Environmental Science Vocab 4

Catalytic Converter

An air pollution abatement device that removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon dioxide and water or reducing them to nitrogen.

CERCLA (The Superfund Act)

An act that gave EPA the authority to clean up abandoned, leaky hazardous waste sites.

Chain Reaction

A self-sustaining series of reactions, in particular those of nuclear fission in which the particles released by one nucleus trigger the fission of at least as many further nuclei.

Channelization

An engineering technique that consists of straightening, deepening, widening, clearing, or lining existing stream channels. The purpose is to control floods, improve drainage, control erosion, or improve navigation. It is a very controversial practice that may have significant environmental impacts.

Chernobyl, Ukraine

In April 1986 there was an explosive leak, caused by overheating, from a nonpressurized boiling-water reactor, one of the largest in Europe. The resulting clouds of radioactive material spread as far as the UK. Thirty-one people were killed in the explosion, and thousands of square kilometers of land were contaminated by fallout. By June 1992, seven times as many children in the Ukraine and Belarus were contracting thyroid cancer as before the accident, and the incidence of leukemia was rising; it was estimated that more than 6,000 people had died as a result of the accident, and that the death toll in the Ukraine alone would eventually reach 40,000.

Chlorofluorocarbons (CFCs)

Highly stable compounds that have been or are being used in spray cans as aerosol propellants and in refrigeration units (the gas that is compressed and expanded in a cooling unit). Emissions of chlorofluorocarbons have been associated with potential global warming and stratospheric ozone depletion.

Cholera

An acute intestinal infection caused by ingestion of contaminated water or food.

Chronic Effects (Exposure)

Long-lasting results of exposure to a toxin; can be a permanent change caused by a single, acute exposure or a continuous, low-level exposure.

Clear-cutting

In timber harvesting, the practice of cutting all trees in a stand at the same time.

Climate

The representative or characteristic conditions of the atmosphere at particular places on Earth. Climate refers to the average or expected conditions over long periods; weather refers to the particular conditions at one time in one place.

Climax State

The final stage of ecological succession and therefore an ecological community that continues to reproduce itself over time, or a stage in ecological succession during which an ecological community achieves the greatest biomass or diversity. (The first definition is the classical definition.)

Closed Systems

A type of system in which there are definite boundaries to factors such as mass and energy such that exchange of these factors with other systems does not occur.

Colorado River

The Colorado River is a river in the southwestern United States and northwestern Mexico, approximately 1,450 mi (2,333 km) long, draining a part of the arid regions on the western slope of the Rocky Mountains. The natural course of the river flows into the Gulf of California, but the heavy use of the river as a fresh water source has desiccated the lower course of the river in Mexico such that it no longer reaches the sea.

Commensalism

A relationship between two kinds of organisms in which one benefits from the relationship and the other is neither helped nor hurt.

Commercial Forestry

In order to retain biodiversity in commercial forest, they must be managed in ways that simulate disturbances that take place in old-growth forests, such as forest fires and storms. Over time, some of the structural characteristics of old-growth forests, such as old trees, deadwood and deciduous trees, can also be added.

Commons

Land that belongs to the public, not to individuals. Historically a part of old English and New England towns where all the farmers could graze their cattle.

Competition

The situation that exists when different individuals, populations, or species compete for the same resource(s) and the presence of one has a detrimental effect on the other. Sheep and cows eating grass in the same field are competitors.

Competitive Exclusion Principle

The idea that two populations of different species with exactly the same requirements cannot persist indefinitely in the same habitat – one will always win out and the other will become extinct. Which one wins depends on the exact environmental conditions. Referred to as a principle, the idea has some basis in observation and experimentation.

Composting

Biochemical process in which organic materials, such as lawn clippings and kitchen scraps, are decomposed to a rich, soil-like material.

Confined Aquifer

An aquifer that is bound above and below by dense layers of rock and contains water under pressure.