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.

At the start of this investigation, students form groups of two 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 prepare their aquariums by removing the label and the upper rounded portion of a clear two liter plastic bottle. Bottles are labeled and given to the teacher to be filled with five centimeters of lake sediment plus one and one half liters of Lake Erie water. Water samples will be taken one meter from the shore. Lids are secured to the top of the bottles using clear packing tape. Each group will have three bottles: one control and two bottles containing experimental set-ups. Experimental set-ups include: one “environmentally friendly” and one that is typically used on a daily bases. The control set-up bottles will contain five centimeters of sediment and 1.5 L of lake water. Five centimeters of sediment, one and one half liters of lake water and ten drops, or one milliliter, of the chosen variable is added to the appropriate variable bottle. Bottles are then placed under a grow lamp that is plugged into a timer that simulates daylight for June 25th at approximated 45 degrees latitude (or seventeen hours of light).

Students will gently swirl their bottles each class period for twenty seconds. This will keep the water from becoming stagnant. After two weeks students will determine the following chemical properties of their lake water: dissolved oxygen, nitrate, and phosphate concentrations. Plus they will determine pH, dry mass of the algae and turbidity. Students will follow the test kit procedures for pH, turbidity, nitrate and phosphate. Vernier dissolved oxygen probes will be used to determine dissolved oxygen concentration. In order to determine the dry mass, the sides of the bottle will be scraped using a metal scoop. Students will swirl the water for 20 seconds. They will then wait twenty seconds to allow the sediment, essentially sand, to settle. Students will label and then determine the mass of three empty 250 mL beakers. A 100 mL sample of each set-up is measured using a graduated cylinder and is poured into the appropriate 250 mL beaker. The water will be evaporated using the fan in the fume hood. The mass of the algae will be determined by subtracting the mass of the empty beaker from the final mass of the beaker and algae.

Upon completion of the above tests there will be a class discussion of the results. Students will then 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 should 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 are 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 are to be both printed and carbon copied to their teacher.

Groups are then to write a proposal to a representative of the parks service (their teacher). In this proposal students are 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 may contain the same solutions as the other two groups with whom they were in contact, but agreement is not required.

Students will be evaluated on the quality and effectiveness of their proposal. Proposals are to include the purpose of their study, background information, description of their results, including a table that clearly shows the data, the conclusions drawn, and their proposed solution. Students are to discuss how the park service will enforce their proposal and if possible the estimated cost of enforcement. If their study shows that a policy is unnecessary, they must support this conclusion with evidence from their study.