Discussion Questions:

Address all questions in short essay format (use your text and Carlson's paper): 1 to 2 sentences for each queastion

1. What is eutrophication, and why is it an ecosystem effect?

2. What is the "twofold effect" of sediment pollution?

3. Based on your calculations in question 4, what is the trophic status of the lake using Carlson's Trophic State Index? What does this trophic status imply about the lake? What would the associated Secchi depth transparency be, and what would that tell us?

4. If you could manipulate the average residence time of the lake to help reduce the amount of phosphorus in the system, what would you need to change?

5. The water from the lake will eventually drain into the Gulf of Mexico contributing to the dead zone. Explain the impact of this flow into the Gulf of Mexico. What is meant by "cultural eutrophication" (see "A Closer Look," 19.2).

6. What are some ways that we can reduce phosphorus and nitrogen loading to lakes and streams? Consider specific best management practices (BMPs) within a watershed that would help reduce nutrient loading.

Article: A trophic state index for lakes by Robert E. Carlso.