The Environmental Literacy Framework (ELF) was made possible through financial support provided by

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1 The Environmental Literacy Framework (ELF) was made possible through financial support provided by Energy Geosphere As part of NOAA Environmental Literacy Grant #NA09SEC to the University of Nebraska Lincoln's, ANDRILL Science Management Office. Environmental Literacy Framework With A Focus On Climate Change Biosphere Atmosphere This material is based on work supported by an Environmental Literacy Grant from the National Oceanic and Atmospheric Administration's Office of Education (NA09SEC ). Any opinions, findings, and conclusions or recommendations expressed in these materials are those of the authors and do not necessarily reflect the views of the NOAA.

2 Environmental Literacy Framework A Focus Questions: What are the origins and locations of the deep ocean currents? Do you ever wonder what the ocean looks like in three dimensions? How is the water in the ocean moving from place to place, and how do the features on the bottom of the ocean affect the movement of the water? Time Part 1--1 class period Part 2--1 class period Flexihibit. Materials Part 1 Tall plastic container such as a 750 ml water bottle with the top section removed (ask an adult for help) Ice Kosher salt Red, blue and yellow food colors Pipette or turkey baster 2 containers or empty milk cartons to hold and mix water samples Preview There are four major deep-water formation sites that drive currents in the global ocean. They are found in the Greenland-Norwegian Sea, the Labrador Sea, the Weddell Sea, and the Ross Sea. On a short-term time scale (decades or centuries), these deep-water currents are the force that gives the push to the global ocean conveyor belt. Look at the map above and hypothesize what all these locations have in common. Part 2 Clear plastic container 1/2 full of water (clear plastic shoeboxes work well) Base map (in blackline graphic) Tape Several sticks of modeling clay to build coastline and underwater features Warm, red water Blue ice cube Yellow, salty ice cube Ice cube tray for freezing ice cubes Kosher salt Pitcher or small cups to transport water from sink to container Styrofoam or other insulated cup for warm water sample 1-2 cm book to raise shoebox Vocabulary (Terms) 175 Bathymetric Density Ocean Current Salinity Temperature Thermohaline

3 Environmental Literacy Framework Activity 3B- A Prepare Activity Steps: Part 1: Density Column--Exploring Water Masses 1. Locate a tall clear plastic container, such as a 750 ml water bottle. Carefully remove the top section of the bottle so that you have a column. (ask an adult to help) 2. Fill the water bottle ½ full with water and plain ice. Dissolve about 2 tablespoons of kosher salt into the water by stirring until granules of salt are no longer visible. (any salt will work, but kosher salt has the advantage of dissolving and leaving the water clear.) 3. Add yellow food color and wait a few minutes until the water has become still again. 4. Fill a cup with cold tap water; add several drops of blue food coloring and a handful of ice. Stir the container and set aside. 5. Fill a second cup with very hot tap water, and add several drops of red food coloring. Stir and set aside. 6. Use the pipette to slowly and carefully add the blue colored fresh water to the side of the column holding the yellow water. Observe what you see. draw a sketch of your column and record any notes about the layering. 7. Once the blue water is in the column, use a clean pipette to slowly add the red colored hot water. Again, add the water gently, touching the side first, so as to allow it to layer. You should now have layered three water masses. Observe and record a second time. 8. Explore a bit more. This time, begin the exploration with the blue fresh water in the column and add the cold, yellow, salty water second. Then add the red warm water. Did the layering change, or is it the same? 176

4 ACTIVITY 3B- Directions for Part 2 & 3 Assemble all materials needed for the lab: Assemble all materials needed for the lab: 1. Prepare and freeze water samples in ice trays or small 250 ml (1 cup) milk containers. Make 10 cubes of each color (blue and yellow). 2. Water sample recipes: Frozen fresh water: 3/4 cup (200 ml) water 3 drops blue food coloring Frozen salt water: 3/4 cup (200 ml) water 2 teaspoons (10 ml) kosher salt 3 drops yellow food coloring Warm water: 3/4 cup (200 ml) water Mix in a microwave-safe container or insulated cup Heat in microwave the day of the lab 3 drops red food coloring 177

5 Part 2: Build the model coastline and seafloor 1. Place the bathymetric map under the clear container so that you can see the contour lines. Line the map up with the edges of the shoebox. Tape the map in place on the bottom of the box. 2. Use the modeling clay to build the edge of the Antarctic coastline and several seafloor features shown on the map. Press the clay tightly onto the bottom and sides of the dry shoebox. 3. Place the shoebox end that has the coastline on a 1-2 cm book to lift the box and give the sea floor additional slope. 4. Turn the box so that the coastline is away from you. You will be looking at the short side of the shoebox. 5. Use a cup or pitcher to fill the shoebox ½ to ¾ full with room temperature, salty water. 6. Wait for the water in the shoebox to settle. (about 3 minutes) Then start Part 3. Building the model coastline and seafloor. 178

6 When the water has settled, continue the lab. Part 3: Simulate Thermohaline Currents 1. Slowly place the yellow-colored, cold salt water ice block in the water at the edge of the shoebox, near the coast of Antarctica where the deepwater formation site is marked on the map. Try not to disturb the water when you add the ice block. This block represents freezing seawater that forms in the fall around Antarctica and the Arctic. When seawater freezes in the process of becoming sea ice, it squeezes out the salt from the water, leaving frozen fresh water as ice and very salty cold water in the ocean just below it. 2. Observe where the yellow, salty currents travel in your shoebox. Observe the shoebox both from above and from the sides of the box. Sketch your observations. 3. Next, add the cold, blue colored ice cube to the same end of the shoebox. Carefully, observe the pathways of this layer of water. This water can be thought of as melting sea ice in the spring months. It, too, is dense because it is cold, but it is less dense than the cold, salty water. 4. Lastly, use a dropper to place approximately 20 ml of red-colored warm water from your cup of warm water onto the surface of the other end of the shoebox from where you placed the ice blocks. This other end represents the equatorial regions of the Earth. Water in the equatorial regions is fresher (less salty) because there is more precipitation around the mid-latitudes. 5. Observe and explore the current patterns in your shoebox. If you have time, carefully add some additional seafloor features, like small rocks or rubber stoppers to your ocean current model. Watch how the currents move around these obstacles. Extension: If your available technology allows, film a movie or set a camera on a tripod and take a picture every 2 seconds. Stitch the pictures together to make a timelapse movie of the currents in your shoebox. Shoebox and currents 179

7 Ponder 1. How were the currents in your shoebox like the currents in the real ocean? 2. How were the currents different from currents in the real ocean? 3. Were there any unexpected events in your model that you would like to explore further? Describe an experiment or exploration you could perform that might explain or clarify the events. 4. Some currents travel underwater for thousands of miles. What do they carry with them besides water? Practice Got the Big Idea? Present Prepare several trays of ice cubes ahead of time. Bring the ice cubes to the event in a cooler or ice chest. Engage your audience with the model and explain that this is what will happen as the polar ice caps melt, releasing large quantities of fresh water into the oceans possibly altering the flow of the ocean conveyor system. Make sure they understand how important this current is to many systems including living organisms in deep water habitats. The black box on the Google Earth map above illustrates the approximate area of the base map on the next page. 180

8 Bathymetric Map North (Towards the Equator) Weddell Sea South (Towards the South Pole) 181

9 Background Information for the Teacher Activity In this hands-on activity, learners create a model that demonstrates how colder, saltier water sinks under warmer, fresher water. By creating a map of the seafloor, students will explore how different seafloor features affect ocean currents and circulation. NSES Physical Sci Standard B: Energy is transferred in many ways. Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature. The sun is a major source of energy for changes on the earth's surface. Earth Science Std D: Water, which covers the majority of the earth's surface, circulates through the crust, oceans, and atmosphere in what is known as the "water cycle." Water evaporates from the earth's surface, rises and cools as it moves to higher elevations, condenses as rain or snow, and falls to the surface where it collects in lakes, oceans, soil, and in rocks underground. NSES Global patterns of atmospheric movement influence local weather. Oceans have a major effect on climate, because water in the oceans holds a large amount of heat. The sun is the major source of energy for phenomena on the earth's surface, such as growth of plants, winds, ocean currents, and the water cycle. History and Nature of Science Std G: Scientists formulate and test their explanations of nature using observation, experiments, and theoretical and mathematical models. 1a: Sunlight reaching the Earth can heat the land, ocean, and atmosphere. Some of that sunlight is reflected back to space by the surface, clouds, or ice. Much of the sunlight that reaches Earth is absorbed and warms the planet. 2a: Earth s climate is influenced by interactions involving the Sun, ocean, atmosphere, clouds, ice, land, and life. Climate varies by region as a result of local differences in these interactions. CLEP 2b: Covering 70% of Earth s surface, the ocean exerts a major control on climate by dominating Earth s energy and water cycles. It has the capacity to absorb large amounts of solar energy. Changes in ocean circulation caused by tectonic movements or large influxes of fresh water from melting polar ice can lead to significant and even abrupt changes in climate, both locally and on global scales. 2f: The interconnectedness of Earth s systems means that a significant change in any one component of the climate system can influence the equilibrium of the entire Earth system. Positive feedback loops can amplify these effects and trigger abrupt changes in the climate system. 4a: Climate descriptions can refer to areas that are local, regional or global in extent. 5b: Environmental observations are the foundation for understanding the climate system. From the bottom of the ocean to the surface of the Sun, CLEP instruments on weather stations, buoys, satellites, and other platforms collect climate data. 7a: Melting of ice sheets and glaciers, combined with the thermal expansion of seawater as the oceans warm, is causing sea level to rise. ELF 1 b: Water transports energy, solutes, and sediments as it moves through the water cycle s different reservoirs. Oceanic energy transport has a major impact on regional and global climate. 2: The ocean circulates water around the Earth on time scales varying from seasonal to hundreds of years. 2 b: Thermohaline circulation is driven by differences in the density of water masses due to changes in salinity and temperature. This circulation incorporates intermediate and deep-water currents in a three-dimensional pattern. 2 d: Plate tectonic motions change the size and shape of ocean basins, and alter coastlines and features on the seafloor. These changes influence ocean circulation patterns over long timescales. 182

10 Background Information What is the global ocean conveyor belt, what are the processes that control it, and how does it influence Earth s climate? The global ocean conveyor belt transports heat, as well as dissolved nutrients and gases, throughout the Earth s oceans. As you read about this important climate-controlling Earth system, follow the diagram on the next page. There are four major deep-water formation sites in the global ocean. These sites are found in four places. In the North Atlantic there are two sites-one in the Greenland-Norwegian Sea, and the other in the Labrador Sea. In the Southern Ocean, near Antarctica, they are in the Weddell Sea and the Ross Sea. On a short-term time scale (decades or centuries), these deep-water formation sites and subsequent currents are the force that drives the global ocean conveyor belt. These formation sites are in polar regions, near areas where seasonal sea ice forms. The coldest and densest of these deep-water masses forms in the Weddell Sea off the coast of Antarctica. It is known as Antarctic Bottom Water. Unlike surface currents, which are driven by wind, thermohaline currents are driven by density differences in ocean water. Because the ocean conveyor belt is controlled by dense, cold water, it is frequently called thermohaline circulation (thermo = temperature, haline =salinity). There is no real beginning or end in this conveyor system, since it is a continuous loop. Cold water is more dense than warm water and will sink. Salty water is more dense than fresh water and will sink. Cold, salty water is very dense. In this journey of the great ocean conveyor belt, we begin with the process that forms the deep ocean mass known as the Mid-Atlantic Water that forms in the North Atlantic Ocean. Off the coast of Greenland, especially during the fall and winter months, cold winds from northern Canada cool the surface waters, causing them to freeze and form new sea ice. As sea ice forms, much of the salt is left in the water beneath the ice. Sea ice formation, combined with surface evaporation, creates cold, salty, and very dense ocean water. This extremely dense water sinks to the bottom of the ocean and begins to flow south along the ocean floor near the coasts of North and South America. As it approaches Antarctica, it encircles the Antarctic continent. Eventually the cold, deep water flows northward and splits into the three ocean basins. There, it moves upwards (due to upwelling) and warms as it flows onward. The cool warming water now becomes part of the wind-driven surface currents, eventually returning to the seas off the shore of Greenland to begin the process again. This journey can take up to one thousand years to complete. The conveyor belt is an important part of the global climate system as it is a major transporter of heat from the equatorial regions to the polar regions. For example, the oceanic conveyor belt, combined with the wind-driven surface currents, is responsible for northern Europe's moderate climate. Northward movement of heat in the Gulf Stream (a wind-driven surface current) provides the British Isles and Scandinavia with milder temperatures than landmasses at similar latitudes on other continents. NSES: National Science Education Standards ( CLEP: Climate Literacy Essential Principles ( ELF: Environmental Literacy Framework ( 183

11 As Earth s temperature warms, the polar ice caps may melt, allowing the fresh water that has been locked for hundreds of thousands of years in the glaciers and ice sheets to enter into the ocean, thus reducing the salinity of the oceans. If the salinity of the North Atlantic surface water drops too low to permit the processes that contribute to the formation of deep-ocean water masses, the oceanic conveyor belt could slow down or even stop. The conveyor system has shut down in the past; for example, it shut down between 1400 and 1850 A.D., leading to what is known as the Little Ice Age. During this period, Northern Europe's climate became markedly colder. Glossary Image credit: NASA Unit Activity Vocabulary Word Bathymetric Density Ocean Current Salinity Temperature Thermohaline Definition Measurements of the depths of the oceans, seas and other large bodies of water. Measurements are relative to the depth below sea level. The calculated mass per unit volume of a substance. Less dense fluids and gases float on more dense fluids and gases unless they mix. Hot air is less dense than cold air, which is why hot air balloons rise. A continuous and directed movement of the ocean s water due to winds, waves, temperature, density, or the movement of the Earth. Containing salt. Salinity in the oceans refers to the water s saltiness. The degree of hotness or coldness of a body or environment. Thermo = heat, haline = salinity. The thermohaline circulation of the ocean refers to the deep water current that is driven by the cold dense salty water and warm surface water. 184