Visualizing Environmental Science

97

150

200

250

100

50

0

1955 1960 1965 1970

Dissolved phosphorus(10

3 Kilograms per year)

1975

Ye a r

Total dissolved phosphorus

Amount of dissolved phosphorus in

sewage effluent

100

75

50

25

0

1965 1970

Year

1975

Percent of maximum level(the year 1964 = 100%)

Chlorophyll

Phosphorus

From W.T. Edmondson, The Uses of Ecology: Lake Washington

and Beyond. University of Washington Press (1991).

From W.T. Edmondson, The Uses of Ecology: Lake Washington

and Beyond. University of Washington Press (1991).

a. Dissolved phosphorus in Lake Washington from 1955 to 1974.

Note that the level of dissolved phosphorus declined in the lake

as the phosphorus contributed by sewage effluent (shaded area)

declined.

b. Cyanobacterial growth from 1964 to 1975, during Lake
Washington’s recovery, as measured indirectly by the amount of
chlorophyll, the pigment involved in photosynthesis. Note that
as the level of phosphorus dropped in the lake, the number of
cyanobacteria (that is, the chlorophyll content) declined.

© Philip James Corwin/CORBIS

CHAPTER OUTLINE

What Is Ecology? 98

The Flow of Energy Through Ecosystems 100

s The First and Second Laws of Thermodynamics

s Producers, Consumers, and Decomposers

s The Path of Energy Flow in Ecosystems

s Ecosystem Productivity

The Cycling of Matter in Ecosystems 106

s The Carbon Cycle

s The Hydrologic Cycle

s The Nitrogen Cycle

s The Sulfur Cycle

s The Phosphorus Cycle

Ecological Niches 11 3

■ What a Scientist Sees: Resource Partitioning

Interactions Among Organisms 11 6

s Symbiosis

■ Environmental InSight: Symbiotic Relationships

■ EnviroDiscovery: Bee Colonies Under Threat

s Predation

s Competition

s Keystone Species

■ Case Study: Global Climate Change: How Does

It Affect the Carbon Cycle?

CHAPTER PLANNER✓✓

❑ Study the picture and read the opening story.

❑ Scan the Learning Objectives in each section:

p. 98 ❑ p. 100 ❑ p. 106 ❑ p. 113 ❑ p. 116 ❑

❑ Read the text and study all figures and visuals.

Answer any questions.

Analyze key features

❑ Process Diagram, p. 103 ❑ p. 104 ❑ p. 107 ❑^

p. 108 ❑ p. 109 ❑ p. 111 ❑ p. 112 ❑

❑ What a Scientist Sees, p. 115

❑ Environmental InSight, p. 117

❑ EnviroDiscovery, p. 118

❑ Case Study, p. 122

❑ Stop: Answer the Concept Checks before you go on:

p. 99 ❑ p. 106 ❑ p. 113 ❑ p. 115 ❑ p. 122 ❑

End of Chapter

❑ Review the Summary and Key Terms.

❑ Answer What is happening in this picture?

❑ Answer the Critical and Creative Thinking Questions.

Interpreting Data

During the years that sewage effluent was initially removed

from the lake, 1963–1968, what happened to concentrations

of dissolved phosphorus? What was the percentage change

in cyanobacteria (as measured by chlorophyll content)?