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Peer
 review of group presentations
Human impacts on Water as ecosystem processes
Open-system self-regulating EcosystemsÕ overall stability ÒdynamicallyÓ maintained by 3 chief mechanisms:
Controlling the rate of chemical and material cycling with the ÒwaterÓ system
Controlling the rate of energy flow through the ÒwaterÓ system
Maintaining a diversity of species & food webs so that system stability is not affected seriously by the loss of some food web links and/or species
Human-induced alterations of ÒnaturalÓ water systems
Disruption of essential material/nutrient cycle:
Changing the rate of cycling by material overloads or leaks in the system
Breaking the cycle
Introduction of human-made chemicals into the water, especially those with no natural decomposition chain
Disruption of energy flow(s)
Entropy or heat build-up in the system by consumption of too much energy by human society
Changing properties and/or composition of the atmosphere leading to an increase or decrease in the solar energy input involved in hydrological cycle
Altering drainage systems (quality, quantity, direction of flow, etc.)
Disruption of the ecosystem by destruction of species diversity and/or the food web

Levels of organization of matter
Second law of (energy) thermodynamics
Comparative Energy Efficiency
Simplified Biogeochemical cycles
Energy flow to and from the earth
Freshwater pond ecosystem
Ecosystem of a field
Detritus feeders
Ecosystem structure and function
Ecosystem structure and function
Range of tolerance for a population of organisms
A food chain
Greatly simplified food web
Generalized model of main one-way flow energy pathways through ecosystems
Energy flow pyramids
Biological magnification