the environment introduction environmental science matter unit 1

Transcription

1 the environment unit 1 introduction sustainability what is it? why should you care? earth systems geosphere hydrosphere atmosphere biosphere anthrosphere environmental science environment biotic and abiotic components ecology organization ecosystems communities assemblage of organisms community ecology study of interactions among organisms and abiotic factors and how these interactions affect communities matter components of matter chemical elements molecules chemical compounds characteristics of matter physical change state change chemical change (reaction) rearrangement of atoms/ molecules law of conservation of matter (-) O H H (+) (+)

2 energy what is energy? kinetic energy potential energy energy quality high vs. low laws of thermodynamics first law of thermodynamics law of the conservation of energy second law of thermodynamics law of entropy - no perpetual motion machine efficiency natural resources natural capital one of the major components of sustainability natural resources renewable vs. non-renewable natural services unsustainable practices high-consumption / high-waste economies let s not name names stimulate economic growth through: using more resources producing more goods and services converts many resources to waste, pollution, low-quality heat INPUTS SYSTEM throughputs OUTPUTS (from environment) (into environment) high-quality matter high-quality energy high-waste economy waste and pollution low-quality energy (heat) copyright Cengage Learning, from Environmental Issues and Solutions

3 unsustainable practices Energy Use doubled in the last 30 years will increase 60% by 2030 mostly non-renewable resources gas, coal and oil sustainability working definitions development that meets the needs of the present without compromising the ability of future generations to meet their own needs -Bruntland Commission, UN, 1987 living on the earth s income rather than eroding its capital. -UK sustainable development strategy leave the world better than you found it, take no more than you need, try not to harm life of the environment, make amends if you do" -Paul Hawken, The Ecology of Commerce, 1993 sustainability three pillars of sustainability economy society environment social science principles of sustainability economics full cost pricing politics win-win solutions ethics responsibility to future generations sustaining life three scientific principles of sustainability solar energy chemical cycling biodiversity

4 ecosystems trophic structure food chains tertiary quaternary quaternary tertiary ecosystems trophic structure food webs tertiary ecosystem dynamics biological magnification this is a big problem for certain types of compounds and elements DDT mercury PCBs DDT concentration increase of 10 million times DDT in small fish 0.5 ppm DDT in large fish 2 ppm DDT in zooplankton 0.04 ppm DDT in water ppm DDT in fish-eating birds 25 ppm ecosystem dynamics ecosystem energy flow energy enters ecosystem through production 10 kcal can be expressed as biomass ecosystems differ in biomass 100 kcal flow of energy in food chain represented as pyramid chemical cycling constantly recycled sunlight 1000 kcal tertiary 10,000 kcal 1,000,000 kcal

5 hydrological cycle chemical cycling resource cycling general model for chemical cycling abiotic reservoirs extract chemicals from abiotic reservoirs decomposers return nutrients to abiotic reservoirs local and global scale is different for different nutrients nutrients available to decomposers abiotic reservoirs carbon cycle phosphorus cycle carbon dioxide cycles globally combustion CO2 in atmosphere phosphate cycling no atmospheric component very long term combustion aerobic respiration photosynthesis uplifting of weathering of wood, fossil fuels higher level runoff phosphates in solution phosphates in phosphates in soil (inorganic) plants animals detritus decomposers animal bodies detritus leaf litter phosphate sediment (precipitation) decomposers

6 nitrogen cycle nitrogen most common gas in atmosphere denitrifying NO3 - in soil nitrifying plant N2 in atmosphere detritus ammonifying animal nitrogen-fixing discussion questions what would happen to an ecosystem and to humans if: soil were lost? all were killed through loss of soil fertility? top level predators were removed from an ecosystem? what do we do about big predators? a shift to sustainable societies... unrealistic? Fermi paradox... what should we focus on? food? transportation? home energy? resource use? NH4 + in soil