of marine life would starve and become extinct. Female Narrator: Plankton and most other kinds of marine life exist in the top layer of the water, within a few meters of its surface. This layer gets the most light and heat from the sun. But light from the sun's rays decreases rapidly as you go deeper into the ocean water. Most of the ocean, in fact, is totally dark. As you descend into the ocean, the water temperature also 18 becomes colder. And there is another change that occurs the deeper into the ocean you go. The pressure of the water increases rapidly with depth. Male Narrator: A simple experiment demonstrates the effects of water depth on pressure. Poke three holes in the side of a milk carton; one near the top, one halfway down, and the third near the bottom. Fill the carton with water and observe the streams of water that escape. The stream at the bottom is the strongest because there is greater water pressure at the bottom of the carton than at the top. Pressure is measured in pounds per square inch. Standing on land at sea level, each square inch of a person's body is being pressed by about 15 pounds of air. At 5 meters, or about 16 feet, below the ocean's surface, the pressure from the weight of the water is much greater enough to make a diver's ears begin to hurt. Scuba divers can swim to depths of only about 75 meters, or about 245 feet. Beyond this depth, the pressure would squeeze against the divers so hard that it would be difficult for them to breathe. 19 Most submarines dive to only 465 meters, or about 1,500 feet. Much beyond this depth the pressure would be great enough to crush a submarine's hull. Female Narrator: There are, however, special submarines, called submersibles, that are designed to resist great pressure. This is the Alvin, owned and operated by the Woods Hole Oceanographic Institute in Massachusetts. The Alvin is used to explore to depths as great as 4,000 meters, over 13,000 feet. Submersibles like the Alvin have allowed humans to explore areas of the ocean depths that were previously unreachable. One of the things they found is that even here life exists, like this lantern fish, whose soft flexible skeleton can resist great pressure. Like many deep water fish, the lantern fish is bioluminescent, which means that its body contains chemicals that give off light. Male Narrator: The flatness of the ocean surface is broken only by waves. But the surface disguises features that are as diverse as those found on land. Scientists have been able to map the ocean bottom using sonar. A sonar device on a ship sends sound waves 20 through the water. These sound waves bounce off the ocean bottom and back to the boat. By measuring how long it takes for the sound waves to return, researchers can tell how deep the ocean is. Satellites provide another way to study the ocean bottom. Using computers, scientists can analyze measurements made by satellites of the height of the ocean surface. These measurements indicate bumps on the surface caused by mountains on the sea floor. Valleys and canyons, on the other hand, cause slight depressions on the ocean surface. Using information from satellites and sonar soundings, researchers have drawn maps of the ocean bottom. This computer-generated image shows what the Earth would look like if its oceans were drained of water. Female Narrator: The part of the ocean floor with which we are most familiar is the continental shelf. The continental shelf is part of a continent that is under water. It extends out from the shore in a gentle slope. This is one part of the ocean that you can partly explore on foot by wading out into the water, as these students are 21 doing at Caumsett State Park on Long Island, New York. Along the continental shelf there is an abundance of sea life, for here the water is shallow and gets a lot of light. By dragging a net carefully through the water, you can see some of the kinds of marine life that live close to shore. The catch here includes tiny hermit crabs and baby flounder. Male Narrator: At the end of the continental shelf, the ocean bottom drops off sharply. This part is called the continental slope. Beyond the slope are large flat areas of the ocean floor that are called the abyssal plain. However, in some places, particularly the Pacific, the continental slope ends in a deep trench. Scientists believe that the earth's surface is made up of large plates or sections of rock that are constantly moving. Trenches are formed when two plates collide and one moves under the other. Some trenches are thousands of kilometers long and are the deepest places in the oceans. The deepest trench of all is the Manannas Trench in the western Pacific. In places it reaches a depth of more than 11,000 meters, or about 36,000 feet below the ocean surface. From its lip to its bottom, the Manannas Trench is several 22 times deeper than the Grand Canyon. Female Narrator: Along the ocean bottom there are also long mountain ranges called mid-ocean ridges. The Mid-Atlantic Ridge stretches down the middle of the Atlantic Ocean and is only one part of a ridge that winds its way around the earth. Ridges are formed where two ocean plates are moving apart. Here, magma - or hot liquid rock - from deep within the earth seeps out between the plates and then cools to form new crust. Near mid-ocean ridges, the Alvin has found hydrothermal vents - cracks in the ocean floor where hot, smoky water shoots up. This water contains hydrogen sulfide. Amazingly, even here there is life. Bacteria absorb the hydrogen sulfide for nourishment. These bacteria, in turn, are food for other living things, including these giant tube worms, white crabs, and giant clams. The living things that exist at ocean vents are different 23 from all other kinds of life. Other living things depend either directly or indirectly on the sun for energy. Through photosynthesis, plants use the energy of light from the sun to manufacture their own food. And animals eat either plants or other animals that eat plants. But the life that exists at ocean vents depends not on the sun for energy but on chemicals from the earth. The discovery of these unusual forms of life emphasizes how much we still don't know about what goes on in the deepest reaches of the oceans. Male Narrator: Other things that occur on the surface are easier to observe. Look at this dock and notice where the water reaches. Here is the same spot 6 hours later. See where the water reaches now. Twice a day, along coasts worldwide, the level of the water rises and falls. The daily rises and falls of ocean waters are called tides. Tides are caused mainly by the moon. Like the earth, the 24 moon has gravity. The moon's gravity pulls both the solid earth and the ocean water, but it pulls the ocean waters nearest it more strongly. This causes the water to bulge toward the moon, resulting in a high tide. At the far end of the earth, the water is pulled less strongly than the earth, and this causes a tidal bulge there as well. Halfway between the two high tides, low tides are formed. These low tides are the result of water's flowing to the locations where there are high tides. If the earth and moon stood still, high and low tides would always be in the same place. However, the moon orbits around the earth, and the earth rotates. This movement of both the moon and the earth results in two high tides and two low tides each day. Female Narrator: Another thing we can observe, even standing on shore, is that the oceans are constantly moving. Every few seconds a new wave breaks onto a beach. This is repeated thousands of times a day, millions of times a year. Most waves are caused by wind that blows across the water's surface. On a calm day, there may be a steady movement of smooth, low waves caused by winds far out at sea. 25 Hurricanes, on the other hand, can cause waves as high as 30 meters, or almost 100 feet. Even with waves this high, however, the water moves up and down, but it doesn't move forward. You can see that this is true by putting a piece of paper in a tray filled with water. Then, using a straw, blow straight down on the water. Air from the straw creates small waves that move the piece of paper up and down, but otherwise the paper keeps its position. Male Narrator: Waves caused by wind are different from another kind of ocean movement that can be seen along most coasts. If you walk along a beach, you may see bottles, wood, pieces of plastic and other things that have washed ashore. Many of these things are debris tossed overboard from boats and ships far out at sea. Even on uninhabited islands in the Pacific, there is debris on the beaches. Some of it came from places thousands of miles away. The debris was carried by currents, rivers of water that flow through the oceans. 26 Female Narrator: Scientists can trace currents by using pictures, taken by satellites, that measure different temperatures of the oceans' water. In this map, warmer temperatures are shown in red and yellow, and cooler temperatures in blue and green. Currents from the equator move warm water toward the poles where it becomes cooler again. Currents from the polar regions move cold water towards the equator, where the water becomes warmer. Surface currents like these are caused by winds and the rotation of the earth. Male Narrator: There are also currents under the ocean surface. Some are caused by differences in the density of water. Just as a submarine sinks when it is more dense than the water around it, cold water is denser and sinks under warmer water. You can simulate the effects of these currents by putting a colored ice cube in a glass of warm water. As the ice melts, the colder, denser water sinks, just as cold water in the oceans sinks. 27 to microscopic plankton that are responsible for producing most of our atmosphere's oxygen to strange tube worms that live near vents in the ocean floor. Female Narrator: We looked at the landscapes that form the ocean bottom, including the shallow continental shelf and the steep continental slope. We saw mountain ranges called mid-ocean ridges where lava from deep in the earth spills out to form new ocean floor, and trenches that are the deepest places on earth. Male Narrator: We also looked at how the moon affects tides. We examined waves and currents And we saw how scientists have used submersibles and other tools to explore parts of the ocean that until recently were hidden from human view. Female Narrator: But the oceans are not just for scientists to explore. There is much that each of us can discover. 29 Even by just wading in the shallow water along a beach, we can all learn more about the oceans. And as we learn, we appreciate more the importance of the oceans to Earth, the blue planet. END. 30 CLOZE EVALUATION QUESTIONS OCEANS: EARTH'S LAST FRONTIER NAME_______ DIRECTIONS: Select the answer, from the four choices given, by circling the correct letter. 1. Our earth is often called the blue planet because about 70% of the planet is covered by water. The ocean _____ is a dynamic environment of plant and animal species. The types and varieties of creatures are as extensive as anything found on land. 1. A. B. C. D. 2. Scientists have studied the ocean for many years and have identified various areas or zones of life forms. At the bottom of the ocean, called the ________ zone, you might find such creatures as crabs and shellfish. 2. A. benthos B. nekton C. cellar D. trench 3. Another ocean zone is found between the bottom and surface regions. This zone is called the _____ and is home to a large variety of fish. Depending upon the ocean, you might find sharks, bluefish, tuna, cod and a multitude of other freeswimming species in this region. 3. A. benthos B. trench C. nekton D. fish region 4. A. zooplankton B. plankton C. phytoplankton D. algae 5. A. protozoa B. algae C. zooplankton D. phytoplankton 6. A. amoeba B. protozoa C. zooplankton D. one-cell-life-forms 7. A. tanker B. submersible C. scuba tank D. snorkel 8. A. continental shelf B. continental slope C. trench D. ocean valley 9. A. trench B. continental shelf C. continental slope D. ocean valley 4. In order for ocean life to thrive there must be producers and consumers of food. One of the ocean's basic food sources is a group of creatures collectively known as _______. These plant and animal life forms are too small to be seen with the naked eye. They live in very large colonies and are of two basic types. 5. The first group of plankton are of the plant variety. These _____ come in a great many shapes and are green in color. They produce food, as plants do on land, through the process of photosynthesis. They are a food source for others. 6. The phytoplankton produce oxygen which is necessary for life in the sea and on land. These creatures serve as a food source for another type of plankton called _____. This type of plankton becomes part of the ocean food chain as they are eaten by small fish as well as the largest ocean dweller, the whale. 7. Scientists have studied the ocean by diving beneath the surface and observing the life forms there. In order to collect data about the life deep in the ocean, a _____ must be used. This device can stand the great water pressure that is found deep below the surface. 8. Over the years, scientists have mapped the world's oceans and the rock and sand formations below the surface. The _____ is a part of the ocean that extends out from the shoreline in a gentle decline. In this region there is an abundance of sea life and here is where marine life is harvested. 9. As the ocean land form begins to drop, we come upon another important ocean feature. This is the _______ and it is an area that leads to some of the ocean's deepest regions. As one travels farther down to the great depths, the marine life diminishes. 10. Other ocean features that are similar to our canyon areas on land are found at great depths. These _____ can be so deep that one in particular, the Marianna formation, is seven times deeper than the Grand Canyon. Our oceans are truly the earth's last frontier and we must do all we can to protect it from pollution and preserve its beauty and life forms. This form may be reproduced without permission from Rainbow Educational Media. bottom current surface ecology 10. A. ocean basins B. ocean valleys C. ridges D. trenches