Extremophiles are living organisms that can thrive in environmental conditions that are inhospitable to most lifeforms. These species may be animals, plants or bacteria; the unusual conditions in which they may persist can involve extreme salinity, acidity, temperature, radiation or pressure. Such occurrences may take place in such unusual climate regimes as Antarctica, or in such unusual geographic features as hypersaline lakes.
They may also be found at extreme ocean depths where high pressures and unusual chemical environments, such as near hydrothermal ocean vents, are encountered. The image to the right shows tubeworms found near such hydrothermal vents.
An extremophile is an organism adapted to unusual limits of one or more abiotic factors in the environment. Some of the extreme conditions are temperature, pH, high salinity,...
East African montane moorlandsLast Updated on 2015-07-02 10:29:19
The East African montane moorlands is a relatively small alpine ecoregion in eastern Africa. The habitat is virtually treeless since it occupies a zone above the treeline. This ecoregion, classified as an element of the montane grasslands and scrublands biome, has a land area measuring only about 1300 square miles. The ecoregion, lying at the upper zones of ancient volcanoes, exhibits low species richness of higher level faunal organisms, but manifests moderate plant and animal endemism, including support of certain extremophiles. There is particularly high endemism among amphibians and small mammals of the ecoregion. Many of the plant species that occur in the ecoregion have adapted interesting morphological features to allow survival in the extreme cold here.
The upper elevations of the ecoregion have persistent glacial cover. Although some of the ecoregion (e.g. Mount Kilamanjaro)... More »
Etosha Pan halophyticsLast Updated on 2014-12-26 13:11:38
WWF Terrestrial Ecoregions Collection
The Etosha Pan Halophytics ecoregion is the relict landform of a prehistoric expansive, inland Pliocene lake. Today, the Etosha Pan is mostly an arid, saline desert. Typically, the intensively cracked, whitish clay is split into hexagonal salt-encrusted fragments, and wildlife is sustained only by scattered freshwater springs, which manifest as watering holes. These springs attract a diverse array of large mammals, especially during the dry season, making Etosha Pan a popular tourist destination. In unusually wet years, when the Ekuma, Oshigambo and Omuramba Ovambo Rivers receive sufficient rainfall, the pan is temporarily transformed into a shallow lake.
When surface water is present, it can be classified as a hypersaline lake, due to the elevated salinity. The Etosha Pan halophytics is considered within the... More »
Marine biodiversityLast Updated on 2014-12-15 19:53:24Biodiversity is now commonly defined as the variety of life in genes, species and habitats. According to the definition of the Convention on Biological Diversity, biodiversity is the variability among living organisms from all sources, including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.
The three domains of life, bacteria, archaea and eukarya are present in the marine environment. In addition there are viruses. About 230,000 species of marine plants and animals have been scientifically described and a few thousand bacteria and archaea. This known biodiversity only represents a small fraction of the number of species existing, except for the macrophytes and seagrasses which are living in coastal environments and, in general, for the pelagic... More »
BacteriaLast Updated on 2014-10-12 18:54:28
Bacteria are any of a very large group of single-celled microorganisms that display a wide range of metabolic types, geometric shapes and environmental habitats—and niches—of occurrence. Normally only several micrometers in length, bacteria assume the form of spheres, rods, spirals and other shapes. Bacteria are found in a very broad gamut of habitats; for example, bacterial extremophiles that thrive in such places as hot springs, arctic environments, radioactive waste, deep sea oil seeps, deep Earth crustal environments, hypersaline ponds and within other living organisms. There are approximately 50 million bacterial organisms in a single gram of typical surface soil. The worldwide bacterial biomass exceeds that of all plants and animals on Earth. However, the majority of bacteria have not yet been characterised,
Bacteria are members of the prokaryote... More »
Marine virusesLast Updated on 2014-06-18 17:18:25
Viruses are parasites of living cells which invade cells and then use their biological machinery to propagate. Most viruses in the ocean consist of nucleic acids surrounded by a protein coat (called a capsid). Viruses are thought to have appeared several times during the evolution of cellular organisms as suggested by the type (DNA vs RNA) or structure of the nucleic acid (double-strand vs single strand; sense vs antisense). In marine environments, they are more numerous than the most abundant cell types, the prokaryotes. Prokaryotes are single-celled organisms without a nucleus and are now considered to consist of the two so-called domains of life, Bacteria and Archaea. Viruses are a major factor for the mortality of marine prokaryotes.
Most viruses in the ocean are thought to infect prokaryotes. They are typically DNA-containing viruses and, if they infect bacteria, are... More »
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