Biogeochemical cycle

Definition

A biogeochemical cycle describes the movement of chemical elements and compounds between living organisms and the physical environment. These cycles are crucial for recycling essential nutrients in ecosystems.

5 Must Know Facts For Your Next Test

1. Microorganisms play a vital role in facilitating various steps of biogeochemical cycles, such as nitrogen fixation and decomposition.
2. The carbon cycle involves microbial processes like photosynthesis, respiration, and fermentation.
3. In the nitrogen cycle, bacteria convert atmospheric nitrogen into forms usable by plants through processes like nitrification and denitrification.
4. Sulfur-oxidizing and sulfur-reducing bacteria are key players in the sulfur cycle, affecting soil fertility and plant growth.
5. Phosphorus cycling is unique because it does not include a gaseous phase; microbes release phosphorus from rocks and organic material.

Review Questions

• What roles do microorganisms play in the nitrogen cycle?
• How do microbes contribute to the carbon cycle?
• Why is phosphorus cycling different from other biogeochemical cycles?

Related terms

Nitrogen Fixation:

The process by which certain bacteria convert atmospheric nitrogen into ammonia, making it available for plant uptake.

Denitrification:

Microbial process converting nitrate to nitrogen gas, releasing it back into the atmosphere.

Decomposition:

Breakdown of organic matter by microorganisms, releasing nutrients back into the ecosystem.