The amount (yield) of water that can be taken from a source of supply each year, over a period of years, without depleting the source beyond its ability for natural replenishment. …
A scale for measuring the strength of hurricanes, which runs from one (minimal damage likely) to five (catastrophic damage potential), based on the maximum sustained wind speed generated by the hurricane. The scale is given in Appendix 4. …
An organized resistance movement which gathered momentum in the 1960s in the western USA, and especially in the state of Nevada, calling for a return of the control of federal lands to individual states. Also known as the Wilderness Lands Sagebrush Rebellion . …
A sand desert which stretches across much of northern Africa, and is the world's largest desert (nine million square kilometres). As recently as 6000 years ago the Sahara was covered with grasses and shrubs, and climate modelling of why it suddenly turned into the driest region on Earth shows that the transition from grass to sand could have occurred in just 300 years. The model starts with a slow…
A narrow zone of land about 500 kilometres wide that runs across much of northern Africa, south of the Sahara and north of the equatorial zone. Annual rainfall is normally between 100 millimetres and 200 millimetres, and most of the rain falls between June and September. The natural vegetation is mainly sparse savanna grassland and shrubland, and traditional forms of agriculture include nomadic he…
Salty, a solution of salts (sulphates and chlorides of sodium and calcium). …
A deposit of salt (sulphates and chlorides of sodium and calcium) in or on a soil, which reduces soil fertility and inhibits the growth of vegetation or crops. …
A soil that contains enough soluble salts (sulphates and chlorides of sodium and calcium) to reduce its fertility. Saline soils are common in hot climates, and usually have fairly uniform profile and contain little humus. …
A measure of the concentration of dissolved salts (sulphates and chlorides of sodium and calcium) in water, normally expressed as parts per thousand (?). Freshwater has a salinity of less than 0.5? (it is described as limnetic), seawater has a salinity greater than 30? (it is euhaline), and brackish water an intermediate salinity. Salinity is not a fixed property of water, because it can be increa…
The change in salinity with depth in a waterbody, such as the ocean. …
A soil‐forming process that involves the accumulation of unusually high concentrations of dissolved salts (sulphates and chlorides of sodium and calcium), often as a result of large‐scale irrigation schemes in semi‐arid areas, where much of the soil water is evaporated off leaving behind the salt residue. Salts can accumulate over time to threshold concentrations at which they become toxic a…
A member of the fish family Salmonides , which includes salmon, trout, and char. …
The common name for the chemical compound sodium chloride (NaCl). …
A process of bedload movement in a river, that involves the hopping or bouncing of small sand‐sized particles along the river bed in the turbulent water flow. …
A site with poor drainage in an arid climate, where the water evaporates, leaving behind salts (sulphates and chlorides of sodium and calcium) in and on the soil. …
An area of low‐lying ground along a coast (usually within a sheltered bay), which is regularly flooded by seawater at average high tide during the growing season, and where salt‐tolerant plants grow. …
The water of the sea and ocean, which has a much higher salinity than freshwater. …
The salinization of groundwater in coastal areas, which occurs mainly where large quantities of fresh groundwater are abstracted for supply purposes (usually by pumping it out) and more is taken out than naturally flows in to replenish it. It is a principal cause of salinization in many coastal areas because saltwater, which is permanently stored in sediments beneath the sea‐bed, can percolate i…
A type of physical weathering of rocks that is most common in arid climates, and involves the growth and expansion of salt crystals within cracks in rocks. Also known as salt wedging . …
To save from ruin, harm, or destruction, including by the reuse of waste materials. …
In forest management, the logging of dead, damaged, or diseased trees in order to improve the overall health of a forest. …
In statistics, the particular set of individuals, alive or not, about which measurements are taken. See also representative sample. Contrast population. …
The process of selecting a representative set of specimens from the full population, so that the subset can be used to make inferences about the population as a whole. …
A major fault line system that runs for 1040 kilometres up the west coast of California, defined by the boundary between the Pacific crustal plate and the North American plate. The Pacific plate is sliding northwest at a speed of a few centimetres a year. Recent global positioning system measurements put the rate of movement along the San Andreas fault between 1990 and 1993 at about 46 millime…
The granting of formal and explicit approval or authorization, or a penalty that is imposed for failure to observe a command or agreed policy. …
Mineral rock fragments (sediment) which have a particle size between 0.06 millimetres and 2.0 millimetres, which is between ?1.0 and 4.0 on the phi (?) scale. …
A ridge (bar) of sand that has been built up by water currents, especially in a river or in coastal waters. …
1 A physical weathering process in which rock is eroded by the impact of sand grains carried by the wind. See also ventifact. 2 A mechanical process that uses sand at high pressure to remove surface material from an object, for example to remove rust from metal objects, or to clean buildings from discoloration. …
A book by Aldo Leopold ( 1948 ), which describes the changing nature, seasons, and his reflections through the year, during which he lived with his family on a run‐down farm in rural Wisconsin. …
A type of hot desert (such as the Sahara), which is often covered by sand dunes and dominated by wind action. …
A ridge (dune) of sand that is formed when sand grains are blown by the wind, and which migrates forward as the individual sand grains are pushed downwind. …
The deliberate extraction of sand from beaches and other deposits for use elsewhere (for example by the construction industry). Contrast beach replenishment. …
A type of prairie that grows on extensive sand deposits, which are usually well‐drained and leached, and have nutrient‐poor soils. …
A clasticsedimentary rock composed of compacted and cemented grains of sand (mostly quartz); it varies in colour, depending on what mineral it contains and what material cements it together. …
Clean and virtually free from germs (micro‐organisms), thus posing little if any danger of infecting something that comes into contact with it. …
A traditional approach to solid waste management, in which material is simply dumped in holes in the ground (landfill) and then covered with soil …
An underground pipe (sewer) that carries off domestic or industrial wastewater but not storm water. …
Waste material (such as refuse) that is generated by normal housekeeping activities and is not hazardous or radioactive. …
Domestic wastewater that comes from kitchen, bathroom, and laundry sinks, baths, and washing machines. Also known in the United States as gray water . …
The control of physical factors in the environment that could harm human health. …
In forest management, the removal of dead, damaged, or susceptible trees, mainly in order to prevent the spread of pests or disease and thus to promote forest health. …
The process of cleaning to levels judged safe by public health standards. …
The name given to a warm, dry adiabatic wind which blows downslope on the lee side of the mountains in the Los Angeles basin (USA). See also chinook, foehn. …
A watery solution of sugars, salts, and minerals (such as nitrates) that circulates through the vessels of a vascular plant, from the roots to the leaves. Also known as xylem sap . …
A type of heterotrophicorganism that feeds on soluble organic compounds from dead plants and animals. Some absorb compounds that are already dissolved, others (including some fungi and many bacteria) break down undissolved foods by secreting digestive enzymes onto them. …
A young tree, usually less than 10 centimetres in diameter. Also known as a pole . …
A soft, fully decomposed rock that is formed in situ in tropical areas by the chemical weathering of igneous or metamorphic rocks. …
An organism (such as a fungus or bacterium) that lacks chlorophyll and derives its food from dead or dying organic matter, allowing nutrients to be recycled within an ecosystem. …
The outer zone of wood in a tree, that lies between the bark and the heartwood. …
See Superfund Amendments and Reauthorization Act. …
1 A natural object that orbits a planet. 2 An artificial object that is placed in orbit around the Earth or another planet in order to collect information or for communication. See also remote sensing. …
The rate at which the temperature of a parcel of saturated air decreases as it is lifted in the atmosphere. The rate depends on temperature and pressure; typical SALR rates are between about 3 and 6?C (the higher the moisture content, the lower the lapse rate). Contrast dry adiabatic lapse rate. See also lapse rate. …
Air that contains as much water vapour as it can possibly hold under existing conditions (of temperature and pressure), so that condensation will occur if any more water vapour is added. …
The movement of water in a soil that is completely filled with water. Contrast unsaturated flow. …
That portion of a soil or an aquifer in which all of the pore space is filled with water. Also known as the phreatic zone . Contrast unsaturated zone, zone of saturation. …
The maximum concentration of water vapour that a parcel of air can hold at a given temperature and pressure. …
The maximum amount of water vapour that is needed to keep moist air in equilibrium with a surface of pure water, which is the maximum amount of water vapour that the air can hold at a given temperature and pressure. See also vapour pressure, relative humidity. …
Extensive open tropical grassland, with scattered trees and shrubs, which covers large areas of Africa, North and South America, and northern Australia. …
A log that is large enough to be cut into sawn timber. …
Trees that are large enough to be cut into timber. …
A shortage or lack of something (such as a particular natural resource), so that supply is insufficient to meet demand. See also absolute scarcity, relative scarcity. …
Loosening topsoil by mechanical action (for example by scratching the surface of it) in order to prepare the ground for regrowth by direct seeding or natural seed fall. …
The sky condition when between one‐tenth and five‐tenths is covered by clouds. …
Showers that cover between a quarter and a half of an area. …
Dispersing or spreading wide, such as the process in which a beam of light is diffused by collisions with particles that are suspended in the atmosphere. …
1 In ecology, to feed on carrion or refuse. 2 In meteorology, a process by which raindrops are formed. …
An organism (including an animal or bird) that feeds on the dead or rotting bodies of other organisms. See also carrion. …
A description of how a situation might develop, based on a particular set of assumptions and factors, which is used to evaluate available options and select ways of dealing with uncertainty. See also worst case scenario. …
The appearance of the natural and human‐made features of a landscape. …
Part of the National Wild and Scenic Rivers System in the USA, which includes rivers or sections of rivers that are readily accessible by road or railway, may have some development along their shorelines, and may have undergone some impoundment or diversion in the past. …
Any place that is designated as containing particularly attractive scenery, and which is specially managed in order to preserve these qualities. …
A North American term for the view seen from a road. See also vista. …
A medium‐grained metamorphic rock in which the minerals are compressed into a plate‐like arrangement, formed by the applying great heat and pressure to banded gneiss. …
Blood fluke; a flatworm parasite in the blood vessels of mammals. …
Plants with hard, woody, short, and often spiky evergreen leaves. …
A forest biome that is found in mediterranean climates and is dominated by scattered woody scrub and widely spaced trees, most of which are less than six metres high. …
The systematic study of the natural world and its physical and biological processes, through observation, identification, description, experimental investigation, and theoretical explanations. …
A book by Barry Commoner ( 1963 ), in which he writes that ?the separation of the laws of nature among the different sciences is a human conceit; nature itself is an integrated whole?, and ?technology has not only built the magnificent material base of modern society, but also confronts us with threats to survival which cannot be corrected unless we solve very grave economic, social, and politi…
A global, interdisciplinary group of scientists and scientific institutions that assembles, reviews, and assesses the information available on induced environmental changes and the effects of these changes on people. …
The approach that science uses to gain knowledge, based on making observations, formulating laws and theories, and testing theories or hypotheses by experimentation. …
A method of writing numbers in terms of powers of ten. For example the number 0.000118 would be represented as 1.18 ? 10-4 or 1.18E?04 where E stands for exponent, as in the exponent that ten is raised by. …
An IUCN Management Category (I) for protected areas that are designed ?to protect nature and maintain natural processes in an undisturbed state in order to have ecologically representative examples of the natural environment available for scientific study, environmental monitoring, education, and for the maintenance of genetic resources in a dynamic and evolutionary state?. …
A term describing a shade‐loving plant which thrives in habitats of low light intensity. Contrast photophilous, photophobia. …
A general term for any single plate of the exoskeleton of an organism. …
See Scientific Committee on Problems of the Environment. …
A process for identifying which potential environmental impacts, alternatives, and other issues will be addressed in an environmental impact statement. …
The effect of abrasion, usually by sand or gravel, on the bed of a river or the sea. …
A root climber plant that raises itself above other vegetation with the aid of thorns or hooks. Contrast twiner. …
1 A small fragment of something. 2 Waste material that is discarded from manufacturing operations but may be suitable for reprocessing. …
Discarded metal that is suitable for reprocessing. …
A slope that is covered with loose rock fragments that have broken off a cliff or steep slope above as a result of frost action and rockfall. Also known as talus or talus cone . …
1 The sifting of sewage through a screen in order to remove coarse solids that are floating and suspended in it. 2 Testing a large number of individuals from a population in order to identify which ones have a particular genetic trait, characteristic, or biological condition. …
Dense vegetation consisting of stunted trees or bushes which colonize open ground, particularly grassland. See also maquis. …
An air pollution control device that uses a spray of water to trap pollutants and cool emissions. …
The process of purifying a gas by washing it with a liquid in a tower. See flue gas scrubbing, limestone scrubbing. …
A North American shrubland vegetation dominated by mountain mahogany, serviceberry, and/or Gambel oak, accompanied by numerous grass and forb species, which is found in temperate areas such as the Central Rockies. …
The true jellyfish; a member of the phylum Cnidaria. …
Part of an ocean or a large body of saltwater that is at least partially enclosed by land. …
A coastal breeze that blows from sea to land. Also known as onshore breeze . Contrast land breeze. …
An artificial structure that is built along a coastline in order to protect cliffs or property from erosion by waves and tides. …
Ice that is formed by the freezing of seawater and can extend out from the land as pack ice, for example around the Antarctic. …
The level of the surface of the ocean, based on the average level between high and low tides, which is used as a datum when calculating the height of features on land or depth in the ocean. It is used as a standard base for measuring heights and depths on the Earth, and it is the baseline for plotting the global hypsometric curve, and for calculating the heights of mountains and the depth of ocean…
A long‐term change in the relative level of land and sea, which can be caused by isostatic adjustment of the land (as a result of tectonic forces), and/or by eustatic change (change in the volume of water that is stored in the oceans). Geological evidence suggests that during the height of the last glaciation (about 18?000 years ago) sea level was between 110 metres and 140 metres lower than it …
A flat‐topped submarine mountain. Also known as a guyot . …
In disaster management, the process of locating and recovering victims and applying first aid and basic medical assistance. …
A coastal or maritime landscape. See also Protected Landscape or Seascape. …
A natural division of the year, defined by the equinoxes and solstices (the four seasons: winter, spring, summer and autumn/fall) or by atmospheric conditions (for example, the monsoon season). …
Occurring during or dependent upon a particular season. …
A plant that flowers and completes its life cycle within a single wet?dry season in equatorial regions. …
A type of polyphenism in which different forms of a species are produced at different times of the year. It is a common form of phenotypic plasticity among insects. …
The spray that blows from the tops of ocean waves. Also known as salt spray . …
Any of the large plants that grow in the sea, particularly marine algae such as kelp. …
Extracting natural resources (such as nodules of manganese) from the sea‐bed. …
The process by which crustal plates beneath the oceans are pushed apart as new magma is pushed upwards from within the Earth's crust to the surface of the ocean floor, in the central trough of the mid‐ocean ridge, where it cools. The new rock mirrors and preserves the magnetic polarity of the Earth at the time of formation. See also constructive plate boundary, plate tectonics. …
A disc that is lowered into a waterbody in order to determine the clarity or transparency (opacity) of the water, based on the depth at which its black and white markings can no longer be seen from the surface. …
air quality standards that are designed to protect human welfare, including the effects on vegetation and fauna, visibility, and structures. Contrast primary ambient air quality standards. …
A carnivore, which sits above (at a higher trophic level than) the primary consumers in a food chain because it eats them. Examples include: on land, lions that eat wildebeest, hawks that eat field mice; in the soil, soil organisms that decompose herbivore remains; in the oceans, herring that eat copepods. …
Manufacturing activities. Contrast primary economic activities, tertiary economic activities. …
A forest that grows on land after the original mature old growth forest has been harvested, or died because of fire or insect attack. Also known as second growth . Contrast primary forest. …
The exchange (under the Kyoto Protocol) of greenhouse gasemission reductions, offsets, or allowances between buyer and seller where the seller is not the originator of the supply. Contrast primary market. …
A material that is recovered from post‐consumer wastes and is reused in the manufacture of a product. Also known as post‐consumer material . …
Minerals (such as clays and oxides) that are formed from the material released by weathering. Contrast primary mineral. …
The elements sodium, calcium, and magnesium that must be taken up and used in sufficient quantities for plants to complete their life cycles. Contrast primary nutrient. See also essential element. …
A pollutant that is created when primary pollutants combine with each other and with other substances, as happens for example when sulphur dioxide reacts with oxygen and moisture to form sulphuric acid and give rise to acid rain. Contrast primary pollutant. …
The amount of new biomass (weight) that is produced by plant‐eating animals (herbivores) in a given period of time. Also known as secondary production . Contrast primary productivity, tertiary productivity. …
A grazing area (range) that is lightly used or unused by livestock when there is limited or no range management. It will not normally be fully used until the primary range has been overused. …
Extracting more oil or gas from a reservoir than can normally be recovered by normal flowing and pumping operations, for example by pumping pressurized gas, steam, or containing chemicals water into a well. …
The pollution limit for criteria air pollutants that is based on environmental effects (such as damage to property, plants, or visibility). Contrast primary standard. …
The re‐establishment of vegetation on land that has had a vegetation cover at some time in the past but which might have been destroyed by natural processes (including lightning fires, severe storms and volcanic eruptions) or by human interference (including forest clearance, building construction, and fires). Contrast primary succession. See also succession. …
The second treatment that is provided at a wastewater treatment plant, in which bacteria consume suspended organic matter in the waste that remains from the primary treatment of sewage. This process removes only limited amounts of nitrogen and phosphorus, which must be removed by advanced wastewater treatment. Also known as secondary wastewater treatment . See also primary waste treatment. …
Use that is incidental to the main purpose of an area or building. …
Woodland on a site that has not been continuously wooded since 1600 ad . Contrast ancient woodland. …
Centrally planned economies, such as those of Eastern Europe between 1948 and 1990 . Contrast First World, Third World. …
A forest that has grown back after being logged, as a result of secondary succession. …
A segment or part of the economy of a country in which particular activities take place. See also commercial sector, industrial sector, residential sector, transportation sector. …
1 Long term change that takes place slowly, as opposed to seasonal or cyclical changes. 2 Not sacred or religious, relating to the worldly. …
A solid waste disposal site (landfill) that is lined and capped with an impermeable barrier in order to prevent leakage or leaching. …
Living in one main place all year round; having a sedentary lifestyle. Contrast nomadism. …
A plant of the family Cyperacae, which resemble grasses but have solid stems, and often grow in wetlands. …
Grains of solid (usually mineral) material that have been deposited by some natural process. …
A type of rock that is formed by deposition, either of cemented fragments of rocks that have been eroded from the land (clastic sedimentary rocks), organic materials (organic sedimentary rocks), or chemicals that are deposited from water (chemical precipitates). Also known as secondary rock . See also rock cycle, diagenesis. …
The deposition of sediment from a state of suspension in water or air. Also known as siltation . …
A wastewater tank in which floating wastes are skimmed off and settled solids are removed for disposal elsewhere. …
The proportion of the soil that is eroded from upland sources that actually reaches a stream channel or storage reservoir. …
The amount of sediment that is transported through a stream cross section over one year, which includes chemicals carried in solution (the dissolved or solution load), small particles carried in suspension (the suspended load), and larger particles that are rolled along the river bed (the bedload). Also known as sediment discharge or sediment yield . …
The study of the nature and character of sediments, and of how they form. …
A natural or artificial pond that is used for the recovery (by settling) of solids from effluent or runoff. …
The fertilized part of a plant that contains food products for germination. …
A special type of gene bank that is designed for the ex situ conservation of individual plant varieties through the preservation and storage of seeds. …
The soil in which seeds are deposited and germinate. …
Putting seeds in or on soil to allow it to germinate and grow. See also broadcast seeding, drill seeding. …
The young plant that grows from a seed that has germinated. …
The amount of viableseed that is produced by an individual plant. …
In forest management, a tree that is left standing in order to provide seed for the natural regeneration of the area that has been harvested. …
A small spring, pool, or other place where water trickles naturally from the ground. …
The slow movement or percolation of water through soil or rock. …
A lake that has either an inlet or an outlet but not both and which receives water mainly from precipitation and groundwater rather than from inflow along tributary streams. …
A wave on the surface of a lake or landlocked bay that is caused by local atmospheric changes, tidal currents, or earthquakes. …
A type of sand dune that is common in hot deserts, in which long ridges of wind‐blown sand are aligned parallel to the dominant wind direction. …
A traditional form of ocean fishing involving the use of curtain nets that are drawn out and pulled along, in order to enclose a shoal of fish. Also known as a ring net . …
Relating to earthquakes, particularly the energy waves that are generated by earthquake activity. …
The geographical and historical distribution of earthquakes, or the number of earthquakes in a particular period of time. …
A technique for determining the detailed structure of the rocks beneath a particular area, which is based on sending acoustic shock waves into the rocks and measuring the signals that are reflected back. …
A shock wave that is generated by an earthquake and measured using a seismograph. The waves travel at different speeds, depending on the density of the material they pass through. There are two main types of seismic wave, the S‐wave (secondary wave) and the P‐wave (primary wave). …
An instrument for measuring and recording Earth tremors and earthquakes, based on recording the passage of seismic waves through the ground. …
Choice between available options. See also artificial selection, natural selection. …
A measure of the effectiveness of natural selection in altering the genetic composition of a population. …
A chemical pesticide that is designed to affect only particular types of pests, leaving other plants and animals unharmed. …
In forest management, the periodic removal (thinning) of individual trees or groups of trees in order to improve or regenerate a stand. Also known as selective cutting . See also line thinning, mechanical thinning. …
A relatively rare non‐metallic element that occurs naturally in rock and soils in certain regions. It is released from copper and lead refineries and municipal wastewater. It is essential to humans and animals in low concentrations and is toxic at very high concentrations. See also acid mine drainage. …
Able to look after yourself, and provide for all of your needs yourself without help from others. …
In greenhouse gas emissions trading, under the Kyoto Protocol, a legally recognized entity (such as an individual, corporation, not‐for‐profit organization, or government) that sells reductions, credits, or allowances to another legally recognized entity through a sale, lease, trade, or other means of transfer. …
A naturally occurring message‐bearing biochemical that organisms use to communicate with each other, and to interrogate their environment. See also allomone, kairomone, pheromone. …
A moderately dry climate, with amounts of rainfall between 250 and 500 millimetres a year, which is usually enough to support the growth of short, sparse grass. See also steppe. …
An aquifer that is partially overlain by a rock formation which has low permeability, through which water can pass only slowly to recharge the aquifer. Contrast confined aquifer. …
Grassland that has been modified by the application of fertilizers and/or herbicides, and by intensive grazing or drainage. Contrast improved grassland. …
A habitat which has been affected directly or indirectly by human activity. Contrast natural habitat. …
A material that will allow some but not all substances to pass through it. Contrast impermeable, non‐permeable, permeable. …
A category of land defined within the recreation opportunity spectrum as ?a predominantly natural or natural appearing environment of moderate to large size?, with a low concentration of users, motorized recreation use permitted only on unmade local primitive roads, and the area managed to have subtle minimum on‐site controls and restrictions. …
A category of land defined within the recreation opportunity spectrum as ?a predominantly natural or natural‐appearing environment of moderate to large size?, with low interaction between users, motorized recreation use not permitted, local roads possibly used on a limited basis for other resource management activities, and the area managed to have minimal but subtle on‐site controls and restr…
A group of organic compounds that are composed primarily of carbon and hydrogen, and have a tendency to evaporate (volatilize) into the air from water or soil. …
The loss of function that accompanies aging, for example in a plant or animal or in a waterbody that is subject to eutrophication. …
Heat that causes a change in temperature (for example of air in the atmosphere) by changing the speed at which the molecules move. …
The transfer of heat that is associated with thermal heating of parcels of air. …
The sensation of temperature that a human body feels, rather than the actual temperature of the environment as measured with a thermometer. …
Plant or animal species which are susceptible to changes in habitat or to impacts from human activities. …
The degree of change in a system that is associated with a given degree of stress or perturbation. See also climate sensitivity, susceptibility. …
A domestic wastewater treatment system (consisting of a septic tank and a soil absorption system) into which wastes are piped directly from the home. Bacteriadecompose the waste, sludge settles to the bottom of the tank, and the treated effluent flows out into the ground through drainage pipes. …
An underground tank for storing wastewater from a home. See also septic system. …
A pattern of multiple cropping in which one crop follows another on the same land, either with or without a break, in successive seasons. …
The removal (sequestering) of greenhouse gases (particularly carbon dioxide) from the atmosphere by biomass (such as trees, soils, and plants), via photosynthesis, in order to help reduce the greenhouse effect and control global warming. See also carbon sequestration, forest sequestration. …
Either of two species of huge coniferous trees, that reach heights of up to 100 metres. See also redwood. …
Jagged pinnacles of ice on the surface of a glacier or ice sheet. …
Of or relating to the series of stages (seres) in ecological or plant succession. …
A recognizable step or stage in the development of an ecological community through succession. …
A transitional stage in the development of a plant community as it changes, through succession, from bare ground to climax. The full sequence of seral communities is a prisere. …
The culture of silkworms ( Bombyx mori ) for the production of silk. …
1 An organism that is sedentary, fixed, or attached and unable to move at will. Contrast motile. 2 A leaf that has no stalk, and is attached to the plant directly at the stem. …
Particulate matter that is suspended in seawater. …
Suspended material that is heavy enough to sink to the bottom of a wastewater treatment tank. …
1 An area where one or more groups of families live together, either in the countryside (See also rural settlement) or in towns and cities (See also urban settlement). 2 The act of establishing a colony. 3 A legal agreement that is reached between two or more individuals or parties. …
A gradual sinking to a lower level by gravity, such as the deposition of suspended solids on the bed of a waterbody. …
A storage tank for the treatment of drinking water and wastewater, in which heavy particles sink by gravity to the bottom from where they can be removed and disposed of. See also septic tank. …
Agricultural land that is removed from food production as part of the Common Agricultural Policy, which allows farmers to claim special payments and creates an opportunity to adopt land management practices that benefit wildlife. …
A major storm that is associated with a depression. Such storms are given different names in different parts of the world, including hurricane (throughout most of the western hemisphere), typhoon (through most of Asia and across the Pacific), cyclone (in the Indian Ocean and Australia), and willy‐willy (in some South Pacific islands). …
A thunderstorm that produces heavy precipitation, frequent lightning, strong, gusty surface winds, or hail, and can cause flash floods and damage structures. …
The site in northern Italy of a major air pollution incident on 10 July 1976 , when a cloud of chemicals containing dioxin was released from a chemical factory, to which an estimated 37?000 people were exposed between Milan and Lake Como, raising concern about the prospects of long‐term health problems. …
A directive of the European Union on the control of major accident hazards involving dangerous substances, that is designed to help prevent such hazards in the wake of the Seveso accident by making information more widely available about the distribution of hazardous substances, and by the adoption of major accident prevention policies and strategies. …
A site where hazardous substances are located, as defined under the Seveso II Directive. Such sites are referred to as either upper tier or lower tier, depending on the level of risk. …