Page 735 - Environment: The Science Behind the Stories

second law of thermodynamics The physi- sinkhole An area where the ground has given source In a nutrient cycle, a pool that releases
cal law stating that the nature of energy tends way with little warning as a result of subsid- more nutrients than it accepts.
to change from a more-ordered state to a less- ence caused by depletion of water from an source reduction The reduction of the amount
ordered state; that is, entropy increases. aquifer.
of material that enters the waste stream to avoid
sediment The eroded remains of rocks. SLOSS (Single Large or Several Small) di- the costs of disposal and recycling, help con-
sedimentary rock One of the three main cat- lemma The debate over whether it is better serve resources, minimize pollution, and save
egories of rock. Formed when dissolved min- to make reserves large in size and few in num- consumers and businesses money.
erals seep through sediment layers and act as ber or many in number but small in size. specialist A species that can survive only in a
a kind of glue, crystallizing and binding sedi- smart growth A city planning concept in narrow range of habitats that contain very spe-
ment particles together. Sandstone and shale which a community’s growth is managed in cific resources. Compare generalist.
are examples of sedimentary rock. Compare ways intended to limit sprawl and maintain or speciation The process by which new species
igneous rock and metamorphic rock. improve residents’ quality of life.
are generated.
seed bank A storehouse for samples of the smelting A process in which ore is heated species A population or group of popula-
world’s crop diversity. beyond its melting point and combined with tions of a particular type of organism whose
seed-tree Timber harvesting approach that other metals or chemicals, in order to form members share certain characteristics and can
leaves small numbers of mature and vigorous metal with desired characteristics. Steel is breed freely with one another and produce fer-
seed-producing trees standing so that they can created by smelting iron ore with carbon, for tile offspring. Different biologists may have
reseed a logged area. example. different approaches to diagnosing species
selection system Method of timber harvesting Smith, Adam (1723–1790) Scottish philoso- boundaries.
whereby single trees or groups of trees are se- pher known today as the father of classical eco- species-area curve A graph showing how
lectively cut while others are left, creating an nomics. He believed that when people are free number of species varies with the geographic
uneven-aged stand. to pursue their own economic self-interest in a area of a landmass or water body. Species
competitive marketplace, the marketplace will
selective breeding See artificial selection. richness commonly doubles as area increases
behave as if guided by “an invisible hand” that
septic system A wastewater disposal method, ensures that their actions will benefit society tenfold.
common in rural areas, consisting of an under- as a whole. Species at Risk Act Canada’s endangered spe-
ground tank and series of drainpipes. Wastewa- smog Term popularly used to describe un- cies protection law, enacted in 2002.
ter runs from the house to the tank, where solids healthy mixtures of air pollutants that often species coexistence An outcome of inter-
precipitate out. The water proceeds downhill to form over urban areas. See industrial smog; specific competition in which no competing
a drain field of perforated pipes laid horizon- photochemical smog. species fully excludes others and the species
tally in gravel-filled trenches, where microbes continue to live side by side.
decompose the remaining waste. snag A dead tree that is still standing. Snags are
valuable for wildlife. species diversity The number and variety of
service Work done for others as a form of busi- species in the world or in a particular region.
ness. social sciences Academic disciplines that
study human interactions and institutions. species richness The number of species in a
sex ratio The proportion of males to females particular region. One way to express species
in a population. Compare natural sciences. diversity. Compare evenness; relative abun-
socially responsible investing Invest-
shale gas Natural gas trapped deep under- ing in companies that have met criteria for dance.
ground in tiny bubbles dispersed throughout sprawl The unrestrained spread of urban or sub-
formations of shale, a type of sedimentary environmental or social sustainability. urban development outward from a city center
rock. Shale gas is often extracted by hydraulic soil A complex plant-supporting system consist- and across the landscape. Often specified as
fracturing. ing of disintegrated rock, organic matter, air, growth in which the area of development out-
water, nutrients, and microorganisms.
shale oil A liquid form of petroleum extracted paces population growth.
from deposits of oil shale. soil degradation A deterioration of soil qual- steady-state economy An economy that does
ity and decline in soil productivity, resulting
shelf-slope break The portion of the ocean not grow or shrink but remains stable.
floor where the continental shelf drops off with primarily from forest removal, cropland agri- steppe See temperate grassland.
relative suddenness. culture, and overgrazing of livestock. Compare
desertification; land degradation. Stockholm Convention on Persistent Organic
shelterbelt A row of trees or other tall peren- Pollutants (POPs) A 2004 international
nial plants that are planted along the edges of soil profile The cross-section of a soil as a
farm fields to break the wind and thereby mini- whole, from the surface to the bedrock. treaty that aims to end the use of 12 persis-
tent organic pollutants nicknamed the “dirty
mize wind erosion. solar cooker A simple portable oven that uses dozen.”
shelterwood Timber harvesting approach that reflectors to focus sunlight onto food and
leaves small numbers of mature trees in place cook it. storage Technique used to generate hydroelec-
to provide shelter for seedlings as they grow. solar energy Energy from the sun. It is perpetu- tric power, in which large amounts of water
are impounded in a reservoir behind a concrete
sick-building syndrome A building-related ally renewable and may be harnessed in several dam and then passed through the dam to turn
illness produced by indoor pollution in which ways. turbines that generate electricity. Compare
the specific cause is not identifiable. solution mining A mining technique in which pumped storage, run-of-river.
silicon The chemical element with 14 protons a narrow borehole is drilled deep into the storm surge A temporary and localized rise
and 14 neutrons. An abundant element in rocks ground to reach a mineral deposit, and water, in sea level brought on by the high tides and
in Earth’s crust. acid, or another liquid is injected down the winds associated with storms.
borehole to leach the resource from the sur-
silt Sediment consisting of particles 0.002– rounding rock and dissolve it in the liquid. The stratosphere The layer of the atmosphere
0.005 mm in diameter. Compare clay; sand.
resulting solution is then sucked out, and the above the troposphere and below the meso-
sink In a nutrient cycle, a pool that accepts desired resource is isolated. Also called in-situ sphere; it extends from 11 km (7 mi) to 50 km
G-20 more nutrients than it releases. recovery. (31 mi) above sea level.

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