Part 5—Use East Pacific Rise Data to Test a Hypothesis

In this section you will observe images taken with the Alvin Submersible. You will look for patterns in the data that may explain more about how the ecosystem around the hydrothermal vents of the East Pacific Rise is organized. Scientists often work at the edge of their understanding, pushing back the boundaries of what they don't yet know. In this section, you will have a chance to think like a scientist, testing hypotheses at the edge of our understanding, in the extreme environment of the East Pacific Rise (EPR) spreading center.

Step 1 – Launch GeoMapApp and Add the Hydrothermal Vent Data and Images

  1. Launch GeoMapApp and add the following data:
  • 5-m ABE high-resolution bathymetry data from the East Pacific Rise.
  • Hydrothermal vent locations from the East Pacific Rise.
  1. Choose Focus Sites > NSF Ridge 2000 Program > East Pacific Rise (9N) > Bathymetry Grids > High-resolution Grids (5m, from ABE).

    2. 1. add ABE grids
  2. Choose Focus Sites > NSF Ridge 2000 Program > East Pacific Rise at (9N) > Tables > Hydrothermal Vent Locations - EPR.

    3. 2 add hydrothermal vent locations

  • Prepare the map for investigation.
    1. Click on the Configure button in the Data Tables Tool Box.
      p5 3 click configure
    2. Reduce the Symbol Size Percent of the symbols that indicate the Hydrothermal Vent Locations - EPR to ten percent (10%) and click OK.

      3. p5 4 configure vent size to 10
    3. On the map, Zoom in to the northern vent colony and High-resolution grids.

      4. p5 5 zoom into northern vent colony
    4. Map zoomed in.
      p5 6 zoom in to n vent colony results



    • Step 2 – Download and Import Images and Data from the East Pacific Rise

    1. Download the following spreadsheet file of images and data: (EPR image observation file complete (Excel 29kB Apr15 10).) Save the file to your desktop or to a location on your computer where you can locate it easily.
    2. Choose File > Import Table or Spreadsheet > From Excel-formatted (.xls) file and browse to the location of your image spreadsheet file.
    3. When you have located it click Open; then in the next window, click OK.
    4. After the table is imported, a Config window will display. In the Config window, reduce the Symbol Size Percent to ten percent (10 %), and check the box near the bottom of the window to make Data Cells Editable. Click OK to load the images into the data table and main map window.
    5. Adjust the map so you can see both the images' locations and the bathymetric features.
    6. The locations for each of the twenty images should be now be visible along the axial trough of the East Pacific Rise. If all of the image locations are not shown, use the Zoom In tool to set the proper window size. Your longitude should extend from 104 degrees 18' 30" W to 104 degrees 16' 30" W and the latitude from 9 degrees 50' N to 10 degrees N.
    7. Click in the first row in the data table to view a thumbnail of an image at a particular location. The arrows in the thumbnail viewer can be used to navigate through the list of images. As you switch between images, the location will be highlighted on the GeoMapApp window with a red dot. You can increase the size of the thumbnail viewer to see more detail in the images, by stretching it from the bottom right corner.
    8. Adjust the width of the caption column so that you can read the caption of each image as you view them.


    Step 3 – Examine Relationships between the Images and Bathymetry

    Once the data and images are imported, it is possible to look for relationships in the data and explore hypotheses about life in extreme environments.



    1. Test hypothesis #1: Life forms are only found inside the axial trough of the East Pacific Rise.
    2. Test hypothesis #2: Life forms at the East Pacific Rise are usually found in locations where hydrothermal fluid mixes with the colder ocean water.
      3. Scientists studying the East Pacific Rise are very interested in the locations of the various vent communities relative to the hydrothermal vents. Use the spreadsheet of observations from East Pacific Rise to test this hypothesis. Recall that the presence of hydrothermal fluid is indicated by cloudy or shimmering water.
  • Test hypothesis #3: Collapse structures at the EPR create cracks and fissures that allow hydrothermal fluids to be released.

    • Scientists have proposed that the cracks and fissures produced as molten rock expands and contracts into a rifting area provide the pathway for hydrothermal fluids to migrate out of the rocks and into the ocean water. Test this hypothesis by comparing your observations of collapse structures in the images to the presence of cloudy or shimmering water.

  • Test hypothesis #4: Water temperature plays an important role in determining where certain species are found at the East Pacific Rise.

    • Observations of tubeworms, crabs, and mussels can be compared to the temperature data in the spreadsheet file to test this hypothesis. Are one or more of these species restricted to a certain temperature range at the East Pacific Rise?

  • Test hypothesis #5: Your own design.

    • Explore the data. What other patterns have you observed during your exploration of the East Pacific Rise? Develop a hypothesis that you can test using the data table and other data that you have loaded into GeoMapApp. Don't worry if your hypothesis needs to be discarded after your testing—it can still help you to understand something new about this amazing ecosystem among the hydrothermal vents of the East Pacific Rise spreading center.

    Click and drag the headers to move the columns in the data table. Look for possible relationships such as chimneys and life forms. Recall that all life has limiting factors, such as nutrient availability and temperature range.


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