Photograph by Michael D. McCumber
1. Read the following Articles:
Article 1:Loss of oxygen in central Lake Erie confounding researchers‘2nd battle’ looms for center of lake2. Search the internet for maps, charts, and other data pertaining to the information presented in the articles. Examples include:
Article 2: Dead zone expected to form in Lake Erie
Article 3: Entering the Zone
Twine Line full issue available online: http://www.sg.ohio-state.edu/pdfs/tl-so-02.pdf
Article 4: The Ghost of Summers Past
Twine Line full issue available online: http://www.sg.ohio-state.edu/pdfs/tl-nd-02.pdf
Source: EPA web site: http://www.epa.gov/glnpo/glindicators
Image site: www.cciw.ca/nwri/sande/ bj_water1.html
Source: EPA web site: http://www.epa.gov/glnpo/glindicators/oxygen/oxygenb.html
3. Answer the following questions
4. In assigned groups, discuss the problem using the PrOACT structure as a guideline to answer the following questions:1. What is the problem?
2. What are the three (3) possible reasons listed in the article that could be causing the problem?
3. Why is the central basin vulnerable to this problem?
4. Name 3 major sources of phosphorus levels in Lake Erie?
5. Areas of anoxia or ‘dead zones’ in Lake Erie and in many bodies of water are not uncommon. What is it about the dead zone that formed last year in the central basin that has scientists baffled?
6. Why should we be concerned about the ‘dead zone’ in the central basin?
7. What impact will this have on the quality of the Lake Erie environment?
- Now that you armed with all this knowledge about the dead zones of Lake Erie, it is time for you to make a decision on what you think could be done to meet the following value-driven objectives:
- We want the water to be safe to drink and swim in
- We want the water to be biologically healthy
- Here is a method that will help your group decide on what to do about the dead zones in Lake Erie and meet the objectives listed above.
- Your group needs to come up with 3 alternatives to the listed objectives. To come up with alternatives, simply come up with answers as to how we can we make Lake Erie’s water to be safe and biologically healthy.
- Now your group needs to deal with the consequences to the alternatives that you chose to meet the objectives. For example, you want to plant a shade tree next to your house. You decide on an oak tree and do research only to find that this type of tree will grow very tall and wide. The tree meets your objective ? to provide shade but the consequences are that the gutters will fill up with leaves, if the tree falls it may damage your house, and it produces a lot of acorns that will attract squirrels but will also litter the ground.
- Consider all of the research that you’ve previously done. Get with your group and discuss all of the consequences of the three alternatives you’ve generated
- Now for the Tradeoffs. What is your group willing to give up so that your objectives are met? Consider the tree decision. A tradeoff would be to decide on a smaller tree that will still provide shade. An easy way to do this is to rank the alternatives against the objectives as being of high importance (H), medium importance (M) or low importance (L).
- So what are you going to do with this data? You need to make a decision and be able to defend your decision using the data and process of coming up with your decision. Choose one of your alternatives and be prepared to discuss and defend your decision with your class.
Do you think that the appearance of the dead zone correlates with the decline in Lake Erie’s walleye population? Walleye are light sensitive fish and so the increased clarity of the water has forced walleye into inhabiting deeper water where it is darker. The graph to the right is from the Lake Erie Walleye Task Group. Research this site about Lake Erie’s walleye problem and decide if you think walleye have left the central basin of Lake Erie because of its anoxic conditions.
Lake Erie Walleye Task Group
The Adobe Acrobat reader (for opening .pdf files) can be downloaded (free) at http://www.adobe.com/products/acrobat/readstep2.html
Other inland lakes other than Lake Erie are infested with Zebra mussels, have high phosphate levels and algae bloom problems that contribute to anoxic conditions including our own Lake Maxinkuckee in Culver, IN. Based on what you learned do you think we could find a dead zone in Lake Max? Defend your answer using the knowledge you gained and the decision making process you used earlier. Lake Maxinkuckee data can be found in the text, " Barton Warren Everman, A. M., Ph. D. and Howard Walton Clark, A. B. A. M. "Lake Maxinkuckee A Physical and Biological Survey" 1920.
Return to list of Lessons