This lesson introduces the concepts of changes in water density associated with (sea) salt, thermohaline circulation, coastal upwelling and its biological significance to large marine animals such as blue whales. The lesson attempts to illustrate how physical-chemical forces impact and shape life in the oceans. The lab activity follows a PowerPoint presentation, and provides students with a fun example of how winds and the Coriolis force interact to form upwellings, and how these in turn may influence the distribution of blue whales. The students are asked to reflect on seawater density, they will also acquire basic knowledge on the ecology (i.e. feeding behavior) of a specific marine animal: the blue whale.

  • This lesson and lab practice enables the students to establish links between geographical features (interpretation of maps), physical phenomena (Coriolis force, winds, currents) and the biological realm.
  • The lesson starts with a short PowerPoint presentation on “Thermohaline circulation, Upwelling and Blue Whales”. During the 20-25 min presentation, students are asked to answer a series of 7 questions.
  • The instructor divides the class into groups of 2 students. Each group is given a (1) Factsheet on upwellings, (2) a Blue whales factsheet, (3) a Lab instructions sheet with 4 questions at the end, to be answered once the students have finished their maps, (4) a map of the US West Coast and of the African East Coast (make a double-sided print) , (5) an image of a blue whale, to be cut out and glued into the map.
  • The “Lab instructions sheet on upwellings and blue whales” walks the students through the activity.
  • Class of maximum 30 students, divided in groups of 2.
  • This activity will take the full 90 minutes, and some students will probably have to finish it during a next class, or as homework. The instructor evaluates the finished maps, the 7 questions during the presentation as well as the 4 questions in the instructions sheet.
  • Prior knowledge: Students should be understand the effect of heat/cold on water density, know the basics on ocean currents, and be familiar with latitude and longitude coordinates.
  • First, the instructor needs to explain that each group has to read the factsheets on upwellings and blue whales, as the information contained therein will be used to make the maps. Groups should first draw in the winds and currents using a pencil and then ask the instructor to check if what they have done is correct. The instructor needs to remind the students to answer the 4 questions at the end of the instructions sheet.
  • The instructor needs to have (1) some knowledge on the simplest marine food chain: phytoplankton-krill-whales; (2) Coriolis force, winds, upwellings and the difference between the aforementioned factors in the Northern vs. the Southern hemispheres (this is why there are two maps in this lab! Coriolis will act in opposing directions).
  • The last part of the lab practice consists in coloring those coastal areas where upwelling could occur. It is an (over)simplification of a very complex phenomenon (the different drivers of sea water density). Therefore, they should be reminded that upwelling is only one of the causes for the higher density of surface waters.

Blue Whale


Lesson Specifics
  • Grade Level: 11th and 12th grade classes.
  • Time Frame: One 90 minutes class or two 50 minute classes. Two students per group.
  • California Science Standard: This lesson was designed for a marine science elective course. The lesson satisfies the National Earth Science Standard 5: students know the generation of horizontal and vertical ocean currents, the geographic distribution of marine organisms, more specifically marine megafauna. The National Science Standards in part C; Interdependence of Organisms & Matter, Energy, and Organization in Living Systems is covered by the part on whale feeding and distribution.

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