Lesson 32 Mineral Cycling - Alaska Geobotany Center

Reasons for focus on greenhouse gases
Courtesy EPA website
• CO 2 ,CH 4 ,andN 2 O are all greenhouse
gases that trap long-wave radiation (heat)
emitted from the surface of the Earth. This
energy would otherwise be radiated to
space. The added heat affects the global
energy budget, and global climate.
• Anthropogenic influence has increased
both N and C to the level of atmospheric
pollutants.
• Nitrogen is the primary growth limiting
nutrient in many if not most plant
communities. It also limits recovery
following disturbance. It is, therefore,
important to study N in conjunction with C
(see slide of Terrestrial Ecosytem Model).
• Nitrogen-saturated ecosystems can
become sources (not sinks) of nitrogen,
causing:
– Nitrous oxide (a greenhouse gas) flux to
the atmosphere and
– Nitrate eutrophication of streams.