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Topic Review
Geobiology
Geobiology is a field of scientific research that explores the interactions between the physical Earth and the biosphere. It is a relatively young field, and its borders are fluid. There is considerable overlap with the fields of ecology, evolutionary biology, microbiology, paleontology, and particularly soil science and biogeochemistry. Geobiology applies the principles and methods of biology, geology, and soil science to the study of the ancient history of the co-evolution of life and Earth as well as the role of life in the modern world. Geobiologic studies tend to be focused on microorganisms, and on the role that life plays in altering the chemical and physical environment of the pedosphere, which exists at the intersection of the lithosphere, atmosphere, hydrosphere and/or cryosphere. It differs from biogeochemistry in that the focus is on processes and organisms over space and time rather than on global chemical cycles. Geobiological research synthesizes the geologic record with modern biologic studies. It deals with process - how organisms affect the Earth and vice versa - as well as history - how the Earth and life have changed together. Much research is grounded in the search for fundamental understanding, but geobiology can also be applied, as in the case of microbes that clean up oil spills. Geobiology employs molecular biology, environmental microbiology, organic geochemistry, and the geologic record to investigate the evolutionary interconnectedness of life and Earth. It attempts to understand how the Earth has changed since the origin of life and what it might have been like along the way. Some definitions of geobiology even push the boundaries of this time frame - to understanding the origin of life and to the role that humans have played and will continue to play in shaping the Earth in the Anthropocene.
  • 920
  • 04 Nov 2022
Topic Review
Geodetic Datum
A geodetic datum or geodetic system (also: geodetic reference datum or geodetic reference system) is a coordinate system, and a set of reference points, used for locating places on the Earth (or similar objects). An approximate definition of sea level is the datum WGS 84, an ellipsoid, whereas a more accurate definition is Earth Gravitational Model 2008 (EGM2008), using at least 2,159 spherical harmonics. Other datums are defined for other areas or at other times; ED50 was defined in 1950 over Europe and differs from WGS 84 by a few hundred meters depending on where in Europe you look. Mars has no oceans and so no sea level, but at least two martian datums have been used to locate places there. Datums are used in geodesy, navigation, and surveying by cartographers and satellite navigation systems to translate positions indicated on maps (paper or digital) to their real position on Earth. Each starts with an ellipsoid (stretched sphere), and then defines latitude, longitude and altitude coordinates. One or more locations on the Earth's surface are chosen as anchor "base-points". The difference in co-ordinates between datums is commonly referred to as datum shift. The datum shift between two particular datums can vary from one place to another within one country or region, and can be anything from zero to hundreds of meters (or several kilometers for some remote islands). The North Pole, South Pole and Equator will be in different positions on different datums, so True North will be slightly different. Different datums use different interpolations for the precise shape and size of the Earth (reference ellipsoids). Because the Earth is an imperfect ellipsoid, localised datums can give a more accurate representation of the area of coverage than WGS 84. OSGB36, for example, is a better approximation to the geoid covering the British Isles than the global WGS 84 ellipsoid. However, as the benefits of a global system outweigh the greater accuracy, the global WGS 84 datum is becoming increasingly adopted. Horizontal datums are used for describing a point on the Earth's surface, in latitude and longitude or another coordinate system. Vertical datums measure elevations or depths.
  • 4.6K
  • 24 Nov 2022
Topic Review
Geography and Cartography in Medieval Islam
Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age (variously dated between the 8th century and 16th century). Muslim scholars made advances to the mapmaking traditions of earlier cultures, particularly the Hellenistic geographers Ptolemy and Marinus of Tyre,:193 combined with what explorers and merchants learned in their travels across the Old World (Afro-Eurasia). Islamic geography had three major fields: exploration and navigation, physical geography, and cartography and mathematical geography. Islamic geography reached its apex with Muhammad al-Idrisi in the 12th century.
  • 2.2K
  • 26 Oct 2022
Topic Review
Geography of Middle-Earth
The geography of Middle-earth encompasses the physical, political, and moral geography of J. R. R. Tolkien's fictional world of Middle-earth, strictly a continent on the planet of Arda but widely taken to mean the physical world, and Eä, all of creation, as well as all of his writings about it. Arda was created as a flat world, incorporating a Western continent, Aman, which became the home of the godlike Valar, as well as Middle-earth. At the end of the First Age, the Western part of Middle-earth, Beleriand, was drowned in the War of Wrath. In the Second Age, a large island, Númenor, was created in the Great Sea, Belegaer, between Aman and Middle-earth; it was destroyed in a cataclysm at the end of the Second Age, in which Arda was remade as a spherical world, and Aman was removed so that Men could not reach it. In The Lord of the Rings, Middle-earth at the end of the Third Age is described as having free peoples, namely Men, Hobbits, Elves, and Dwarves in the West, opposed to peoples under the control of the Dark Lord Sauron in the East. Some commentators have seen this as implying a moral geography of Middle-earth.
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  • 25 Oct 2022
Topic Review
Geomatic Sensors for Heritage Documentation
Geomatic technologies have been widely populated for cultural heritage applications, while the scientific field is quite broad: from underwater to close-range to low-altitude and satellite observations. Geomatic sensors have been used in applications such as close-range approaches with red-green-blue (RGB) cameras and Terrestrial Laser Scanners (TLS), as well as underwater studies. Low-altitude sensors on Unmanned Aerial Vehicles (UAVs) have also been widely used with RGB and multispectral cameras, as well as lidar and thermal sensors.
  • 320
  • 25 Oct 2023
Topic Review
Geomatics
Geomatics is defined in the ISO/TC 211 series of standards as the "discipline concerned with the collection, distribution, storage, analysis, processing, presentation of geographic data or geographic information". Under another definition, it "consists of products, services and tools involved in the collection, integration and management of geographic data". It includes geomatics engineering (and surveying engineering) and is related to geospatial science (also geospatial engineering and geospatial technology).
  • 534
  • 01 Nov 2022
Topic Review
Global 200
The Global 200 is the list of ecoregions identified by WWF, the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". So, for example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none. The WWF assigns a conservation status to each ecoregion in the Global 200: critical or endangered; vulnerable; and relatively stable or intact. Over half of the ecoregions in the Global 200 are rated endangered.
  • 572
  • 06 Oct 2022
Topic Review
Global Earth Observation System of Systems
The Global Earth Observation System of Systems (GEOSS) is being built by the Group on Earth Observations (GEO) on the basis of a 10-Year Implementation Plan running from 2005 to 2015. GEOSS seeks to connect the producers of environmental data and decision-support tools with the end users of these products, with the aim of enhancing the relevance of Earth observations to global issues. GEOSS aims to produce a global public infrastructure that generates comprehensive, near-real-time environmental data, information and analyses for a wide range of users. The Secretariat Director of Geoss is Barbara Ryan.
  • 319
  • 17 Nov 2022
Topic Review
Global Storm Activity of 2009
Global storm activity of 2009 profiles the major worldwide storms, including blizzards, ice storms, and other winter events, from January 1, 2009 to December 31, 2009. Wintery storms are events in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.e. freezing rain). It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm, hailstorm, etc.). Summer storms including flooding, severe thunderstorms and extratropical cyclones (which can occur in summer or winter) are also included in this list to a certain extent. As this occurred a heat wave and/or unforeseen monsoon weather also hit parts of Australia in 2009 and 2010. Victoria, the scene of horrific bushfires the year before, had a far colder summer, with hot weather arriving more than a month later than usual in 2009. August 17 saw a dust storm at Laguna Mar Chiquita as a major drought hit Argentina , and flooding and hailstorms hit southeastern Australia and Queensland in March 2010. The lack of winter precipitation in parts of China, however, contributed to a severe drought in the southwest. Bolivia, Venezuela, Mali, Mauritania, Morocco and Spain have also seen periods of drought in 2009 and 2010. On between May 12 and 26, both Mauritania, the Sénégal River Area and neighbouring parts of both Senegal and Mali faced both a drought and famine in 2010. A storm (from Proto-Germanic *sturmaz "noise, tumult") is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather. Storms are created when a centre of low pressure develops, with a system of high pressure surrounding it. This combination of opposing forces can create winds and result in the formation of storm clouds, such as the cumulonimbus. Small, localized areas of low pressure can form from hot air rising off hot ground, resulting in smaller meteorological disturbances such as dust devils and whirlwinds.
  • 1.0K
  • 09 Nov 2022
Topic Review
Golan Heights
The Golan Heights (Arabic: هَضْبَةُ الْجَوْلَانِ or Arabic: مُرْتَفَعَاتُ الْجَوْلَانِ, Hebrew: רמת הגולן‎, romanized: Ramat HaGolan), or simply the Golan, is a region in the Levant spanning about 1,800 square kilometres (690 sq mi). The region defined as the Golan Heights differs between disciplines: as a geological and biogeographical region, the term refers to a basaltic plateau bordered by the Yarmouk River in the south, the Sea of Galilee and Hula Valley in the west, the Anti-Lebanon with Mount Hermon in the north and Wadi Raqqad in the east. As a geopolitical region, it refers to the border region captured from Syria by Israel during the Six-Day War of 1967; the territory has been occupied by the latter since then and was subject to a de facto Israeli annexation in 1981. This region includes the western two-thirds of the geological Golan Heights and the Israeli-occupied part of Mount Hermon. The earliest evidence of human habitation on the Golan dates to the Upper Paleolithic period. According to the Bible, an Amorite kingdom in Bashan was conquered by the Israelites during the reign of King Og. Throughout the Biblical period, the Golan was "the focus of a power struggle between the kings of Israel and the Aramaeans who were based near modern-day Damascus." After Assyrian and Babylonian rule, the region came under the domination of Persia, following which Jews were freed from Babylonian captivity and allowed to return and resettle in the land. The Itureans, an Arab or Aramaic people, settled in the area in the 2nd century BCE. In the 16th century, the Golan was conquered by the Ottoman Empire. Within Ottoman Syria, the Golan was part of the Syria Vilayet. The area later became part of the French Mandate in Syria and the State of Damascus. When the mandate terminated in 1946, it became part of the newly independent Syrian Arab Republic. By the late-19th century, the Golan Heights was inhabited mostly by colonized peasants (fellaḥîn), Bedouin Arabs, Druze, Turkmen, and Circassians. Since the Six-Day War of 1967, the western two-thirds of the Golan Heights has been occupied and administered by Israel, whereas the eastern third remains under the control of Syria. Following the war, Syria dismissed any negotiations with Israel as part of the Khartoum Resolution at the 1967 Arab League summit. Construction of Israeli settlements began in the remainder of the territory held by Israel, which was under a military administration until the Knesset passed the Golan Heights Law in 1981, which applied Israeli law to the territory; the move has been described as an annexation. The Golan Heights Law was condemned by the United Nations Security Council in Resolution 497, which stated that "the Israeli decision to impose its laws, jurisdiction, and administration in the occupied Syrian Golan Heights is null and void and without international legal effect", and Resolution 242, which emphasizes the "inadmissibility of the acquisition of territory by war". Israel maintains it has a right to retain the Golan, also citing the text of Resolution 242, which calls for "secure and recognized boundaries free from threats or acts of force". After the onset of the Syrian Civil War in 2011, control of the Syrian-administered part of the Golan Heights was split between the state government and Syrian opposition forces, with the United Nations Disengagement Observer Force (UNDOF) maintaining a 266 km2 (103 sq mi) buffer zone in between to help implement the Israeli–Syrian ceasefire across the Purple Line. From 2012 to 2018, the eastern half of the Golan Heights became a scene of repeated battles between the Syrian Army, rebel factions of the Syrian opposition (including the United States -backed Southern Front) as well as various jihadist organizations such as al-Nusra Front and the Islamic State of Iraq and the Levant-affiliated Khalid ibn al-Walid Army. In July 2018, the Syrian government regained full control over the eastern Golan Heights. On 25 March 2019, then-President of the United States Donald Trump proclaimed US recognition of the Golan Heights as a part of the State of Israel, making it the first country to do so. The 28 member states of the European Union declared in turn that they do not recognize Israeli sovereignty, and several experts on international law reiterated that the principle remains that land gained by either defensive or offensive wars cannot be legally annexed under international law.
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  • 18 Nov 2022
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