Upwelling as a Seasonal Event

Materials / Preparation

• Computer with internet and projector, projector screen or student computers with internet access.
• Animation about seasonal winds from Central California COAMPS Winds. This is also accessible from Seasonal Winds located on the Exploring Oceans Student Web Page.
• Excel Graphs of Abiotic Seasonal Data: MBARI Graphs
• Graph paper (1 sheet per student + 2 sheets per group)
• Data tables (1 for each student): MBARI Data Table
• Blank overhead transparencies and markers for each group
• Seabirds & Shorebirds Maps and Graphs shows sea bird biomass maps (we prefer the map labeled Marine Bird Biomass During Periods of Warm, Cold, and Normal Water). This and Marine Mammals Histogram are both linked from the section called Plankton, Sea Birds and Marine Mammals on the Exploring Oceans Student Web Page.
• Marine Mammals Histogram requires Adobe Reader to open.

Grouping

Class discussion and small groups (divide the class into 5 groups or 10 groups and have pairs of groups graphing or analyzing the same data sets)

Teacher tips

The wind direction animation is best done as a class demonstration and discussion. You may want to practice with the animations at Central California COAMPS Winds before showing the wind patterns to the students. The controls aren’t very intuitive, but if you can manage to manually move through the months (by using the +1/-1 buttons,) it will be easier for the students to see the changes that occur.

This activity is written as a graphing exercise, however, it could be modified to simply be an activity about interpreting graphs. Depending on the math skills of your class, this activity could take one-three class periods. For students who haven’t done much graphing, it is advisable to go slowly, divide up the data, and work in small groups. Teachers may also want to provide templates for younger students. More advanced students should graph each data set individually. You could also have them access the data from the original Monterey Bay Time Series Data instead of the data table we’ve generated.

Depending on your students’ computer skills, you might also consider having them use Excel to generate the graphs. We have included graphs and data spreadsheets generated in Excel as part of this teaching box. If you don’t wish to have your students generate the graphs, students can analyze the data using the graphs provided. It is important for the learning outcomes of this box that students analyze the results of the graphs, how they get the graphs is less important.

Procedures

1. Begin the class by continuing the discussion started at the end of lesson 2. Ask students questions such as:
   • What is upwelling?
   • What causes upwelling?
   • How does upwelling affect the biotic world?
   • What abiotic factors influence upwelling?
   • How does upwelling change the surface of the ocean? (both seen and unseen).
   Use this discussion to generate a class list that includes things such as: colder waters on surface, winds from the North cause offshore currents, phytoplankton get nutrients from benthic zone, zooplankton feed on phytoplankton, fish feed on phytoplankton, birds/mammals feed on phytoplankton and fish.
2. Continue the discussion:
   • When does upwelling occur? (Possible responses for discussion : year-round, annually, rarely). Ask students to share their ideas.
   • What types of evidence might tell us when upwelling is taking place (Answer: winds from the north, colder surface water temperatures, increased nutrients on the surface, abundant life on the surface)
3. Confirm that students remember/understand that upwelling off the coast of California is caused by winds from the north.
a. Demonstrate the wind animation starting in January 1999 Central California COAMPS Winds.
b. Ask students what the arrows mean (Answer: they show both direction and strength of winds). Ask if the January 1999 winds could cause upwelling?
c. Move to February 1999 and ask if the winds could cause upwelling. Move through the year in this manner having students pause to analyze the wind speeds and directions.
d. When you get to December 1999, ask students to review the months where they saw northerly winds that could cause upwelling.
e. Ask the students if they think this is a predictable pattern with winds. Ask students to make a hypothesis for the next year. Look at the 2000 months to test the student hypotheses.
f. Ask students to identify additional evidence that would help confirm whether or not upwelling took place during those months.
4. Ask the students when there would be the most sunlight available to phytoplankton? If your students have not yet studied photoperiods you may wish to have a brief discussion about changes in sunrise and sunset throughout the year. (Answer: during spring/summer months when the photoperiod is longer).
   NOTE: At this point in the lesson students will either generate graphs and analyze them or just analyze Excel-generated graphs.
5. As a class, graph seasonal temperature (or have students review the seasonal temperature graph). Each student should have a MBARI Data Table and a copy of the graph template for temperature. Work as a class or have students work independently depending on their ability level.
   a. When the graph is complete, ask students if their predictions were correct.
   b. Tell them they will next graph (or look at graphs of) nutrient levels and photoperiods in small groups.
6. Divide students into 5 groups. Assign each group one abiotic factor to graph (nitrates, phosphates, silicates, iron, or dissolved oxygen). You might choose to have a 6 th group graph chlorophyll, alternatively you could have the chlorophyll graph copied/printed onto an overhead to show the class. Distribute the graph paper and transparencies (or graphs).
   a. After the students have finished graphing, have them trace their results onto an overhead transparency and label the factor being graphed.
   b. Look at each graph (see NOTE below) and have a class discussion about the meaning of the results from each graph. Guide students to identify the reasons for the seasonal changes and their relationship to upwelling.
   c. As you look at each graph with the students ask questions such as: Do you see any changes through the year? Describe the pattern. In what months is this resource abundant? In what months is it scarce? How is this resource related to upwelling? How is it used in the food web? What organisms might be affected if this resource is abundant? How would they be affected? How would these organisms be affected if this resource were scarce?
   d. What evidence do the graphs provide that tells us when upwelling is happening?
   NOTE: Start with the graphs of the abiotic factors and build up to the chlorophyll graph. For example, if students say that phytoplankton would be affected by changes in dissolved nutrients, look at the phytoplankton (chlorophyll) graph right after the dissolved nutrients. Students can then check their hypotheses. This is a great opportunity for students to make predictions about how parts of the food web affect one another and to immediately check their predictions.
7. Ask students when in the year the phytoplankton would have the most available light and nutrients?
Ask what else might happen at this time? Guide students to think about how a plankton bloom would affect higher trophic level organisms.
8. Have the students look at the biomass maps at Seabirds & Shorebirds Maps and Graphs and the Marine Mammals Histogram.
   NOTE: These sites are both available on the Exploring Oceans Student Web Page.
   a. Assist the students in interpreting the data and connecting it to a plankton bloom.
   b. Ask questions such as: Are the numbers of birds/mammals changing through the year? (Answer: yes)
• In what months are their numbers highest? (Answer: summer)
• How do you think their numbers change? (Answer: reproduction and migration)
• Why would they reproduce/migrate in the summer? (Answer: more food available)
• How does this relate to upwelling? (Answer: seasonal upwelling creates plankton blooms which provide food for zooplankton and fish, then sea birds and marine mammals eat fish and zooplankton)
9. Place all of the overhead transparencies on the screen together.
Ask students to describe what they see? What months are the most active?
10. End the class by returning to the pictures of the active and quiet sea looked at in Lesson 1, Activity 1. Ask the students to predict the months that each picture might have been taken.
Tell them that they will re-evaluate the five pictures in the next activity.

Resources used

Seabirds & Shorebirds Maps and Graphs
http://www.teachingboxes.org/catalog.jsp?id=DLESE-000-000-008-934

Marine Mammals Histogram
http://www.teachingboxes.org/catalog.jsp?id=DLESE-000-000-008-935

Monterey Bay Time Series Data
http://www.teachingboxes.org/catalog.jsp?id=DLESE-000-000-008-936

MBARI Data Table
http://www.teachingboxes.org/upwelling/lessons/lesson3_supplement/StudentDataforGraphing.pdf

Central California COAMPS Winds
http://www.teachingboxes.org/catalog.jsp?id=TBOXR-000-000-000-097