Ionizing Radiation
enough energy to dislodge electrons from atoms, forming ions; capable of causing cancer (gamma, X-rays, UV)
High Quality Energy
organized and concentrated; can perform useful work (fossil fuel and nuclear)
Low Quality Energy
disorganized, dispersed (heat in ocean or air wind, solar)
First Law of Thermodynamics
energy is neither created nor destroyed, but may be converted from one form to another ( Law of Conservation of Energy)
Second law of Thermodynamics
when energy is changed from one form to another, some useful energy is always degraded into lower quality energy, usually heat
Natural radioactive decay
unstable radioisotopes decay releasing gamma rays, alpha particles, and beta particles
Half-life
the time it takes for 1/2 the mass of a radioisotope to decay
Estimate of how long a radioactive isotope must be stored until it decays to a safe level
approximately 10 half-lives
Nuclear Fission
nuclei of isotopes split apart when struck by neutrons
Nuclear Fusion
two isotopes of light elements (H) forced together at high temperatures until they fuse to form a heavier nucleus (He). Process is expensive; break-even point not reached yet
Ore
a rock that contains a large enough concentration of a mineral making it profitable to mine
Organic fertilizer
slow-acting and long-lasting because the organic remains need time to be decomposed
Best solutions to energy shortage
conservation, increase efficiency, explore alternative energy options
Surface mining
cheaper and can remove more minerals; less hazardous to workers
Humus
organic, dark material remaining after decomposition by microorganisms
Leaching
removal of dissolved materials from soil by water moving downwards
Illuviation
deposit of leached material in lower soil layers (B)
Loam
perfect agricultural soil with equal portions of sand, silt, clay (40%, 40%, 20%)
Conservation
allowing the use of resources in a responsible manner
Preservation
setting aside areas and protecting them from human activities
Parts of the hydrologic cycle
evaporation, transpiration, runoff, condensation, precipitation, infiltration
Aquifer
any water-bearing layer in the ground
Cone of depression
lowering of the water table around a pumping well
Salt water intrusion
near the coast, over-pumping of groundwater causes saltwater to move into the aquifer
ENSO
El Nino Southern Oscillation, see-sawing of air pressure over the South Pacific
During an El Nino Year
trade winds weaken and warm water sloshes back to South Atlantic
During a non El Nino year
easterly trade winds and ocean currents pool warm water in the western Pacific, allowing upwelling of nutrient rich water off the west coast of South America
Effects of El Nino
upwelling decreases, disrupting food chains; North U.S. has mild winters, Southwest U.S. has increased rainfall, less Atlantic hurricanes
Nitrogen fixing
because atmospheric nitrogen cannot be used directly by plants it must first be converted into ammonia (NH3) by bacteria (rhizobium)
Ammonification
decomposers convert organic waste into ammonia
Nitrification
ammonia (NH3) is converted to nitrate ions (NO3-)
Assimilation
inorganic nitrogen is converted into organic molecules such as DNA/amino acids and proteins
Phosphorous does not circulate as easily as nitrogen because
it does not exist as a gas, but is released by weathering of phosphate (PO4)3- rocks
Sustainability
the ability to meet the current needs of humanity without compromising the ability of future generations to meet their needs
How excess phosphorous is added to aquatic ecosystems
runoff of animal wastes, fertilizer, discharge of sewage
Photosynthesis
plants convert atmospheric carbon (CO2) into complex carbohydrates (C6H1206)
Aerobic respiration
O2-consuming producers, consumers and decomposers break down complex organic compounds and convert C back into CO2
Largest reservoirs of carbon
1) carbonate rocks. 2) oceans
Biotic and abiotic
living and nonliving components of an ecosystem
Producer/Autotroph
photosynthetic or chemosynthetic life
Fecal coliform/Enterococcus bacteria
indicater of sewage contamination
Energy flow in food webs
only 10% of the usable energy is transferred because usable energy is lost as heat (second law of thermodynamics); not all biomass is digested and absorbed; predators expend energy to catch prey
Good chlorine
disinfects water
Bad chlorine
forms trihalomethanes
Primary succession
development of communities in a lifeless area not previously inhabited by life, or those in which the soil profile is totally destroyed (lava flows); begins with lichen action
Secondary succession
life progresses where soil remains (clear-cut forests, fire)
Cogeneration
using waste heat to make electricity
Mutualism
symbiotic relationship where both partners benefit
Commensalism
symbiotic relationship where one partner benefits and the other is unaffected
Parasitism
relationship in which one partner obtains nutrients at the expense of the host
Biome
large distinct terrestrial region having similar climate, soil, plants and animals
Carrying capacity
the number of individuals that can be sustained in an area
R strategist
reproduce early in life; many small unprotected offspring
K strategist
reproduce late in life; few offspring; care for offspring
Positive feedback
when a change in some condition triggers a response that intensifies the changing condition (warmer Earth - snow melts - less sunlight is reflected and more is absorbed, therefore warmer earth)
Negative feedback
when a change in some condition triggers a response that counteracts the changed condition (warmer earth - more ocean evaporation - more stratus clouds - less sunlight reaches the ground - therefore cooler earth)
Malthus
said human population continue to increase exponentially; consequences will be war, famine, and disease
Doubling time
rule of 70; 70 divided by the percent growth rate
Replacement level fertility
the number of children a couple must have to replace themselves (2.1 in developed countries)
World Population (U.S. Population)
~6.7 billion (~305 million)
Preindustrial stage
(demographic transition) birth and death rates high, population grows slowly, infant mortality high
Transitional stage
(demographic transition) death rate lower, better health care, population grows quickly
Industrial stage
(demographic transition) decline in birth rate, population growth slows
Post-industrial stage
(demographic transition) low birth and death rates
Age structure diagrams
broad base = rapid growth; narrow base = negative growth; uniform shape = zero growth
First, second, and third most populated countries
China, India, U.S.
Most important thing affecting population growth
low status of women
Ways to decrease birth rate
family planning, contraception, economic rewards and penalties
Percent water on earth by type
97.5% seawater, 2.5% freshwater
Salinization of soil
in arid regions, water evaporates leaving salts behind
Ways to conserve water
agriculture = drip/trickle irrigation; industry = recycling; home = use gray water, repair leaks, low flow fixtures
Point vs. non-point sources
Point = from specific location, such as a pipe. Non-point = from over an area, such as runoff
BOD
Biological Oxygen Demand; amount of dissolved oxygen needed by aerobic decomposers to break down organic materials
Eutrophication
rapid algal growth caused by an excess of nitrates (NO3)- and phosphates (PO4)3- in the water
Hypoxia
when aquatic plants die, the BOD reises as aerobic decomposers break down the plants, the dissolved oxygen levels drop and the water cannot support life
Minamata disease
1932-1968, Japan; mental impairments caused by methylmercury poisoning
Primary air pollutants
produced by humans and nature (CO, CO2, SOx, NOx, hydrocarbons, particulates)
Natural selection
organisms that possess favorable adaptations that are passed on to the next generation
Particulate matter
Source: burning fossil fuels and diesel exhaust; Effect: reduces visibility and respiratory irritation; Reduction: filtering, electrostatic precipitators, alternative energy
Nitrogen Oxides (NOx)
Source: auto exhaust; Effects: acidification of lakes, respiratory irritation, smog and ozone; Equation for acid formation: NO+O2 = NO2 + H2O = HNO3; Reduction: catalytic converter
Sulfur oxides (SOx)
Source: coal burning; Effects: acid deposition, respiratory irritation, damages plants; Equation for acid formation: SO2 + O2 = SO3 + H2O = H2SO4; Reduction: scrubbers, burn low sulfur fuel
Carbon oxides (CO and CO2)
Source: auto exhaust, incomplete combustion; Effects: CO binds to hemoglobin, reducing blood's ability to carry O2; CO2 contributes to global warming; Reduction: catalytic converter, emission testing, oxygenated fuel, mass transit
Ozone (O3)
Formation: secondary pollutant, NO2 + UV = NO + O
O
+ O2 = O3, with volatile organic compounds; Effects: respiratory damage, plant damage; Reduction reduce NO and VOC emissions
Radon (Rn)
naturally occurring colorless, odorless, radioactive gas, found in some types of soil and rock, can seep into homes and buildings, formed from the decay of uranium (U), causes lung cancer
Photochemical smog
formed by chemical reactions involving sunlight (NO, VOC, O*)
Acid deposition
caused by sulfuric and nitric acids (H2SO4, HNO3), resulting in lowered pH of surface waters
Greenhouse gases
Examples: H2O, CO2, O3, chlorofluorocarbons (CFCs), methane (CH4); Effect: trap outgoing infrared (heat) energy, causing Earth to warm
Effects of global warming
rising sea levels (thermal expansion), extreme weather, drought, famine, extinctions
Causes of ozone depletion
CFCs, methyl chloroform or trichloromethane (CHCl3), carbon tetrachloride (CCl4), halon (haloalkanes), methyl bromide (CH3Br) - all of which attack stratospheric ozone
Effects of ozone depletion
increased UV, skin cancer, cataracts, decreased plant growth
Love Canal, NY
(1950s+) chemicals buried in old canal; school and homes built over it; caused birth defects and cancer
Main component of municipal solid waste (MSW)
paper; most is landfilled
True cost / External costs
harmful environmental side effects that are not reflected in a product's price
Sanitary landfill problems and solutions (leachate)
solution = liner with collection system
Sanitary landfill problems and solutions (methane gas)
solution = collect gas and burn it
Sanitary landfill problems and solutions (volume of garbage)
solution = compact and reduce
Incineration advantages
volume of waste reduced by 90%, and waste heat can be used
Incineration disadvantages
toxic emissions (polyvinyl chloride, dioxins), scrubbers and electrostatic precipitators needed, ash disposal (contains heavy metals)
Best way to solve waste problem
reduce the amounts of waste at the source
Keystone species
species whose role in an ecosystem in an ecosystem is more important than others, such as a sea otter, sea stars, grizzly bear, prairie dogs
Indicator species
species that serve as early warnings that an ecosystem is being damaged; example: trout
Characteristics of endangered species
small range, large territory, or live on an island
In natural ecosystems, methods which control 50-90% of pests
predators, diseases, parasites
Major insecticide groups (and examples)
chlorinated hydrocarbons (DDT); organophosphates (malathion); carbamates (aldicarb)
Pesticide pros
saves lives from insect-transmitted diseases, increases food supply, increases profits for farmers
Pesticide cons
genetic resistance, ecosystem imbalance, pesticide treadmill, persistence, bioaccumulation, biological magnification
Natural pest control
better agricultural practices, genetically resistant plants, natural enemies, biopesticides, sex attractants
Electricity generation methods
using steam from water boiled by fossil fuels or nuclear reactions; falling water to turn a turbine to power a generator
Petroleum formation
microscopic aquatic organisms in sediments converted by heat and pressure into a mixture of hydrocarbons
Pros of petroleum
relatively cheap, easily transported, high-quality energy
Cons of petroleum
reserves will be depleted soon; pollution during drilling, transport, and refining; burning makes CO2
Steps in coal formation
peat, lignite, bituminous, anthracite
Major parts of a nuclear reactor
core, control rods, steam generator, turbine, containment building
Two most serious nuclear accidents
Chernobyl, Ukraine (1986) and Three Mile Island, PA (1979)
Alternate energy sources
wind, solar, waves, biomass, geothermal, fuel cells
LD50 (LD-50)
(the amount of a chemical that kills 50% of the animals in a test population
Mutagen
causes hereditary changes through mutations
Teratogen
causes fetus deformities
Carcinogen
causes cancer
Endangered species
a group of organisms in danger of becoming extinct if the situation is not improved; population numbers have dropped below the critical number of organisms; North spotted owl, Arctic polar bear, and many others
Invasive/Alien/Exotic species
non-native species to an area; often thrive and disrupt the ecosystem balance; examples: kudzu vine, purple loosestrife, African honeybee "killer bee", water hyacinth, fire ant, zebra mussel
The Tragedy of the Commons
(1968) paper by ecologist Garret Hardin) global commons such as atmosphere and oceans are used by all and owned by none
Volcano and Earthquake occurrence
at plate boundaries (divergent = spreading, mid-ocean ranges; convergent = trenches; transform = sliding, San Andreas fault)
Sources of mercury
burning coal, compact fluorescent bulbs
Major source of sulfur
burning coal
Threshold dose
the maximum dose that has no measurable effect
Temperature inversion
layer of dense, cool air trapped under a layer of warm dense air, pollution in trapped layer may build to harmful levels; frequent in Los Angeles, CA and Mexico City, Mexico
Transpiration
process where water is absorbed by plant roots, moves up through plants, passes through pores (stomata) in leaves or other parts, evaporates into atmosphere as water vapor
Monoculture
cultivation of a single crop, usually in a large area
Food
wheat, rice, and corn provide more than 1/2 of the calories in the food consumed by the world's people
Surface Forest Fire
usually burn only under growth and leaf litter on forest floor
Crown Forest Fire
hot fires, may start on ground but eventually leap from treetop to treetop
Ground Forest Fire
go underground, may smolder for days or weeks, difficult to detect and extinguish (peat bogs)
Surface Mining Control and Reclamation Act
1977; requires coal strip mines to reclaim the land
Madrid Protocol
1991; Suspension of mineral exploration (mining) for 50 years in Antarctica
Safe Drinking Water Act (SDWA)
1974; set maximum contaminant levels for pollutants in drinking water tha may have adverse effects on human health
Clean Water Act (CWA)
1972; set maximum permissible amounts of water pollutants that can be discharged into waterways; aims to make surface waters swimmable and fishable
Ocean Dumping Ban Act
1988; bans ocean dumping of sewage sludge and industrial waste in the ocean
Clean Air Act (CAA)
1970; set emission standards for cars and limits release of air pollutants
Kyoto Protocol
2005; controlling global warming by setting greenhouse gas emissions targets for developed countries
Montreal Protocol
1987; phase-out of ozone depleting substances
Resource Conservation and Recovery Act (RCRA)
1976; controls hazardous waste with a cradle to grave system
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
1980; "superfund," designed to identify and clean up abandoned hazardous waste dump sites
Nuclear Waste Policy Act
1982; U.S. government must develop a high level nuclear waste site (Yucca Mountain)
Endangered Species Act
1973; identifies threatened and endangered species in the U.S. and puts their protection ahead of economic considerations
Convention on International Trade in Endangered Species (CITES)
1973; lists species that cannot be commercially traded as live specimens or wildlife products
Magnuson-Stevens Act
1976; management of marine fisheries
Food Quality Protection Act
1996; set pesticide limits in food, and all active and inactive ingredients must be screened for estrogenic/endocrine effects
National Environmental Policy Act
1969; Environmental Impact Statements must be done before any project affecting federal lands can be started
Stockholm Convention on Persistent Organic Pollutants
2004; Seeks to protect human health from the 12 most toxic chemicals (includes 8 chlorinated hydrocarbons pesticides / DDT can be used for malaria control)