Peggy J. Najarian
Environmental Science Teacher
Work: 248-489-3535
Introduction
Each year campers and backpackers flock to our national and state parks in order to have the ultimate “outdoors” experience. Several will make the extra effort to purchase products designed to limit their impact on the environment. Examples of such items include Campsuds and no-rinse camping shampoo.
After spending a few days on South Manitou Island, located in the Sleeping Bear Dunes National Lakeshore, I noticed algal growth and some persistent soapsuds along the shores of Lake Michigan. I also noticed that similar suds and algae had collected a few days later on the shore of Lake Manitou, which is found on North Manitou Island. This led me to question if this was caused by the use of everyday cleaning agents, i.e. dishwashing detergent or shampoo, or if it could be caused by the improper use of the camping cleaning agents.
Persistent suds were once commonly found in lakes and streams whose run-off contained phosphate-based detergents. Phosphorus is a limiting factor in lakes. Botkin and Keller (1998) define a limiting factor as the single requirement in the least supply in comparison to the need of an organism. If this factor becomes abundant, excess growth of an organism, or group of organisms, that require that factor will occur. If the organism is an alga, we call this excess growth an algal boom. Algal booms are often caused by a phenomenon called cultural eutrophication. This is described as the overnourishment (or increase in a limiting factor or nutrient) of aquatic ecosystems with plant nutrients because of human activities (Miller, 2000).
Algal blooms can lead to a decrease in the dissolved oxygen level in a lake. This decrease in oxygen occurs when algae reproduce so much that they form a thick mat. This results in a decrease in the amount of sunlight that reaches the photosynthetic organisms under the mat during the day. This decreases the amount of photosynthesis and subsequently the amount of oxygen produced by photosynthesis. Benthic photosynthetic organisms may die if too little sunlight reaches them. Dead organic matter becomes a food source for decomposers; this increases the amount of cellular respiration. Cellular respiration requires oxygen and this reduces the dissolved oxygen in the body of water. Therefore, the amount of dissolved oxygen is decreased two ways. The first is due to the decrease in photosynthesis and the second is due to the increase in cellular respiration.
Golfers often notice evidence of this decrease in dissolved oxygen. Thick, foul smelling, mats of decaying algae are found in the lakes on golf courses. This is due to massive quantities of fertilizers that are added to the grounds. The fertilizers increase both nitrates and phosphates (or nitrogen and phosphorus). Since nitrogen and phosphorus are limiting factors of algal growth, an increase in these nutrients leads to algal blooms. Fish kills may occur for a number if reasons. However, we do see fish kills in lakes and streams after an algal bloom because of this lack of dissolved oxygen. The fish essentially suffocate. Both the algal blooms on golf courses and the fish kills are evidence of an imbalance in the ecosystem
The purpose of this investigation is to determine the effects of various cleaning agents on both the biotic and abiotic properties in the Great Lakes. Students will work collaboratively with students in other schools in order to form a plan that recommends solutions to reduce the impact of the cleaning agents on the Great Lakes.
Objectives:
Students will: (State of Michigan Content Standards)
CS1.1.3 Design and conduct scientific investigations.
CS3.5.3 Describe general factors relating population size in an ecosystem.
CS3.5.4 Describe responses of an ecosystem that cause it to change.
CS3.5.5 Describe how water, carbon dioxide, and soil nutrients cycle through selected ecosystems.
Resources/Materials:
Three 2 liter pop bottles
Water from the Great Lakes
Cleaning agents: Campsuds, Ivory, Palmolive dish soap, no-rinse camping shampoo
Vernier dissolved oxygen probes
Hach/LaMotte test kits for phosphate test, pH, turbidity and nitrate
Graduate, three 250mL beaker and a balance for algae dry mass
Procedure
At the start of this investigation, students formed groups of three and select variables to test. For example, if a group chooses to test shampoo, they would select a typical daily shampoo, e.g. Suave, and Campsuds, an “environmentally friendly” cleaner/shampoo.
Students prepared their aquariums by removing the label and the upper rounded portion of a clear two liter plastic bottle. Bottles were labeled and given to the teacher to be filled with approximately three centimeters of lake sediment plus one and one half liters of Lake Erie water. Water samples were taken one meter from the shore. Lids were secured to the top of the bottles using clear packing tape. Each group had three bottles: one control and two bottles containing experimental set-ups. Experimental set-ups included both “environmentally friendly” cleaners and those that are typically used on a daily bases. The control set-up bottles contain three centimeters of sediment and 1.5 L of lake water. Three centimeters of sediment, one and one half liters of lake water and ten drops, or one milliliter, of the chosen variable was added to the appropriate variable bottle. Bottles were then placed under a grow lamp that was plugged into a timer that simulated daylight for June 25th at approximated 45 degrees latitude (or seventeen hours of light). See Appendix A.
Students gently swirled their bottles each class period, or three times a week, for twenty seconds. The intent was to keep the water from becoming stagnant. After three weeks students determined the following chemical properties of their lake water: pH, dissolved oxygen, nitrate, and phosphate concentrations. Plus they determined the dry mass of the algae and turbidity. Students followed the test kit procedures for turbidity, nitrate and phosphate. Vernier pH and dissolved oxygen probes were used to determine pH and dissolved oxygen concentration. In order to determine the dry mass, the sides of the bottle were scraped using a metal scoop. Students stirred the water for 20 seconds. They will then waited for twenty seconds to allow the sediment, essentially sand, to settle. Students labeled and then determined the mass of three empty 250 mL beakers. A 100 mL sample of each set-up was measured using a graduated cylinder and poured into the appropriate 250 mL beaker. The water was evaporated using hot plates. The mass of the algae was determined by subtracting the mass of the empty beaker from the final mass of the beaker and algae. See Appendix B for a the data sheet.
Closure:
Upon completion of the chemical and physical tests students compiled group data and we had a class discussion of the results. Students were supposed to be given the email addresses of two different student groups who tested the same variables, one from Petoskey High School and one from the Macomb Academy of Arts and Sciences. Conversation between groups was to include a discussion of the results, including possible problems, and possible solutions that would reduce the suds found on the shore of the Lake Michigan or Lake Manitou. Students were to compare effectiveness of the products they tested and whether or not they contribute to an increase in algae growth. Copies of all email transactions were to be both printed and carbon copied to their teacher.
Groups were then to write a proposal to a representative of the parks service (their teacher). In this proposal students were to describe their findings, why these findings are important and suggest one or more ways to alleviate the “suds” problem found along the shore. This proposal could have contained the same solutions as the other two groups with whom they were in contact, but agreement is not required.
Unfortunately, due to timing issues and technology availability, abstracts and pictures of the experimental set-ups were only exchanged between my students and those at Petoskey High School. Our abstracts and pictures were sent to the Macomb Academy of Arts and Sciences. My students did not have access to their data when writing their formal laboratory reports or proposals. My students used their class data and the abstracts from the students at Petoskey High School sent via email to write their formal laboratory reports and their proposals.
Assessment strategies:
Students were given a pre-test and a post-test. The questions can be found in Appendix C.
Thirteen of my fifteen students returned their permission slips. (See Appendix D for a copy of the
permission slip.) Their pre- test and post-test results can be found in Table One.
Table One: Pre-test and Post-test Results*
Student
|
 |
Question #1
|
|
Question #2a
|
|
Question #2b
|
|
Question #3
|
|
Question #4
|
|
Pre-
|
Post
|
Pre
|
Post
|
Pre
|
Post
|
Pre
|
Post
|
Pre
|
Post
|
1
|
0
|
0
|
0
|
3
|
0
|
1
|
1
|
1
|
1
|
1
|
2
|
0
|
1
|
1
|
2
|
0
|
0
|
1
|
1
|
1
|
1
|
3
|
1
|
1
|
0
|
1
|
0
|
1
|
1
|
1
|
0
|
1
|
4
|
1
|
2
|
0
|
3
|
0
|
1
|
1
|
0
|
1
|
1
|
5
|
1
|
1
|
2
|
2
|
0
|
1
|
1
|
1
|
1
|
1
|
6
|
2
|
2
|
0
|
3
|
0
|
0
|
1
|
1
|
1
|
1
|
7
|
1
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
0
|
1
|
8
|
1
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
1
|
1
|
9
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
10
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
0
|
1
|
11
|
1
|
1
|
0
|
2
|
0
|
0
|
1
|
1
|
1
|
1
|
12
|
0
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
1
|
1
|
13
|
1
|
3
|
1
|
3
|
1
|
0
|
1
|
1
|
1
|
1
|
Key:
1 = question answered accurately
|
2 = Very good answer
|
3 = Outstanding answer
|
Student answers reflected a 30% increase in understanding of the concept of limiting factors. There was a 77% increase in understanding of eutrophication. With regards to the difference between cultural eutrophication, there was only a 31% increase. I believe that this would have been higher if I had made it a separate question. Several students did not answer the question. It is my belief that they used up the majority of the space provided on the first part of the question and did not go back to finish the second part. There was no net change in student understanding of the concept of biodegradability. An increase of 23% of the students knew the results of biodegradable cleaners use. One interesting observation is that student nine did not perform well on the pre-test or post-test. However, this student did score the second highest grade on the unit test that included information from this experiment. This student also has consistently had the highest grade in the class for the entire semester.
Students were also evaluated on the quality and effectiveness of their proposal. This proposal was written as a final step of a formal laboratory report. (See Appendix E for a copy of rubric that was used to grade the formal lab reports and proposals.) Proposals included the purpose of their study, background information, description of their results, the conclusions drawn, and their proposed solution to the “sud” problem. Students suggested methods that the park service could use to enforce their proposal and if possible the estimated cost of enforcement. Suggestions included everything from a ban on all cleaning products to hefty fines if a person is caught using cleaning products in a manner that is not outlined on the package. In case a student group believed that a policy was unnecessary, they were to support this conclusion with evidence from their study. This was not the case.
Improvements for future studies:
Coordinating data between three schools was a very good idea in theory. It is has some practical drawbacks. We had difficulty starting and stopping the experiment at the same time and sharing information in a timely manner. I do not cast blame on any school, but I do think that it would be easier to share and coordinate with teachers in the same building or district.
At the end of our experiment, some of bottles were quite malodorous. The control set-up bottles were clear and generally odor free. The bottles that contained cleaners were not. While this is what I would have expected, the smell was much worse than anticipated. I would have abandoned the entire project it there weren't two other teachers who needed our data. In the future, I would have students stir more often and I would end the experiment after seven to ten days. Finally, we tested too many different cleaners. In the future, I think that three of four cleaners would be sufficient. That way there will be more repeat set-ups to compare. This will allow the results to be more consistent.
Overall Effectiveness:
I believe that this project did teach students the intended objectives. If I implement the changes that I proposed, I believe that this experiment will be more effective at teaching the concepts of limiting factors, (cultural) eutrophication and how the use of cleaning agents can alter an ecosystem.
Resources
Bodkin, Daniel B. and Edward A. Keller. 1998. Environmental Science: Earth As A Living Planet.
2nd ed. New York: John Wiley & Sons, Inc.
Miller, G. Tyler Jr. 2000. Living in the Environment. 11th ed. Pacific Grove, CA. Brooks/Cole
Publishing.
APPENDICES
APPENDIX A: Picture of Set-up
APPENDIX B: Soaping Up in the Great Lakes Data Sheet
APPENDIX C: Soaping Up in the Great Lakes Pre/Post-Test
APPENDIX D: Permission Slip
APPEBDIX E: Grading Rubric for Formal Lab Report and Proposal
APPENDIX A
APPENDIX B
Procedure:
Collect your bottle without disturbing it.
Describe the color, odor, and clarity of your sample below. Also describe any plant or animal material below.
Go to the computer with the DO probe and find the DO of your sample.
Put on goggles and an apron.
Take a sample of your water and perform the TP or total phosphate test.
While you heat your phosphate set-up, perform a nitrate test, pH (using the pH probe), and turbidity (you will need to share).
Using a wax pencil, label a 250mL beaker. Find the mass and record below. Scrape the sides of your bottle, if necessary, and stir for 20 seconds. Wait for 20 seconds. Then take a 100mL sample and heat it gently on the hot plate until the water evaporates.
Mass of dried solids + beaker ___________
Mass of empty beaker ___________
Mass of dry solid ___________
Description of your sample: (Be descriptive saying bad or rank is not acceptable.)
APPENDIX C
Soaping Up in the Great Lakes Pre/Post-Test
What is a limiting factor?
What is eutrophication? How does it relate to cultural eutrophication?
What does biodegradable mean?
What can a consumer expect when using a biodegradable soap or cleaner?
APPENDIX D
To the Parents of the Advance Placement Environmental Science Students:
Over the summer I was given the opportunity to attend a graduate level class at Michigan Technological University. The course was called Island Hopping Across the Curriculum. One of the requirements of the course was to develop a lesson or unit about the environment. Class participants noticed soapsuds along Lake Michigan and Lake Manitou as well as algae growth. Two other teachers and I decided to develop a collaborative project. Our students will study the impact of various cleaners on the Great Lakes. Our students will then collaborate with each other via email in order to develop a proposal that would reduce the effects of the cleaning agents on the Great Lakes.
In order for me to receive credit for my course, I am to write a paper evaluating the lesson. Neither individual student names nor their scores will be used. I am asking for your permission to use your child's work to write my paper. Please sign below and return by Wednesday, September 26, 2001.
Thank you,
Peggy J. Najarian
I give Peggy Najarian permission to use __________________________ work to write an evaluation for her graduate course. I realize that neither my student's name nor grade will be used in the paper. Participation will not influence my child's class grade in AP Environmental Science.
____________________________________
Parent Signature
I do NOT give Peggy Najarian permission to use __________________________ work to write an evaluation for her graduate course. I realize that participation will not influence my child's class grade in AP Environmental Science.
____________________________________
Parent Signature
APPENDIX E
Prepare a formal lab report. It is to be typed, double-spaced with a 12 point font and one inch margins. Use the following information as your guideline.
Title page (1)
Abstract (5)
Introduction
Includes background information and defined terms such as cultural eutrophication, DO, biodegradable, limiting factor, etc. (3)
Purpose (1)
Hypothesis in if/then statement (1)
Materials and Methods
List the materials used including quantities (where possible). (1)
Describe procedure in detail so that someone in another class could follow it. (1)
Data, Observations, and Results
A. Data table should be neat and in a titled table (Table ONE: ***) (3)
B. Labeled/titled picture of set-up (Figure One: ***) (2)
C. Describe results without interpreting them (2)
Analysis and Conclusion
A. Interpret your results (what do they mean?) (3)
B. Did you support or reject your hypothesis? Explain. (2)
C. What conclusions can you draw from your data? (2)
Proposal (13)
A. Purpose of their study, background information
B. Description of results with a conclusion
C. Proposed solution to the “sud” problem
D. Possible methods of enforcement
E. Estimated cost of enforcement
Total Point: 40
