6.2B - Terrestrial Sequestering
Terrestrial primary producers sequester carbon during photosynthesis; some of this carbon is returned to the atmosphere during respiration by consumer organisms.
- Plants (primary producers in an ecosystem) sequester carbon out of the atmosphere during photosynthesis. In this way, carbon enters the food chains and nutrients cycles of terrestrial ecosystems.
- When animals consume plant matter, the carbon sequestered in the plant becomes part of their fat and protein. Respiration, particularly by consumer animals, returns some of the carbon back to the atmosphere.
- Waste from animals is eaten by micro-organisms (bacteria and fungi) and detritus feeders (e.g. beetles).
- As a consequence, carbon becomes part of these creatures. When plants and animals die and their remains fall to the ground, carbon is released into the soil.
Carbon fluxes within ecosystems vary on two timescales:
- Diurnally: during the day, fluxes are positive - from the atmosphere into the ecosystem. The reverse applies at night when respiration occurs but not photosynthesis.
- Seasonally: during winter, carbon dioxide concentrations increase because of the low levels of plant growth. However, as soon as spring arrives and plants grow, these concentrations begin to decrease until the onset of autumn.