Earth's Global Ocean

Initial Publication Date: June 22, 2015

Time required to complete this unit:

This page is under development and may be edited at any time. Some resources have not been cataloged, pending project approval.
3 weeks, or 12.5 hours, or 750 minutes (estimated)

Earth Science Content:

Key Terms: ocean, salinity, density, current, oceanography, barrier island, coastline, embayment, reef, gyre, convection, ocean circulation, thermohaline, photodegradation

Unit Storyline

The global ocean comprises 71% of the Earth's surface, providing the ultimate reservoir for all the world's water and, through evaporation, providing the source of water for the precipitation that feeds the global water cycle. Surface currents and deep circulation of heat make the global ocean a dominant part of Earth's climate system. These currents are also responsible for transporting the nutrients necessary to support the ocean's vast biodiversity. Human impacts can be magnified in the ocean through overfishing and ecosystem misuse, and by the long-distance transport of pollution and contaminants.

Developed by the DIG Texas Blueprints North Texas Development Team

Students will be able to (do)

  • Illustrate ocean basin features.
  • Analyze global ocean temperature data in order to predict the consequences of changing ocean temperature on coral bleaching and biodiversity.
  • Classify the ocean by using multiple layering systems, and infer how the layers change on multiple timescales.
  • Analyze and explain how global ocean circulation is the result of wind-created surface currents, water density differences, and the shape of the ocean basins, resulting in global thermohaline circulation.
  • Describe ocean surface currents and examine how human produced pollution is a concern.
  • Describe how corals grow and reproduce, and explain the process by which corals extract reef-building material from seawater in order to build reef structures.
  • Create physical models of coral growth, reproduction, and reef formation.

Students will know

  • That the geosphere continuously changes over a range of time scales involving dynamic and complex interactions among Earth's subsystems.
  • That the fluid Earth is composed of the hydrosphere, cryosphere, and atmosphere subsystems that interact on various time scales with the biosphere and geosphere.
  • That Earth's global ocean stores solar energy and is a major driving force for weather and climate through complex atmospheric interactions.
  • That interactions among the five subsystems influence climate and resource availability, affecting Earth's habitability.
  • How the composition of the ocean affects currents, density and life.


The activities we have selected are congruent with the Next Generation Science Standards (NGSS), and are arranged to build upon one another. Therefore, to follow the storyline we recommend that teachers complete the activities in the order provided. To open an activity in a new tab or window, right click the activity link and select the preferred option.

Exploring Seafloor Topography

View Activity

Students will use GeoMapApp to visualize the seafloor by generating and interpreting graphs. The activity teaches how technology is used to map Earth's ocean basins and coastlines. Students gain experience working with authentic data and scientific visualization.

Instructional Strategies: Inquiry

Resource Type: Laboratory investigation, experiment or demonstration

Time Required: 150 minutes

Ocean Layering: Density, Temperature, Salinity and Circulation

View Activity

In this set of three related labs from the Scripps classroom collection, students investigate the role of density in the ocean, examine how temperature, salinity and density create layers in the ocean, and learn about the application of modern technology in studying seasonal changes in the ocean.

Instructional Strategies: Inquiry

Resource Type: Classroom learning activity

Time Required: 210 minutes

Hot, Cold, Fresh and Salty

View Activity

The NOAA Ocean Service Education lab requires students create and manipulate solutions simulating different ocean water characteristics in order to recognize that the effects of salinity and temperature are the drivers of thermohaline circulation.

Instructional Strategies: Inquiry

Resource Type: Laboratory investigation, experiment or demonstration

Time Required: 80 minutes

The Global Conveyor Belt

View Activity

NASA JPL video, showing linkage between oceans and movement of water. This allows students to SEE the movement of ocean current and links the idea between conveyer action and oceanic current flowing throughout.

Instructional Strategies: Lecture

Resource Type: Video

Time Required: 1 minute

NASA Perpetual Ocean

View Activity

The swirling flows of ocean currents is captured in this scientific visualization created by the NASA's Goddard Flight Center. Students gain an appreciation of both the order and chaos of of the water's of Earth's surface ocean.

Instructional Strategies:

Resource Type: Video

Time Required: 3 minutes


View Activity

A series of six lessons presented in this EarthLabs module on Corals expose students to current scientific research, data, and visualizations in a way that allows them to become active participants in both learning about and conserving coral reefs.

Instructional Strategies: Inquiry

Resource Type: Classroom learning activity , Laboratory investigation, experiment or demonstration

Time Required: 750 minutes for all 6 labs in the module.

For this unit, we have selected three labs: Anatomy of a Coral (Lab 2B), Building a Reef (Lab 3) and Finding Coral's Ideal Environment (Lab 4). The time required to complete these labs is 300 minutes.

  • Anatomy of a Coral (Corals Lab 2B) (teacher instructions) (specific student activity)

Students learn about the anatomy of coral and build a simple physical model of a single coral polyp.

Time Required: 50 minutes

  • Building a Reef (Corals Lab 3)

Students learn about the life cycle of corals, including how they grow and reproduce. They also consider the chemistry of seawater and conduct an experiment to show how calcium carbonate precipitates to form skeletal reef material. The interactive format includes readings, demonstrations, and laboratory activities.

Time Required: 120 minutes
  • Finding Coral's Ideal Environment (Corals Lab 4)

Students examine temperature, depth and ocean chemistry data to discover coral reefs' favored environments. The interactive format includes readings and the interoperation of data displayed visually.

Time Required: 120 minutes

Charles Moore: Seas of Plastic

View Activity

In this TED talk, Captain Charles Moore of the Algalita Marine Research Foundation draws attention to the growing problem of plastic debris accumulating in all the gyres of the ocean.

Instructional Strategies: Lecture

Resource Type: Video

Time Required: 8 minutes

Inside the Plastic Vortex

View Activity

This video produced by Scripps Institution of Oceanography's Explorations e-magazine follows a groundbreaking student-led research cruise on the Research Vessel (RV) New Horizon to help define a rising environmental threat, plastic pollution in the ocean.

Instructional Strategies: Lecture

Resource Type: Video

Time Required: 8 minutes

Field Trip

Studies that examine how geologists think and learn about the Earth point to the value of field experiences in helping students develop practices that constitute geologic reasoning. We encourage teachers to take students into the field as much as possible. To this end, we include ideas for virtual and actual field trips. The former recognizes the limitations of the K-12 classroom setting. Field learning provides a chance to encourage the ability to see features that are important to professional practice. Indeed, many geoscientists report that fieldwork was a key factor influencing their choice of geoscience as a career.

Virtual Field Trip

Google Earth: Ocean

Travel to new depths with Ocean in Google Earth. This video introduces students to the features of Google Earth: Ocean.

Scaffolding Notes

Teachers must develop their own individual plan for how they will teach the unit. The learning activities and educational resources in this unit are intended to complement other instructional activities led by the teacher. Many of the selected learning experiences provide links to excellent background preparatory materials, additional hands-on resources, teaching tips, and cross-curricular connections.

Teachers will need to create their own multimedia presentations, deliver lectures and assign ancillary work to their students in order to set the stage for effective use of the learning activities contained herein. Therefore, it is imperative to allocate time to review the activities and background material prior to using the learning experiences in this unit and to probe students for their prior knowledge before starting an activity.

In addition, although some activities may incorporate assessments, teachers may need to create their own assessments to ensure that are appropriate for the students they teach.

Asterisks (*) indicate teacher resource and background information recommendations for activity support.


*This unit begins with an examination of the major physical features of the global ocean, including ocean floor topography, the thermal and chemical structure of the ocean, and the dynamic circulation of this global system. The unit continues with a broad exploration of marine ecosystems and a focus on coral reefs as a case study of the sensitivity and selectivity of marine life with respect to physical and chemical characteristics of the ocean. Finally, the unit closes with a study of the intersection of human activities with ocean circulation with a look at the rising threat of plastic pollution in circulation eddies.

*Before beginning this unit, we recommend that teachers download and review the Ocean Essential Principals and Fundamental Concepts. Developed by scientists and educators, this guide defines ocean literacy and identifies the principles and concepts of ocean science that should be included in K-12 curricula. Remind students the Earth has one global ocean with many physical features. Examples include ocean basins, mid-ocean ridges, submarine volcanoes, deep ocean trenches, and coastal embayments.

Exploring Seafloor Topography focuses on the physical features of the global ocean. The activity uses GeoMapApp, a software program. Teachers must download the application to the computers in advance and practice running the application before teaching the topic. Help may be needed from the school's IT specialists. The website is easy to navigate with very good instructions. Screen shots and example work are included. In part 3 of this activity students make a contour map of the seafloor using real seafloor data and create a cross-sectional profile. We recommend that teachers review topographic/bathymetric maps and the rules for drawing them.

*Teachers may find NASA Goes Below the Surface to Understand Salinity to be a very helpful illustration of the types of equipment and technology, along with their layout, used in the process of gathering salinity measurements and related ocean layer data. This illustration includes glider paths that are referenced in activity 3 found below.

Ocean Layering: Density, Temperature, Salinity and Circulation from the Scripps Classroom Collection consists of three learning activities that examine the vertical structure of the ocean and a Review and Quiz. The activities give students a chance to work with actual data as they learn about global thermohaline circulation and investigate some of the smaller scale features that stir and mix the waters of the ocean. All the lessons have multiple parts: PowerPoint lectures, activities, work sheets, among others. Teachers may select those parts that support the learning goals of their course. The files for the resources may be downloaded as an Office file or a PDF, as well as in a Zipped Archive that contains both files. It is recommended that you use the PDF because of possible conflicts through Microsoft products. For full implementation of all activities the estimated time required would be 210 minutes.

1- Density and Density's Role in the Ocean lesson: The teacher or students can construct a classic density column that very nicely demonstrates the behavior of liquids of differing densities. A lab activity allows students to analyze the floating or sinking of objects based on density differences in samples of water.

2- Layers in Ocean Water lesson: A mixing activity has students model the ocean waters using colors of clay that represent different characteristics of the ocean waters and then analyze what happens after they "mix" it. The Global Layers activity engages students in analyzing water movement in the Atlantic Ocean due to temperature and salinity differences. The handouts required can be downloaded in color or in grayscale without loss of resolution. An answer key is provided.

3- Using Ocean Gliders to Study Seasonal Changes lesson: Students analyze a vertical column of data obtained by an ocean glider to explore seasonal changes in the North Pacific Ocean and highlights the use technology in data acquisition. The handouts required can be downloaded in color or in grayscale without loss of resolution. An answer key designating skill levels is provided.

The lab activity Hot, Cold, Fresh and Salty is a hands-on water lab. The lab itself links to a few tutorials on thermohaline circulation, if needed. Very specific and detailed information is provided for obtaining materials, managing supplies, and making solutions.

The Global Conveyor Belt is a short animation that demonstrates how surface currents and density differences caused by salinity and temperature variations drive circulation in the deep ocean. This video helps reinforce concepts covered in the Density lesson and introduces the idea of thermohaline circulation. The video moves a bit fast so after completely showing it, teachers should replay it and pause it at key points for questions and discussions with students. One lesson approach is to have students draw the current patterns on a blank oceans map using different colors for hot and cold currents to reinforce the idea. Teachers will have to download the QuickTime video. The video is also available on YouTube at The Global Conveyor Belt.

There is often confusion between the components of ocean circulation that are density driven and those that are wind driven. Therefore, we recommend that teachers also review surface currents, which are wind driven, and show NASA's Perpetual Ocean video. We recommend downloading the video from the website in advance to avoid potential technical glitches. An alternative URL is at Perpetual Ocean. This video is also available in a 20-minute version (found at the bottom of the website) and an hour-long version found on YouTube. The 3 minute and 7 minute videos can also be found on Vimeo.

If time and technology permit, the 20-minute version will allow teachers to provide more detailed instruction and give students time to identify currents and digest all the information. The video, which is based on real data, reveals the extent to which typical maps of surface ocean circulation are oversimplified. An additional video that centers on the North Atlantic and Greenland is found at NASA's The Thermohaline Circulation - The Great Ocean Conveyor Belt. If you would like to show an interactive model, one can be found at the NOAA: Science on a Sphere webpage Ocean Circulation (ConveyorBelts).

*Marine ecosystems are vital to the health of our planet. The topic is too broad to be covered fully in this unit. However, we suggest that teachers provide an introduction to marine ecosystems and explain the links between terrestrial and marine ecosystems. Examples of marine ecosystems include salt marshes and coastal wetlands, estuaries, mid-ocean ridge hydrothermal systems, and coral reefs. In this unit, we emphasize coral reefs, which are among the most diverse ecosystems in the world.

The EarthLabs Corals module requires Internet access. In Anatomy of a Coral (Lab 2B) teachers need to collect materials for the model building activity ahead of time. In Building a Reef (Lab 3) teachers will need to prepare materials for a wet lab for Part A, including a limewater solution that requires 24 hours of standing time. Part B requires that students use the models previously made. In Finding Coral's Ideal Environment (Lab 4) students examine factors such as depth, salinity, aragonite saturation, and temperature to determine corals' ideal environment. The lab is broken into 3 parts each of which examines one or two factors controlling coral location. If time is a factor you could have different groups of students looking into each factor then have them discuss their results as a panel of scientists would, explaining to the class how they reached their conclusions.

The Charles Moore: Seas of Plastic TED talk and video focuses on plastic debris accumulating in ocean gyres. The commentary by Captain Moore is a little fast. A video of the talk is also available on YouTube. This TED talk transports students from their everyday lives to a remote part of the ocean where they can observe the impact of human activity on the environment from plastic pollution. As an extension activity, weigh an empty plastic water/soda bottle (or provide the weight) and have students calculate how much plastic they contribute to the trash stream (by week/month/year/decade) if, instead of recycling, they were to throw their plastic bottles into the general garbage.

Inside the Plastic Vortex is a podcast that highlights a Scripps Institution of Oceanography student-led research cruise on the R/V New Horizon. Get students involved by asking them what questions they would generate and investigate as researchers if they where on-board the ship.

Next Generation Science Standards

We anticipate that students should be able to achieve the NGSS Performance Expectation(s) listed after completing the activities in this unit. However, we have not carried out educational research to verify this.

HS-ESS2-1. Develop a model to illustrate how Earth's internal and surface processes operate at different spatial and temporal scales to form continental and ocean-floor features.

HS-ESS2-2. Analyze geoscience data to make the claim that one change to Earth's surface can create feedbacks that cause changes to other Earth systems.

HS-ESS2-4. Use a model to describe how variations in the flow of energy into and out of Earth's systems result in changes in climate.

HS-ESS2-6. Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

HS-ESS2-7. Construct an argument based on evidence about the simultaneous coevolution of Earth's systems and life on Earth.

HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.

HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.

These Performance Expectations integrate the Disciplinary Core Ideas, Cross Cutting Concepts and Science and Engineering Practices of the NGSS as shown in the unit table (link to table).

These Performance Expectations integrate the Disciplinary Core Ideas, Cross Cutting Concepts and Science and Engineering Practices of the NGSS as shown in the unit table NGSS Congruence: Earth's Global Ocean (Acrobat (PDF) 69kB Jul20 15).

Additional Resources

The recommended additional resources may be used to extend or augment the storyline.

Ocean & Climate is an Earth Observatory article/activity. Students access the website and research a contemporary environmental issue. Students will read, summarize and reflect on the content

Nautilus Live is the link to watch live ocean exploration or view highlights from previous dives.

Earth Observatory - Readings from NASA

The water cycle-revisit the water cycle and the effects the ocean has on water cycle.
As the seasons change, will the phytoplankton? Changes in ocean acidification and temperature and the effects on sea life are seen in this reading.
What are phytoplankton?

Humans and climate destroy reef ecosystem in this reading. It shows anthropogenic effects on the reef system. May be tied to the coral module to reiterate important concepts

Joseph Pawlik on Sponge Overgrowth in the Caribbean

Joan Kleypas on Ocean Acidification

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