Ocean Gyre Circulation and Patterns of Global Primary Productivity
This teaching activity provides a visual framework for understanding the relationship/connection between ocean gyre circulation and primary productivity. Students demonstrate their own understanding of surface circulation in ocean gyres and how it is related to broad patterns of global primary productivity by completing a schematic sea surface map and sea surface profile of the Atlantic Ocean. This simple in-class activity allows students to recognize any misconceptions they have about the relationship/connection between surface circulation and primary productivity and to correct them.
Undergraduate introductory oceanography course
Skills and concepts that students must have mastered
Coriolis, effect, atmospheric circulation, surface ocean circulation, Ekman transport, divergence, convergence, downwelling, upwelling and primary productivity.
How the activity is situated in the course
This activity is a summary of how the topics above are related and their implications. It is used at or near the end of the topic of ocean circulation to provide students with an opportunity to check their understanding of the above relationships and recognize misconceptions they may have and to correct them and allow instructor to verify their level of understanding of ocean circulation.
Content/concepts goals for this activity
Students should be able to:
- Identify the direction of Ekman transport in a major ocean gyre.
- Distinguish divergence and convergence surface water flow from one another and describe why they happen.
- Describe the ocean circulation implications of divergence and convergence, which are downwelling and upwelling, respectively.
- Relate the ocean circulation implications to broad patterns of global primary productivity.
Higher order thinking skills goals for this activity
Synthesizing class material on coriolis effect and its impact on ocean and atmospheric circulation, geostrophic flow, eastern and western boundary currents and primary productivity.
Other skills goals for this activity
Translating information from a map perspective to a sea surface profile perspective.
Description and Teaching Materials
This very simple in-class activity is a way to tie up several important ideas, concepts and processes related to ocean circulation and primary productivity. There is a single front and back handout that students get. The front has a schematic map of the north and south Atlantic Ocean with simplified circulation gyres in each ocean basin and the back has a north to south profile of sea surface topography illustrating that the sea surface is not flat. Students annotate the map with arrows representing Ekman transport, compare their map with their neighbor and then they locate areas of convergence, divergence, upwelling and downwelling, and wrap up with class discussion. Using the back side, students locate regions of convergence, divergence, upwelling and downwelling again, compare the profile with neighbors and wrap up with full class discussion. Lastly, students consider the relationship between these circulation patterns and primary productivity by annotating both the map and the profile with regions of high and low productivity. See Notes to instructor (below) for detailed, step-by-step instructions on how to proceed.
Teaching Notes and Tips
See notes to instructor documents (including answer key).
One way to assess the students' understanding of the above relationships is to create a short quiz using a similar map only calling it the Pacific Ocean. Ideally, they should be able to translate these relationships to the ocean gyres of a different ocean basin. The examples of assessment questions document provides some questions to use in evaluating students' understanding in either a quiz or exam format.
References and Resources