ENVIRONMENTAL SYSTEMS: GLOSSARY OF TERMS
Prepared by Environmental Systems students
Acid Deposition
Wet Deposition: when acid containing droplets dissolve in rain and snow, and fall out of the atmosphere.
Dry Deposition: when nitrate and ammonium salts fall out of the atmosphere.
Anticyclone: Any large wind system occurring in regions outside of the equatorial belt, about a center of high atmospheric pressure and its flow is the reverse of that of a cyclone.
Biodiversity: The number and variety of organisms found within a specified geographic region. The variability among living organisms on the earth, including the variability within and between species and within and between ecosystems.
Climax community: Last stage of succession- relatively stable, long lasting, complex and interrelated community plants, animals, fungi and bacteria.
Stable, long-lasting, complex and interrelated community of plants, animals, and fungi.
Community: A group of plants and/or animals living and interacting with one another in a specific region under relatively similar environmental conditions. The region occupied by a group of interacting organisms.
Cyclone: Large system of winds that rotates about a center of low atmospheric pressure in a counter-clockwise direction, north of the equator, and a clockwise direction to the south.
Demographic transition: Evolution towards industrialization. As countries become industrialized, birth and death rates decline.
Ecosystem: An ecological community together with its physical and chemical environment, functioning as a unit.
Within the biosphere, the total expanse of water, land, and atmosphere are able to sustain life, the basic ecological unit is the ecosystem.
Ekman Spiral: The orbital motion of water induced by surface waves penetrates a few meters beneath the sea surface. The direct effect of the wind, however, penetrates to a depth of scores of metres. This is because of a larger scale physical force balance than the microscale pressure anomalies causing wave motion. The resulting flow varies with depth in the Ekman Spiral. Small –scale circulation cells driven by this spiral are know as Langmuir circulation cells.
The description of a consequence of the Coriolis force effect on ocean currents, whereby currents flow at an angle to the winds that drive them. In the northern hemisphere, surface currents are deflected to the right of the wind direction. The surface current then drives the subsurface layer at an angle to its original deflection. Consequent subsurface layers are similarly affected, so that the effect decreases with increasing depth. The result is that most water is transported at about right-angles to the wind direction. Directions are reversed in the southern hemisphere.
Greenhouse Gases: Gases that warm the earth and cause Global Warming. They include ozone, CO2, CFCs, methane and chlorine. Greenhouse gases are gas compounds found inside the earth, they come from burning of fossil fuels, methane, man-made gases, and deforestation.
Hadley cells: Model of the earth’s atmospheric circulation which consists of a single wind system in each hemisphere, with westward and equator-ward flow near the surface and eastward and pole-ward flow at higher altitudes.
Halogenated Gases: Include aerosols, and contain chlorine, bromine (halons), and organic gases.
Halons: Group of greenhouse gases that only have bromine.
K- selected: Large organisms that have long life cycles, that produce large number of offspring and do take care of their young> Population size is controlled by the carrying capacity limit. A survival strategy. Example: humans
Rossby waves: Atmospheric currents that travel from east to west, which influence the climatic properties of the earth. They also contribute to phenomena such as anticyclones and El Niño. They do not go fast; the speed varies with latitude and increases equator-ward. They are also referred to as planetary waves.
Speciation: The evolutionary formation of new biological species, usually by the division of a single species into two or more genetically distinct ones.
Species: A fundamental category of taxonomic classification, below a genus or subgenus. Consists of related organisms capable of interbreeding. An organism belonging to such a category, represented in binomial nomenclature by an uncapitalized Latin adjective or noun following a capitalized genus name, as in Ananas comosus, the pineapple, and Equus caballus, the horse.
Succession: Regular predictable changes in the structure of a community. Occur because organisms cause changes in their surroundings that make their environment less suitable for themselves and more suitable for other kinds of organisms.
Two types of succession:
Primary - begins with bare mineral surfaces or water. In terrestrial primary succession the organisms are exposed to the damaging effects of wind, lack of minerals and nutrients, few places are available for organisms to attach themselves.
Secondary – takes place after a severe disturbance such as volcanic eruptions and any other land disturbing events.
Pioneer organisms: surviving organisms after primary succession. They break down waste for new organisms to arrive.
Population: The total number of inhabitants constituting a particular race, class, or group in a specified area. All the organisms that constitute a specific group or occur in a specified habitat.
r- selected: Small organisms have short life cycles, that produce in large number of offspring and do not take care of their young do not reach a carrying capacity (survival strategy). Example: rats
Sources:
Encarta.com
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