Botkin Environmental Science Earth as Living Planet 8th txtbk

CHAPTER
6
The Biogeochemical
Cycles
LEARNING
OBJECTIVES
Life is composed of many chemical elements, which
have to be available in the right amounts, the right
concentrations, and the right ratios to one another. If
these conditions are not met, then life is limited. The
study of chemical availability and biogeochemical
cycles—the paths chemicals take through Earth’s
major systems—is important in solving many
environmental problems. After reading this chapter,
you should understand . . .
What the major biogeochemical cycles are;
How life, over the Earth’s history, has greatly altered
chemical cycles;
The major factors and processes that control
biogeochemical cycles;
As a result of biogeochemical cycles marine life is plentiful in the Santa
Barbara Channel of southern California.
Why some chemical elements cycle quickly and
some slowly;
How each major component of Earth’s global
system (the atmosphere, waters, solid surfaces,
and life) is involved and linked with biogeochemical
cycles;
How the biogeochemical cycles most important to
life, especially the carbon cycle, generally operate;
How humans affect biogeochemical cycles.
People around the world are wearing masks
to protect themselves against swine flu.
(Source: http://www.baltimoresun.com/news/
nation-world/ny-swineflu-photos,0,859331.
photogallery [Getty Images Photo / May 2,
2009].)