A Collaborative EffortA Collaborative Effort

Title: Phosphates, Nitrates, and Algal BloomsClass: Environmental ScienceGrade: 11-12Timeframe: 1 day for setup, approximately a week for results

Knowledge Gap Topic How does human use of fertilizers and detergents affect watersheds?

Subject Matter/Key Vocabulary

Phosphates, Nitrates, Algal Bloom, Oxygen deprivation, detergents, fertilizers

Essential Question/Over-Arching Concept/Key Understanding

Essential Question 2: How human activities influence stream?Essential Question 3: How does energy and /or nutrients flow in the watershed?

Curriculum Connections OGT standards Local standards

Physical Science Standards 9-10: B Explain how atoms react with each other to form other substances and how molecules react with each other or other atoms to form even different substances.

Earth Science Standards 9-10: D Describe the finite nature of Earth's resources and those human activities that can conserve or deplete Earth's resources.

Instructional Objectives O1) Students will explore natural flow of phosphates and nitrates in the watershed by setting up control and experimental beakers of chlorella algae and treat them with various concentrations of nitrates from fertilizers and phosphates from detergentsO2) Students will conduct a qualitative observation of resulting algal blooms due to treatments as compared to controlsO3) Students will determine human activities involving fertilizers, detergents which cause environmental problems such as algal blooms that upset natural balance and cause O2 deprivation in system

Materials Nitrates from fertilizers, phosphate detergents, algal culture (we used Chlorella), beakers, pond or stream water, light source. These can be cheaply obtained in a kit for teachers first trying this out … Wards, Science Kit, Carolina all have them.

Additional DocumentsIntroduction

focus event varies with teacher

Go over basic nitrogen and phosphate cycles so students see that these are natural products and part of natural cycles, just like Carbon Cycle.

Development major parts of unit/

lesson

1) Students set up three situations … control solutions, phosphate treated solutions and nitrate treated solutions of Chlorella in beakers. 2) Different % can be given to teams if desired3) Beakers are exposed to light for 5-7 days and student observes changes.If quantitative data is desired, a photometer or colorimeter may be used to measure % of light transmitted. As populations grow, less light will be transmitted.

Rigor/Relevance Quadrant(s) link to rigor/relevance

document

A: Must use terms correctlyB: Setup simulates real world conditions in ponds and watersheds and their interactions with fertilizers and detergentsC: Students think through the fact that overpopulation of algae will actually cause more decomposer growth which causes oxygen deprivation rather

Designing Watershed-based Education and Extension Efforts through a Mental Models Research ApproachUSDA-CSREES National Integrated Water Quality Program

than more oxygen.D: Brainstorm ways to restrict fertilizer run off or change our way of cleaning with detergents

Product/Artifacts/Student Evidence of Understanding

If students use quantitative measurements, they can produce graphs of algal growth over time with colorimeter or photometer data

Accommodations plan B differentiated instruction

Doing the quantitative part of measuring light transmittance is not necessary for basic idea … student can readily see differences without graphing data.

Formative Assessment/Feedback

measure of progress

Use questions during lecture to assess understanding of basic phosphate and nitrate cyclesAsk probing questions about student predictions while they are setting up solutions and correct any misconceptions at that time

Final Evaluation project rubric oral or paper quiz/test portfolio

Qualitative: Students take digital photographs of results as evidence supporting that excess phosphates and nitrates cause algal bloomsQuantitative: Student collect % transmittance data over several days and graph results to show evidence that supports excess phosphates and nitrates cause algal blooms

Teacher Reflection complete after lesson

This is a very simple, yet effective lab for showing problems that occur when using fertilizers or detergents.

Designers/Email: Fred Donelson (fdonelson@gjps.org)

Additional Comments: I will probably use colorimeters next time to add a quantitative piece to this lab, but students certainly found this easy to understand.

Designing Watershed-based Education and Extension Efforts through a Mental Models Research ApproachUSDA-CSREES National Integrated Water Quality Program