Ecosystem: nutrient cycles

Objectives

1. Know that nutrients cycle in ecosystems, and contrast the

characteristics of gaseous and sedimentary cycles. [G1]

2. Describe the major features of the carbon cycle, as a single

cycle for ecological purposes. [G1]

3. Know the amounts of carbon added to the atmosphere from

natural and human sources, the increasing atmospheric

concentration of CO2, and ecological consequences. [W2]

4. Understand the nitrogen cycle as a double cycle, of

nitrification and use by plants, and of nitrogen fixation and

denitrification. [G1]

5. Describe the phosphorus cycle as a double cycle, of

biological use and of sedimentation and erosion. [G1]

Simplified carbon cycle.

Atmospheric CO2 in Hawaii, 1958-2003.

Source: Raven & Berg (2006) Environment (5th edition). Wiley.

Current and projected range of beech trees in North America

Source: Raven & Berg (2006) Environment (5th edition). Wiley.

Simplified nitrogen cycle.

Simplified phosphorus cycle.