Student Activity

Overview
People in Peru have come to rely on cool, deep water to rise and bring nutrients to the surface. The small fish that are their livlihood eat the microscopic marine plants that use these nutrients. There are years where the cool, nutrient rich water comes to the surface, supporting enough fish for everyone. Some years there are hardly any fish. These years are tough on the coastal people who make their living from fishing. Can the fluctuations be predicted? Is Peru the only place where there are such fluctuations?

Upwelling is a phenomenon that occurs in a number of places in the global ocean. The term refers to cold, nutrient-rich water rising to the surface from depths of over 50 meters. Upwelling is created by wind blowing across the ocean's surface and pulling the surface water with it. As the surface water leaves an area, the 'hole' left behind is filled in by water upwelling from below.

Goals
You will:

  • Learn how to read satellite maps.
  • Understand the importance of upwelling areas.
  • Analyze maps to predict areas of high fish productivity.
  • Compare predictions of fish productivity to actual catch data

Explanation of Questions
This lesson is designed to help you create a hypothesis, research it, and make a conclusion about effects of ocean upwelling. You can do this by using the NOAA/NESDIS website to help you find data for research. Your teacher will help to guide you in the appropriate direction by helping your group create a valid hypothesis, discover the best methods to research your hypothesis, and show you ways to find appropriate data to support your hypothesis. This lesson will give you a few examples of questions and supporting data so that you can come up with questions and supporting data of your own.

Questions
All external links open in a new window.

  1. Pick any monthly-averaged SST map from the following website. Can you identify areas that show colder temperatures than surrounding waters? (Focus on the equatorial Pacific or coastal regions first since we know they are usually most prominent.) http://www.nodc.noaa.gov/dsdt/oisst/index.html


  2. Look at a few months in chronological order. Do you see any upwelling areas that are continuous over that time span?

  3. One new tool that scientists use to evaluate many quantities, both in and out of the ocean, is animation. A static map of one month offers a great deal of information, but a 'movie' can show a different perspective by looking at how certain things change over time. Look at the following two animationsof SST and ocean color. They are both from the same year (2001). Do they agree with each other in terms of the prominent upwelling areas? (Consider both space and time in your assessment).

    Animations will open in a new window. Click on Refresh to replay animations.
    SST Animation

    Ocean Color Animation

  4. Which animation (SST or ocean color) do you think is better? If you were a scientist, with which one would you prefer to work? Why?

Upwelling Investigation
Use SST data and fishery catch data to explain the differences between the El Nino and La Nino events?

  1. To Find the El Nino/La Nina Events:

    a . Look at the following map of SST for January of 2001. Identify areas that are colder than surrounding waters at the same latitude.

    http://www.nodc.noaa.gov/dsdt/oisst/monthly/gif/200001.gif

    b. Now compare a map of January 1998 with one of 2001. Despite the fact that both maps are of January, do you see a difference? (Hint: January of 1998 was in the middle of a large El Nino event.)

    http://www.nodc.noaa.gov/dsdt/oisst/monthly/gif/199801.gif

    Be able to identify the El Nino/La Nina events through SST data. Describe the differences you can observe through satellite data.

  2. Evaluate the rate and duration of upwellings in specific upwelling localities in 1996 and 1998.

    a. Look at the SST maps for 1996 in chronological order. Assess the following areas (which are known to be productive coastal upwelling areas) in terms of rate and duration of upwelling: (a)California/Oregon (b) Peru (c) Northwestern tip of Africa (d) Southwestern tip of Africa. Use "low", "moderate", or "high" for rate, and use "short" (< 8 months) or "long" (> 8 months) for duration. Do the same for 1998.
    Rate and Duration Worksheet (MS Excel)

    b. Focusing on California/Oregon, assess which of the two years would have produced a higher yield from fishing.
    What is the evidence that you use to determine fishing possibilities?
    Or consider, what is the biological result of upwelling events?
    Going even further, can you tell which months would have had highest fishing yield?
    Remember there is a few-months' delay between upwelling and increased numbers of fish.

  3. Go to the National Marine Fisheries website and look up the landings for Oregon for both of the above years.

    Fill in the fields as follows:
    Species: All species combined Year Range: From: 1996 To: 1996 Time Frame: Year by Month Geographical Area: Oregon Output Form: Table, then hit Submit Query.
    http://www.st.nmfs.gov/st1/commercial/landings/monthly_landings.html

    Compare your upwelling evaluations with the fishery data for both years.
    How well do they agree?
    Is there some way you can improve your upwelling evaluation based on the comparison?

  4. Look at the most recently available maps of SST.
    What predictions can you make about fisheries in the near future for the Oregon coast?
    Now, you have the tools to predict fishing potential at any upwelling site in the world's ocean!