flows of energy and matter 2.3. energy budget: boxes and circles represent storage and arrow...
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FLOWS OF ENERGY AND
MATTER2.3
Energy Budget:
Boxes and Circles represent Storage and Arrow thickness represents magnitude of flow
• Only a very small part of the total sunlight reaching the Earths surface is ever transformed into energy used by living organisms.
• A study of an Illinois cornfield suggested only 1.6% was actually used by the corn.
Pathways of radiation through ecosystem
■Conversion of light energy to chemical energy
■Transfer of chemical energy from one trophic level to another (efficiency varies)
■Overall conversion of ultraviolet and visible light to heat energy by organisms in ecosystem
■Re-radiation of heat energy to the atmosphere
Energy currency: C-H bondsphotosynthesis
■6
respiration
■ 6
Summary:
■Energy is conserved in ecosystems – First law of Thermodynamics
■Chemical energy used by “buffalo and bacteria” must be less than the chemical energy generated via primary production, due to unavoidable inefficiencies in energy capture.
■Photosynthesis is the dominant source of energy in most ecosystems through conversion of light to C-H bonds in organic material.
Summary:
■The flow and fate of carbon is tightly linked to energy flow.
■This fact is fundamental to understanding how carbon and energy flow are – linked to other elements and nutrients– support patterns of biodiversity– connect carnivores, herbivores, and plants
Work Cited
■ Beman, J. (2010) Energy Economics in Ecosystems. Nature Education Knowledge 3(10):13
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