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Antarctic Convergence: area in the southern ocean where warmer northern waters meet cold Antarctic waters.

Aurora australis: moving streams or curtains of light, caused by the interaction of charged particles from the sun with the outer fringes of the earth's atmosphere occurring in the southern ("austral") hemisphere (comparable to the Aurora Borealis in the northern hemisphere.)

Austral summer: period from August through February in Antarctica when the sun shines for 24 hours every day.

Baleen: long, narrow horny plates that hang from the inner upper jaws of some whales and act as filters or sieves to collect food.

Biotic: factors of the environment due to living things eg. predation, food supply, competition.

Brash Ice: accumulations of floating ice made up of fragments not more than 2m across.

Calving: word used to describe the breaking off of ice from ice shelves to form icebergs.

Centigrade (C): temperature scale in which the melting point of water is 0 degrees and the boiling point is 100 degrees. 100 degrees C is equal to 212 degrees Fahrenheit. To convert Fahrenheit to Centigrade: C degrees x9/5+32.

Cetacean: scientific name given to the sea mammal group that includes whales, dolphins and porpoises.

Chlorofluorocarbon (CFC): compound consisting of chlorine, fluorine, and carbon, very stable in the troposphere. Commonly used in refrigerants, solvents, and foam blowing agents.

Crevasse: cracks in ice formed when the ice moves over uneven rocks or when floating ice spreads.

Diatom: single-cell plant with siliceous shell, common in surface waters of polar regions in summer, important as the main photosynthesizers or "fixers" of solar energy.

Distribution: arrangement and interdependence of a group, such as krill.

Ecosystem: biological community of plants and animals and the physical environment around the community.

Fahrenheit: temperature scale in which the melting point of water is 32 degrees and the boiling point is 212 degrees. 32 degrees F is equal to 0 degrees Centigrade. To convert Fahrenheit degrees into Centigrade: F degrees-32x5/9.

Forbs: A non-grasslike herb.

Glacier: any natural accumulation of ice that moves. Glaciers are often described as rivers of ice.

Gondwanaland: former super-continent situated in the southern hemisphere, which contained the areas we now call Antarctica, South America, Africa, Australia, India and New Zealand. About 160 million years ago Gondwanaland began to break up and individual land masses moved to their current positions.

Grasses: family of plants with mostly rounded and hollow jointed stems, sheathing leaves, flowers borne on spikelets. The fruit is a seedlike grain.

Grazers: organisms which feed on growing plants (at the bottom of the food chain).

Greenhouse effect: the heating of the earth's atmosphere caused by the increased levels of carbon dioxide, water vapor and other gases, which prevents the escape of reflected solar energy.

Hypothermia: reduction in temperature of the body core to below 35° C. Occurs as a result of exposure to extreme cold.

Ice Edge: demarcation between the open sea and sea ice of any kind whether fast (fixed to the shore) or drifting.

Ice Floe: large piece of floating ice.

Ice Shelf: floating ice of considerable thickness showing 2-50 meters or more above sea level, attached to the coast.

Infrared imagery: pictures obtained by detecting the amount of infrared light (heat) an object emits.

International Geophysical Year (IGY): the International Council for Scientific Unions agreed to coordinate a research program with special emphasis on meteorology, oceanography and geomagnetism in Antarctica during 1957-58. IGY was so successful in Antarctica that the Scientific Committee on Antarctic Research (SCAR) was set up to continue its work.

Knot: a unit of speed equal to 1 nautical mile per hour. (multiply by 1.85 to convert to km/h).

Krill: small shrimp-like creatures that exist in huge numbers in the southern ocean and provide a vital link in Antarctic food chains between producers (plants) and herbivores.

Lead: any fracture or passageway through sea ice which is navigable by surface vessels.

Lichen: organisms made up of algae living in the threads of a fungus. The algal cells benefit from the protection and water-retaining properties of the fungus; the fungus benefits from being able to share the food made by the photosynthesizing algal cells.

Melt Pool: small frozen body of fresh water in a glacier or snow surface.

Nanometer: distance of one billionth of a meter.

Nunataks: places where mountain peaks appear through the ice.

Ozone: chemically active gas that is made up of three atoms of oxygen. Nearly 90% of the Earth's ozone is in the stratosphere and is referred to as the ozone layer.

Ozone layer: approximately 15-40 kilometers (10-25 miles) above the Earth's surface, in the stratosphere. Depletion of this layer will lead to higher UV-B levels, which can cause increased skin cancers, cataracts and potential damage to some marine organisms, plants, and plastics.

Pack Ice: broken pieces of floating ice which forms when storms or warmer weather melt the sea ice.

Pelagic fish: fish that live in the upper levels of the water column nearer the water surface.

Phytoplankton: microscope plant life (unicellular algae) that lives in the sea. Phytoplankton provide the majority of plant life upon which the Antarctic food chain depends.

Polynyas: areas of open water in pack ice.

Rookery: a colony of penguins (or seals).

Salinity: amount of salt in water.

Sea Ice: ice formed from sea water frozen during the onset of winter, reaching its maximum in September, covering 20 million square kilometers, and a minimum in February of about 4 million square kilometers. In midwinter the ice can reach thicknesses of 3-4 meters.

Skidoo: tracked personnel carrier for one or two people used on snow or ice, and towing sleds.

Skua: hawk-like gulls that prey on rookeries and unprotected penguin chicks.

Stratosphere: layer of atmospheric air above the troposphere, extending from about 10km to 50km in altitude.

Troposphere: lowest part of the atmosphere, extending from the surface up to about 10 km in altitude, although this height varies with latitude. Almost all weather takes place in the troposphere.

UV (Ultraviolet radiation): portion of the electromagnetic spectrum below visible light. The sun produces UV, which is commonly split into three bands: UV-A, UV-B, and UV-C. UV-A is not absorbed by ozone and is not as harmful as UV-B. UV-B is mostly absorbed by ozone, although some reaches the Earth. UV-B causes damage to plants and animals. Damage depends upon the amount of atmospheric ozone that acts as a filter, the angle of sun in the sky, and cloud cover, which shields the surface from some UV radiation.UV-C is completely absorbed by ozone.

Vascular of or relating to a channel for the transporting of a fluid, such as the sap of a plant or the blood of an animal, throughout the body

Zooplankton: small animals which drift in the surface waters of the ocean.

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