oxygen-poor layer
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Ozone layer — The ozone layer is a layer in Earth s atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 97–99% of the Sun s high frequency ultraviolet light, which is potentially damaging to the life forms on Earth.[1] It … Wikipedia
climate — /kluy mit/, n. 1. the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years. 2. a region or… … Universalium
History of the Earth — For the history of modern humans, see History of the world. Geological time put in a diagram called a geological clock, showing the relative lengths of the eons of the Earth s history The history of the Earth describes the most important events… … Wikipedia
History of Earth — The history of Earth covers approximately 4.6 billion years (4,567,000,000 years), from Earth’s formation out of the solar nebula to the present. This article presents a broad overview, summarizing the leading, most current scientific… … Wikipedia
earth — /errth/, n. 1. (often cap.) the planet third in order from the sun, having an equatorial diameter of 7926 mi. (12,755 km) and a polar diameter of 7900 mi. (12,714 km), a mean distance from the sun of 92.9 million mi. (149.6 million km), and a… … Universalium
marine ecosystem — Introduction complex of living organisms in the ocean environment. Marine waters cover two thirds of the surface of the Earth. In some places the ocean is deeper than Mount Everest is high; for example, the Mariana Trench and the… … Universalium
Meromictic lake — Lac Pavin in France is a meromictic crater lake … Wikipedia
Meromictic — A meromictic lake has layers of water which do not intermix. [Wetzel, Robert G. (2001). Limnology: Lake and River Ecosystems (Third Edition) (Academic Press, New York). ISBN 978 0127447605. ] In ordinary, holomictic lakes, at least once each year … Wikipedia
South America — South American. a continent in the S part of the Western Hemisphere. 271,000,000; ab. 6,900,000 sq. mi. (17,871,000 sq. km). * * * Continent, Western Hemisphere. The world s fourth largest continent, it is bounded by the Caribbean Sea to the… … Universalium
Geography and ecology of the Everglades — The geography and ecology of the Everglades involve the complex elements affecting the natural environment throughout the southern region of the U.S. state of Florida. Before drainage, the Everglades were an interwoven mesh of marshes and… … Wikipedia
