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Issue of the day: CO 2 and Global Warming.
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Issue of the day: CO2 and Global Warming Inhofe, who held an impromptu press conference in the Bella Center, said the chances of passage of pending climate and energy legislation were "zero" and would remain so if such a bill was financially harmful to Americans in any way. He said the recent hacking, and publishing, of e-mails from a prominent climate change research group at East Anglia University in England showed that "the science has been debunked.“ Boston Globe, 12/17/2009
Some facts about CO2 , one greenhouse gas • CO2 is required for photosynthesis; it is essentially a plant fertilizer • CO2 cycles are natural • Oceans absorb CO2 • Without a greenhouse effect, the earth would be uninhabitable
It is a matter of degree • Must understand “dynamic balance” • Contributors include physical, biological and cultural factors – “Ecosystems” • How can we characterize “ecosystems”? • Describe: Where does one start and stop? • Internal components, flows, dynamics? • Compare: How do different ecosystems interact to contribute to global patterns? • How does balance depend on scale?
What do we mean by “scale”? • Do we look very close or from a distance? • Are we concerned about changes over hours, days, years or longer?
Compartment models illustrate carbon stocks and flows over different scales
Carbon and “productivity” are linked • Primary Productivity from plants & bacteria • Secondary Productivity from consumers • More primary production supports more diverse types of producers & consumers
What material cycles are important? • It depends • What is limiting productivity? • Are materials damaging? • Terrestrial systems • N, P, K fertilizer components • Freshwater systems – phosphorus • Oceanic systems – fixed nitrogen
Water flow and atmospheric circulation link ecosystems • Terrestrial-to-aquatic links • Watersheds and river systems: continent-to-ocean links • Oceanic currents: ocean-to-ocean links (and effects on global climate) • Ocean-to-continent winds
How can we characterize “ecosystems”? • Establish limits of major concern: Where does one start and stop? • Identify internal components, flows, dynamics
Task: Characterize a local ecosystem • Identify the relevant “compartments” • Where is carbon found and in what form? • Indicate a hypothesis about how these materials move among compartments • Indicate possible important influences on those exchanges
Flow of carbon in an arctic ecosystem Atmosphere Plants People Decomposers Caribou Wolves Soil
What is ecosystem diversity? • Variety on many scales, such as: • Genetic variety within populations • Polymorphism within species • The number of different species • The variety of trophic levels