Page 730 - Environment: The Science Behind the Stories

nitrogen fixation The process by which inert atom. Several processes, each of which in- omnivore An organism that consumes both
nitrogen gas combines with hydrogen to form volves transforming isotopes of one element plants and animals. Compare carnivore; her-
ammonium ions (NH ), which are chemically into isotopes of other elements, can convert bivore.
+
4
and biologically active and can be taken up by nuclear energy into thermal energy, which is open cycle An approach in ocean thermal en-
plants. then used to generate electricity. See also nu- ergy conversion whereby warm surface water
clear fission; nuclear reactor.
nitrogen-fixing bacteria Bacteria that live in- is evaporated in a vacuum, its steam turns tur-
dependently in the soil or water, or those that nuclear fission The conversion of the energy bines, and it is then condensed by cold water.
form mutualistic relationships with many types within an atom’s nucleus to usable thermal en- open pit mining A mining technique that in-
of plants and provide nutrients to the plants by ergy by splitting apart atomic nuclei. Compare volves digging a gigantic hole and removing
converting gaseous nitrogen to a usable form. nuclear fusion. the desired ore, along with waste rock that sur-
nitrogen oxide (NO ) One of a family of com- nuclear fusion The conversion of the energy rounds the ore.
X
pounds that includes nitric oxide (NO) and ni- within an atom’s nucleus to usable thermal ore A mineral or grouping of minerals from
trogen dioxide (NO ). energy by forcing together the small nuclei
2 which we extract metals.
of lightweight elements under extremely high
no-analog community (novel commu- temperature and pressure. Developing a com- organic agriculture Agriculture that uses no
nity) An ecological community composed of mercially viable method of nuclear fusion re- synthetic fertilizers or pesticides but instead
a novel mixture of organisms, with no current mains an elusive goal. relies on biological approaches such as com-
analog or historical precedent. posting and biocontrol. Compare low-input
nuclear reactor A facility within a nuclear
noise pollution Undesired ambient sound. agriculture; sustainable agriculture.
power plant that initiates and controls the
nonconsumptive use Fresh water use in process of nuclear fission in order to generate organic compound A compound made up of
which the water from a particular aquifer or electricity. carbon atoms (and, generally, hydrogen atoms)
surface water body either is not removed or is nucleic acid A macromolecule that directs the joined by covalent bonds and sometimes in-
removed only temporarily and then returned. production of proteins. Includes DNA and RNA. cluding other elements, such as nitrogen, oxy-
The use of water to generate electricity in hy- gen, sulfur, or phosphorus. The unusual ability
droelectric dams is an example. Compare con- nutrient An element or compound that organ- of carbon to build elaborate molecules has
sumptive use. isms consume and require for survival. resulted in millions of different organic com-
pounds showing various degrees of complexity.
nongovernmental organization (NGO) An nutrient cycle The comprehensive set of cycli-
organization not affiliated with any national cal pathways by which a given nutrient moves organic fertilizer A fertilizer made up of natu-
government, and frequently international in through the environment. ral materials (largely the remains or wastes of
scope, that pursues a particular mission or ad- organisms), including animal manure; crop res-
vocates for a particular cause. idues, fresh vegetation, and compost. Compare
observational science See descriptive science. inorganic fertilizer.
nonmarket value A value that is not usually ocean acidification The process by which
included in the price of a good or service. today’s oceans are becoming more acidic (at- organismal ecology The scientific study of an
non-point source A diffuse source of pollut- taining lower pH) as a result of increased car- organism and its relationships to its environ-
ment.
ants, often consisting of many small sources. bon dioxide concentrations in the atmosphere.
Compare point source. Ocean acidification occurs as ocean water ab- Organization of Petroleum Exporting Coun-
sorbs CO from the air and forms carbonic acid. tries (OPEC) Cartel of predominantly Arab
nonrenewable natural resources Natural 2 nations that in 1973 embargoed oil shipments
resources that are in limited supply and are This impairs the ability of corals and other to the United States and other nations sup-
organisms to build exoskeletons of calcium
formed much more slowly than we use them. porting Israel, setting off the nation’s first oil
Compare renewable natural resources. carbonate, imperiling coral reefs and the many shortage.
organisms that depend on them.
North American Free Trade Agreement outdoor air pollution Air pollution that occurs
(NAFTA) A 1994 treaty among Canada, ocean thermal energy conversion (OTEC) A outdoors. Also called ambient air pollution.
potential energy source that involves harness-
Mexico, and the United States that reduced
or eliminated barriers to trade (such as tariffs) ing the solar radiation absorbed by tropical overburden The rock and soil that are removed
ocean water. See closed cycle; open cycle.
among these nations. Side agreements were from a site to mine the minerals underneath.
negotiated to minimize the degree to which oil See petroleum. See strip mining.
protections for workers and the environment oil sands (tar sands) Deposits that can be overgrazing The consumption by too many an-
were undermined. mined from the ground, consisting of moist imals of plant cover, impeding plant regrowth
North Atlantic Deep Water (NADW) The sand and clay containing 1–20% bitumen. Oil and the replacement of biomass. Overgrazing
deep portion of the thermohaline circulation in sands represent crude oil deposits that have can exacerbate damage to soils, natural com-
the northern Atlantic Ocean. been degraded and chemically altered by water munities, and the land’s productivity for further
erosion and bacterial decomposition. Widely grazing.
no-till Agriculture that does not involve tilling envisioned as a replacement for crude oil as overnutrition A condition of excessive food
(plowing, disking, harrowing, or chiseling) the this resource is depleted. intake in which people receive more than their
soil. The most intensive form of conservation daily caloric needs.
tillage. oil shale Sedimentary rock filled with kero-
gen that can be processed to produce liquid overshoot The amount by which humanity’s re-
not-in-my-backyard (NIMBY) Syndrome in petroleum. Oil shale is formed by the same source use, as measured by its ecological foot-
which people do not want something (e.g., a processes that form crude oil but occurs print, has surpassed Earth’s long-term capacity
polluting facility) near where they live, even if when kerogen was not buried deeply enough to support us.
they may want or need the thing to exist some- or subjected to enough heat and pressure to GLOSS ARY
where else. oxbow lake A U-shaped water body that be-
form oil. comes isolated from a river when river water
novel community See no-analog community.
oligotrophic Term describing a water body that erodes a shortcut from one end of an oxbow
nuclear energy The energy that holds together has low nutrient and high oxygen conditions. to the other, so that the river pursues a direct
protons and neutrons within the nucleus of an Compare eutrophic. course. G-15

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