Overview | What is bioluminescence, and what function does it play in living organisms? How have researchers harnessed bioluminescence in studies of toxicity and pollution? In this lesson, students explore deep-sea bioluminescence, learn how scientists use this property to identify contaminants in water and participate in a forum on water pollution.
Materials | Student journals, computers with Internet access, projector.
Warm-Up | Have students spend a few minutes responding to the following questions in their journals:
Have you heard of bioluminescence? If so, what is it? If not, what do you think it might be?
What organisms do you know or believe have this property?
What functions do you think bioluminescence has?
What are three questions you have about the property of bioluminescence?
Invite students to share their thoughts, then show the video “Edith Widder’s New Crusade.”
Ask: Were you surprised to learn about how widespread bioluminescence is in the ocean? What are some of the ways in which marine animals use this property? How does Dr. Widder propose using it to tackle the challenge of ocean pollution?
To reinforce some of the ideas presented in the video, you might look together at the images and captions in The Times’s slide show “Natural Light.”
Explain that they will now read an article that goes into greater depth about how Dr. Widder studies bioluminescence in marine organisms and her plans for using it to better inform policy makers regarding water pollution.
Related | In the article “Illuminating the Perils of Pollution, Nature’s Way,” Erik Olsen reports on deep-sea biologist Edith Widder’s latest venture to track aquatic pollution:
Over a career spanning almost 30 years, Dr. Widder has made hundreds of dives in deep-sea submersibles to study the remarkable number and diversity of animals that make light. This ability, called bioluminescence, is strikingly common, shared by as many as 90 percent of the creatures in the open ocean.
“Animals use light to help them survive, to help them find food, to attract mates and to defend against predators,” she said. For example, in the ocean — “where there are no trees or bushes to hide behind” — a bioluminescent creature can use light to attract larger predators to its own enemies.
Now, Dr. Widder has found a way to put bioluminescence to work to fight pollution in the Indian River Lagoon, a 156-mile estuary that scientists say is one of Florida’s most precious and threatened ecosystems.
Read the entire article with your class, using the questions below.
Questions | For discussion and reading comprehension:
- What is bioluminescence? How do animals use this property?
- What are sediments?
- How does Dr. Widder use bioluminescence to detect the presence of toxins in sediment samples she collects?
- Why does she say sediments are a better indicator of pollution levels than water samples?
- What is the Eye-In-The-Sea? How is this device able to document deep-sea creatures that have long eluded scientists in research submarines?
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Activity | Remind students that in the video they watched, Dr. Widder says, “If you want to help a dolphin, clean up its water.” Explain that in keeping with her suggestion, they will participate in a forum on water pollution.
Begin by having the class, as a class or in small groups, brainstorm a list of questions they might ask about water pollution, like, “What are some of the most common sources of pollution in ocean ecosystems?” or “What are some sources of water pollution in our community?” Jot ideas on the board.
After a few minutes of brainstorming, divide the class into four groups (and subdivide further as necessary depending on class size). Assign each group one of the topics identified below to research in preparation for a forum on water pollution. To help students get started, give each group the following guiding questions to direct their research. Groups also should be sure to address any related questions that came up during the class brainstorm.
Group 1: Types and Sources of Water Pollution
Topics to consider include some or all of the following:
- Sewage outflows.
- Hydraulic fracturing, or “fracking,” which the Environmental Protection Agency recently implicated in tainting groundwater supplies.
- Shipping and other industries contributing to marine pollution.
- Phosphorus and plastics pollution in the oceans, which the United Nations recently identified as emerging global issues.
- Point source and nonpoint source pollution.
- Major water pollution events like the Gulf oil spill.
Group 2: Emerging Technologies to Identify Sources of Water Pollution
Students in this group should explain and describe emerging technologies like these:
- Use of living organisms to detect pollution, starting with Dr. Widder’s work to “make the invisible visible” as well as the steps in the FAST test she developed, and interpret the data the test provides.
- Other applications of bioluminescent bacteria in systems like wastewater treatment.
- Testing microbial genetics.
- Using organisms like tadpoles to detect pollution.
Group 3: Policies and Water Regulation
Students in this group should focus on government policy and regulation, especially the work of the Environmental Protection Agency with respect to water. They should also:
- Describe the Clean Water Act and identity recent recommendations for changes to the act.
- Explore some of the provisions of the Act that establish various water pollution control measures, like the National Pollutant Discharge Elimination System, which regulates companies, municipal facilities and other point sources of pollution, and the requirement that states adopt water quality standards that set guidelines for the maximum amounts of various pollutants that can enter a body of water.
- Consider how the Act covers Explore the Safe Drinking Water Act.
- Find out what other regulations the Environmental Protection Agency makes with respect to water.
Group 4: Health and Ecological Consequences of Water Pollution
This group should do the following:
- Find out how the provisions of the Clean Water Act and the Safe Drinking Water Act are routinely violated and the consequences of these violations.
- Explore how pollution affects habitats around the globe and the organisms that live in them, from the oceans to freshwater systems.
- Consider not just the negative effects of pollution for the wildlife in these habitats but also how these consequences affect people, like the presence of mercury in both freshwater and ocean fish.
When group research is complete, convene a forum on the issues in which groups share and discuss their findings. You might consider opening an online backchannel during the forum for students to chime in with comments and share links, and to extend the discussion beyond class time.
To wrap up, remind students of Dr. Widder’s goal: “It’s my belief if we can make pollution visible, and let people know what small things they are doing are actually making an improvement in this incredible environment,” she said, “I think it could make a huge difference. It can be a game-changer.”
Ask students to consider their topics in the context of Dr. Widder’s call to make pollution visible. How can they make the material they researched more “visible”? How might they use the information they gathered to make suggestions to community leaders or policy makers? How might “making the invisible visible” bring about change?
Going Further | Students can identify water polluters in their neighborhoods using the Times interactive “Find Water Polluters Near You” or find out what contaminants have been found in their drinking water using the Times feature “What’s in Your Water,” and then write letters to local government representatives, drawing on what they have learned to explain the risks to health and habitats from these violations, and asking what they plan to do about Clean Water Act violators.