Glossary - Environmental Science - page 319

autotrophs Another term for producers in the environment.
autumnal equinox The date with equal day and night that marks the beginning of fall in the Northern Hemi-
sphere and spring in the Southern Hemisphere, occurring on or about September 23.
background extinction rate The natural rate of extinction, as opposed to the accelerated rate due to human
activity.
bioaccumulation The process of a toxin concentrating in muscle tissues of organisms.
biodiversity The total number of types of species in a given area at a specific time.
biogeochemical cycles The natural movement of nutrients and other products through ecosystems (for ex-
ample, the water or nitrogen cycles).
biological weathering The process of rock material being changed chemically or physically by the activities
of living organisms, most commonly splitting due to tree roots but also including reactions with the acids con-
tained in lichens, plants, and/or animals.
biomagnifications The buildup of toxins within an organism through the consumption of other organisms con-
taining toxins (for example, mercury accumulation in tuna).
biomass The total dry weight of all the living organisms that can be supported at each trophic level in a food
chain or food web; the dry weight of all the organic material in an ecosystem; plant material and animal waste
used as a fuel for energy production.
biome A large ecological area primarily defined by a dominant plant type (for example, a coniferous forest).
biophilia The instinctive connection of humans to nature and other life.
biosphere reserves Protected areas designated with the intention of preserving biodiversity while balancing it
with sustainable land use, education, and scientific research.
biotic potential An organism's potential number of offspring.
Black Death The deadliest pandemic in history, it was an outbreak of bubonic plague, peaking in Europe
between 1348 and 1350. It is estimated to have killed between 30 percent and 60 percent of Europe's popula-
tion. It took approximately 150 years for Europe's population to recover.
boreal Another name for the taiga, a forest biome that consists primarily of coniferous trees (pines), located
south of the Arctic tundra in North America, Europe, and Asia.
bottom-trawling A method of fishing in which a large net is dragged along the ocean bottom to capture
benthic organisms.
Bt-corn Genetically modified corn that contains insecticide, eliminating the need for chemical spraying.
Bt-cotton Genetically modified cotton that contains insecticide, eliminating the need for chemical spraying.
by-catch Fish and other organisms caught unintentionally.
carbon monoxide (CO) A colorless, odorless gas that results when fossil fuels are not fully combusted.
carbonic acid (H 2 CO 3 ) Formed when water reacts with carbon dioxide; used to carbonate soft drinks.