How does this ocean current affect ocean productivity?

Objectives
Students will be able to:

interpret chlorophyll a concentration maps and sea surface temperature data use the data to determine concentrations of phytoplankton in the ocean

Materials
computers with Internet access
Student Worksheet

Background
The Living Sea; Predators and Prey (Background on the ocean food web and remote sensing applications)

SeaWifs Teachers Guide Studying Ocean Color from Space.

When investigating the productivity of the ocean, it is necessary to look at the first link in the ocean food chain. These are often single-celled plants called phytoplankton. (Click here to see pictures of phytoplankton taken with a microscope.) These primary producers, which contain the pigment chlorophyll, require sunlight, nutrients, carbon dioxide and water to continue the process of photosynthesis and respiration. This is called plankton primary productivity.  The rate at which this process of primary production occurs can be limited by nutrient supply and the amount of available sunlight. Therefore, areas of the ocean where abundances of phytoplankton pigment concentrations are found should, theoretically, be abundant in nutrients supply and receive adequate amounts of sunlight.


Procedure
When investigating the productivity of the ocean, it is necessary to look at the first link in the ocean food chain, single-celled plants called phytoplankton. These primary producers contain the pigment chlorophyll and require sunlight, nutrients, carbon dioxide and water to continue the process of photosynthesis and respiration.  In order to determine ocean productivity, we can use chlorophyll a as an indicator.

 6                     6             solar energy              1                  6
molecules + molecules -------------------> molecule + molecules      (Photosynthesis)
carbon           water           chlorophyll            sugar        oxygen
dioxide

     1               6                              6                 6               life
molecule + molecules --------> molecules + molecules + support     (Respiration)
  sugar         oxygen                    carbon          water         energy
                                                  dioxide

1.  Open another browser window and explore the SeaWiFS Browser.  (right click on the link and select "Open in New Window")

2.  Use the table of links below the global map image to select the current year and month.  This will give you averaged results for an entire month's data. **If you are at the beginning of a month, you may choose the previous month's data for a better image.

3.  Click on the rainbow box in the top left side toolbar of the page and answer the questions on the Student Worksheet.

4.  Open another browser window and compare the recent chlorophyll a concentration maps with current sea surface temperature data.

5.  To see changes in ocean productivity throughout the year, use the archived images on the SeaWiFS browser and click through the monthly images over the course of one year.

6.  Concentrate looking at the polar regions and the North Atlantic basin and answer the questions on the Student Worksheet.


Assessment

Sea Surface Temperature	Chlorophyll a Concentration

1. According to these images, is the Gulf Stream adding nutrient-rich or nutrient-deprived waters to the northern Atlantic Ocean?
2. Where will abundances of zooplankton live in relation to abundances of phytoplankton?  Explain.
3. Why are phytoplankton so important?
4. Why would a fisherman be interested areas of high phytoplankton concentrations?
5. How can ocean currents effect phytoplankton?
6. What other factors may effect phytoplankton concentrations?  Explain.


Extension
Global Comparisons
1.  Using the "select region" feature on the SeaWiFS site, compare and contrast the chlorophyll -a concentrations, sea surface temperatures, and air temperatures for Hawaii and the North Sea for a one year period. 



Implementation Tips
For students having difficulty comparing the images, it is helpful to print the images on overheads using a color printer.  Then the students can overlay the images to make comparisions.