Description.

Like the sporophytes of seed plants, those of ferns consist of stems, leaves and roots. Ferns differ from seed plants in reproducing by spores and from bryophytes in that, like seed plants, they are Polysporangiophytes, their sporophytes branching and producing many sporangia. Unlike bryophytes, fern sporophytes are free-living and only briefly dependent on the maternal gametophyte.  Stems: Fern stems are often referred to as rhizomes, even though they grow underground only in some of the species. Epiphytic species and many of the terrestrial ones have above-ground creeping stolons (e.g., Polypodiaceae), and many groups have above-ground erect semi-woody trunks (e.g., Cyatheaceae). These can reach up to tall in a few species (e.g., "Cyathea brownii" on Norfolk Island and "Cyathea medullaris" in New Zealand).  Leaf: The green, photosynthetic part of the plant is technically a and in ferns, it is often referred to as a "frond". New leaves typically expand by the unrolling of a tight spiral called a crozier or fiddlehead into fronds. This uncurling of the leaf is termed circinate vernation. Leaves are divided into two types a trophophyll and a sporophyll. A trophophyll frond is a vegetative leaf analogous to the typical green leaves of seed plants that does not produce spores, instead only producing sugars by photosynthesis. A sporophyll frond is a fertile leaf that produces spores borne in sporangia that are usually clustered to form sori. In most ferns, fertile leaves are morphologically very similar to the sterile ones, and they photosynthesize in the same way. In some groups, the fertile leaves are much narrower than the sterile leaves, and may even have no green tissue at all (e.g., Blechnaceae, Lomariopsidaceae). The anatomy of fern leaves can either be simple or highly divided. In tree ferns, the main stalk that connects the leaf to the stem (known as the stipe), often has multiple leaflets. The leafy structures that grow from the stipe are known as pinnae and are often again divided into smaller pinnules.  Roots: The underground non-photosynthetic structures that take up water and nutrients from soil. They are always fibrous and structurally are very similar to the roots of seed plants.  Like all other vascular plants, the diploid sporophyte is the dominant phase or generation in the life cycle. The gametophytes of ferns, however, are very different from those of seed plants. They are free-living and resemble liverworts, whereas those of seed plants develop within the spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte typically consists of:

Taxonomy.

Carl Linnaeus (1753) originally recognized 15 genera of ferns and fern allies, classifying them in class Cryptogamia in two groups, Filices (e.g. "Polypodium") and Musci (mosses). By 1806 this had increased to 38 genera, and has progressively increased since ("see Figure 1"). Ferns were traditionally classified in the class Filices, and later in a Division of the Plant Kingdom named Pteridophyta or Filicophyta. Pteridophyta is no longer recognised as a valid taxon because it is paraphyletic. The ferns are also referred to as Polypodiophyta or, when treated as a subdivision of Tracheophyta (vascular plants), Polypodiopsida, although this name sometimes only refers to leptosporangiate ferns. Traditionally, all of the spore producing vascular plants were informally denominated the pteridophytes, rendering the term synonymous with ferns and fern allies. This can be confusing because members of the division Pteridophyta were also denominated pteridophytes ("sensu stricto").  Traditionally, three discrete groups have been denominated ferns: two groups of eusporangiate ferns, the families Ophioglossaceae (adder's tongues, moonworts, and grape ferns) and Marattiaceae; and the leptosporangiate ferns. The Marattiaceae are a primitive group of tropical ferns with large, fleshy rhizomes and are now thought to be a sibling taxon to the leptosporangiate ferns. Several other groups of species were considered fern allies: the clubmosses, spikemosses, and quillworts in Lycopodiophyta; the whisk ferns of Psilotaceae; and the horsetails of Equisetaceae. Since this grouping is polyphyletic, the term fern allies should be abandoned, except in a historical context. More recent genetic studies demonstrated that the Lycopodiophyta are more distantly related to other vascular plants, having radiated evolutionarily at the base of the vascular plant clade, while both the whisk ferns and horsetails are as closely related to leptosporangiate ferns as the ophioglossoid ferns and Marattiaceae. In fact, the whisk ferns and ophioglossoid ferns are demonstrably a clade, and the horsetails and Marattiaceae are arguably another clade.

Molecular phylogenetics.

Smith et al. (2006) carried out the first higher-level pteridophyte classification published in the molecular phylogenetic era, and considered the ferns as monilophytes, as follows:  Molecular data, which remain poorly constrained for many parts of the plants' phylogeny, have been supplemented by morphological observations supporting the inclusion of Equisetaceae in the ferns, notably relating to the construction of their sperm and peculiarities of their roots. However, there remained differences of opinion about the placement of the genus "Equisetum" (see Equisetopsida for further discussion). One possible solution was to denominate only the leptosporangiate ferns as "true ferns" while denominating the other three groups as fern allies. In practice, numerous classification schemes have been proposed for ferns and fern allies, and there has been little consensus among them.  The leptosporangiate ferns are sometimes called "true ferns". This group includes most plants familiarly known as ferns. Modern research supports older ideas based on morphology that the Osmundaceae diverged early in the evolutionary history of the leptosporangiate ferns; in certain ways this family is intermediate between the eusporangiate ferns and the leptosporangiate ferns. Rai and Graham (2010) broadly supported the primary groups, but queried their relationships, concluding that "at present perhaps the best that can be said about all relationships among the major lineages of monilophytes in current studies is that we do not understand them very well". Grewe et al. (2013) confirmed the inclusion of horsetails within ferns "sensu lato", but also suggested that uncertainties remained in their precise placement. Other classifications have raised Ophioglossales to the rank of a fifth class, separating the whisk ferns and ophioglossoid ferns.  One problem with the classification of ferns is that of cryptic species. A cryptic species is a species that is morphologically similar to another species, but differs genetically in ways that prevent fertile interbreeding. A good example of this is the currently designated species "Asplenium trichomanes" (maidenhair spleenwort). This is actually a species complex that includes distinct diploid and tetraploid races. There are minor but unclear morphological differences between the two groups, which prefer distinctly differing habitats. In many cases such as this, the species complexes have been separated into separate species, thus raising the total number of species of ferns. Possibly many more cryptic species are yet to be discovered and designated.

Phylogeny.

The ferns are related to other higher order taxa, as shown in the following cladogram:

Nomenclature and Subdivision.

The classification of Smith et al. (2006) treated ferns as four classes:  In addition they defined 11 orders and 37 families. That system was a consensus of a number of studies, and was further refined. The phylogenetic relationships are shown in the following cladogram (to the level of orders). This division into four major clades was then confirmed using morphology alone. Subsequently, Chase and Reveal considered both lycopods and ferns as subclasses of a class Equisetopsida (Embryophyta) encompassing all land plants. This is referred to as Equisetopsida "sensu lato" to distinguish it from the narrower use to refer to horsetails alone, Equisetopsida "sensu stricto". They placed the lycopods into subclass Lycopodiidae and the ferns, keeping the term monilophytes, into five subclasses, Equisetidae, Ophioglossidae, Psilotidae, Marattiidae and Polypodiidae, by dividing Smith's Psilotopsida into its two orders and elevating them to subclass (Ophioglossidae and Psilotidae). Christenhusz et al. (2011) followed this use of subclasses but recombined Smith's Psilotopsida as Ophioglossidae, giving four subclasses of ferns again.  Christenhusz and Chase (2014) developed a new classification of ferns and lycopods. They used the term Polypodiophyta for the ferns, subdivided like Smith et al. into four groups (shown with equivalents in the Smith system), with 21 families, approximately 212 genera and 10,535 species;  This was a considerable reduction in the number of families from the 37 in the system of Smith et al., since the approach was more that of lumping rather than splitting. For instance a number of families were reduced to subfamilies. Subsequently, a consensus group was formed, the Pteridophyte Phylogeny Group (PPG), analogous to the Angiosperm Phylogeny Group, publishing their first complete classification in November 2016. They recognise ferns as a class, the Polypodiopsida, with four subclasses as described by Christenhusz and Chase, and which are phylogenetically related as in this cladogram: In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the Polypodiopsida consist of four subclasses, 11 orders, 48 families, 319 genera, and an estimated 10,578 species. Thus Polypodiopsida in the broad sense ("sensu lato") as used by the PPG (Polypodiopsida "sensu" PPG I) needs to be distinguished from the narrower usage ("sensu stricto") of Smith et al. (Polypodiopsida "sensu" Smith et al.) Classification of ferns remains unresolved and controversial with competing viewpoints (splitting vs lumping) between the systems of the PPG on the one hand and Christenhusz and Chase on the other, respectively. In 2018, Christenhusz and Chase explicitly argued against recognizing as many genera as PPG I.

Evolution and biogeography.

Fern-like taxa ("Wattieza") first appear in the fossil record in the middle Devonian period, ca. 390 Mya. By the Triassic, the first evidence of ferns related to several modern families appeared. The great fern radiation occurred in the late Cretaceous, when many modern families of ferns first appeared.

Distribution and habitat.

Ferns are widespread in their distribution, with the greatest abundance in the tropics, and least in arctic areas. The greatest diversity occurs in tropical rainforests. New Zealand, for which the fern is a symbol, has about 230 species, distributed throughout the country.

Ecology.

The stereotypical image of ferns growing in moist shady woodland nooks is far from a complete picture of the habitats where ferns can be found growing. Fern species live in a wide variety of habitats, from remote mountain elevations, to dry desert rock faces, to bodies of water or in open fields. Ferns in general may be thought of as largely being specialists in marginal habitats, often succeeding in places where various environmental factors limit the success of flowering plants. Some ferns are among the world's most serious weed species, including the bracken fern growing in the Scottish highlands, or the mosquito fern ("Azolla") growing in tropical lakes, both species forming large aggressively spreading colonies. There are four particular types of habitats that ferns are found in: moist, shady forests; crevices in rock faces, especially when sheltered from the full sun; acid wetlands including bogs and swamps; and tropical trees, where many species are epiphytes (something like a quarter to a third of all fern species).  Especially the epiphytic ferns have turned out to be hosts of a huge diversity of invertebrates. It is assumed that bird's-nest ferns alone contain up to half the invertebrate biomass within a hectare of rainforest canopy.  Many ferns depend on associations with mycorrhizal fungi. Many ferns grow only within specific pH ranges; for instance, the climbing fern ("Lygodium palmatum") of eastern North America will grow only in moist, intensely acid soils, while the bulblet bladder fern ("Cystopteris bulbifera"), with an overlapping range, is found only on limestone.  The spores are rich in lipids, protein and calories, so some vertebrates eat these. The European woodmouse ("Apodemus sylvaticus") has been found to eat the spores of "Culcita macrocarpa" and the bullfinch ("Pyrrhula murina") and the New Zealand lesser short-tailed bat ("Mystacina tuberculata") also eat fern spores.

Life cycle.

Ferns are vascular plants differing from lycophytes by having true leaves (megaphylls), which are often pinnate. They differ from seed plants (gymnosperms and angiosperms) in reproducing by means of spores and they lack flowers and seeds. Like all land plants, they have a life cycle referred to as alternation of generations, characterized by alternating diploid sporophytic and haploid gametophytic phases. The diploid sporophyte has 2"n" paired chromosomes, where "n" varies from species to species. The haploid gametophyte has "n" unpaired chromosomes, i.e. half the number of the sporophyte. The gametophyte of ferns is a free-living organism, whereas the gametophyte of the gymnosperms and angiosperms is dependent on the sporophyte.  The life cycle of a typical fern proceeds as follows:

Uses.

Ferns are not as important economically as seed plants, but have considerable importance in some societies. Some ferns are used for food, including the fiddleheads of "Pteridium aquilinum" (bracken), "Matteuccia struthiopteris" (ostrich fern), and "Osmundastrum cinnamomeum" (cinnamon fern). "Diplazium esculentum" is also used in the tropics (for example in "budu pakis", a traditional dish of Brunei) as food. Tubers from the "para", "Ptisana salicina" (king fern) are a traditional food in New Zealand and the South Pacific. Fern tubers were used for food 30,000 years ago in Europe. Fern tubers were used by the Guanches to make gofio in the Canary Islands. Ferns are generally not known to be poisonous to humans. Licorice fern rhizomes were chewed by the natives of the Pacific Northwest for their flavor.  Ferns of the genus "Azolla", commonly known as water fern or mosquito ferns are very small, floating plants that do not resemble ferns. The mosquito ferns are used as a biological fertilizer in the rice paddies of southeast Asia, taking advantage of their ability to fix nitrogen from the air into compounds that can then be used by other plants.  Ferns have proved resistant to phytophagous insects. The gene that express the protein Tma12 in an edible fern, "Tectaria macrodonta", has been transferred to cotton plants, which became resistant to whitefly infestations.  Many ferns are grown in horticulture as landscape plants, for cut foliage and as houseplants, especially the Boston fern ("Nephrolepis exaltata") and other members of the genus "Nephrolepis". The bird's nest fern ("Asplenium nidus") is also popular, as are the staghorn ferns (genus "Platycerium"). Perennial (also known as hardy) ferns planted in gardens in the northern hemisphere also have a considerable following.  Several ferns, such as bracken and "Azolla" species are noxious weeds or invasive species. Further examples include Japanese climbing fern ("Lygodium japonicum"), sensitive fern ("Onoclea sensibilis") and Giant water fern ("Salvinia molesta"), one of the world's worst aquatic weeds. The important fossil fuel coal consists of the remains of primitive plants, including ferns.  Ferns have been studied and found to be useful in the removal of heavy metals, especially arsenic, from the soil. Other ferns with some economic significance include:

Culture.

Pteridologist.

The study of ferns and other pteridophytes is called pteridology. A pteridologist is a specialist in the study of pteridophytes in a broader sense that includes the more distantly related lycophytes.

Pteridomania.

Pteridomania is a term for the Victorian era craze of fern collecting and fern motifs in decorative art including pottery, glass, metals, textiles, wood, printed paper, and sculpture "appearing on everything from christening presents to gravestones and memorials." The fashion for growing ferns indoors led to the development of the Wardian case, a glazed cabinet that would exclude air pollutants and maintain the necessary humidity. The dried form of ferns was also used in other arts, being used as a stencil or directly inked for use in a design. The botanical work, "The Ferns of Great Britain and Ireland", is a notable example of this type of nature printing. The process, patented by the artist and publisher Henry Bradbury, impressed a specimen on to a soft lead plate. The first publication to demonstrate this was Alois Auer's "The Discovery of the Nature Printing-Process".  Fern bars were popular in America in the 1970s and 80s.

Folklore.

Ferns figure in folklore, for example in legends about mythical flowers or seeds. In Slavic folklore, ferns are believed to bloom once a year, during the Ivan Kupala night. Although alleged to be exceedingly difficult to find, anyone who sees a fern flower is thought to be guaranteed to be happy and rich for the rest of their life. Similarly, Finnish tradition holds that one who finds the seed of a fern in bloom on Midsummer night will, by possession of it, be guided and be able to travel invisibly to the locations where eternally blazing Will o' the wisps called aarnivalkea mark the spot of hidden treasure. These spots are protected by a spell that prevents anyone but the fern-seed holder from ever knowing their locations. In the US, ferns are thought to have magical properties such as a dried fern can be thrown into hot coals of a fire to exorcise evil spirits, or smoke from a burning fern is thought to drive away snakes and such creatures.

Organisms confused with ferns.

Misnomers.

Several non-fern plants (and even animals) are called ferns and are sometimes confused with ferns. These include:

Fern-like flowering plants.

Some flowering plants such as palms and members of the carrot family have pinnate leaves that somewhat resemble fern fronds. However, these plants have fully developed seeds contained in fruits, rather than the microscopic spores of ferns.

A fern (Polypodiopsida or Polypodiophyta) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the sporophyte is the dominant phase. Ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter group including horsetails or scouring rushes, whisk ferns, marattioid ferns, and ophioglossoid ferns.

Kapradiny ("Polypodiophyta") jsou oddělení výtrusných cévnatých rostlin, čili kapraďorostů ("Pteridophyta"), jehož zástupci jsou hojně rozšířeni po celé Zemi. Současné druhy jsou z velké většiny byliny, ale v některých tropických oblastech rostou i stromovité druhy. Vymřelé stromovité kapradiny se hojně vyskytovaly v permokarbonských lesích. Kapradiny se poprvé objevily ve spodním devonu a největší rozvoj zažily právě během karbonu a permu. V druhohorách a třetihorách spíše kapradiny vymíraly. Evolučně pravděpodobně navazují na oddělení "Rhyniophyta". Kapradiny druhotně netloustnou (tzn. nezvětšují tloušťku stonku nebo kořenu činností laterálního meristému kambia, případně felogénu). Oddělení kapradiny obsahuje jedinou recentní třídu Polypodiopsida (používají se i synonymická označení Filicopsida či Pteridopsida).


Early life.

Sakic was born in Burnaby, British Columbia, to Marijan and Slavica Šakić (originally Šakić, ), immigrants from Croatia in what was then Yugoslavia. Growing up in Burnaby, he did not learn to speak English well until kindergarten, having been raised with Croatian as his mother tongue. At the age of four, Sakic attended his first NHL game, a match between the Vancouver Canucks and Atlanta Flames; after watching the game, Sakic decided that he wanted to become a hockey player. As a smaller player, he was forced to use skill rather than size to excel, and modelled himself after his idol, Wayne Gretzky. After showing exceptional promise as a young hockey player in Burnaby, Sakic was referenced as a new Wayne Gretzky in the making. He scored 83 goals and 156 points in only 80 games for Burnaby, while attending school at Burnaby North Secondary Soon after, he was added to the Lethbridge Broncos of the Western Hockey League (WHL) for the last part of the 1985–86 season.  During the 1986–87 season, the Broncos relocated to Swift Current, Saskatchewan, becoming the Swift Current Broncos. Sakic, playing in his first full season, was named Rookie of the Year of the WHL. He notched 60 goals and 73 assists for 133 points. But while Sakic enjoyed success on the ice, he and his team faced a tragedy on the night of December 30, 1986. The Broncos were driving to a game against the Regina Pats, and due to bad weather conditions, the bus crashed after the driver lost control on a patch of black ice outside of Swift Current. While Sakic was unharmed, four of his teammates (Trent Kresse, Scott Kruger, Chris Mantyka and Brent Ruff) were killed. This incident had a lasting impact on the young Sakic, who declined to talk about the crash throughout his career. The next year, in 1987–88, Sakic was named the WHL Most Valuable Player and Canadian Major Junior Player of the Year. He scored 160 points (78 goals, 82 assists), tying him with Theoren Fleury of the Moose Jaw Warriors for the WHL scoring title.

NHL career.

Quebec Nordiques.

Sakic was drafted 15th overall by the Quebec Nordiques in the 1987 NHL Entry Draft. Rather than make the immediate jump, he told the Nordiques management he would prefer to spend the 1987–88 season in Swift Current to prepare for the NHL. He made his NHL debut on October 6, 1988, against the Hartford Whalers and registered an assist. His first NHL goal came two days later against goaltender Sean Burke of the New Jersey Devils. During the season, he wore #88 because his preferred number, #19 was already taken by a teammate, Alain Côté. While considered a front-runner for the Calder Memorial Trophy as rookie of the year due to his rapid scoring pace, an ankle injury that forced him to miss 10 games in December and the resulting scoring slump helped quash any hopes of winning the award. He would finish his rookie season with 62 points in 70 games, and finishing eighth in voting for the Calder; defenceman Brian Leetch, who won the rookie scoring race with 28 goals and 48 assists, won with forty-two first-place votes, while Sakic only received two third-place votes.  In 1989–90, his second NHL season, Sakic was able to switch his number back to his familiar #19 (Alain Côté had retired over the summer), and scored 102 points, which was ninth overall in the league. At the start of the next season, 1990–91, he was named co-captain along with Steven Finn (Sakic was captain for home games, Finn for away games) and again passed the 100 point mark, improving to 109 points and sixth overall in the league, but would slip during 1991–92 to 94 points, having missed 11 games. Early on in the season, Sakic showed some of his leadership qualities, even while Mike Hough was serving as captain, as he stood firm in the Eric Lindros holdout issue. With Lindros holding out against the Nordiques, who were one of the worst teams in league, Sakic commented, "We only want players here who have the passion to play the game. I'm tired of hearing that name. He's not here and there are a lot of others in this locker room who really care about the game." Lindros was traded a year later, ending the situation and bringing in a number of quality players, which vastly improved the Nordiques. During their first four seasons with Joe Sakic, the Nordiques finished last place in the Adams Division and last in the entire league for three straight years, from 1989 to 1991.  Starting with the 1992–93 season, Sakic became the sole captain of the franchise. Under his leadership, the Nordiques made the playoffs for the first time in six years and set a franchise record for wins and points in the process (since broken by the 2000–01 Colorado Avalanche team). Sakic reached the 100-point plateau, the third time he did so in five years, by scoring 48 goals and 105 points in the regular season, and added another six points in the playoffs. In the shortened 1994–95, after the 1994–95 NHL lock-out, Sakic was eight points behind Jaromír Jágr for the scoring title with a fourth-place finish, and helped the Nordiques win the division title, their first since the 1985–86 season.

Colorado Avalanche.

In May 1995, the Nordiques announced that the team had been sold and were relocating from Quebec. Before the start of the 1995–96 season, the franchise moved to Denver, Colorado, and was renamed the Colorado Avalanche. Sakic led the team to its first Stanley Cup championship in its first year, scoring 120 points in 82 regular season games and 34 points in 22 playoff games. He was awarded the Conn Smythe Trophy as the most valuable player of the 1996 NHL playoffs. During the run for the Cup, Sakic again proved himself to be an effective team leader. Although his Nordiques had missed the playoffs in five of his first seven years in the NHL, he scored 18 goals, including six game-winners, and 34 points. He was one goal off from the record for goals in a playoff year, and his game-winning goals established a new record. In the 1996–97 season, Sakic only played in 65 games due to a lacerated calf, yet still managed to score 74 points as the Avalanche earned their first Presidents' Trophy and third straight division title. He had another great playoff season with eight goals and 17 assists, and took the Avalanche all the way to the conference finals, where they eventually lost to the Detroit Red Wings in six games. As a free agent during the summer of 1997, Sakic signed a three-year, $21 million offer sheet with the New York Rangers as a restricted free agent. Under the collective bargaining agreement at the time, the Avalanche had one week to match the Rangers' offer or let go of Sakic in exchange for five first-round draft picks as compensation. While it seemed as if the Avs could not afford to keep Sakic as they had already committed large amounts of salary to Peter Forsberg and Patrick Roy, an unlikely lifeline would appear in the form of the movie "Air Force One", produced by Avalanche owners COMSAT and a blockbuster hit that summer. Its profits enabled Colorado to match the offer, which instigated a salary raise for many NHL players.  Injuries would again limit Sakic's playing time in the 1997–98 season. While playing in his first Olympics with Team Canada, Sakic hurt his knee and was forced to miss 18 games with the Avalanche. In the 64 games he did play in, he still scored 63 points, enough to earn him his seventh All-Star appearance. He finally rebounded from his injury problems in the 1998–99 season, finishing fifth in the league in scoring with 41 goals and 96 points in only 73 games. He led the Avalanche all the way to within one game of the Stanley Cup Finals, where they lost to the eventual champion Dallas Stars. After the season ended, Sakic was ranked number 94 on "The Hockey News"' list of the 100 Greatest Hockey Players.  During the 1999–2000 season, Sakic reached several career milestones. Injuries limited him to only 60 games, but he still managed to lead the team in scoring with 81 points. On December 27, 1999, against the St. Louis Blues, Sakic earned an assist to become the 56th player in NHL history to reach 1,000 career points. Later in the season, on March 23, 2000, he scored a hat trick against the Phoenix Coyotes, and became the 59th player to score 400 career goals. It also gave him 1,049 points with the Quebec/Colorado franchise, passing Peter Šťastný as the all-time leader on the team.  Sakic eclipsed the 100 point mark again in 2000–01, finishing with 118 along with a career best 54 goals, both being second-best in the league. He won the Hart Memorial Trophy, the Lady Byng Memorial Trophy and the Lester B. Pearson Award (the latter presented to him by former Nordiques mentor Peter Šťastný), while also being a finalist for the Frank J. Selke Trophy. He led the Avalanche to their second Stanley Cup championship, defeating the defending title holders New Jersey Devils in seven games. Memorably, after receiving the Cup from the NHL commissioner, Sakic broke with tradition by not hoisting it first as most captains do, instead passing the Cup straight to Ray Bourque, a player who had waited a record-breaking 22 seasons to win the Stanley Cup.  Sakic led the Avalanche in scoring again in the 2001–02 season, finishing sixth in the league with 79 points. On March 9, 2002, he played in his 1,000th career game. The Avalanche once again reached the Western Conference Finals, but lost to the eventual Cup-winning Detroit Red Wings. The following year, Sakic appeared in only 58 games and finished with just 58 points. He rebounded the following year, finishing third in the league with 87 points. It also marked the first time since the 1993–94 season that his team did not win the division title, which was won by the Vancouver Canucks.  Following the 2004–05 NHL lock-out, the Avalanche were forced to lose many of their key players in order to stay below the salary cap. Even with the loss of teammates Peter Forsberg and Adam Foote, Sakic still helped the Avalanche get into the playoffs, where they eventually lost to the Anaheim Ducks in the conference semi-finals. In June 2006, Sakic signed a one-year, $5.75 million deal to keep him with the Avalanche for the 2006–07 season. Upon the retirement of Steve Yzerman a month later, on July 3, 2006, Sakic became the League leader for most NHL career points scored among active players.  Sakic had another strong season in the 2006–07. He scored his 600th career goal on February 15, 2007, against the Calgary Flames, becoming the 17th player in history to reach the milestone and third that year. On the final day of the regular season, he scored his 100th point, reaching the milestone for the sixth time in his career. At the same time, Sakic became the second-oldest NHL player to score 100 points in a season at age 37, alongside hockey legend Gordie Howe. Despite his efforts as well as a late-season charge, Sakic and the Avalanche missed the playoffs for the first time in 11 years, finishing one point behind the eighth placed Calgary Flames. On May 1, the NHL announced that Sakic was named as one of the three finalists of the Lady Byng Trophy, but it was eventually awarded to Pavel Datsyuk of the Detroit Red Wings.  In April 2007, Sakic signed on for a 19th NHL season with the Colorado Avalanche, signing a one-year deal for 2007–08. Sakic commented on the deal, saying "at this stage in my career, I prefer to do one-year deals as I evaluate my play year-to-year." Upon signing Sakic to the deal, Avalanche General Manager François Giguère said, "Joe is the heart of this organization and his leadership and value to this team and especially our young players is unquestioned." On October 7, 2007, he scored a goal and had an assist against the San Jose Sharks, moving past Phil Esposito into eighth place on the NHL career points list with 1,591. Nineteen days later, Sakic scored a goal and assisted Ryan Smyth for an overtime game-winning goal against the Calgary Flames, reaching his 1,600th point in the NHL. On December 27, 2007, it was announced that Sakic underwent hernia surgery to accelerate the recovery of an injury that had forced him to miss the previous 12 games after a 232 consecutive games played streak. The operation caused him to miss a career-high 38 games. He was activated off of the injured reserve on February 24 and played that night, scoring an assist. On March 22, 2008, Sakic recorded his 1,000th career assist against the Edmonton Oilers, becoming the 11th player in NHL history to reach this milestone.  In June 2008, Sakic had a talk with Colorado General Manager François Giguère and said that he is uncertain with his future with the Avalanche. However, it was announced on August 27, 2008, that Sakic decided to sign a one-year contract with the team. Injuries limited Sakic's playing time in 2008–09. A herniated disk in his back forced him to stop playing in early November, after playing in 15 games, in which Sakic scored 12 points. While at home letting his back heal, Sakic broke three fingers in a snow-blower accident. He announced his retirement on July 9, 2009 The Avalanche retired his jersey, #19, prior to their 2009–10 season opener on October 1, 2009, with a "C" on the banner to represent his lengthy service as team captain (having been the only captain of the Avalanche until he retired). Sakic was also named the inaugural member of the Avalanche Alumni Association.

All-Star Games.

Sakic was voted into the NHL All-Star Game 13 times and played in 12 of them, serving as a captain for two of them, the last in 2007. He had at least one point in 11 of them. The only one that he missed entirely was the 1997 All-Star Game, due to an injury. Sakic won the Most Valuable Player award in the 2004 All-Star Game after scoring a hat trick, despite the Western Conference losing the game. He is the all-time assist leader in All-Star Games with 16 assists and is third place in all-time all-star scoring with 22 points, behind Mario Lemieux (23 points) and Wayne Gretzky (25 points). His best record in an All-Star Game was in 2007, when he scored four assists for the winning team; however the MVP award was given to Daniel Brière, who had a goal and four assists.

International play.

Sakic had an extensive international hockey career, representing Canada at seven international competitions. After being drafted by the Nordiques in 1987, he went on and helped Canada win the 1988 World Junior Championship. His next tournament was the 1991 World Championships, where Canada won the silver medal and Sakic contributed eleven points in ten games. He tried out for the 1991 Canada Cup Canadian team, but was the first player to be cut, being cited for his weak leg strength. Sakic was bitter about the experience, feeling he was not given a good enough chance to prove himself, and called the whole experience "a complete waste of time."  Sakic's first successful professional tournament was the 1994 World Championships, where Canada won its first gold medal in the tournament since 1961. Sakic's seven points in eight games were a crucial part of the team's success. During the 1996 World Cup of Hockey, he played only a minor role in Canada's second-place finish as he scored one goal and two assists in six games. However, the tournament allowed him to showcase that he was indeed a dominant player who had simply been overlooked.  Sakic's first Olympic appearance came in 1998 at Nagano, Japan, the first tournament in which NHL players participated. Bothered by a knee injury, he only scored three points in four games, as the Canadian squad failed to meet expectations and finished in fourth. His second Olympic appearance came in 2002 in Salt Lake City; led by his strong play, the Canadian team reached the gold medal match against Team USA, in which Sakic scored four points and helped Canada win its first gold medal in 50 years. He was later named MVP of the tournament with a cumulative tally of four goals and six assists and became one of the first Canadian members of the Triple Gold Club. Sakic also played a part in Canada's triumph in the 2004 World Cup of Hockey, where he scored six points in six games.  On December 21, 2005, Sakic was named captain of Team Canada for the 2006 Winter Olympics in Turin, Italy. Once again, Team Canada was heavily favoured and given high expectations, but they failed to medal, finishing seventh overall. Sakic finished the tournament with three points.

Post-playing career.

After he retired, Sakic decided to take time off from hockey and spent time with his family. In 2011, two years after his retirement, Sakic returned to the Avalanche to work in their front office. He was named an executive advisor and alternate governor for the team, effective at the end of the 2010–11 season. In his role as an advisor, Sakic would advise the team in hockey-related matters, and as an alternate governor, would represent the team at Board of Governors meetings.  On June 26, 2012, Sakic was selected to the Hockey Hall of Fame in his first year of eligibility. He was inducted into the Hockey Hall of Fame on November 12, 2012, along with Mats Sundin, Pavel Bure and Adam Oates. Sakic was the only member of his class who won the Stanley Cup during his career.  On May 10, 2013, the Avalanche promoted Sakic to Executive Vice President of Hockey Operations. In this expanded role, Sakic has the final say on all matters regarding hockey personnel. During Patrick Roy's time as head coach, they shared most of the duties normally held by a general manager. General Manager Greg Sherman remained in his post, but served mainly in an advisory role to Roy and Sakic. This de facto arrangement was formalized the following season, when Sakic was formally named general manager and Sherman was demoted to assistant general manager.  Apart from his two years away from hockey, Sakic has spent almost three decades with the Nordiques/Avalanche organization as either a player or executive.

Personal life.

Sakic and his wife Debbie have three children: son Mitchell, born in 1996, and fraternal twins; son Chase and daughter Kamryn, born in October 2000. They met at a local high school while he was playing in Swift Current, and they frequently return to the town during the off-season. Sakic is an avid golfer, and competed in the celebrity Pro Am golf tournament in Lake Tahoe in the summer of 2006. Each summer, he also hosts his own charity golf tournament which benefits the Food Bank of the Rockies. His charity work, which is estimated to have provided more than seven million meals to poor children and families, has earned an NHL Foundation Player Award in 2007.  Sakic was a fan favourite in his hometown of Burnaby, where a street has been named Joe Sakic Way in his honour. Throughout British Columbia, he is affectionately known as "Burnaby Joe"; in Colorado, he is known simply as "Super Joe." His younger brother Brian joined the Swift Current Broncos during Joe's final season with the team, and later played for the Flint Generals of the United Hockey League. Sakic also has an uncredited role in the movie Happy Gilmore as a "player at hockey tryouts".

Legacy.

Milestones.

Sakic recorded his 1,000th career point on December 27, 1999, against the St. Louis Blues. He became the 11th player to reach 1,500 points, doing so on October 25, 2006, with an assist against the Washington Capitals, and the sixth to do so with one franchise. Gordie Howe, Wayne Gretzky, Mario Lemieux, Ray Bourque and Steve Yzerman are the others who have achieved this feat. On March 22, 2008, Sakic notched his 1,000th career assist against the Edmonton Oilers on a second period goal scored by Tyler Arnason.  Sakic played his 1,000th career game on March 9, 2002, against the Los Angeles Kings. His 500th career goal came against the Vancouver Canucks on December 11, 2002. In a February 15, 2007, game against the Calgary Flames, Sakic scored his 600th career goal. He also earned his 900th assist, the 16th player to do so, against the Flames in a game on March 12, 2006.  During the final game of the 2006–07 season, Sakic scored his 100th point of the year. This made him, at age 37, the second oldest player in NHL history, after Gordie Howe, to record 100 points in a regular season. He became the longest active tenured captain in the league, with fifteen seasons leading the Nordiques/Avalanche franchise, after the retirement of Steve Yzerman at the conclusion of the 2005–06 regular season. On March 22, 2008, against the Edmonton Oilers, Sakic recorded the 1,000th assist of his career, the 11th player to do so. The gloves he wore in the game were later sent to the Hockey Hall of Fame.  Alongside Bobby Clarke, Wayne Gretzky and Mark Messier, Sakic is one of four players to captain his team to a Stanley Cup championship and win the Hart Memorial Trophy in the same year. Sakic is also a member of the Triple Gold Club, a term used in ice hockey to describe players who have won an Olympic Gold medal, a World Championship Gold medal and the Stanley Cup.

Records.

In his 20-year career with the Nordiques and Avalanche, Sakic has obtained nearly all of the franchise scoring records, including most all-time goals (625), assists (1,016) and points (1,641). He also holds the franchise record for most games played (1,363), and is on several notable NHL records which are most All-Star game assists (16) and most playoff overtime goals (8).  Sakic is also the only player ever to score 100 points in a season for a team that finishes dead last in the NHL regular season standings, accomplishing this feat in 1989–90 with Quebec Nordiques.

Leadership.

Throughout his career, Sakic was one of the top scorers in the league, but in his early years, he was criticized for not leading his team to playoff success. While in Quebec, the Nordiques were one of the worst teams in the league, finishing last in their division five out of the seven years Sakic was with the team, including three straight years of being last overall in the league. After leading the Avalanche to the Stanley Cup in 1996 with his 34 playoff points, Sakic began to be seen as capable of leading a team to success, and he was seen as one of the league's premier players.  Though Sakic was a quiet individual, he was able to motivate his team to play at higher levels, which earned him the respect of his peers and executives. The first signs of Sakic's leadership began to show while still a member of the Swift Current Broncos of the WHL. After the bus crash that killed four of his teammates, Sakic was seen as the leader of the team, acknowledging that the experience changed his outlook on life. Early in his career with the Nordiques (when Mike Hough was still captain), with the team hoping to rebuild around their top draft pick Eric Lindros, and holding onto Lindros' rights for the season when he refused to sign, Sakic suggested that the team could progress without Lindros, saying, "We only want players here who have the passion to play the game. I'm tired of hearing that name. He's not here and there are a lot of others in this locker room who really care about the game." Lindros was traded a year later, bringing in a number of quality players, which vastly improved the Nordiques. Sakic's leadership qualities led him to be courted by other teams, such as in the summer of 1997, when the New York Rangers offered him a large contract in order to replace departed captain Mark Messier, though the Avalanche ultimately matched the offer and retained Sakic.  One of the most defining actions of Sakic's career was at the conclusion of the 2001 playoffs. Defying the NHL tradition of the captain being the first to skate around with the Stanley Cup, Sakic passed it off to teammate Ray Bourque. Bourque, one of the best defencemen to ever play, had been traded to the Avalanche the year before after spending 21 years with the Boston Bruins and setting the record for most games played without winning the Cup. Sakic's handing of the Stanley Cup exemplifies his classiness and how he performs through actions rather than words.  When an eye injury forced Steve Yzerman (who normally wore number 19 for Canada) to miss the 2004 World Cup of Hockey, Sakic and Joe Thornton both refused the number out of respect for their injured countryman, even though both players each wore the number 19 for their respective NHL clubs and who were now eligible to wear it for Team Canada in Yzerman's absence.  Sakic's leadership qualities and abilities helped carry the Avalanche in the years after their 2001 Stanley Cup, which saw the team lose key players to retirement and free agency, especially after the 2004–05 lock-out.

Joseph Steven Sakic (; born July 7, 1969) is a Canadian professional ice hockey executive and former player. He played his entire 21-year National Hockey League (NHL) career with the Quebec Nordiques/Colorado Avalanche franchise. Named captain of the team in 1992 (after serving as a co-captain in 1990–91), Sakic is regarded as one of the greatest team leaders in league history and was able to consistently motivate his team to play at a winning level. Sakic led the Avalanche to Stanley Cup titles in 1996 and 2001, being named the most valuable player of the 1996 playoffs, and honoured as the MVP of the NHL in 2001 by the hockey writers and his fellow players. He is one of six players to participate in both of the team's Stanley Cup victories. Sakic was also named to play in 13 NHL All-Star Games and selected to the NHL First All-Star Team at centre three times.

Joe Sakic celým jménem Joseph Steven Sakic, (* 7. červenec 1969, Burnaby, Britská Kolumbie) je bývalý kanadský hokejista. Zajímavostí je, že jeho rodiče (pův. jm. Šakić) se do Kanady přistěhovali z chorvatského města Imotski. Od roku 2002 je členem prestižního Triple Gold Clubu, jenž sdružuje hráče, kteří vyhráli všechny tři hlavní hokejové turnaje (Stanley Cup, Olympijské hry a Mistrovství světa). U příležitosti 100. výročí NHL byl v lednu 2017 vybrán jako jeden ze sta nejlepších hráčů historie ligy.


History.

In the pre-Roman era, the hills in the Piran area were inhabited by Illyrian Histri tribes who were farmers, hunters and fishermen. They were also pirates who disrupted Roman trade in the northern Adriatic. The Piran peninsula was incorporated into the Roman Empire in 178 and 177 BC and settled in the following years with rural homes ("villae rusticae"). The decline of the Roman Empire, from the 5th century AD onward, and incursions by the Avars and Slavs at the end of the 6th century, prompted the Roman population to withdraw into easily defensible locations such as islands or peninsulas. This started local urbanisation and by the 7th century, under Byzantine rule, Piran had become heavily fortified. Despite the defences, the Franks conquered Istria in 788 and Slavs settled in the region. By 952, Piran had become a part of the Holy Roman Empire.  The earliest reliable records of the area are in the 7th century work Cosmographia by an anonymous cleric of Ravenna. The name of the town most probably originates from the Greek "pyrrhos", which means "red", because of the reddish flysch stones commonly found in the town's area. Some historians also refer it to "pyros", meaning fire, due to ancient lighthouses which were supposed to be on the edge of the marina.  From 1283 to 1797, the town became part of the Republic of Venice, where it was governed in a semi-autonoumous way, with a council of local noblemen assisting the Venetian delegate. Several enemy (e.g. from the Republic of Genoa) and pirate assaults were repelled during the late Middle Ages; a great pestilence hit the town in 1558, killing about two thirds of the population. The last decades of Venetian rule were marked by decadence, due to the competition with the nearby Austrian port town of Trieste.  The town was annexed to the Austrian Empire in 1797; but during the years from 1806 to 1814, when it was ceded to the Napoleonic Empire. On 22 February 1812, the Battle of Pirano was fought between a British and a French ship of the line in the vicinity of Piran. This was a minor battle of the Adriatic campaign of the Napoleonic Wars. The French "Rivoli" had been recently completed at Venice. The French naval authorities intended her to bolster French forces in the Adriatic, following a succession of defeats in the preceding year. Captain John Talbot of HMS "Victorious" arrived off Venice in mid-February and blockaded the port. When the "Rivoli" attempted to escape under the cover of fog, Talbot chased her and forced her to surrender in a five-hour battle, the "Rivoli" lost over half her crew as either wounded or dead. This was the only battle ever fought in the sea nowadays belonging to Slovenia.  At the end of the 19th century and the beginning of the 20th century, Piran was an Austro-Hungarian town with over 12,000 inhabitants, larger than the nearby Koper. It was a flourishing market and spa town with good transport connections. The first trolleybus line in the Balkans was introduced to public service on 24 October 1909 in Piran. In 1912, it was replaced by a tramway that operated on the same route till 1953.  After the First World War, together with Trieste and all Istria, the town was ceded to Italy. There were no particular events in those years, until Italy entered the Second World War in 1940. With the defeat of the Axis powers and the rise of Tito's rule, Piran was assigned to the Free Territory of Trieste, Zone B, under Yugoslavian administration. The town was annexed to Yugoslavia in 1954, according to the London Memorandum signed together with Italy. A significant part of Piran's population chose to emigrate to Italy or abroad in the final phase of the Istrian exodus, rather than stay in socialist Yugoslavia. The annexation to Yugoslavia was finally ratified with the Osimo Treaty in 1975, signed by Italy as well. Since 1991, Piran has been part of independent Slovenia.  On 24 October 2010, Slovenia became the first country of former communist Europe to elect a black mayor. The physician Peter Bossman, who came from Ghana in the late 1970s, was elected the Mayor of Piran. He officially took office at the first constitutional meeting of the Municipal Council on 12 November 2010, succeeding Tomaž Gantar. He represents the Social Democrats.  The territorial claims of Croatia and Slovenia in the Gulf of Piran remain an important matter of debate in the Croatia–Slovenia border disputes that began after the dissolution of Yugoslavia.

Culture and education.

Piran is the birthplace of the composer and violinist Giuseppe Tartini, who played an important role in shaping its cultural heritage. The town's main square, Tartini Square (, ), is named after him. In 1892, the 200th anniversary of his birth, a monument to Tartini was erected in Piran. Venetian artist Antonio Dal Zotto was commissioned to create a larger-than-life bronze statue, which was mounted on its pedestal in 1896. The statue dominates the square, overlooked by the Cathedral of Saint George. The painter Cesare Dell'Acqua was also born in Piran.  Piran is the seat of the Euro-Mediterranean University of Slovenia (EMUNI), founded in 2008 as one of the cultural projects of the. The Piran Coastal Galleries, a public institution encompassing a group of six public contemporary art galleries, is based in Piran.

Cultural events.

Musical Evenings of Piran have taken place for decades in Greyfriars Franciscan monastery's atrium, one of the most beautiful cloister atriums in the Slovenian Littoral, which has good acoustics. The municipality's festival is 15 October, which celebrates the foundation of the first Slovenian partisan naval detachment, named Koper, in 1944. This was the first Slovenian naval unit.

Geography and climate.

Piran is located at the tip of the Piran peninsula on the Gulf of Piran.  To the east of the town, along the northern coastline (in the direction to Strunjan) there is a small tourist settlement named Fiesa. Piran and Fiesa are connected by a promenade along the beach. Piran has a humid subtropical climate with warm summers and cool rainy winters. Snow is rare (usually 3 days per year, almost always in traces). There are 22 days a year with maximum temperatures of or higher; on one day a year the temperature does not exceed. Fog appears about 4 days per year, mainly in winter.

Demographics.

According to the Austrian language census of 1910, there were 7,379 inhabitants in the town proper, 95.97% Italians and 0.09% Slovenes. In 1945, the town proper had 5,035 inhabitants, 91.32% Italian and 8.54% Slovene speakers. In 1956 there were 3.574 inhabitants, 67.6% Slovene and 15.5% Italian. After 1947, the ethnic composition changed radically due to the exodus of Italians to Italy and their replacement by Slovene settlers, both from other areas of Slovenian Istria and from interior areas of the country.

Monuments.

Piran was heavily influenced by the Venetian Republic and Austria-Hungary, therefore the monuments differ greatly from those in inner parts of Slovenia. The Piran town walls were constructed to protect the town from Ottoman incursions; many parts of the town walls from different eras remain, and are of interest to tourists. In the middle of the town is the Tartini Square, with a monument in memory of Giuseppe Tartini. Nearby are located various important buildings, such as Tartini’s house, first mentioned in 1384 and one of the oldest in town, the Municipal Palace, Loggia and Benečanka, among others. On the hill above the town is the biggest and most important church, the Church of Saint George, with a Franciscan monastery nearby.

Communications and transport.

There is an international airport and a marina in the vicinity of the town. The medium-wave transmitter of Radio Koper is in Piran. It transmits on 1170 kHz and has a 123.6-metre-tall guyed mast with cage antenna. The town is connected with Koper, Izola, Portorož (the location of the airport), Sečovlje and Lucija by a cheap bus line. The lines of other coastal settlements operate mostly during the tourist season.  The first trolleybus line in the Balkans entered public service on 24 October 1909 in Piran, then part of Austria-Hungary. It ran from Tartini Square along the coast and the shipyard to Portorož and Lucija. The town authorities bought five trolleybuses manufactured by Austrian company Daimler-Motoren-Gesellschaft. In 1912, it was replaced by a tram system that operated until 1953, when it was superseded by buses.

Sports.

Pod Obzidjem Stadium () is a multi-purpose stadium in Piran. It is used for football matches and is the home ground of football team NK Portorož Piran. The stadium currently holds 750 spectators, 500 of them can be seated.

International relations.

Twin towns and sister cities.

Piran is twinned with:

Piran (; ) is a town in southwestern Slovenia on the Gulf of Piran on the Adriatic Sea. It is one of the three major towns of Slovenian Istria. The town has much medieval architecture, with narrow streets and compact houses. Piran is the administrative seat of the Municipality of Piran and one of Slovenia's major tourist attractions. Until the mid-20th century, Italian was the dominant language, but it was replaced by Slovene as demographics shifted.

Piran (, ) je město na výběžku slovinského pobřeží. Jeho dominantou je kostel a pro stísněná přímořská městečka netypické velké kruhové náměstí. Na jeho místě původně stálo nádraží místní dráhy do Koperu, pro které se našlo místo díky zasypání původního slaniska. Po zrušení dráhy byl prostor využit pro náměstí, na kterém dnes stojí socha místního rodáka, slavného italského houslisty Giuseppe Tartiniho.


Geology.

Mauna Kea is one of five volcanoes that form the island of Hawaii, the largest and youngest island of the Hawaiian–Emperor seamount chain. Of these five hotspot volcanoes, Mauna Kea is the fourth oldest and fourth most active. It began as a preshield volcano driven by the Hawaii hotspot around one million years ago, and became exceptionally active during its shield stage until 500,000 years ago. Mauna Kea entered its quieter post-shield stage 250,000 to 200,000 years ago, and is currently dormant. Mauna Kea does not have a visible summit caldera, but contains a number of small cinder and pumice cones near its summit. A former summit caldera may have been filled and buried by later summit eruption deposits.  Mauna Kea is over in volume, so massive that it and its neighbor, Mauna Loa, depress the ocean crust beneath it by. The volcano continues to slip and flatten under its own weight at a rate of less than per year. Much of its mass lies east of its present summit. Mauna Kea stands above sea level, about higher than its neighbor Mauna Loa, and is the highest point in the state of Hawaii. Measured from its base on the ocean floor, it rises over, significantly greater than the elevation of Mount Everest above sea level.  Like all Hawaiian volcanoes, Mauna Kea has been created as the Pacific tectonic plate has moved over the Hawaiian hotspot in the Earth's underlying mantle. The Hawaii island volcanoes are the most recent evidence of this process that, over 70 million years, has created the -long Hawaiian Ridge–Emperor seamount chain. The prevailing, though not completely settled, view is that the hotspot has been largely stationary within the planet's mantle for much, if not all of the Cenozoic Era. However, while Hawaiian volcanism is well understood and extensively studied, there remains no definite explanation of the mechanism that causes the hotspot effect.  Lava flows from Mauna Kea overlapped in complex layers with those of its neighbors during its growth. Most prominently, Mauna Kea is built upon older flows from Kohala to the northwest, and intersects the base of Mauna Loa to the south. The original eruptive fissures (rift zones) in the flanks of Mauna Kea were buried by its post-shield volcanism. Hilo Ridge, a prominent underwater rift zone structure east of Mauna Kea, was once believed to be a part of the volcano; however, it is now understood to be a rift zone of Kohala that has been affected by younger Mauna Kea flows.  The shield-stage lavas that built the enormous main mass of the volcano are tholeiitic basalts, like those of Mauna Loa, created through the mixing of primary magma and subducted oceanic crust. They are covered by the oldest exposed rock strata on Mauna Kea, the post-shield alkali basalts of the "Hāmākua Volcanics", which erupted between 250,000 and 70–65,000 years ago. The most recent volcanic flows are hawaiites and mugearites: they are the post-shield "Laupāhoehoe Volcanics", erupted between 65,000 and 4,000 years ago. These changes in lava composition accompanied the slow reduction of the supply of magma to the summit, which led to weaker eruptions that then gave way to isolated episodes associated with volcanic dormancy. The Laupāhoehoe lavas are more viscous and contain more volatiles than the earlier tholeiitic basalts; their thicker flows significantly steepened Mauna Kea's flanks. In addition, explosive eruptions have built cinder cones near the summit. These cones are the most recent eruptive centers of Mauna Kea. Its present summit is dominated by lava domes and cinder cones up to in diameter and hundreds of meters tall.  Mauna Kea is the only Hawaiian volcano with distinct evidence of glaciation. Similar deposits probably existed on Mauna Loa, but have been covered by later lava flows. Despite Hawaii's tropical location, during several past ice ages a drop of a degree in temperature allowed snow to remain at the volcano's summit through summer, triggering the formation of an ice cap. There are three episodes of glaciation that have been recorded from the last 180,000 years: the "Pōhakuloa" (180–130 ka), "Wāihu" (80–60 ka) and "Mākanaka" (40–13 ka) series. These have extensively sculpted the summit, depositing moraines and a circular ring of till and gravel along the volcano's upper flanks. Subglacial eruptions built cinder cones during the Mākanaka glaciation, most of which were heavily gouged by glacial action. The most recent cones were built between 9000 and 4500 years ago, atop the glacial deposits, although one study indicates that the last eruption may have been around 3600 years ago.  At their maximum extent, the glaciers extended from the summit down to between of elevation. A small body of permafrost, less than across, was found at the summit of Mauna Kea before 1974, and may still be present. Small gullies etch the summit, formed by rain- and snow-fed streams that flow only during winter melt and rain showers. On the windward side of the volcano, stream erosion driven by trade winds has accelerated erosion in a manner similar to that on older Kohala.  Mauna Kea is home to Lake Waiau, the highest lake in the Pacific Basin. At an altitude of, it lies within the Puu Waiau cinder cone and is the only alpine lake in Hawaii. The lake is very small and shallow, with a surface area of and a depth of. Radiocarbon dating of samples at the base of the lake indicates that it was clear of ice 12,600 years ago. Hawaiian lava types are typically permeable, preventing lake formation due to infiltration. Either sulfur-bearing steam altered the volcanic ash to low-permeability clays, or explosive interactions between rising magma and groundwater or surface water during phreatic eruptions formed exceptionally fine ash that reduced the permeability of the lake bed.  No artesian water was known on the island of Hawaii until 1993 when drilling by the University of Hawaii tapped an artesian aquifer more than below sea level, that extended more than of the borehole's total depth. The borehole had drilled through a compacted layer of soil and lava where the flows of Mauna Loa had encroached upon the exposed Mauna Kea surface and had subsequently been subsided below sea level. Isotopic composition shows the water present to have been derived from rain coming off Mauna Kea at higher than above mean sea level. The aquifer's presence is attributed to a freshwater head within Mauna Kea's basal lens. Scientists believe there may be more water in Mauna Kea's freshwater lens than current models may indicate. Two more boreholes were drilled on Mauna Kea in 2012, with water being found at much higher elevations and shallower depths than expected. Donald Thomas, director of the University of Hawaii's Center for the Study of Active Volcanoes believes one reason to continue study of the aquifers is due to use and occupancy of the higher elevation areas, stating: "Nearly all of these activities depend on the availability of potable water that, in most cases, must be trucked to the Saddle from Waimea or Hilo — an inefficient and expensive process that consumes a substantial quantity of our scarce liquid fuels."

Human history.

Native history.

The first Ancient Hawaiians to arrive on Hawaii island lived along the shores, where food and water were plentiful. Settlement expanded inland to the Mauna Loa – Mauna Kea region in the 12th and early 13th centuries. Archaeological evidence suggests that these regions were used for hunting, collecting stone material, and possibly for spiritual reasons or for astronomical or navigational observations. The mountain's plentiful forest provided plants and animals for food and raw materials for shelter. Flightless birds that had previously known no predators became a staple food source.

Modern era.

There are three accounts of foreigners visiting Hawaii before the arrival of James Cook, in 1778. However, the earliest Western depictions of the isle, including Mauna Kea, were created by explorers in the late 18th and early 19th centuries. Contact with Europe and America had major consequences for island residents. Native Hawaiians were devastated by introduced diseases; port cities including Hilo, Kealakekua, and Kailua grew with the establishment of trade; and the adze quarries on Mauna Kea were abandoned after the introduction of metal tools.  In 1793, cattle were brought by George Vancouver as a tribute to King Kamehameha I. By the early 19th century, they had escaped confinement and roamed the island freely, greatly damaging its ecosystem. In 1809 John Palmer Parker arrived and befriended Kamehameha I, who put him in charge of cattle management on the island. With an additional land grant in 1845, Parker established Parker Ranch on the northern slope of Mauna Kea, a large cattle ranch that is

Ascents.

In pre-contact times, natives traveling up Mauna Kea were probably guided more by landscape than by existing trails, as no evidence of trails has been found. It is possible that natural ridges and water sources were followed instead. Individuals likely took trips up Mauna Kea's slopes to visit family-maintained shrines near its summit, and traditions related to ascending the mountain exist to

Ecology.

Background.

Hawaii's geographical isolation strongly influences its ecology. Remote islands like Hawaii have a large number of species that are found nowhere else (see Endemism in the Hawaiian Islands). The remoteness resulted in evolutionary lines distinct from those elsewhere and isolated these endemic species from external biotic influence, and also makes them especially vulnerable to extinction and the effects of invasive species. In addition the ecosystems of Hawaii are under threat from human development including the clearing of land for agriculture; an estimated third of the island's endemic species have already been

Alpine environment.

The summit of Mauna Kea lies above the tree line, and consists of mostly lava rock and alpine tundra. An area of heavy snowfall, it is inhospitable to vegetation, and is known as the Hawaiian tropical high shrublands. Growth is restricted here by extremely cold temperatures, a short growing season, low rainfall, and snow during winter months. A lack of soil also retards root growth, makes it difficult to absorb nutrients from the ground, and gives the area a very low water retention capacity.  Plant species found at this elevation include "Styphelia tameiameiae", "Taraxacum officinale", "Tetramolopium humile", "Agrostis sandwicensis", "Anthoxanthum odoratum", "Trisetum glomeratum", "Poa annua", "Sonchus oleraceus", and "Coprosma ernodiodes". One notable species is Mauna Kea silversword ("Argyroxiphium sandwicense" var. "sandwicense"), a highly endangered endemic plant species that thrives in Mauna Kea's high elevation cinder deserts. At one stage reduced to a population of just 50 plants, Mauna Kea silversword was

Māmane–naio forest.

The highest forested zone on the volcano, at an elevation of, is dominated by māmane ("Sophora chrysophylla") and naio ("Myoporum sandwicense"), both endemic tree species, and is thus known as māmane–naio forest. Māmane seeds and naio fruit are the chief foods of the birds in this zone, especially the palila ("Loxioides bailleui"). The palila was formerly found on the slopes of Mauna Kea, Mauna Loa, and Hualālai, but is now confined to the slopes of Mauna Kea—only 10% of its former range—and has been declared critically endangered.  The

Lower environment.

A band of ranch land on Mauna Kea's lower slopes was formerly "Acacia koa" – "Metrosideros polymorpha" (koa-ōhia) forest. Its destruction was driven by an influx of European and American settlers in the early 19th century, as extensive logging during the 1830s provided lumber for new homes. Vast swathes of the forest were burned and cleared for sugarcane plantations. Most of the houses on the island were built of koa, and those parts of the forest that survived became a source for firewood to power boilers on the sugarcane plantations and to heat homes. The once vast forest had almost disappeared by 1880, and by 1900, logging interests had shifted to Kona and the island of Maui. With the collapse of the sugar industry

Summit observatories.

Mauna Kea's summit is one of the best sites in the world for astronomical observation due to favorable observing conditions. The arid conditions are important for submillimeter and infrared astronomy for this region of the electromagnetic spectrum. The summit is above the inversion layer, keeping most cloud cover below the summit and ensuring the air on the summit is dry, and free of atmospheric pollution. The summit atmosphere is exceptionally stable, lacking turbulence for some of the world's best astronomical seeing. The very dark skies resulting from Mauna Kea's distance from city lights are preserved by legislation that minimizes light pollution from the surrounding area; the darkness level allows the observation of faint astronomical objects. These factors historically made Mauna Kea an excellent spot for stargazing.  In the early 1960s, the Hawaii Island Chamber of Commerce encouraged astronomical development of Mauna Kea, as economic stimulus; this coincided with University of Arizona astronomer Gerard Kuiper's search for sites to use newly improved detectors of infrared light. Site testing by Kuiper's assistant Alika Herring in 1964 confirmed the summit's outstanding suitability. An intense three-way competition for NASA funds to construct a large telescope began between Kuiper, Harvard University, and the University of Hawaii (UH), which only had experience in solar astronomy. This culminated in funds being awarded to the "upstart" UH proposal. UH rebuilt its small astronomy department into a new Institute for Astronomy, and in 1968 the Hawaii Department of Land and Natural Resources gave it a 65-year lease for all land within a radius of its telescope, essentially that above. On its completion in 1970, the UH was the seventh largest optical/infrared telescope in the world. By 1970, two telescopes had been constructed by the US Air Force and Lowell Observatory. In 1973, Canada and France agreed to build the 3.6 m CFHT on Mauna Kea. However, local organisations started to raise concerns about the environmental impact of the

Climate.

Mauna Kea has an alpine climate. Due to the influence of its tropical latitude, temperature swings are very low in spite of its high elevation. Frosts are common year round, but in spite of the elevation no month

Recreation.

Mauna Kea's coastline is dominated by the Hamakua Coast, an area of rugged terrain created by frequent slumps and landslides on the volcano's flank. The area includes several recreation parks including Kalopa State Recreation Area, Wailuku River State Park and Akaka Falls State Park.  There are over 3,000 registered hunters on Hawaii island, and hunting, for both recreation and sustenance, is a common activity on Mauna Kea. A public hunting program is used to control the numbers of introduced animals including pigs, sheep, goats, turkey, pheasants, and quail. The Mauna Kea State Recreation Area functions as a base camp for the sport. Birdwatching is also common at lower levels on the mountain. A popular site is "Kīpuka Puu Huluhulu", a kīpuka on Mauna Kea's flank that formed when lava flows isolated the forest on a hill. Mauna Kea's great height and the steepness of its flanks provide a better view and a shorter hike than the adjacent Mauna Loa. The height with its risk of altitude sickness, weather concerns, steep road grade, and overall inaccessibility make the volcano dangerous and summit trips difficult. Until the construction of roads in the mid-20th century, only the hardy visited Mauna Kea's upper slopes; hunters tracked game animals, and hikers traveled up the mountain. These travelers used stone cabins constructed by the Civilian Conservation Corps in the 1930s as base camps, and it is from these facilities that the modern mid-level Onizuka Center for International Astronomy telescope support complex is derived. The first Mauna Kea summit road was built in 1964, making the peak accessible to more people.  Today, multiple hiking trails exist, including the Mauna Kea Trail, and by 2007 over 100,000 tourists and 32,000 vehicles were going each year to the Visitor Information Station (VIS) adjacent to the Onizuka Center for International Astronomy. The Mauna Kea Access Road is paved up to the Center at. One study reported that around a third of visitors and two thirds of professional astronomers working on the mountain have experienced symptoms of acute altitude sickness; visitors traveling up the volcano's flanks are advised to stop for at least half an hour and preferably longer at the visitor center to acclimate to the higher elevation. It is strongly recommended to use a four-wheel drive vehicle to drive all the way to the top. Brakes often overheat on the way down and there is no fuel available on Mauna Kea. A free Star Gazing Program was previously held at the VIS every night from 6-10 pm, with the program canceled due to both a change in operating hours and closure due to the ongoing COVID-19 pandemic. Between 5,000 and 6,000 people visit the summit of Mauna Kea each year, and to help ensure safety, and protect the integrity of the mountain, a ranger program was implemented in 2001.

Mauna Kea ( or, ; abbreviation for "Mauna a Wākea") is a dormant volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii. Most of the volcano is underwater, and when measured from its underwater base, Mauna Kea is the tallest mountain in the world, measuring in height. Mauna Kea is about a million years old, and has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous, resulting in a steeper profile. Late volcanism has also given it a much rougher appearance than its neighboring volcanoes due to construction of cinder cones, decentralization of its rift zones, glaciation on its peak, and weathering by the prevailing trade winds. Mauna Kea last erupted 6,000 to 4,000 years ago and is now considered dormant. The peak is about higher than Mauna Loa, its more massive neighbor.

Mauna Kea (v překladu z jazyka původních obyvatel: "bílá hora") je nejvyšší neaktivní štítová sopka ležící na ostrově Havaj v Tichém oceánu a zároveň je nejvyšší horou celých Havajských ostrovů. Nad hladinu oceánu ční do výšky 4205 m, ale i s podvodní částí je vysoká 10 205 m, což z ní činí na Zemi nejvyšší horu, která při měření od báze převyšuje i Everest.


Pollutants.

An air pollutant is a material in the air that can have adverse effects on humans and the ecosystem. The substance can be solid particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made. Pollutants are classified as primary or secondary. Primary pollutants are usually produced by processes such as ash from a volcanic eruption. Other examples include carbon monoxide gas from motor vehicle exhausts or sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant. Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants.  Pollutants emitted into the atmosphere by human activity include:  Secondary pollutants include: Minor air pollutants include:  Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potentially significant impacts on human health and the environment.

Sources.

Anthropogenic (man-made) sources.

These are mostly related to the burning of fuel.  There are also sources from processes other than combustion

Emission factors.

Air pollutant emission factors are reported representative values that attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per tonne of coal burned). Such factors facilitate estimation of emissions from various sources

Exposure.

Air pollution risk is a function of the hazard of the pollutant and the exposure to that pollutant. Air pollution exposure can be expressed for an individual, for certain groups (e.g. neighborhoods or children living in a country), or for entire populations. For example, one may want to calculate the exposure to a hazardous air pollutant for a geographic area, which includes the various microenvironments and age groups. This can be calculated as an inhalation exposure. This would account for daily exposure in various settings (e.g. different indoor micro-environments and outdoor locations). The exposure needs to include different age and other demographic groups, especially infants, children, pregnant women and other sensitive subpopulations. The exposure to an air pollutant must integrate

Indoor air quality.

A lack of ventilation indoors concentrates air pollution where people often spend the majority of their time. Radon (Rn) gas, a carcinogen, is exuded from the Earth in certain locations and trapped inside houses. Building materials including carpeting and plywood emit formaldehyde (HCO) gas. Paint and solvents give off volatile organic compounds (VOCs) as they dry. Lead paint can degenerate into dust and be inhaled. Intentional air pollution is introduced with the use of air fresheners, incense, and other scented items. Controlled wood fires in stoves and fireplaces can add significant amounts of smoke particulates into the air, inside and out. Indoor pollution fatalities may be caused by using pesticides and other chemical sprays indoors without proper ventilation.  Carbon monoxide poisoning and fatalities are often caused by faulty vents and chimneys, or by the burning of charcoal indoors or in a confined space, such as a tent. Chronic carbon monoxide poisoning can result even from poorly-adjusted pilot lights. Traps are built into all domestic plumbing to keep sewer

Health effects.

In 2012, air pollution caused premature deaths on average of 1 year in Europe, and was a significant risk factor for a number of pollution-related diseases, including respiratory infections, heart disease, COPD, stroke and lung cancer. The health effects caused by air pollution may include difficulty in breathing, wheezing, coughing, asthma and worsening of existing respiratory and cardiac conditions. These effects can result in increased medication use, increased doctor or emergency department visits, more hospital admissions and premature death. The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, and the individual's health status and genetics. The most common sources of air pollution include particulates, ozone, nitrogen dioxide, and sulfur dioxide. Children aged less than five years that live in developing countries are the most vulnerable population in terms of total deaths attributable to indoor and outdoor air pollution.

Mortality.

The World Health Organization estimated in 2014 that every year air pollution causes the premature death of some 7 million people worldwide. Studies published in March 2019 indicated that the number may be around 8.8 million.  India has the highest death rate due to air pollution. India also has more deaths from asthma than any other nation according to the World Health Organization. In December 2013 air pollution was estimated to kill 500,000 people in China each year. There is a positive correlation between pneumonia-related deaths and air pollution from motor vehicle emissions.  Annual premature European deaths caused by air pollution are estimated at 430,000-800,000 An important cause of these deaths is nitrogen dioxide and other nitrogen oxides (NOx) emitted by road vehicles. In a 2015 consultation document the UK government disclosed that nitrogen dioxide is responsible for 23,500 premature UK deaths per annum. Across the European Union, air pollution is estimated to reduce life expectancy by almost nine months. Causes of deaths include strokes, heart disease, COPD, lung cancer, and lung infections.  Urban outdoor air pollution is estimated to cause 1.3 million deaths worldwide per year.

Cardiovascular disease.

A 2007 review of evidence found that, ambient air pollution exposure is a risk factor correlating with increased total mortality from cardiovascular events (range: 12% to 14% per 10 microg/m increase).  Air pollution is also emerging as a risk factor for stroke, particularly in developing countries where

Lung disease.

Research has demonstrated increased risk of developing asthma and COPD from increased exposure to traffic-related air pollution. Additionally, air pollution has been associated with increased hospitalization and mortality from asthma and COPD. Chronic obstructive pulmonary disease (COPD) includes diseases such as chronic bronchitis and emphysema.  A study conducted in 1960–1961 in the wake of the Great Smog of 1952 compared 293 London residents with 477 residents of Gloucester, Peterborough, and Norwich, three towns with low reported death rates from chronic bronchitis. All subjects were male postal truck drivers aged 40 to 59. Compared to the subjects from the outlying towns, the London subjects

Cancer (lung cancer).

A review of evidence regarding whether ambient air pollution exposure is a risk factor for cancer in 2007 found solid data to conclude that long-term exposure to PM2.5 (fine particulates) increases the overall risk of non-accidental mortality by 6% per a 10 microg/m increase. Exposure to PM2.5 was also associated with an increased risk of mortality from lung cancer (range: 15% to 21% per 10 microg/m increase) and total cardiovascular mortality (range: 12% to 14% per a 10 microg/m increase). The review further noted that living close to busy traffic appears to be associated with elevated risks of these three outcomes – increase in lung cancer deaths, cardiovascular deaths, and overall non-accidental deaths. The reviewers also

Children.

In the United States, despite the passage of the Clean Air Act in 1970, in 2002 at least 146 million Americans were living in non-attainment areas—regions in which the concentration of certain air pollutants exceeded federal standards. These dangerous pollutants are known as the criteria pollutants, and include ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. Protective measures to ensure children's health are being taken in cities such as New Delhi, India where buses now use compressed natural gas to help eliminate the "pea-soup" smog. A recent study in Europe has found that exposure to ultrafine particles can increase blood pressure in children. According to a WHO report-2018, polluted air is a main cause poisoning millions of children under the age of 15 years and ruining their lives which resulting to death of some six hundred thousand children annually.

Infants.

Ambient levels of air pollution have been associated with preterm birth and low birth weight. A 2014 WHO worldwide survey on maternal and perinatal health found a statistically significant association between low birth weights (LBW) and increased levels of exposure to PM2.5. Women in regions with greater than average PM2.5 levels had statistically significant higher odds of pregnancy resulting in a low-birth weight infant even when adjusted for country-related variables. The effect is thought to be from stimulating inflammation and increasing oxidative stress.  A study by the University of York found that in 2010 exposure to PM2.5 was strongly associated with 18% of preterm births globally, which was approximately 2.7 million premature births. The countries with the highest air pollution associated preterm births were in South and East Asia, the Middle East, North Africa, and West sub-Saharan Africa.  The source of PM 2.5 differs greatly by region. In South and East Asia, pregnant women are frequently exposed to indoor air pollution because of the wood and other biomass fuels used for cooking which are responsible for more

"Clean" areas.

Even in the areas with relatively low levels of air pollution, public health effects can be significant and costly, since a large number of people breathe in such pollutants. A study published in 2017 found that even in areas of the U.S. where ozone and PM2.5 meet federal standards, Medicare recipients who are exposed

Central nervous system.

Data is accumulating that air pollution exposure also affects the central nervous system.  In a June 2014 study conducted by researchers at the University of Rochester Medical Center, published in the journal "Environmental Health Perspectives", it was discovered that early exposure to air pollution causes the same damaging changes in the brain as autism and schizophrenia. The study also shows that air pollution also affected short-term memory, learning ability, and impulsivity. Lead researcher Professor Deborah Cory-Slechta said that "When we looked closely at the ventricles, we could see that the white matter that normally surrounds them hadn't fully developed. It appears that inflammation had damaged those brain cells and prevented that region of the brain from developing, and the ventricles simply expanded to fill the space. Our findings add to the

Agricultural effects.

In India in 2014, it was reported that air pollution by black carbon and

Economic effects.

Air pollution costs the world economy $5 trillion per year as a result of productivity losses and degraded quality of life, according to a joint study by the World Bank and the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. These productivity losses are caused by deaths due to diseases caused by air pollution. One out of ten deaths in

Historical disasters.

The world's worst short-term civilian pollution crisis was the 1984 Bhopal Disaster in India. Leaked industrial vapours from the Union Carbide factory, belonging to Union Carbide, Inc., U.S.A. (later bought by Dow Chemical Company), killed at least 3787 people and injured from 150,000 to 600,000. The United Kingdom suffered its worst air pollution event when the

Alternatives to pollution.

There are now practical alternatives

Reduction efforts.

Various pollution control technologies and strategies are available to reduce air pollution. At its most basic level, land-use planning is likely to involve zoning and transport infrastructure planning. In most developed countries, land-use planning is an important part of social policy, ensuring that land is used efficiently for the benefit of the wider economy and population, as well as to protect the environment.  Because a large share of air pollution is caused by combustion of fossil fuels such as coal and oil, the reduction of these fuels can reduce air pollution drastically. Most effective is the switch to clean power sources such as wind power, solar power, hydro power which don't cause air pollution. Efforts to reduce pollution from mobile sources includes primary regulation (many developing countries have permissive regulations), expanding regulation to new sources (such as cruise and transport ships, farm equipment, and small gas-powered equipment such as string trimmers, chainsaws, and snowmobiles), increased fuel efficiency (such as through the use of hybrid vehicles), conversion to cleaner fuels or conversion to electric vehicles.  Titanium dioxide has been researched for its ability to reduce air pollution. Ultraviolet light will release free electrons from material, thereby creating free radicals, which break up VOCs and NOx gases. One form is superhydrophilic.  In 2014, Prof. Tony Ryan and Prof. Simon Armitage of University of Sheffield prepared a 10 meter by 20 meter-sized poster coated with microscopic, pollution-eating nanoparticles of titanium dioxide. Placed on a building, this giant poster can absorb the toxic emission from around 20 cars each day.  A very effective means to reduce air pollution is the transition to renewable energy. According to a study published in Energy and Environmental Science in 2015 the switch to 100% renewable energy in the United States would eliminate about 62,000 premature mortalities per year and about 42,000 in 2050, if no biomass were used. This would save about $600 billion in health costs a year due to reduced air pollution in 2050, or about 3.6% of the 2014 U.S. gross domestic product.  There is limited evidence that efforts to reduce particulate matter in the air can result in better health in Africa, the Middle East, Eastern Europe, Central Asia, and Southeast Asia.

Control devices.

The following items are commonly used as pollution control devices in industry and

Regulations.

In general, there are two types of air quality standards. The first class of standards (such as the U.S. National Ambient Air Quality Standards and E.U. Air Quality Directive) set maximum atmospheric concentrations for specific pollutants. Environmental agencies enact regulations which are intended to result in attainment of these target levels. The second class (such as the North American air quality index) take the form of a scale with various thresholds, which is used to communicate to the public the relative risk of outdoor activity. The scale may or may not distinguish between different pollutants.

Canada.

In Canada, air pollution and associated health risks are measured with the Air Quality Health Index or (AQHI). It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution.  The Air Quality Health Index or "AQHI" is a federal program jointly coordinated by Health Canada and Environment Canada. However, the AQHI program would not be possible without the commitment and support of the provinces, municipalities and NGOs. From air quality monitoring to health risk communication and community engagement, local partners are responsible for the vast majority of work related to AQHI implementation. The AQHI provides a number from 1 to 10+ to indicate the level of health risk associated with local air quality. Occasionally, when the amount of air pollution is abnormally high, the number may exceed

Germany.

TA Luft is

Hotspots.

Air pollution hotspots are areas where air pollution emissions expose individuals to increased negative health effects. They are particularly common in highly populated, urban areas, where there may be a combination of stationary sources (e.g. industrial facilities) and mobile sources (e.g. cars and trucks) of pollution. Emissions from these sources can cause respiratory disease, childhood asthma, cancer, and other health problems. Fine particulate matter such as diesel soot, which contributes to more than 3.2 million premature deaths around the world each year, is a significant problem. It is very small and can lodge itself within the lungs and enter the bloodstream. Diesel soot is concentrated in densely populated areas, and one in six people in the U.S. live near a diesel pollution hot spot.  While air pollution hotspots affect a variety of populations, some groups are more likely to be located in hotspots.

Cities.

Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy

Governing urban air pollution.

In Europe, Council Directive 96/62/EC on ambient air quality assessment and management provides a common strategy against which member states can "set objectives for ambient air quality in order to avoid, prevent or reduce harmful effects on human health and the environment... and improve air quality where it is unsatisfactory".  On 25 July 2008 in the case Dieter Janecek v Freistaat Bayern CURIA, the European Court of Justice ruled that under this directive citizens have the right to require national authorities to implement a short term action plan that aims to maintain or achieve compliance to air quality limit values.  This important case law appears to confirm the role of the EC as centralised regulator to European nation-states as regards air pollution control. It places a supranational legal obligation on the UK to protect its citizens from dangerous levels of air pollution, furthermore superseding national interests with those of the citizen.  In 2010, the European Commission (EC) threatened the UK with legal action against the successive breaching of PM10 limit values. The UK government has identified that if fines are imposed, they could cost the nation upwards of £300 million per year.  In March 2011, the Greater London Built-up Area remains the only UK region in breach of the

Projections.

It is expected that Africa could represent the half of the world's pollution emissions by 2030, warns Cathy Liousse director of research of atmospheric sounding of the CNRS, along with many other researchers. According the report the sub-Saharan Africa is experiencing a fast increasing pollution, derived to many causes, such as burning wood for cooking, burning open waste, traffic, agri-food and chemical industries, the sand dust from the Sahara carried by the winds through the Sahel area, all this reinforced by a greater demography and urban density.

Air pollution occurs when harmful or excessive quantities of substances are introduced into Earth's atmosphere. Sources of air pollution include gases (such as ammonia, carbon monoxide, sulfur dioxide, nitrous oxides, methane and chlorofluorocarbons), particulates (both organic and inorganic), and biological molecules. It may cause diseases, allergies and even death to humans; it may also cause harm to other living organisms such as animals and food crops, and may damage the natural or built environment. Both human activity and natural processes can generate air pollution.

Znečištění ovzduší je chemicko-fyzikálně-biologický stav v zemské atmosféře vyvolaný přírůstkem znečišťujících látek v původní atmosféře (znečišťováním atmosféry), na nějž mohou navazovat a navazují procesy a reakce v zemské atmosféře, v jejichž důsledku se mění vlastnosti zemské atmosféry tak, že negativně působí na lidské zdraví nebo na životní prostředí. Znečištění ovzduší tak přispívá k faktorům zkracujícím délku lidského života, je příčinou rozvoje nemocí, např. dýchacích cest, rakoviny a srdečních onemocnění. Některé náhlé změny vlastností po změně stavu v ovzduší vyvolávají dokonce hromadná rychlá úmrtí a mají dalekosáhlé dopady nejen od místa zdroje znečištění, ale i na jiné složky životního prostředí a jeho využitelnosti k životu (například stav a reakce po výbuchu v jaderné elektrárně Černobyl nebo po svržení a vybuchnutí atomové bomby na Hirošimu a Nagasaki). Mezi nejčastější a nejběžnější zdroje nečistot (polutantů) vypouštěných do ovzduší patří stacionární zdroje, (velké teplárny a tepelné elektrárny i malé lokální topeniště, např. v domech). Dále mobilní zdroje (především v automobilové dopravě, ale i v železniční nebo lodní dopravě). K nejzávažnějšímu znečištění ovzduší dochází po jaderném výbuchu, jehož radiační účinky pronikají do ovzduší. Na stav ovzduší a děje v atmosféře působí také meziplanetární vlivy a energie ze sluneční soustavy, zejména sluneční záření, které nelze lidskou vůlí ovládat a regulovat.


History.

In 1681, an island in the mouth of the Cuyuni River was cleared and planted with cassava for the use of the Dutch garrison. By 1694, a new plantation on the Cuyuni River above the fort was established. By 1703 a post was established on the Pariacot Savannah, in the upper Cuyuni.  On January 2, 1895 the "Incident of the Cuyuni river" names by the general Domingo Antonio Sifontes, was an armed confrontation between Venezuelans and British occurred in the region of River by the territorial dispute that had Venezuela with the British Guyana, in which by direction of Sifontes the Venezuelans left winners. At dawn, British police men led by "Inspector Barnes" of England, took an unoccupied military station of Venezuelan nationality, located on the left coast of the river, in which the men of Barnes hoisted the British flag in Venezuelan lands during the day.  Facing this fact, the captain Andrés Avelino Domínguez, second to the control of Sifontes, was sent to recover the settlement. The result was the withdrawal of the British and the capture of Barnes and his men, who were taken to the General Police Station, which increased tensions between the two countries amid an internal crisis in Venezuela. Some of the Kali'na people live in the Cuyuni River valley, part of which is in Guyana.  The Kamaria hydroelectric power site is located on the Cuyuni River.  The river is a source of alluvial gold.  Ankoko Island is at the confluence of the Cuyuni and Wenamu River and has been the subject of further disputes between Venezuela and Guyana.

The Cuyuni River is a South American river and a tributary of the Essequibo River. It rises in the Guiana Highlands of Venezuela where it descends northward to El Dorado, and turns eastward to meander through the tropical rain forests of Guyana. It finally turns southeastward, flowing to its confluence with the Mazaruni River. The Cuyuni River marks the limit of the disputed territory of Guyana Essequibo for approximately.

Cuyuni (, ) je řeka ve Venezuele a v Guyaně v Jižní Americe. Je 600 km dlouhá. Povodí má rozlohu 80 000 km2.