Can Algae Clean Up and Power Up? A Dual-Enrollment Biology Investigation

Can a culture of algae help capture carbon, improve water quality, and contribute to a system that generates electricity?

That is the question launching our next project in dual-enrollment biology. My students will investigate an algal fuel-cell system while exploring three connected ideas: energy production, carbon capture, and bioremediation.

We are beginning with possibilities and questions. Whether our classroom system delivers measurable results, and how confidently we can explain those results, will be part of the investigation.

Connecting Biology to an Environmental Challenge

Photosynthesis, cellular respiration, membrane transport, and microbial metabolism often appear in separate chapters. This project asks students to bring those ideas together.

To understand their system, students will need to explain where energy enters, how organisms use it, where carbon moves, and how changes in the environment affect biological processes. They will also need to connect those explanations to measurements. A green culture is an interesting observation. Explaining what that culture is doing requires evidence.

Our driving question is: How can we use biological processes to address environmental problems, and what evidence would demonstrate that our system works?

Three Goals, Three Sets of Questions

Although the project brings several processes together, we will evaluate each goal separately. Can the system contribute to electricity generation? Students will investigate the fuel-cell design and develop a model explaining the roles of organisms, electrodes, and electron movement.

Detecting an electrical signal will lead to further questions. How consistent is it? How does it compare with a control? What evidence connects the output to the biological activity we are investigating? We also want students to distinguish the energy cells use internally, including ATP, from the electrical energy measured in a circuit.

What happens to the carbon?

Students will trace carbon into and through the system. Where could carbon enter? Where might it accumulate? Through which processes could it leave? We will pay particular attention to the difference between taking up carbon during growth and keeping that carbon out of the environment over time. Any claim about carbon capture will need a clear explanation of what we measured and what remains unknown.

Can biological activity improve water quality?

Our bioremediation investigation will focus on a defined water-quality question. Students will need to identify the substance or indicator they are tracking and explain what a change in that measurement means. If a substance decreases in the water, where did it go? Did organisms take it up? Did it change form? Could another process explain the result? Those questions will help students move from “the water looks different” to a defensible biological explanation.

Starting With Models and Predictions

Before collecting results, students will create initial models of the system.

Their drawings will identify proposed inputs and outputs, distinguish carbon movement from energy transfer, and show the biological processes they think connect the parts.

These models will serve as working explanations. As evidence arrives, students will revise them, add missing relationships, and reconsider ideas that no longer fit.

We will also use predictions to make their reasoning visible. Students will explain what they expect to happen when a condition changes and why they expect that result. Later, they will compare those predictions with their observations.

What Counts as Success?

A successful investigation does not require every culture or fuel cell to perform as expected. Students can learn from a weak signal, an unexpected change, or a result that raises more questions. The important work is deciding what the evidence supports, identifying alternative explanations, and proposing a useful next test.

By the end of the project, I want students to be able to:

• Connect a biological mechanism to an observed result.

• Design meaningful comparisons and controls.

• Interpret measurements without claiming more than they show.

• Revise a model using evidence.

• Explain the limitations of a proposed environmental solution.

Following the Investigation

This post begins Can Algae Clean Up and Power Up?, a series following our classroom investigation.

I will share our experimental-design decisions, student-created models, selected observations, and the revisions that follow. A recurring feature will compare students’ thinking before and after the evidence, showing how their explanations develop.

We are starting with an ambitious environmental question and a classroom-scale system. The next step is to turn that question into tests that can give us meaningful answers.