Organisms Survive and Obtain Energy in Dark Caves

Shown are several pictures from the Coldwater Caves.

Picture 1: Visible extremophile bacteria in the Coldwater Caves.
Picture 2: Close-up of extremophile bacteria in the Coldwater Caves.
Picture 3: Close-up of extremophile bacteria in the Coldwater Caves under a UV light to highlight that it glows.

The reason it glows is the bacteria is creating the carbon from organic matter which produces energy that causes it to glow under a blacklight. This is a great example of aerobic and anaerobic processes because these extremophile bacteria switch between the two processes to survive in the coldwater caves.

Winneshiek County

Iowa Core Standard

HS-LS2-3

Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions

Driving Question

How can organisms survive and obtain energy in a dark cave where there is no sunlight and little oxygen?

Probing Questions

What do you think the environment of a cave is like?
What resources would an organism need to survive in a cave like this?
Where do extremophiles fit in the cycling of matter in aerobic and anaerobic conditions?
Where might these organisms get the energy they need to stay alive?
How would an organism produce energy if oxygen were not available?

Classroom Suggestions

Students could:

Look at the picture and complete a notice and wonder activity when given the driving question.
Learn where they fit in the energy cycle and add these extremophiles into an existing diagram on energy flow.
Predict how an environmental change might impact the extremophile bacteria.
Create an argument about whether or not these organisms or organisms like these could exist on other planets or moons.

Resources

National Park Service | Extremophiles of the Madison Aquifer: An article on research being done in Wind Cave National Park in the Madison aquifer.
National Geographic | Bioluminescence: Article discussing bioluminescence.

Contributors

Media courtesy of Dr. Josh Sebree, University of Northern Iowa.

Contributed by Mallory Wills-Howe with support from the Coldwater Cave Project.