Amazon River Plume Inquiry Activity

Created by Deena Bollinger

Notes to Reader: This Amazon River plume inquiry activity was inspired by the 10/23/04 “Earth2Class Workshops for Teachers” at the Lamont-Doherty Earth Observatory of Columbia University, with guest scientist Dr. Ajit Subramanian.  A student handout follows the Lesson Plan below.

Objective: Students will make predictions, and determine what factors (wind, Coriolis, ocean currents) determine the direction of flow of river water and the materials it carries once it enters an ocean (the river’s plume).

Materials Needed: (for each student or pair of students)

• World Map with at least South America, the Amazon River, and the Atlantic Ocean labeled
• Worksheet showing the above locations, on which students can write
• Earth Science Reference Tables "Global Ocean Currents" chart (p. 4) (Click for a pdf version.)
• SeaWIFS image of the Amazon River plume available at http://www.gsfc.nasa.gov/gsfc/earth/pictures/2001/0327colors_of_life/carbon.htm    

(Scroll toward the bottom to find “EQUATORIAL ATLANTIC – RIVER OUTLETS SUPPORT LIFE”)
      An animation of the flow out of the Amazon is found at http://www.gsfc.nasa.gov/gsfc/earth/pictures/2001/0327colors_of_life/amazon.mpeg.

• Student handout, optional

Procedure:

1. Have students look at a world map showing the Amazon River and its basin.
2. Explain to students that where a river meets an ocean, the river produces a ‘plume’ of organic material mixed with river water that spreads into the ocean. This organic material includes a wide variety of decomposing material from the rainforests.
3. Ask students to use their prior knowledge to predict the direction of the Amazon River’s plume once it enters the Atlantic Ocean.
4. Have students draw their prediction directly on their copy of a world map.
5. Then have students look at the Earth Science Reference Tables Global Ocean Currents map. (Click for a pdf version.)
6. Ask students if they wish to revise their predictions on their map worksheet, based on the ocean currents.
7. Show students the SeaWIFS image of the Amazon Plume, and explain that what they are seeing is the dispersion of organic matters carried by the Amazon River into the Atlantic Ocean.
8. Ask students if their initial or revised predictions were correct.
9. Have students write the factor(s) they think are responsible for the direction of a river plume’s flow.

Assessment:

1. Ask students: Would you expect other rivers such as the Hudson, Mississippi, and Congo to empty into the ocean in the same direction as the Amazon plume? (Ans: No, the plume’s direction depends on local ocean currents)
2. Have students draw arrows on their world map worksheet predicting the direction of plume flow for several other rivers by using the Global Ocean Currents map in the Earth Science Reference Tables. (Click for a pdf version.)

Follow-up:

1. Ask students to list situations in which knowing the direction of a river’s plume would be beneficial.
2. Show students the seasonal variations in the Amazon River plume by using SeaWIFS images and have them try to explain why the plume is not constant in width and direction year-round.

Animation available at http://www.gsfc.nasa.gov/gsfc/earth/pictures/2001/0327colors_of_life/amazon.mpeg

Name ______________________                                                      Date ___________

What determines the direction of a river’s flow once it reaches an ocean?

Procedure:

            Look at a world map showing the Amazon River and its basin.  Where a river meets an ocean, the river produces a ‘plume’ of organic material mixed with river water that spreads into the ocean.  Use your prior knowledge to predict the direction of the Amazon River’s plume once it enters the Atlantic Ocean.  Draw your prediction on your world map worksheet. 

            Now look at the Earth Science Reference Tables Global Ocean Currents map. (Click for a pdf version.) Do you wish to revise your prediction?  If so, draw your new prediction on your world map worksheet, using a different color than your original prediction.

            Observe the SeaWIFS image of the Amazon River plume provided by your teacher. (You can find the image at http://www.gsfc.nasa.gov/gsfc/earth/pictures/2001/0327colors_of_life/carbon.htm, or you can go directly to the animation at http://www.gsfc.nasa.gov/gsfc/earth/pictures/2001/0327colors_of_life/amazon.mpeg.)

     What you are seeing in the SeaWIFS image is the dispersion of organic matter carried by the Amazon River into the Atlantic Ocean, as viewed from space.

Was your initial prediction correct? ______ Your revised prediction? _________

Analysis Questions:

1. What factor(s) do you think are responsible for the direction of a river plume’s flow?

2. List at least three situations in which knowing the direction of a river’s plume would be beneficial.

3. Observe the seasonal variations in the Amazon River plume by using SeaWIFS images.  Why do you think the plume is not constant in width and direction year-round?

4. Use the Global Ocean Currents map in the Earth Science Reference Tables to predict the direction of plume flow for several other rivers on your world map worksheet, as directed by your teacher. (Click for a pdf version.)