The Struma or Strymónas ( Bulgarian : Струма [ˈstrumɐ] ; Greek : Στρυμόνας [striˈmonas] ;) is a river in Bulgaria and Greece . Its ancient name was Strymṓn ( Greek : Στρυμών [stryˈmɔːn] ). Its drainage area is 17,330 km (6,690 sq mi), of which 8,670 km (3,350 sq mi) in Bulgaria , 6,295 km (2,431 sq mi) in Greece and the remaining 2,365 km (913 sq mi) in North Macedonia and Serbia . It takes its source from the Vitosha Mountain in Bulgaria , runs first westward, then southward, forming a number of gorges, enters Greece near the village of Promachonas in eastern Macedonia . In Greece it is the main waterway feeding and exiting from Lake Kerkini , a significant centre for migratory wildfowl. Also in Greece, the river entirely flows in the Serres regional unit into the Strymonian Gulf in Aegean Sea , near Amphipolis . The river's length is 415 kilometres (258 miles) (of which 290 kilometres (180 mi) in Bulgaria, making it the country's fifth-longest and one of the longest rivers that run solely in the interior of the Balkans .
124-724: Parts of the river valley belong to a Bulgarian coal -producing area, more significant in the past than nowadays; the southern part of the Bulgarian section is an important wine region . The Greek portion is a valley which is dominant in agriculture, being Greece's fourth-biggest valley. The tributaries include the Konska River , the Dragovishtitsa , the Rilska River , the Blagoevgradska Bistritsa ,
248-456: A Western Siberia breeding area) was found to utilize an average home range in winter of 65 km (25 sq mi), which contracted 24% before it migrated in the spring, taking from late February to late April to migrate over 5,500 km (3,400 mi). Wintertime territory in Spain was found to be smaller, at 27.2 km (10.5 sq mi). The southernmost migration record of
372-417: A bush , utility pole , or steep riverbank . It is not uncommon for greater spotted eagles to forage from the ground, or rest there in a somewhat hunched posture. Adult greater spotted eagles are generally a rather uniform dark to blackish brown, though the coloration may appear purplish and glossy. They may appear more starkly contrasted when freshly moulted . The upperwing covert feathers are often
496-544: A clutch of one to three eggs. The female of a pair incubates and broods the young while the male hunts and delivers prey. Parents rarely raise more than one fledgling per year. As is common among a few species of raptors, the oldest chick is much larger than its younger siblings, and will often attack and kill the younger siblings. The greater spotted eagle's range overlaps with the closely-related lesser spotted eagle ( Clanga pomarina ). The two species are known to breed together frequently, forming hybrid offspring , which
620-512: A cyclothem . Cyclothems are thought to have their origin in glacial cycles that produced fluctuations in sea level , which alternately exposed and then flooded large areas of continental shelf. The woody tissue of plants is composed mainly of cellulose, hemicellulose, and lignin. Modern peat is mostly lignin, with a content of cellulose and hemicellulose ranging from 5% to 40%. Various other organic compounds, such as waxes and nitrogen- and sulfur-containing compounds, are also present. Lignin has
744-432: A monophyletic group within the larger Accipitridae family. All booted eagles have feathers covering their legs. Members of this diverse, wide-ranging family may be found on every continent except Antarctica . Thirty-eight species of booted eagle are recognized. Booted eagles are often grouped with the genera Buteo and Haliaeetus , and other more heavy-set Accipitridae , but they may be more closely related to
868-571: A species complex or clade . The spotted eagles were ultimately reclassified as a distinct genus, Clanga , due to overwhelming genetic evidence and large divergences in morphology and ecology between spotted eagles and their sister taxa. The scientific name Clanga may derive from Ancient Greek κλαγγή ( lit. ' scream ' ), or its root may be the Greek word klangos (a variant form of plangos ) for "a kind of eagle" as mentioned by Aristotle . Extensive hybridization between
992-866: A day. The flight speeds of migrating eagles of the species was documented as 26.6–45.5 km/h (16.5–28.3 mph) in the Baikal region, with peak movements times from noon to 6:00 PM. There is limited information on discrepancies in how different ages and sexes migrate. Fewer numbers are generally recorded in spring migration compared to autumn migration. Generally, migrants of the species move on broad fronts in singles or pairs, but groups as large as 10 have been seen northbound over Bhutan in late February. In Malaysia, immatures outnumbered adults six to one. At Lake Baikal , 96% of migrating greater spotted eagles were observed to be adults, an imbalance that concerned researchers. Greater spotted eagles tend to be scarce at traditional migratory bottlenecks such as Bosphorus and
1116-654: A few in Morocco, Egypt, the Nile Valley , Sudan , Ethiopia , and occasionally points further south. Birds from various origin sites may end up in the Middle East (mainly Arabia), South Asia (from Pakistan, most often Punjab and Sind, northern India, and Nepal), east to Indochina, the Malay Peninsula, and southern and eastern China. Greater spotted eagles on an Eastern European track predominantly migrate to
1240-595: A greater spotted eagle was one that traveled 9,270 km (5,760 mi) from the Biebrza National Park in Poland to Zambia in southern Africa . Several other purportedly greater spotted eagles were tracked to several areas of Africa, but nearly half were actually hybrids with lesser spotted eagles and were migrating in more typical fashion and location to that species. Improbably, at least seven records show immature greater spotted eagles staying through
1364-418: A harsh chrr-chrr-chaa-chaa , kyak-yak-yak , and kyew-kyew-kyew . The cumulative effect of the repeated call has been compared to that of a "small hound ". As with many raptors, the female’s tone is lower pitched and hoarser. One individual greater spotted eagle recorded over two days was found to utter an unusual ringing call that sounded remarkably similar to the first two syllables of the typical call of
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#17327648309711488-837: A lowland bird. However, they have been recorded at elevations up to 4,000 m (13,000 ft) in northern Iran. One greater spotted eagle was recorded on migration at 4,370 m (14,340 ft) in Ladakh in the Himalayas . Greater spotted eagles are almost entirely migratory birds . However, they are not considered long-distance migrants compared to other birds of prey. They migrate between late August to October, occasionally lasting into November. The return flight typically starts in early February, peaking in March and ending in April. However, migration has been documented well into May, near
1612-605: A maximum of 85 has been recorded in northern Israel in autumn. An adult captured near Mecca in western Saudi Arabia in late October was radiotracked 850 km (530 mi) to Yemen , where it remained from late November until early February, before returning 5,526 km (3,434 mi) via southern Iraq, across the Iranian highlands, skirting the south edge of the Aral Sea , and finally flying to its Siberian breeding area near Omsk , covering 4,516 km (2,806 mi) of
1736-413: A near 5% size difference in favor of Indian wintering birds over Middle Eastern ones. The greater spotted eagle is a medium-sized eagle , but also a large raptor . This species shows strong sexual dimorphism in favor of the female in size, though the plumage is similar between sexes. The size difference is up to 26% linearly, and females can be as much as twice as heavy as the males, making them rival
1860-417: A process called carbonization . Carbonization proceeds primarily by dehydration , decarboxylation , and demethanation. Dehydration removes water molecules from the maturing coal via reactions such as Decarboxylation removes carbon dioxide from the maturing coal: while demethanation proceeds by reaction such as In these formulas, R represents the remainder of a cellulose or lignin molecule to which
1984-545: A shade paler than the rest, though these eagles generally appear uniformly dark with two contrasting features: a pale beak and a narrow white U above the tail, though the latter is usually concealed at rest. The species is sexually dimorphic or even polymorphic . Pale and intermediate phenotypes are rare, although they can be slightly more common in eastern ranges. Pale adults, sometimes referred to as Clanga clanga fulvescens , have bicolored plumage. The tail, flight feathers , and greater wing coverts are all blackish, with
2108-490: A single (not double) whitish crescent at the base of primaries. In fulvescens (pale) morph adults, most of the wing coverts on both surfaces and body are contrastingly buffy to tawny. Juveniles on the wing normally appear very dark with liberal spotting above and below, though some juveniles appear with spots restricted to wings, scapulars, and trousers. All juveniles, when seen well, show characteristic white end spots on wing coverts forming two to three wing bars. Otherwise,
2232-540: A switch in fuels happened in London in the late sixteenth and early seventeenth centuries. Historian Ruth Goodman has traced the socioeconomic effects of that switch and its later spread throughout Britain and suggested that its importance in shaping the industrial adoption of coal has been previously underappreciated. The development of the Industrial Revolution led to the large-scale use of coal, as
2356-561: A tenth. Indonesia and Australia export the most, followed by Russia . The word originally took the form col in Old English , from reconstructed Proto-Germanic * kula ( n ), from Proto-Indo-European root * g ( e ) u-lo- "live coal". Germanic cognates include the Old Frisian kole , Middle Dutch cole , Dutch kool , Old High German chol , German Kohle and Old Norse kol . Irish gual
2480-403: A weight basis. This composition reflects partly the composition of the precursor plants. The second main fraction of coal is ash, an undesirable, noncombustable mixture of inorganic minerals. The composition of ash is often discussed in terms of oxides obtained after combustion in air: Of particular interest is the sulfur content of coal, which can vary from less than 1% to as much as 4%. Most of
2604-406: A weight composition of about 54% carbon, 6% hydrogen, and 30% oxygen, while cellulose has a weight composition of about 44% carbon, 6% hydrogen, and 49% oxygen. Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. The low oxygen content of coal shows that coalification removed most of the oxygen and much of the hydrogen
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#17327648309712728-522: Is 97–105 mm (3.8–4.1 in) in males and 96–112 mm (3.8–4.4 in) in females. Reportedly, the culmen length can range from 32.5 to 39 mm (1.28 to 1.54 in). The greater spotted eagle is quite noisy when breeding and is often very vocal in winter, especially when in small loose flocks. The most common call, often heard during intraspecies conflicts, is a soft, one-syllable, penetrating, high-pitched, urgent whistle, variously transcribed as kyack , kluh , tyuck , or dyip . The call
2852-508: Is almost certainly not a stable breeding population today. They also breed in northern Mongolia , and rather far into Northeastern China and northern North Korea . Greater spotted eagles disperse widely during migration, usually through September to November in the fall, and February to April in the spring. They are found more widely during migration than during breeding or wintering. While migrating, greater spotted eagles may be seen in much of Eastern Europe, Anatolia , and throughout
2976-636: Is also a cognate via the Indo-European root. The conversion of dead vegetation into coal is called coalification . At various times in the geologic past, the Earth had dense forests in low-lying areas. In these wetlands, the process of coalification began when dead plant matter was protected from oxidation , usually by mud or acidic water, and was converted into peat . The resulting peat bogs , which trapped immense amounts of carbon, were eventually deeply buried by sediments. Then, over millions of years,
3100-464: Is an opportunistic forager, especially during the winter. It will readily scavenge a variety of food sources, including carrion , as well as small mammals (principally rodents ), frogs, and a variety of smaller birds (especially water birds), and occasionally reptiles and insects. The eagle is primarily an aerial hunter, gliding from concealed perches over marshes or wet fields to catch prey. This species builds stick nests in large trees, laying
3224-429: Is burned in a turbine). Hot exhaust gases from the turbine are used to raise steam in a heat recovery steam generator which powers a supplemental steam turbine . The overall plant efficiency when used to provide combined heat and power can reach as much as 94%. IGCC power plants emit less local pollution than conventional pulverized coal-fueled plants. Other ways to use coal are as coal-water slurry fuel (CWS), which
3348-538: Is detrimental to the population of the rarer greater spotted eagles. The greater spotted eagle is classified as a vulnerable species by the International Union for Conservation of Nature . Its populations are threatened by habitat destruction , collisions with objects, and hybridization with lesser spotted eagles. Greater spotted eagles are members of the Aquilinae , or "booted eagles", subfamily,
3472-603: Is entirely vertical; however, metamorphism may cause lateral changes of rank, irrespective of depth. For example, some of the coal seams of the Madrid, New Mexico coal field were partially converted to anthracite by contact metamorphism from an igneous sill while the remainder of the seams remained as bituminous coal. The earliest recognized use is from the Shenyang area of China where by 4000 BC Neolithic inhabitants had begun carving ornaments from black lignite. Coal from
3596-619: Is favorable up through much of Arkhangelsk Oblast to as far as the lower coasts of the White Sea . They are found across much of Central Russia , with their probable northern limits being in Shuryshkarsky and Pitkyarantsky Districts. They are also found in a broad strip across southern Siberia reaching well into the Amur region. Their range outside Russia includes much of northern Kazakhstan , with isolated breeding areas known in
3720-562: Is highly restricted to small, non-contiguous pockets in Poland , Belarus , Ukraine , Bulgaria , Romania , Serbia , and Hungary . A more continuous breeding range begins in Eastern Europe and includes the eastern parts of Estonia , Latvia , and Lithuania , and central Belarus. An uncertain number of breeding birds spill over into the edge of eastern Finland . They are found broadly throughout European Russia , where habitat
3844-455: Is made when metallurgical coal (also known as coking coal ) is baked in an oven without oxygen at temperatures as high as 1,000 °C, driving off the volatile constituents and fusing together the fixed carbon and residual ash. Metallurgical coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace . The carbon monoxide produced by its combustion reduces hematite (an iron oxide ) to iron. Pig iron , which
Struma (river) - Misplaced Pages Continue
3968-409: Is more abundant, and anthracite. The % carbon in coal follows the order anthracite > bituminous > lignite > brown coal. The fuel value of coal varies in the same order. Some anthracite deposits contain pure carbon in the form of graphite . For bituminous coal, the elemental composition on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on
4092-432: Is mostly carbon with variable amounts of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . Coal is a type of fossil fuel , formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during
4216-456: Is not always reliable. Hybrids of the two spotted eagles can be more difficult to distinguish, and are often muddled and varied in appearance, with some hybrids being much closer in appearance to one species or the other. Pure greater spotted eagles can be told from pure lesser spotted eagles via in-hand measurements such as bill height, width and extent of white spots on the juvenile, and the length of middle toe. The greater spotted eagle on
4340-413: Is not unlike that of lesser spotted eagles but is slightly deeper and more ringing. The calls are higher pitched than steppe eagles' and much higher pitched than those of the eastern imperial eagles ( Aquila heliaca ), the latter having a guttural call somewhat reminiscent of a frog. Additionally, a similar three-syllable bark is seemingly used to warn off intruders at a feeding site, sometimes considered
4464-815: Is sometimes documented in central and east Afghanistan . They also may also be found in East Asia across the southern part of the Russian Far East , eastern China, and occasionally in Southeast Asia from Myanmar and Thailand down through the Malay Peninsula . Occasionally, greater spotted eagles are documented even in Indonesia (i.e. Sumatra ). Dedicated wintering areas tend to be more limited and isolated than their range during migration. The central wintering areas are principally
4588-449: Is somewhat diverse, at slightly fewer than 150 known prey species; this is more diverse than the known diet of the steppe eagle, similar in diversity to that of the lesser spotted eagle, and possibly about half as diverse of the diet of the eastern imperial eagle. Greater spotted eagles hunt mainly on the wing, quartering over relatively open ground (somewhat like a harrier ) or soaring high above and dropping or diving steeply when prey
4712-701: Is spotted. Brown and Amadon describe the hunting greater spotted eagle, saying: "Although not a very active species it is not exactly sluggish, and on the wing it has the look of a true eagle." Greater spotted eagles will scatter waterfowl by stooping low over their flock, then selecting isolated individuals to attack. Sometimes the greater spotted eagle still-hunts from a perch, a method more commonly employed by other eagles of similar distribution, and often hunts on foot as well. It mostly takes prey on ground or water. The species also sometime carries out kleptoparasitic attacks on other birds of prey. Although scavenging for carrion seems to occur almost aseasonally, it
4836-423: Is too rich in dissolved carbon, is also produced. Greater spotted eagle Aquila clanga The greater spotted eagle ( Clanga clanga ), also called the spotted eagle , is a large migratory bird of prey in the family Accipitridae . It is a member of the subfamily Aquilinae , commonly known as "booted eagles". It was once classified as a member of the genus Aquila , but has been reclassified to
4960-452: Is used as fuel. 27.6% of world energy was supplied by coal in 2017 and Asia used almost three-quarters of it. Other large-scale applications also exist. The energy density of coal is roughly 24 megajoules per kilogram (approximately 6.7 kilowatt-hours per kg). For a coal power plant with a 40% efficiency, it takes an estimated 325 kg (717 lb) of coal to power a 100 W lightbulb for one year. In 2022, 68% of global coal use
5084-870: The Bosphorus in Turkey. On average, migration peaks earlier in the eastern end of their range, such as in Bhutan , where the largest numbers are seen in late February. They migrate around two weeks later than lesser spotted eagles and return earlier than that species as well. At known migration stopovers, lesser spotted eagles almost always outnumber greater spotted eagles. Greater spotted eagles who breed in Europe may migrate to southern France (especially Camargue ), Spain, Italy, and sometimes Sweden . Western breeding birds also regularly end up in North Africa , with
Struma (river) - Misplaced Pages Continue
5208-715: The Bronze Age (3000–2000 BC), where it formed part of funeral pyres . In Roman Britain , with the exception of two modern fields, "the Romans were exploiting coals in all the major coalfields in England and Wales by the end of the second century AD". Evidence of trade in coal, dated to about AD 200, has been found at the Roman settlement at Heronbridge , near Chester ; and in the Fenlands of East Anglia , where coal from
5332-650: The East Kazakhstan Region and in southern Kazakhstan. Greater spotted eagles also breed in an isolated area reaching from Kyrgyzstan and adjacent areas of Russia down to Xinjiang in China . At times, greater spotted eagles have been known to breed in the Indian subcontinent , reportedly from Gujarat northwards to Punjab , with recorded breeding as far south as Saurashtra and as far north as Maharashtra . However, this may only be historical, and there
5456-521: The Fushun mine in northeastern China was used to smelt copper as early as 1000 BC. Marco Polo , the Italian who traveled to China in the 13th century, described coal as "black stones ... which burn like logs", and said coal was so plentiful, people could take three hot baths a week. In Europe, the earliest reference to the use of coal as fuel is from the geological treatise On Stones (Lap. 16) by
5580-429: The Indian spotted eagle ( Clanga hastata ), was recognized as a distinct species from the similarly-sized lesser spotted eagle in 2006. The greater spotted eagle is rather large and compact. Normally, it is black-brown with a contrasting yellow beak . This species has a short neck with a large and often shaggy-naped head, a strong beak, and a short gape-line with round nostrils. The wings are broad and long, reaching
5704-693: The Mediterranean Basin , the Middle East , and the Indomalayan realm . Small pockets may exist in southwestern Spain and bordering Portugal , South France , northeastern Italy , western Greece (where it is sometimes considered the most common wintering eagle), small areas of southern Bulgaria , eastern Romania, and southern Moldova . Other wintering areas including northeastern Egypt , southern Sudan and adjacent South Sudan , north-central Ethiopia , and scattered areas of
5828-576: The Middle East , Central Asia (from Kazakhstan south), and western South Asia . This species is prone to vagrancy, and has been reported in several countries in Europe including the Netherlands , Great Britain , Gibraltar , and the Czech Republic . Its regular breeding range no longer extends as far westwards as Germany , but birds are still occasionally seen there with a few records per decade. Young birds also disperse widely;
5952-607: The Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and Roman forts , particularly in Northumberland , dated to around AD 400. In the west of England, contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath ), although in fact easily accessible surface coal from what became
6076-730: The Sandanska Bistritsa , the Strumitsa , the Pirinska Bistritsa and the Angitis . The river's name comes from Thracian Strymón , derived from Proto-Indo-European * srew- 'stream', akin to English stream , Old Irish sruaimm 'river', Polish strumień 'stream', Lithuanian straumuo 'fast stream', Bulgarian струя ( struia ) 'water flow', Greek ῥεῦμα ( rheũma ) 'stream', Albanian rrymë 'water flow', shi 'rain'. The name Strymón
6200-728: The Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron -working in the city during the Roman period has been found. In Eschweiler , Rhineland , deposits of bituminous coal were used by the Romans for the smelting of iron ore . No evidence exists of coal being of great importance in Britain before about AD 1000, the High Middle Ages . Coal came to be referred to as "seacoal" in
6324-716: The Staatliches Museum für Tierkunde Dresden has a specimen (C 21845) shot in November 1914 near Bernsdorf in Saxony . It is a juvenile, and though its exact age cannot be determined, it is heavily spotted and probably less than 20 months old. Additionally, vagrancy has been reported in Africa, including in Morocco , Algeria , Tunisia , Libya , Cameroon , Chad , Kenya , Tanzania , Zambia , and Botswana . It
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#17327648309716448-491: The coal gap in the Permian–Triassic extinction event , where coal is rare. Favorable geography alone does not explain the extensive Carboniferous coal beds. Other factors contributing to rapid coal deposition were high oxygen levels, above 30%, that promoted intense wildfires and formation of charcoal that was all but indigestible by decomposing organisms; high carbon dioxide levels that promoted plant growth; and
6572-500: The crested serpent eagle ( Spilornis cheela ). Field identification of greater spotted eagle can be quite difficult. This species is primarily differentiated from lesser spotted eagles by its structure and proportions, though distant birds may be practically indistinguishable. Compared to the lesser spotted eagle, the adult appears very broad winged, which in turn makes the head look relatively small. However, greater spotted juveniles can appear less bulky, narrower, more rounded along
6696-641: The eastern imperial eagle can resemble fulvescens greater spotted eagles but are larger and appear structurally different. The imperial has much longer and narrower wings, a longer neck, a bigger, more prominent beak with an oblong (rather than oval) nail, a longer and narrower gape line, more conspicuous pale inner primaries, no carpal arc, a brown-streaked breast (though greater spotteds can show some diffuse marks), unmarked tarsal feathering, pale irides , and an obvious pale window on inner primaries. Beyond structural dissimilarities, subadult steppe eagles can be distinguished from paler morph greater spotted eagles by
6820-417: The fulvescens and intermediate morphs resemble a large number of eagles, but can be distinguished by underwing colour and pattern—such as their distinct carpal arc and dark, thinly barred quills—from pale or intermediate morphs of the similarly sized tawny eagle ( Aquila rapax ), which is usually less darkly backed without a defused dark face and possesses more typical, narrower wing proportions. Juveniles of
6944-962: The martial eagle ( Polemaetus bellicosus ) as possibly the most sexually dimorphic member of the Aquilinae . However, the largest male greater spotted eagles can overlap in most linear and mass measurements with smaller females. The total length of full-grown greater spotted eagles can vary from 59 to 74 cm (23 to 29 in). In wingspan, males have been reported to measure 155–177 cm (61–70 in) while females can measure 167–185 cm (66–73 in). Body mass for males has been reported to range from 1,537 to 2,000 g (3.389 to 4.409 lb), while females range from 1,820 to 3,250 g (4.01 to 7.17 lb). Among standard measurements, wing chord can range 477–519 mm (18.8–20.4 in) in males and 507–545 mm (20.0–21.5 in) in females. The shortish tail varies 227–249 mm (8.9–9.8 in) in males and 235–268 mm (9.3–10.6 in) in females. The fairly long tarsus
7068-583: The saker falcon , the eastern imperial eagle and the greater spotted eagle . The Greek lamprey , which is listed as a critically endangered species on the IUCN Red List and is considered the rarest species of lamprey in the world, is only found at the Struma basin and the basin of the much smaller Louros river. Coal Coal is a combustible black or brownish-black sedimentary rock , formed as rock strata called coal seams . Coal
7192-447: The steam engine took over from the water wheel . In 1700, five-sixths of the world's coal was mined in Britain. Britain would have run out of suitable sites for watermills by the 1830s if coal had not been available as a source of energy. In 1947 there were some 750,000 miners in Britain, but the last deep coal mine in the UK closed in 2015. A grade between bituminous coal and anthracite
7316-407: The 13th century; the wharf where the material arrived in London was known as Seacoal Lane, so identified in a charter of King Henry III granted in 1253. Initially, the name was given because much coal was found on the shore, having fallen from the exposed coal seams on cliffs above or washed out of underwater coal outcrops, but by the time of Henry VIII , it was understood to derive from the way it
7440-596: The Carboniferous, and suggested that climatic and tectonic factors were a more plausible explanation, reconstruction of ancestral enzymes by phylogenetic analysis corroborated a hypothesis that lignin degrading enzymes appeared in fungi approximately 200 MYa. One likely tectonic factor was the Central Pangean Mountains , an enormous range running along the equator that reached its greatest elevation near this time. Climate modeling suggests that
7564-598: The Central Pangean Mountains contributed to the deposition of vast quantities of coal in the late Carboniferous. The mountains created an area of year-round heavy precipitation, with no dry season typical of a monsoon climate. This is necessary for the preservation of peat in coal swamps. Coal is known from Precambrian strata, which predate land plants. This coal is presumed to have originated from residues of algae. Sometimes coal seams (also known as coal beds) are interbedded with other sediments in
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#17327648309717688-525: The Greek scientist Theophrastus (c. 371–287 BC): Among the materials that are dug because they are useful, those known as anthrakes [coals] are made of earth, and, once set on fire, they burn like charcoal [anthrakes]. They are found in Liguria ;... and in Elis as one approaches Olympia by the mountain road; and they are used by those who work in metals. Outcrop coal was used in Britain during
7812-516: The Indian subcontinent might be confused with Indian spotted eagles . The Indian species is smaller (similar in size to the lesser spotted eagle), somewhat narrower-winged and longer-tailed, with primary fingers more deeply cut and square-ended. The Indian species has a more distinct pale window in primaries, paler and less distinctly streaked underparts, and paler upperparts (more like a steppe eagle in color) with less distinct, more diffuse pale tips to
7936-836: The Middle East including northern Israel , Kuwait , and central Syria . More continuously, they are found through much of the southern coastal Arabian Peninsula , including broadly along the Red Sea coast in Saudi Arabia , west and southern Yemen , southern Oman , coastal United Arab Emirates , and eastern Saudi Arabia. Furthermore, they winter in southeastern Turkey , Azerbaijan , southeastern Georgia , eastern Iraq , broadly in western, northern and eastern Iran , southern Turkmenistan , western Afghanistan , and far western Pakistan . They are also found discontinuously in eastern Pakistan, northern India , Bangladesh , southern Bhutan , and into northwestern Myanmar . In India,
8060-772: The Middle East or Northeast Africa, while others migrate through the Carpathian Mountains to the Balkan Peninsula , and some continue through Central Europe and Western Europe to Southwestern Europe . The main wintering sites of the Asian populations are located in the Arabian Peninsula , Indian subcontinent , Indochina Peninsula , and East China . During migration, greater spotted eagles commonly cover around 150 km (93 mi) per day but can cover up to 350 km (220 mi) within
8184-456: The body and the rest of the wing coverts appearing light yellow or pale golden buff, sometimes becoming creamy when aged. The buff colour of the fulvescens phenotype is usually contrasted with diffuse dark coloring around the eyes, on the leading edges of wings, and more rarely and sparsely on the chest. Intermediate and other variants are very rare, but include those with a slightly paler body and variable yellowish-brown streaking or mottling on
8308-491: The contrasting paler underbody. The juvenile greater spotted eagle is generally uniformly black-brown with whitish to yellowish drop-shaped spots. Some juveniles appear heavily spotted all over, while others are less so. They always show an obvious row of spots along the upperwing coverts, forming clear wing bars tail and flight feathers, except the outer primaries. Juveniles' feathers underneath are often broadly cream-tipped, often showing some buffy streaks below, especially on
8432-876: The distinct genus Clanga , along with the two other species of spotted eagle. During breeding season, greater spotted eagles are widely distributed across Eastern Europe, parts of Central Europe, central Russia, central Asia and parts of China, along with other isolated areas. During winter, they migrate , primarily to South Asia, Southeast Asia, the Middle East, the upper Mediterranean Basin , and parts of East Africa. Greater spotted eagles favor wetter habitats than most other booted eagles, preferring riparian zones as well as bogs , lakes, ponds, and other bodies of water surrounded by woodland. They breed primarily on floodplains, especially ones that experience high water levels. During winter and migration, they often seek out similar wetland habitats, but have also been observed in dry upland areas such as savanna plateaus . The eagle
8556-502: The entire Greek peninsula sieged and conquered Amphipolis. According to the ancient sources, the river was navigable from its mouth up to the ancient (and today dried) Cercinitis lake , which also favored the navigation; and thus was formed in antiquity an important waterway that served the communication between the coasts of Strymonian Gulf and the Thracian hinterland and almost to the city of Serres . The decisive Battle of Kleidion
8680-571: The environment , causing premature death and illness, and it is the largest anthropogenic source of carbon dioxide contributing to climate change . Fourteen billion tonnes of carbon dioxide were emitted by burning coal in 2020, which is 40% of total fossil fuel emissions and over 25% of total global greenhouse gas emissions . As part of worldwide energy transition , many countries have reduced or eliminated their use of coal power . The United Nations Secretary General asked governments to stop building new coal plants by 2020. Global coal use
8804-430: The evolution of the first trees . But bacteria and fungi did not immediately evolve the ability to decompose lignin, so the wood did not fully decay but became buried under sediment, eventually turning into coal. About 300 million years ago, mushrooms and other fungi developed this ability, ending the main coal-formation period of earth's history. Although some authors pointed at some evidence of lignin degradation during
8928-519: The factors involved in coalification, temperature is much more important than either pressure or time of burial. Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F). Although coal is known from most geologic periods , 90% of all coal beds were deposited in the Carboniferous and Permian periods. Paradoxically, this
9052-418: The flanks and trousers. In fulvescens -type greater spotted eagles, juveniles are like the pale adult but show the typical heavily spotted wings and tail of typical juveniles, and often show some darker centers to the scapulars and median coverts. By the second to third year, the plumage is often considerably worn but white tips still create sufficiently prominent wing bars (unlike in lesser spotted eagles) until
9176-418: The fore upperwing coverts (which can make them look similar to juvenile lesser spotted eagles), or mottled yellow-brown with a dark-streaked breast and pale-tipped wing coverts (like the juvenile eastern imperial eagle ( Aquila heliaca )). These intermediate types may show the typical dark brown to black on the upper body, but in flight display pale mottled grey wing linings, or even normal coloration apart from
9300-498: The form of iron pyrite (FeS 2 ). Being a dense mineral, it can be removed from coal by mechanical means, e.g. by froth flotation . Some sulfate occurs in coal, especially weathered samples. It is not volatilized and can be removed by washing. Minor components include: As minerals, Hg, As, and Se are not problematic to the environment, especially since they are only trace components. They become however mobile (volatile or water-soluble) when these minerals are combusted. Most coal
9424-406: The former's morphology, usually darker wing linings, and differences in appearance of primary patch and carpal arc. The juvenile usually lacks the pale nape patch of the lesser spotted eagle, but it is sometimes present, "albeit only slightly paler than rest of plumage and never ochre or orange". Typically, the spotting and barring pattern is much stronger in juvenile greater spotted eagles, but this
9548-458: The former's thicker well-spotted quill bars and paler underwing diagonal. In the eastern portion of range, they can be told apart from the even darker black eagle , which is much slimmer and has paddle-shaped wings and a long and clearly barred tail. This raptor breeds primarily in the Palearctic and the Indomalayan regions. It also breeds in central and southeastern Europe; however, it
9672-414: The greater spotted eagle and the lesser spotted eagle occurs perhaps because the two species have one of the closest relationships of any closely studied Accipitrid taxa, despite significant genetic differences. The mitochondrial genetic sequences of these species have more than 3% divergence, about twice what is considered the minimum genetic difference to distinguish two species. A third spotted eagle,
9796-448: The greater spotted eagle will sometimes prey on amphibians, reptiles (mainly small-to-mid-sized snakes), and occasionally small fish and insects. Pellets are considered the most reliable way to determine the diets of greater spotted eagle, as prey remains alone can be biased towards birds. As can be expected by their habitat preferences, greater spotted eagles tend to eat vertebrates associated with water. Generally, its prey spectrum
9920-476: The greater spotted eagle, which has a shorter neck, smaller bill with a shorter gape line, no pale nape patch (seen in adult steppe), narrower and less baggy trousers, and generally much shorter, slightly broader wings. Although visually similar at a distance, the steppe eagle has bolder, more extensive barring on the greyer flight feathers, complete lack of carpal arcs below, paler throat and nape, and larger but more diffuse primary patch. Greater spotted eagles of
10044-475: The heat and pressure of deep burial caused the loss of water, methane and carbon dioxide and increased the proportion of carbon. The grade of coal produced depended on the maximum pressure and temperature reached, with lignite (also called "brown coal") produced under relatively mild conditions, and sub-bituminous coal , bituminous coal , or anthracite coal (also called "hard coal" or "black coal") produced in turn with increasing temperature and pressure. Of
10168-431: The increasing tendency of the anthracite to break with a conchoidal fracture , similar to the way thick glass breaks. As geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade or rank increases successively into: There are several international standards for coal. The classification of coal is generally based on the content of volatiles . However
10292-563: The juvenile has a creamy trailing edge to the wings and tail. Below, juvenile greater spotted eagles have largely black (apart from the creamy crissum) wing linings contrasting with paler grayer-soot flight feathers. Other juvenile plumages are variably paler but with quills as those of a typical juvenile. Birds that breed in the Volga – Ural area are slightly larger and more muted in plumage characteristics. Slightly smaller individuals seem to be prevalent farther west in Europe. There appears to be
10416-431: The larger wing-coverts. Furthermore, the Indian spotted eagle has a notably deeper gape extending behind its eye. Compared to non-spotted eagles of similar or larger sizes, the greater spotted eagle tends to be fairly compact in features with proportionately broad (and short-looking) wings, a shortish tail, and an overall darker and distinctly patterned plumage. The steppe eagle is similar to but larger and bulkier than
10540-518: The late Carboniferous ( Pennsylvanian ) and Permian times. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution . With the invention of the steam engine , coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity . Some iron and steel -making and other industrial processes burn coal. The extraction and burning of coal damages
10664-453: The morphology and some properties of the original plant. In many coals, individual macerals can be identified visually. Some macerals include: In coalification huminite is replaced by vitreous (shiny) vitrinite . Maturation of bituminous coal is characterized by bitumenization , in which part of the coal is converted to bitumen , a hydrocarbon-rich gel. Maturation to anthracite is characterized by debitumenization (from demethanation) and
10788-405: The most important distinction is between thermal coal (also known as steam coal), which is burnt to generate electricity via steam; and metallurgical coal (also known as coking coal), which is burnt at high temperature to make steel . Hilt's law is a geological observation that (within a small area) the deeper the coal is found, the higher its rank (or grade). It applies if the thermal gradient
10912-763: The native mangrove and Phragmites reed-beds that once lined the coastal bays have been almost entirely eliminated. In southern Iran, they are usually found in mangrove areas. A key habitat in Iraq is the Mesopotamian Marshes . Wintering habitats in Israel are the wettest available valleys and damp open zones, chiefly cultivated fields and fishponds near patches of trees, with similar habitats used in Oman. Greater spotted eagles are typically found from sea level to 300 m (980 ft) and are characteristically
11036-407: The nature of Carboniferous forests, which included lycophyte trees whose determinate growth meant that carbon was not tied up in heartwood of living trees for long periods. One theory suggested that about 360 million years ago, some plants evolved the ability to produce lignin , a complex polymer that made their cellulose stems much harder and more woody. The ability to produce lignin led to
11160-823: The northern tip of Vietnam , discontinuously in southeastern Vietnam and much of Cambodia , and southern coastal Malaysia . In China , wintering greater spotted eagles range from Jiangsu and Anhui continuously down to northern Guangdong across to Taiwan , and rarely in Korea . Greater spotted eagles are found in open wet forests and forest edges , often adjoining marshes , swampy patches , bogs , or wet meadows , as well as river-valley woodlands and floodplain forests. They are generally found in wetlands more often than lesser spotted eagles, but can be found in drier hillside forests in Central Asia . The difference in habitat preferences between these species
11284-455: The number of double bonds between carbon). As carbonization proceeds, aliphatic compounds convert to aromatic compounds . Similarly, aromatic rings fuse into polyaromatic compounds (linked rings of carbon atoms). The structure increasingly resembles graphene , the structural element of graphite. Chemical changes are accompanied by physical changes, such as decrease in average pore size. The macerals are coalified plant parts that retain
11408-418: The outermost three primaries, the secondaries, and the innermost primaries. At close range, nine to eleven dense narrow dark bars fading toward wing tips are visible. When seen in flight, the normal adult is uniformly blackish with a faint pale U above the tail, barely paler wing coverts, and paler quills. It is not unusual for adults to have slightly paler wing linings, similar to lesser spotted eagles, but only
11532-456: The pre-combustion treatment, turbine technology (e.g. supercritical steam generator ) and the age of the plant. A few integrated gasification combined cycle (IGCC) power plants have been built, which burn coal more efficiently. Instead of pulverizing the coal and burning it directly as fuel in the steam-generating boiler, the coal is gasified to create syngas , which is burned in a gas turbine to produce electricity (just like natural gas
11656-427: The reacting groups are attached. Dehydration and decarboxylation take place early in coalification, while demethanation begins only after the coal has already reached bituminous rank. The effect of decarboxylation is to reduce the percentage of oxygen, while demethanation reduces the percentage of hydrogen. Dehydration does both, and (together with demethanation) reduces the saturation of the carbon backbone (increasing
11780-671: The return journey in less than a month. Satellite tracking of an eagle breeding in Estonia confirmed it consistently used the same wintering ground in coastal Catalonia , Spain, over seven consecutive years. Despite some individual devotedness to wintering grounds, one radiotracked individual initially trapped in the United Arab Emirates was found the following winter to go instead to Pakistan from its Kazakh breeding grounds, showing some variability in this regard. A wintering greater spotted eagle in southwest Saudi Arabia (from
11904-527: The river's entrance to the Aegean, at the site previously known as Ennea Hodoi ('Nine roads'). When Xerxes I of Persia crossed the river during his invasion in 480 BC he buried alive nine young boys and nine maidens as a sacrifice to the river god. The forces of Alexander I of Macedon defeated the remnants of Xerxes' army near Ennea Hodoi in 479 BC. In 424 BC the Spartan general Brasidas after crossing
12028-450: The second winter, when most coverts are then newly molted with smaller pale tips. From about the middle of third year onwards, the plumage is more adult-like with few or no indistinct spots left, but remiges are of unequal age and untidy looking. The subadult is generally more uniform in color, but often still shows some pale tips to the greater coverts. Maturity is obtained by about the fifth year, though sometimes they may not breed until
12152-442: The sixth. The bare parts change little in color at different ages, with eyes being dark brown, while the beak and feet are yellow in all ages. In flight, this is a large, dark raptor (often looking bigger than its true size) with a well-protruding head, long wings (which often look shorter due to their broadness), slightly bulging secondaries , and rather squared seven-finger tips, although juvenile wings can look more rounded. On
12276-548: The slenderer accipitrine hawks than previously believed. The greater spotted eagle's closest living relative is the lesser spotted eagle. They are believed to have diverged from their most recent common ancestor around the middle Pliocene , approximately 3.6 million years ago (mya). This "proto-spotted eagle" probably lived in the general region of modern-day Afghanistan , and split into northern and southern lineages when both glaciers and deserts advanced in Central Asia at
12400-522: The spotted eagles form a monophyletic group with each other and the long-crested eagle ( Lophaetus occipitalis ). Studies suggest that the spotted eagles should be grouped with Lophaetus , or that all of these species should be grouped within Aquila . Furthermore, a close relationship has been found between the spotted eagles and the black eagle ( Ictinaetus malaiensis ) native to Asia. The spotted eagles, long-crested eagle, and black eagle may comprise
12524-524: The start of the last ice age . The northern lineage subsequently separated into the greater (eastern) and lesser (western) spotted eagle species of today, probably around the Pliocene– Pleistocene boundary, almost 2 mya. Spotted eagles were classified as part of the genus Aquila , along with several other mostly large, brownish eagles. However, molecular phylogenetic studies using one mitochondrial and two nuclear gene sequences showed that
12648-886: The steppe, and in forested swamps. In Kazakhstan, riparian forests in lowland steppes and forest-steppes mosaics are their primary habitat. In winter, much like during breeding, they usually occur in wetter habitats than most other eagles, including forested river deltas , mangrove forests , marshes , lakeshores , and, in India especially, jheels . However, greater spotted eagles have also been documented in semi-arid Acacia savannas in northeastern Africa. Reportedly in Eritrea , they occur in open moorland , around villages, and lowland grasslands , while in Sudan they are usually in shrubby areas. One seen wintering in Ankara , Turkey,
12772-681: The straits of the Red Sea . Old claims of as many as a thousand migrating eagles in the fall at Bosphorus are possibly erroneous (although there has possibly been a reduction of up to 75% from historic peak migrating numbers). In South Baikal in Irkutsk Oblast , Russia, greater spotted eagles accounted for only 0.2% of the observed migrating raptors in autumn migration (7–34 individuals annually; 137 individuals over 8 years). The largest (modern?) counts were 86 and 74 at Suez , Egypt, in autumn and spring, respectively, with smaller numbers recorded crossing into Africa at Bab-el-Mandeb , although
12896-399: The sulfur and most of the nitrogen is incorporated into the organic fraction in the form of organosulfur compounds and organonitrogen compounds . This sulfur and nitrogen are strongly bound within the hydrocarbon matrix. These elements are released as SO 2 and NO x upon combustion. They cannot be removed, economically at least, otherwise. Some coals contain inorganic sulfur, mainly in
13020-603: The summer in Saudi Arabia. Similarly, records show lingering numbers of this species into at least May in Peninsular Malaysia. The greater spotted eagle is a slightly opportunistic predator but tends to favor rather particular prey types. Their diet tends to be composed mostly of small mammals. Despite some dietary similarities with the lesser spotted eagle, the greater spotted eagle's diet includes more birds and favors larger prey. Beyond mammals and birds,
13144-418: The tail tip. The tail is relatively short and rounded. The overall effect of the broad wings and short tail can give them an almost vulture -like silhouette. The feet are large, and the feathers covering the legs are less compactly arranged than on lesser spotted eagles. Greater spotted eagles tend to perch in the open. Most perches are on treetops at a forest edge , or more isolated vantage points such as
13268-742: The wing, and longer-tailed, making their proportions closer to the lesser. Greater spotted eagles can be clearly larger in size, with females effectively dwarfing most lesser spotted eagles, but there is a broad size overlap between the two species. In some cases, male greater spotted eagles can be scarcely any larger than male lesser spotted eagles. Side-by-side, greater spotted eagles are typically conspicuously darker than lesser spotted eagles, and notable for their dark uppertail coverts, lack of nape patch, blackish-brown uniform arms, and uniform, dark upperwing coverts (not contrastingly rusty brownish). Although difficult, intermediate greater spotted eagles can be distinguished from young lesser spotted eagles by
13392-512: The wing, greater spotted eagles appear heavy-bodied, often appearing suspended below the wings and with a relatively short, broad tail. They have quick wing beats with little upstroke and appear to have comparatively lighter flight actions than steppe eagles ( Aquila nipalensis ), but appear somewhat heavier, less graceful, and less Buteo -like than lesser spotted eagles. Greater spotted eagles soar on almost flat wings, with hands often slightly lowered and their primaries well spread. When gliding,
13516-408: The wings are bowed with a clear angle between arms and hands, emphasizing the wings' short look. On their upperwings, greater spotted eagles variably show a pale primary patch formed mainly by white based shafts and partially pale outer webs. This is seen at all ages but is much smaller and less obvious on adults. The underwing almost invariably has a single white crescent formed by the white base of
13640-636: The winter range is through the Indo-Gangetic Plain to Bihar , Jharkhand , West Bengal to Assam (including the North Cachar hills), and northeastern hill states extending south through central India. They were once reasonably common in the Malabar and Carnatic coasts but likely only before a hundred years ago. After another gap, they are found in much of southern and central Myanmar, central and southern Thailand, southern Laos ,
13764-415: The world's coal-generated electricity. Efforts around the world to reduce the use of coal have led some regions to switch to natural gas and renewable energy . In 2018 coal-fired power station capacity factor averaged 51%, that is they operated for about half their available operating hours. Coke is a solid carbonaceous residue that is used in manufacturing steel and other iron-containing products. Coke
13888-590: Was 8.3 billion tonnes in 2022, and is set to remain at record levels in 2023. To meet the Paris Agreement target of keeping global warming below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030, and "phasing down" coal was agreed upon in the Glasgow Climate Pact . The largest consumer and importer of coal in 2020 was China , which accounts for almost half the world's annual coal production, followed by India with about
14012-468: Was a hydronym in ancient Greek mythology , referring to a mythical Thracian king that was drowned in the river. Strymón was also used as a personal name in various regions of Ancient Greece during the 3rd century BC. In Macedonian it is called Струма [ˈstrumɐ] ; while in Turkish : Karasu [kaɾaˈsu] , 'black water'). In 437 BC, the ancient Greek city of Amphipolis was founded near
14136-574: Was based on the trading of this commodity. Coal continues to arrive on beaches around the world from both natural erosion of exposed coal seams and windswept spills from cargo ships. Many homes in such areas gather this coal as a significant, and sometimes primary, source of home heating fuel. Coal consists mainly of a black mixture of diverse organic compounds and polymers. Of course, several kinds of coals exist, with variable dark colors and variable compositions. Young coals (brown coal, lignite) are not black. The two main black coals are bituminous, which
14260-510: Was carried to London by sea. In 1257–1259, coal from Newcastle upon Tyne was shipped to London for the smiths and lime -burners building Westminster Abbey . Seacoal Lane and Newcastle Lane, where coal was unloaded at wharves along the River Fleet , still exist. These easily accessible sources had largely become exhausted (or could not meet the growing demand) by the 13th century, when underground extraction by shaft mining or adits
14384-588: Was confirmed in northeastern Poland, where greater spotted eagles nested in wooded areas on floodplains with considerably more annual flooding than those nested in by lesser spotted eagles. Although typically scarce while breeding in areas modified by heavy human development, they have been seen hunting over cultivated land in Estonia and migrating over lowland farms in the Czech Republic . In Russia, they are found in transition zones between taiga forest and open steppe (often around river valleys ), in pine forests , near dwarf forests , in wet, wooded areas of
14508-612: Was developed in the Soviet Union , or in an MHD topping cycle . However these are not widely used due to lack of profit. In 2017 38% of the world's electricity came from coal, the same percentage as 30 years previously. In 2018 global installed capacity was 2 TW (of which 1TW is in China) which was 30% of total electricity generation capacity. The most dependent major country is South Africa, with over 80% of its electricity generated by coal; but China alone generates more than half of
14632-408: Was developed. The alternative name was "pitcoal", because it came from mines. Cooking and home heating with coal (in addition to firewood or instead of it) has been done in various times and places throughout human history, especially in times and places where ground-surface coal was available and firewood was scarce, but a widespread reliance on coal for home hearths probably never existed until such
14756-497: Was during the Late Paleozoic icehouse , a time of global glaciation . However, the drop in global sea level accompanying the glaciation exposed continental shelves that had previously been submerged, and to these were added wide river deltas produced by increased erosion due to the drop in base level . These widespread areas of wetlands provided ideal conditions for coal formation. The rapid formation of coal ended with
14880-902: Was fought close the river in 1014 between the Bulgarians under Emperor Samuel and the Byzantines under Emperor Basil II and determined the fall of the First Bulgarian Empire four years later. In 1913, the Greek Army was nearly surrounded in the Kresna Gorge of the Struma by the Bulgarian Army during the Second Balkan War , and the Greeks were forced to ask for armistice. The river valley
15004-707: Was in an upland forest area. In the Mediterranean Basin, a study found that the preferred habitats of wintering greater spotted eagles were salt marshes and coastal lagoons with freshwater areas. They are not uncommon in paddy fields and sometimes garbage dumps in Asia during winter, being much more adaptable to human-modified areas in this season, though by and large prefer assorted wetlands, mudflats, large rivers, estuaries, and mangroves. In Arabia, they are largely found now in manmade habitats—such as sewage farms, reservoirs , and agricultural land—since
15128-627: Was once known as "steam coal" as it was widely used as a fuel for steam locomotives . In this specialized use, it is sometimes known as "sea coal" in the United States. Small "steam coal", also called dry small steam nuts (DSSN), was used as a fuel for domestic water heating . Coal played an important role in industry in the 19th and 20th century. The predecessor of the European Union , the European Coal and Steel Community ,
15252-803: Was part of the Macedonian front in World War I . The ship Struma , which took Jewish refugees out of Romania in World War II and was torpedoed and sunk in the Black Sea , causing nearly 800 deaths, was named after the river. The river's mouth and Lake Kerkini , a lake that the river is feeding and exiting, are both national parks and part of the Natura 2000 network. More than 300 bird species have been observed at these locations and some of them are considered endangered or vulnerable , like
15376-430: Was used for electricity generation. Coal burnt in coal power stations to generate electricity is called thermal coal . It is usually pulverized and then burned in a furnace with a boiler . The furnace heat converts boiler water to steam , which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process varies between about 25% and 50% depending on
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