Page 150 - Environment: The Science Behind the Stories

4. A simple change in the flux between just two reservoirs 6. ThINK IT ThrOUGh You are an oysterman in the
in a single nutrient cycle can potentially have major Chesapeake Bay, and your income is decreasing because
consequences for ecosystems and, indeed, for the the dead zone is making it harder to harvest oysters. One
entire Earth. Explain how this can be, using one exam- day your senator comes to town, and you have a one-
ple from the carbon cycle and one example from the minute audience with her. What steps would you urge her
nitrogen cycle. to take in Washington, D.C., to try to help alleviate the
5. How do you think we might solve the problem of dead zone and bring back the oyster fishery?
eutrophication in the Chesapeake Bay? Assess several Now suppose you are a Pennsylvania farmer who has
possible solutions, your reasons for believing they might learned that the government is offering incentives to farm-
work, and the likely hurdles we might face. Explain who ers to help reduce fertilizer runoff into the Chesapeake
should be responsible for implementing these solutions, Bay. What types of approaches described in the text
and why. might you be willing to try, and why?

Calculating Ecological Footprints

In the United States, a common dream is to own a suburban other care—all of which raise environmental and health con-
home with a weed-free green lawn. Nationwide, Americans cerns. Using the figures for a typical lawn in the table, calcu-
tend about 40.5 million acres of lawn grass. But conventional late the total amount of fertilizer, water, and gasoline used in
lawn care involves inputs of fertilizers, pesticides, and irriga- lawn care across the nation each year.
tion water, and using gasoline or electricity for mowing and

Acreage of lawn Fertilizer used (lbs) Water used (gal) Gasoline used (gal)
For the typical 1/4-acre 0.25 37 16,000 4.9
lawn
For all lawns in your
hometown
For all lawns in the United 40,500,000
States
Data from Chameides, B., 2008. http://www.nicholas.duke.edu/thegreengrok/lawns.

1. How much fertilizer is applied each year on lawns decrease fertilizer use in a yard and the environmental
throughout the United States? Where does the nitrogen impacts of nutrient pollution?
for this fertilizer come from? What becomes of the nitro- 3. How much gasoline could Americans save each year if
gen and phosphorus applied to a suburban lawn that is not they did not take care of lawns? At today’s gas prices,
taken up by grass? how much money would this save?
2. Leaving grass clippings on a lawn decreases the need for
fertilizer by 50%. What else might a homeowner do to CHAPTER 5 • Envi R onm E n TA l S y STE m S A nd E C o S y STE m E C ology

STUDENTS INSTRUCTORS
Go to MasteringenvironmentalScience for assignments, the Go to MasteringenvironmentalScience for automatically
etext, and the Study Area with practice tests, videos, current graded activities, current events, videos, and reading questions
events, and activities. that you can assign to your students, plus Instructor Resources.

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