Windows into Wonderland

Hotwater eTrip: Gibbon River Study




The student will:

  • Use raw data to create 2 graphs with 100% accuracy.
  • Use 2 graphs to make connections between relative abundances of different macroinvertebrates with 100% accuracy.
  • Use 2 graphs and raw data to identify trends in macroinvertebrates across a span of years with 100% accuracy.
  • Complete 3 mathematical calculations with 100% accuracy.
  • Create a visual representation of the Gibbon River based on the raw data and graphs.


  • Attachment A - Percentages of Gibbon River Macroinvertebrates at Four Sample
  • Sites (56 KB pdf)
  • Attachment B - Gibbon River Study Worksheet (13 KB pdf)
  • Attachment C - Gibbon River Study Worksheet Answer Key (10 KB pdf)
  • Graph Paper or graphing software
  • At least 5 different colored pencils
  • Pencil/eraser


The Gibbon River is one of the major waterways of Yellowstone National Park. It flows in a southwesterly direction from Grebe Lake, and then takes a northward turn, forming an inverted “u” around Norris Geyser Basin. Thereafter, the river continues its journey to the southwest, falling over the 84 foot high Gibbon Falls. The Gibbon and Firehole Rivers come together at Madison Junction to form the Madison River. En route, (especially at Norris Geyser Basin), the river is fed by infusions of hydrothermal water.

The New Zealand mud snail is an invasive aquatic species that was first observed in Yellowstone waters in 1994 and is now found in the Gibbon, Firehole, and Madison Rivers. This animal is about 1/8 of an inch or 2-4 mm long and lives in dense colonies on aquatic vegetation and rocks along streambeds. The snails crowd out native aquatic insect communities, which provide nourishment for fish. They also eat algae, another primary food source for fish and other native species. Studies indicate that they can pass through the digestive tract of a trout unharmed, while offering no nutritional value.

No one is sure how this exotic organism was introduced into the park’s waters, but likely it arrived via boaters and anglers who unknowingly carried it from other fishing locations around the country. New Zealand mud snails have been found downstream of thermal additions in both the Firehole and Gibbon Rivers, but are almost nonexistent in the upstream portions. Research has shown that these organisms can tolerate a wide range of temperatures, but their distribution may be limited more by the rivers’ water chemistries. Also, algae, a major food source for the snails, are more abundant in warmer, thermally influenced water.

“EPT” is an abbreviation for Ephemeroptera, Plecoptera, and Trichoptera.The common names for EPTs are mayflies, stoneflies, and caddisflies. Diptera refers to “true flies.” Coleoptera refers to beetles and “non-insects” (other than New Zealand mud snails) refers to such animals as clams, snails, shrimp, mussels, etc.

Attachment A shows the percentages of macroinvertebrates collected at four sites (A-D) along the course of the Gibbon River during 3 consecutive years. Site A is located upstream of thermal infusions into the river. Site B is located downstream of Norris Geyser Basin and Beryl Spring, Site C is located father downstream from any significant hydrothermal additions, and Site D is located at the Gibbon River’s confluence with the Firehole River at Madison Junction (note: it is estimated that at their confluence, 20% and 25% of the water in the Gibbon and Firehole Rivers, respectively, comes from hydrothermal sources.) Download more maps of Yellowstone from the park website.


The instructor will:

  1. Provide the students with information on the New Zealand mud snails, EPT species, other non-insect macroinvertebrates, Diptera, and Coleoptera as provided in the Background section.
  2. Provide the students with copies of Attachment A and B.
  3. Inform students that they will be creating two line graphs depicting information from Attachment A.
  4. Direct students to obtain graph paper and at least 5 sharpened different colored pencils.*
  5. Inform students that the horizontal (x) axis will denote the years 2002 to 2004 and the vertical (y) axis will denote percentage of macroinvertebrates. Students should choose a scale for the vertical (y) axis that will be easy to plot and read and should label both axes.
  6. Direct students to plot the percentage of New Zealand mud snails that have occurred in Site B during the years 2002 to 2004. They should then plot the occurrence of each of the other macroinvertebrate types (as listed on Attachment A) in Site B, using a different colored pencil for each type of macroinvertebrate.
  7. Direct students to prepare a key and title for their graph.
  8. Direct students to prepare a second graph* where the horizontal (x) axis denotes the years 2002 to 2004 and the vertical (y) axis denotes the percentage of macroinvertebrates.
  9. Tell students to use a red colored pencil to plot the percentages of New Zealand mud snails that have occurred in Site C between 2002-2004. They should use a dashed line to connect the points. Students should then plot the percentages of New Zealand mud snails that have occurred in Site D in 2002-2004, connecting the points with a solid red line.
  10. Tell students to repeat the plotting exercise for the EPT species in Sites C and D, using a dashed and solid blue line respectively to connect the points. All four lines should occur on the same graph.
  11. Direct students to prepare a key and title for their graphs.
  12. Tell students to use their graphs and Attachment A to answer the questions on Attachment B.

*The instructor may prefer to have students create the graphs using graphing software.


Gibbon River Study Rubric (40KB pdf)


National Science Standards for Grades 5-8


National Mathematics Standards for Grades 6-8

National Visual Arts Standards for Grades 5-8

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