Botkin Environmental Science Earth as Living Planet 8th txtbk

G-16 Glossary
Reserves Known and identified deposits of earth materials
from which useful materials can be extracted profitably
with existing technology and under present economic and
legal conditions.
Resource-based agriculture Agricultural practices that rely
on extensive use of resources, so that production is limited
by the availability of resources.
Resources Reserves plus other deposits of useful earth materials
that may eventually become available.
Respiration The complex series of chemical reactions in
organisms that make energy available for use. Water,
carbon dioxide, and energy are the products of respiration.
Responding variable See Variable, dependent.
Restoration ecology The field within the science of ecology
whose goal is to return damaged ecosystems to ones that are
functional, sustainable, and more natural in some meaning
of this word.
Reuse With respect to waste management, refers to finding
ways to reuse products and materials so they need not be
disposed of.
Riffle A section of stream channel characterized at low flow
by fast, shallow flow. Generally contains relatively coarse
bed-load particles.
Risk The product of the probability of an event occurring
and the consequences should that event occur.
Risk assessment The process of determining potential adverse
environmental health effects to people following exposure
to pollutants and other toxic materials. It generally includes
four steps: identification of the hazard, dose-response assessment,
exposure assessment, and risk characterization.
Risk-benefit analysis In environmental economics, weighing
the riskiness of the future against the value we place on
things in the present.
Rock (engineering) Any earth material that has to be blasted
in order to be removed.
Rock (geologic) An aggregate of a mineral or minerals.
Rock cycle A group of processes that produce igneous, metamorphic,
and sedimentary rocks.
Rotation time Time between cuts of a stand or area of forest.
Rule of climatic similarity Similar environments lead to the
evolution of organisms similar in form and function (but
not necessarily in genetic heritage or internal makeup) and
to similar ecosystems.
Ruminants Animals having a four-chambered stomach within
which bacteria convert the woody tissue of plants to
proteins and fats that, in turn, are digested by the animal.
Cows, camels, and giraffes are ruminants; horses, pigs, and
elephants are not.
Sand Grains of sediment between 1/16 and 2 mm in diameter;
often sediment composed of quartz particles of this size.
Sand dune A ridge or hill of sand formed by wind action.
Sanitary landfill A method of disposal of solid waste without
creating a nuisance or hazard to public health or safety.
Sanitary landfills are highly engineered structures with
multiple barriers and collection systems to minimize environmental
problems.
Savanna An area with trees scattered widely among dense grasses.
Scientific method A set of systematic methods by which
scientists investigate natural phenomena, including gathering
data, formulating and testing hypotheses, and developing scientific
theories and laws.
Scientific theory A grand scheme that relates and explains
many observations and is supported by a great deal of
evidence, in contrast to a guess, a hypothesis, a prediction,
a notion, or a belief.
Scoping The process of early identification of important
environmental issues that require detailed evaluation.
Scrubbing A process of removing sulfur from gases emitted
from power plants burning coal. The gases are treated with
a slurry of lime and limestone, and the sulfur oxides react
with the calcium to form insoluble calcium sulfides and
sulfates that are collected and disposed of.
Second growth A forest that has been logged and regrown.
Secondary enrichment A weathering process of sulfide ore
deposits that may concentrate the desired minerals.
Secondary pollutants Air pollutants produced through reactions
between primary pollutants and normal atmospheric
compounds. An example is ozone that forms over urban
areas through reactions of primary pollutants, sunlight,
and natural atmospheric gases.
Secondary production See Production, secondary.
Secondary succession The reestablishment of an ecosystem
where there are remnants of a previous biological
community.
Secondary treatment (of wastewater) Use of biological
processes to degrade wastewater in a treatment facility.
Second-law efficiency The ratio of the minimum available
work needed to perform a particular task to the actual work
used to perform that task. Reported as a percentage.
Second law of thermodynamics The law of thermodynamics
which states that no use of energy in the real (not theoretical)
world can ever be 100% efficient.
Secure landfill A type of landfill designed specifically for
hazardous waste. Similar to a modern sanitary landfill in
that it includes multiple barriers and collection systems to
ensure that leachate does not contaminate soil and other
resources.
Sediment pollution By volume and mass, sediment is our
greatest water pollutant. It may choke streams, fill reservoirs,
bury vegetation, and generally create a nuisance that is difficult
to remove.
Seed-tree cutting A logging method in which mature trees
with good genetic characteristics and high seed production
are preserved to promote regeneration of the forest. It is an
alternative to clear-cutting.
Seismic Referring to vibrations in Earth produced by
earth-quakes.
Selective cutting In timber harvesting, the practice of cutting
some, but not all, trees, leaving some on the site. There
are many kinds of selective cutting. Sometimes the biggest
trees with the largest market value are cut, and smaller trees
are left to be cut later. Sometimes the best trees are left
to provide seed for future generations. Sometimes trees are
left for wildlife habitat and recreation.