Environmental Engineering Reference
In-Depth Information
soil pollution
The contamination of soil by anthropogenic chemicals, commonly including fertilizers, pesti-
cides, oil and fuel spills, leaching of waste from landfills, and the movement of contaminated surface water to
subsurface areas; also called land pollution.
soil porosity
The amount of open space between soil particles; the ratio of void space to total volume.
soil profile
A soil cross-section showing the depths of the layers including (from the surface down) the O Ho-
rizon, A Horizon, E Horizon, B Horizon, C Horizon, and R Horizon.
solar
Energy coming from the sun.
solstice
The date at which the sun is most north or south of the celestial equator. The summer solstice is June
21 and the winter solstice is December 21.
specialists
Organisms that are adapted to only one specific environment, making them more vulnerable to any
type of ecosystem change.
speciation
The process through which new species are created.
species
A group of organisms that share particular characteristics and can breed and reproduce to create fertile
offspring.
species richness
The number of species in an area, related to biodiversity.
stabilizing selection
Natural selection in which extreme traits are selected against, creating a population with
relatively homogenous traits and low genetic variation.
stratopause
The boundary between the stratosphere and the mesosphere.
stratosphere
The second layer of the Earth's atmosphere. The ozone layer that protects the Earth from harmful
UV radiation is located within the stratosphere.
stratospheric ozone
The ozone layer that protects the Earth.
strike slip fault
A fault caused by tectonic plates sliding past one another horizontally.
subduction
A plate boundary phenomenon resulting from tectonic plate movement, in which a denser oceanic
plate is pushed below a lighter continental plate, creating a subduction zone.
subsidy
Financial assistance given by the government to a business, person, or economic sector in an effort to
support an activity that is thought to be beneficial to the public.
subsistence agriculture
A method of crop production resulting in the production of enough food for one fam-
ily but not for others or for commerce.
subsurface mining
A form of mining that uses deep underground shafts to access and extract resources from
pockets or seams.
sulfur dioxide (SO
2
)
Formed when sulfur combusts (usually when burning coal and oil) and the released sul-
fur reacts with oxygen in the atmosphere.
sulfur oxide (SO
x
)
The gases containing sulfur and oxygen that play a role in industrial smog. They include
sulfur dioxide (SO
2
) and sulfur trioxide (SO
3
).
