Freshwater resources provide essential services to society, the most important of which is fresh drinking water for municipalities around the world.
Point-source pollution from agriculture and municipal waste can affect water quality in numerous ways (up to and including the devastation of aquatic environments and native species). Education and research, both in the classroom and in the field, can greatly increase students’ awareness and understanding of this issue, which affects all communities.
This lesson gives students an opportunity to witness the real-world implications of their research. It requires them to conduct online research during class time, formulate hypotheses, design and carry out experiments in the field, and then gather and assess their findings in a formal report.
Before introducing the lesson to students, set up a free account at PBworks, a collaborative website that will allow them to post and share information in a controlled environment.
Begin the lesson by explaining to students how farming and dairy activities can affect aquatic systems — specifically, how runoff from fertilization and excretory waste can cause eutrophication, in which a body of water’s trophic status (the balance of nitrogen, phosphorus and other biologically useful nutrients) is compromised. This, in turn, can lead to a series of undesirable events, including algal blooms (a rapid increase or accumulation of algae in the water); lack of available oxygen for living organisms in the water, resulting in diminished biodiversity and macroinvertebrate populations; and the infiltration of nonnative species.
Divide the class into groups of three to four students. Have each group research an assigned water quality–related topic, such as pH, temperature, nitrates, dissolved oxygen, turbidity, acid rain, farming and fertilization, sewage treatment, water pollution, macroinvertebrates in aquatic systems, eutrophication or algal blooms. Students should then prepare and post oral or digital presentations summarizing their research on the class PBworks site, as well as comment on other groups’ presentations.
Next, challenge each group to formulate a hypothesis on an aquatic system variable to be tested (such as pH, nitrates, dissolved oxygen or temperature) and design an experiment to be conducted in the field. The experiments that students devise should include data collection using sensors and probes, hand lenses and similar tools. Some manufacturers of these devices, such as Vernier Software & Technology, will loan schools the necessary equipment at no charge. Many local offices of the United States Department of Agriculture’s Cooperative Extension System also offer free water-testing equipment to teachers.
For example, students might hypothesize that ammonia in fertilizers would lower a water system’s pH from natural levels, resulting in acidic water and decreased biodiversity. They would then test that hypothesis using data-collection equipment and water-testing kits.
As students conduct their experiments in the field, they should collect data on their notebook computers and then record their findings on the PBworks site. They should also write formal lab reports and post them online. The reports, typically three to five pages long, should include an introduction of the scientific issue or question being investigated, background information (including relevant, already published research findings), a statement of the hypothesis, an explanation of research procedures, raw and processed data from the experiment, an analysis of the findings and a conclusion that includes recommendations concerning what communities can do to correct identified problems. (North Layton Jr. High School students, for example, have submitted their research findings to local water agencies and governments for review.)
Conclude the lesson by having students evaluate their peers’ reports and share comments on the PBworks site. Then, discuss as a class what students learned from the site experiments and how future water quality investigations could advance their understanding of aquatic ecosystem issues.
This lesson was designed to focus on high school biology and environmental science concepts, but it could be adapted into a cross-curricular lesson that incorporates chemistry, mathematics and English/language arts content.
This lesson fulfills Standard I of the Biology Core Curriculum established by the Utah State Office of Education: “Students will understand that living organisms interact with one another and their environment.” The standard’s objectives challenge students to:
This activity also meets Common Core State Standards for English Language Arts & Literacy in History/Social Studies, Science and Technical Subjects and several of the National Educational Technology Standards for Students set forth by the International Society for Technology in Education.
Students should be graded on the quality of their research presentations, group work, final lab reports and peer evaluations.