Ecosystem Measurement Tools
for Living Environment students
Hudson River Ecosystem Unit Plan
Once students have completed the introduction to the Hudson River and basic aquatic ecosystem science, we can move on to the exciting next step of using the tools that scientists use to understand aquatic ecosystems including the Hudson River. A key measurement tool for aquatic ecosystems is dissolved oxygen, abbreviated DO. By understanding the dynamics of DO, scientists can know how the aquatic animals and plants relate to each other and the chemistry and physical parameters of the water in which they're living. Plants produce oxygen in photosynthesis and both plants and animals use oxygen during respiration. Those plants and animals and the oxygen levels in the water respond to temperature in important ways. This section focuses largely on this very important measure of aquatic ecosystem health and balance: dissolved oxygen.
Day 1-2:
Introduction to Dissolved Oxygen:
Objective: Students will know how dissolved oxygen enters the water and be able to explain the difference between a water sample that has been exposed to the air and one that has not.
Activities:
1. Students brainstorm what organisms need to survive 2. Teacher
demonstrates presence of oxygen using cups of water 3. Students
use dissolved oxygen kits to test samples of water 4. Students
shake samples and retest water 5. Students record and discuss
results
Assignment: Read “Dissolved Oxygen” prior to lesson. Complete lab worksheet
Materials: plastic cups and tap water, lab handout. For each group (3-4 students): plastic cup and water, dissolved oxygen test kit, canning jars filled to the top with water samples
Day 3:
Excel Tutorial:
Objective: Students will know how to use Excel and be able to create graphs and explain the trends using Hudson River data.
Activities:
Students complete Excel tutorial with computers
Assignment: Complete tutorial
Materials: copies of tutorial, computers with Excel
- Downloads:
- Lesson Plan >>
- Excel Tutorial >>
Day 4-5:
Inquiry Oxygen:
Objective: Students will know the factors that change dissolved oxygen levels and be able to design an experiment to test their ideas.
Activities:
1. Students discuss the possible implications of low dissolved
oxygen levels in aquatic environments. 2. In groups, students
hypothesize different ways to change the DO. 3. Students create
a research plan for approval by the teacher. 4. Students carry
out their experiment, and summarize their results for the class.
Assignment: Complete lab report
Materials: water, mason jars with lids, hot plates, dissolved oxygen test kits (or a meter), aquatic plants (both submerged and floating-duckweed and elodea work well), snails, salt, thermometer, BTB, fish tank bubbler, nitrogen fertilizer, ice
- Downloads:
- Lesson Plan >>
- Worksheet >>
Day 6:
Dissolved Oxygen and Temperature:
Objective: Students will know how temperature affects dissolved oxygen and be able to create a graph showing this relationship.
Activities:
1. Students think about the adaptations of animals to live in
different water temperatures 2. Students test four different
water temperatures for dissolved oxygen (samples at 50 ºC and
100 ºC are prepared and cooled ahead of time) 3. Students report
and discuss the implications of increased temperature on DO
4. Students use Hudson River data to look at the impact of
temperature and dissolved oxygen throughout the seasons.
Assignment: Complete lab worksheet & graphing
Materials: For demonstration: Cups with hot and cold water, ice For lab activity (per group):, copies of lab sheet, dissolved oxygen test kit, thermometer (up to 100ºC), one jar at room temperature, one jar with ice, one jar that was boiled for 20 minutes and then cooled & sealed, one jar that was heated to 50º C for several hours and then cooled & sealed
Day 7-8:
Dissolved Oxygen & Respiration:
Objective: Students will know that plants use oxygen underwater and be able to design an experiment that will test this question.
Activities:
1. Students discuss whether plants need oxygen, or just carbon
dioxide 2. Students design experiments to test whether plants
use oxygen 3. On the second day, students record and report
results 4. Students compare their data with data from the Hudson River
Assignment: Graphing activity: Dissolved Oxygen & Time
Materials: 2 pint or ½ pint glass jars-must be the same size for comparison purposes , 3 strands of elodea per jar, aged tap water at room temperature, dissolved oxygen kit
Day 9-10:
Dissolved Oxygen & Photosynthesis:
Objective: Students will know that plants produce oxygen underwater and be able to design an experiment that will test this question.
Activities:
1. Students discuss whether plants give off oxygen, and how to
measure this 2. Students measure the increase in dissolved
oxygen over time (one class day) 3. Students experiment with
different light sources and/or intensities 4. Report and discuss
results
Assignment: Complete lab worksheet
Materials: classroom aquarium with aquatic plant, glass jar For each group: 2 canning jars, strands of elodea (or other aquatic plant), dissolved oxygen test kit , 2 canning jars of boiled water which was sealed and left to cool at room temperature, pencils/tape or waterproof markers
Day 11:
Animals & Dissolved Oxygen:
Objective: Students will know that aquatic animals use oxygen and need it in order to survive.
Activities:
1. Students discuss what animals need to survive in water 2.
Students observe animal behavior in low-oxygen waters 3. Students
discuss implications of low-oxygen as related to thermal pollution
at Indian Point Nuclear Power Plant
Assignment: Complete lab sheet
Materials: feeder goldfish or other aquatic animals, aged tap water, tap water that has been boiled and cooled, large jars of water or individual jars for groups to do observations, straws of different sizes
- Downloads:
- Lesson Plan >>
- Worksheet >>
Day 12-13:
Photosynthesis & Respiration:
Objective: Students will know the relationship between plants and animals in an aquatic ecosystem and be able to predict the effects of low dissolved oxygen on the organisms.
Activities:
1. Students create microcosms with plants, animals, or both 2.
Students use observation skills to determine which microcosm
was more successful (define this before starting) 3. Review
photosynthesis and respiration 4. Students answer review questions
5. Students extend their knowledge using Hudson River data
Assignment: Complete lab worksheet
Materials: Per group: four one-quart jars with lids, aged tap water, several pieces of Elodea, aquarium thermometers, several aquarium guppies and/or water snails, copies of worksheet
- Downloads:
- Lesson Plan >>
- Worksheet >>
Day 14-15:
Dissolved Oxygen and Decomposition:
Objective: Students will know the relationship between plants and animals in an aquatic ecosystem and be able to predict the effects of low dissolved oxygen on the organisms. Students will know the relationship between dissolved oxygen levels and the amount of organic matter in the water.
Activities:
1. Students brainstorm about the impact of organic material on
water quality. 2. After collecting detritus, students set up
an experiment to observe the impact of decomposition on dissolved
oxygen (or different water quality parameters, if time permits).
3. Students present and discuss results.
Assignment: Complete lab worksheet
Materials: about 5 g of leaves, sticks, and other detritus, dissolved oxygen kits or meter, pond water, plastic containers, plastic wrap, scale, graduated cylinder
- Downloads:
- Lesson Plan >>
- Worksheet >>
