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Jamie Durie

Jamie Paul Durie (born 3 June 1970) is an Australian horticulturalist and landscape designer, furniture designer, television host, television producer, and author of eleven books on landscape architecture, garden design and lifestyle. He is the founder and director of a design company PATIO Landscape Architecture and Durie Design and also is a 2008 Gold Medal winner at Britain's prestigious Royal Horticultural Society (RHS) Chelsea Flower Show in Chelsea, London for Australian Garden and designed by Durie. As of 2018, Durie has hosted more than 50 design shows around the world.

Durie was the television host of the 2008 Australian lifestyle program The Outdoor Room, broadcast on the Seven Network. He hosted the dynamic design makeover show HGTV Showdown in 2009. Durie hosted the US PBS series The Victory Garden from 2007 to 2010. The show is PBS network's longest-running gardening TV series.

Following the end of The Outdoor Room on the Seven Network in 2010, Durie relocated the concept of the series to broadcast on the American HGTV network as The Outdoor Room with Jamie Durie. Unable to bring his own Australian design team along, Durie put together a new team of top-notch designers, horticulturists and contractors. In his HGTV series, Durie rescues forlorn yards in Southern California with design schemes inspired by gardens and landscapes from around the world. Filmed mostly in and around Los Angeles, The Outdoor Room with Jamie Durie uses sustainable ideas - such as low-water plantings and reclaimed hardscape - to design intimate, livable environments for erstwhile non-gardeners.

Since 2015, Durie has co-presented as a visiting expert in gardening & landscaping, on the Australian lifestyle program, The Living Room, which airs on Network Ten.

Durie is currently contracted to RUSH Entertainment Group, that organises events.

Early life
Durie was born in Manly, northern Sydney, New South Wales, and spent his formative years living in the mining town Tom Price in the Pilbara region of Western Australia, with his mother and maternal grandmother both Sri Lankan. His grandmother, Daphne de Zylva, was born in Sri Lanka and met his English grandfather in the air force during World War II. They moved to Australia in the 1950s. Durie recalls that he and his grandmother baked and gardened together. She taught him how to make his first curry. He has inherited a love of the Sri Lankan culture and lifestyle. His parents separated when Durie was age 10, and he relocated with his mother and brother Clyde Hep, to the Gold Coast, in Queensland. His paternal grandmother, called Nanna, was a volunteer surf-lifesaver on the NSW Central Coast. Having left high-school in Brisbane at age 15, he tried his hand at cabinetmaking, and modeled beachwear part-time. Durie got his showbiz start in his teens as an exotic dancer in the Australian all-male revue troupe called Manpower Australia. Durie's agent introduced him to Manpower Australia, a touring dance troupe best known for its male dance performances and for its dancers' distinctive physical attractiveness and sex appeal. For seven years, Durie toured internationally with Manpower Australia, acting as manager, and also as principal dancer, performing acrobatics and trapeze acts to large audience venues in Las Vegas, NV. "I was the lead performer and designed the sets and costumes" he says. Durie notes that while Manpower Australia was perceived as putting the risqué into risky, the shows were highly professional acts that even his grandmother was comfortable with. The timing was ideal, as "The 1960s, 1970s and 1980s in Australia were very chauvinistic and the female body was overexploited", as he explains, "There needed to be social change." Retiring from Manpower Australia at age 26, Durie made up for his early exit from schooling by completing a four-year horticultural and landscape design course.

Landscape design and television hosting
Durie founded the landscape design company Patio Landscape Architecture and Design in 1998. In 2002, Durie registered the Australian business company, JPD Media & Design.

Within a few short years, he made hosting appearances on Australian reality show DIY television programs. Durie was the main host and the lead landscaper on the garden makeover program Backyard Blitz, on the Nine Network - created and produced by horticulturist Don Burke - from 2000 to 2005. Don Burke, whose production company recruited Durie in 1999 to front Backyard Blitz , describes him as a "born showman".

Durie was the host on the TV renovation show The Block, on the Nine Network. The original The Block TV series first ran for two consecutive seasons in 2003 and 2004, hosted by Durie.

In 2007, Durie participated in the 6th Australian series of Dancing with the Stars, in which he was eliminated in 7th place, on 17 April 2007. In 2007, Durie hosted Australia's Best Backyards on the Seven Network. The show was a lifestyle garden program, similar to Backyard Blitz on the Nine Network.

In 2007, Durie has filmed lifestyle segments with Oprah Winfrey, on the Oprah Winfrey Network (U.S. TV channel), whom he credits as giving him his US TV breakthrough. Durie states that Winfrey "wholly and solely" is responsible for his career being launched in the US. When Oprah came calling, Durie relocated to the US. And with her ringing endorsement it meant that executive doors were opened, and Durie's already significant businesses were expanded in a country far bigger than Australia.

Durie hosted the US PBS series The Victory Garden from 2007 to 2010. The show is PBS network's longest running gardening TV series, which equips viewers with the confidence and inspiration to roll up their sleeves and get their hands dirty in the garden and in the kitchen. Durie hosted the dynamic design makeover show HGTV Showdown on the HGTV network in 2009.

In 2008, Durie was the television host of the Australian lifestyle program The Outdoor Room, broadcast on Seven Network, with repeats broadcast on 7Two. The premise of the show was that Durie set out to "bring the world to your very own backyard".

Following the end of The Outdoor Room show on the Seven Network, in 2010, Durie relocated the concept of the series to broadcast on the HGTV network as The Outdoor Room with Jamie Durie. Unable to bring his own Australian design team along, Durie put together a new team of designers, horticulturists and contractors. In his HGTV series, Durie rescues forlorn yards in Southern California with design schemes inspired by gardens and landscapes from around the world. Filmed mostly in and around Los Angeles, The Outdoor Room with Jamie Durie uses sustainable ideas, such as low-water plantings and reclaimed hardscape, to design intimate, livable environments for erstwhile non-gardeners.

Since 2015, Durie has co-presented as a visiting expert in gardening & landscaping, on the Australian lifestyle program, The Living Room, a quad-triple award-winner of the Logie Award for Most Popular Lifestyle Program, that airs on Network Ten.

In 2019, Durie joined Australia's Seven Network reality renovation series House Rules as a new judge.

In August 2022, Durie was revealed to be the Tiger on the fourth season of Network 10's The Masked Singer Australia.

Furniture design and merchandise lines
In 2010, Durie's company Patio Landscape Architecture and Design was renamed Durie Design, committed to not just rejuvenating the existing gardens, but offering new exciting outdoor destinations for the clients, and with an emphasis on funky furniture design.

With his furniture design success, Durie has worked for Hollywood celebrity clients, such as designing 100 pieces of furniture for American talk show host and comedian Chelsea Handler and he designed garden landscapes for actress Charlize Theron for two years.

Awards and accolades
The Australian reality television garden makeover program Backyard Blitz, on the Nine Network, was the winner of six Logie Awards of Most Popular Lifestyle Program (from 2001 until 2006). Durie won the Logie Award for the Most Popular New Talent award in 2001, and was nominated for the Most Popular Presenter award for his role in Backyard Blitz from 2003 to 2005.

Durie's 2003 landscape design book, Patio - Garden Design and Inspiration, (Allen & Unwin - ISBN 9781741146547) was short-listed APA Book Design Awards, for Best Designed Illustrated Book 2003 Australia.

In 2008, Durie won a gold medal at Britain's prestigious Royal Horticultural Society (RHS) Chelsea Flower Show in Chelsea, London. A team of 22 workers built the AU$800,000, 200sqm celebration of the Kimberley landscape, called Australian Garden and designed by Durie, in 16 days. Australian Garden won one of the eight Gold Medals given in the Show Garden category. All the materials were shipped from Australia.

In 2012, Durie was awarded the Medal of the Order of Australia (OAM) for services to the environment, and charity work.

In 2013, Durie began collaborating with the Italian luxury furniture brand Natuzzi Group Riva 1920. Durie and Riva 1920 launched a bespoke collection of five furniture pieces, including the Tubular dining table, to widespread acclaim at Milan Furniture Fair 2013. The Tubular table and chair (the range also includes bookshelves) and Durie's Bungalow range were both finalists in the New York Design Awards, announced in Manhattan on 20 May 2014, for Product Design Category, Furniture Indoor & Outdoor.

2012–2017 company lawsuit
As of 2012, Durie has been engaged in a legal battle for a breach of contract claim brought by a disgruntled former business manager and licensing agent, Michael Curnow. Curnow sued Durie after Curnow's services were terminated. At the start, Durie declared he would fight the breach of contract claim worth more than AU$750,000 brought by Curnow, who worked in the Mona Vale office of Durie's landscape and interior design business, Durie Design.

In the NSW Supreme Court case, in September 2017, Justice Michael Slattery found largely in favour of Curnow. Durie, who was partially victorious over a claim by Curnow for commissions on work brought to Durie by other agents, disputes that he would be facing damages of more than AU$800,000 as claimed by Curnow. Costs are yet to be determined with a directions hearing in late 2017, though after a 3½-year legal battle and some of the most expensive lawyers in the country, final costs could be another AU$800,000. Durie was reluctant to discuss the judgment when The Sydney Morning Herald spoke with him at the time of the ruling, although he did express his disappointment at the finding and that he had been targeted "because I have a public profile ...that guy has made millions out of me over the years".

In June 2018, it was reported that Durie's company JPD Media & Design has been forced into voluntary administration, with Simon Cathro from Worrells Solvency and Forensic Accountants appointed to look into the company's financial situation.

Personal life
Durie owns properties in Pittwater, on the Northern Beaches of Sydney, Australia, and in Los Angeles. Durie is unmarried, but he has been engaged three times. He has stated, "I've always been career-focused and my relationships have suffered because of that". Durie's former partner, Nadine Bush, is the creative director at Durie Design, and is the co-author of Living Design (2016, Lantern Australia Publishers). Durie says she is a friend and colleague.

Durie has a grown-up daughter who lives in Los Angeles named Taylor, from his previous relationship with Michelle Glennock. Durie says, "We go camping together, surfing and bike riding". Durie describes his life as "I want simply to find more balance and walk down the little path of self discovery...".

Durie is currently engaged to Ameka Jane. They have a daughter, Beau J Durie, born in July 2021.

Each year, Durie donates his time and resources to many charities, including FSHD Global Research Foundation facioscapulohumeral muscular dystrophy (FSHD), the Children's Cancer Institute and The Children's Hospital at Westmead (also called the Royal Alexandra Hospital for Children or Sydney Children's Hospital Network, Westmead), Sydney, New South Wales, Australia.

Filmography

 * Television

title: Jamie Durie


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Pin (chess)

In chess, a pin is a tactic in which a defending piece cannot move out of an attacking piece's line of attack without exposing a more valuable defending piece. Moving the attacking piece to effect the pin is called pinning; the defending piece restricted by the pin is described as pinned. Only a piece that can move any number of squares along a horizontal, vertical, or diagonal line (i.e. a bishop, rook, or queen) can pin. Any piece can be pinned except the king. The pin is one of the most powerful chess tactics.

The inverse of a pin is a skewer, in which a more valuable piece under direct attack may move to expose a less valuable piece to an attack.

Absolute pin
An absolute pin is one where the piece shielded by the pinned piece is the king. In this case it is illegal to move the pinned piece out of the line of attack, as that would place one's king in check (see diagram). A piece pinned in this way can still give check or defend another piece from capture by the opposing king.

Relative pin
A relative pin is one where the piece shielded by the pinned piece is a piece other than the king, but typically is more valuable than the pinned piece. Moving such a pinned piece is legal but may not be prudent, as the shielded piece would then be vulnerable to capture.

Partial pin
Independently of whether it is absolute or relative, a pin might be a partial pin, in which the pinned piece can still move along the line of the pin, and it might be able to capture the piece that is pinning it, but it cannot leave that line. For example, a rook or queen can be partially pinned along a or, or a bishop or queen can be partially pinned along a. Capturing the pinning piece can still be advantageous to the pinning player, as in the example diagram (the pinning rook is defended, so capturing it with the queen would lose ).

A queen can only ever be partially pinned, as it can move in any linear direction, while a knight cannot be partially pinned due to its unique movement. The pawn is a more complex case; due to its limited and conditional movement, whether a pin on a pawn is partial depends on the line and direction of the pin and on whether there are opposing pieces available for it to capture.

It is possible for two opposing pieces to be partially pinning each other.

Situational pin
Sometimes a piece may be considered to be in a situational pin. A situational pin does not legally restrict the piece from moving; however, moving the pinned piece out of the line of attack can result in some detriment to the player (e.g. checkmate, immediate loss of the game, occupation of a critical square by the opponent, etc.).

Consider the diagrammed position, it is White's turn to move. The black bishop on d5 is unprotected and White can capture it with 1.Nxd5; however, White should not play the capture or otherwise move the knight, due to the skewer attack 1...Rb1+ winning White's rook (the king is forced to move, then 2...Rxh1). It can be said that the white knight is "pinned to the b1-square" rather than pinned to a piece.

Cross-pin
A cross-pin consists of two or more pins, of any type, on the same piece. As there is only one king per side, only one of the pins can be absolute, but there are otherwise no restrictions on the types of pins involved.

Pin combinations
Pinning can also be used in combination with other tactics. For example, a piece can be pinned to prevent it from moving to attack, or a defending piece can be pinned as part of tactic undermining an opponent's defense. Another tactic which takes advantage of a pin can be called working the pin. In this tactic, other pieces from the pinning piece's side attack the opposing pinned piece. Since the pinned piece cannot move out of the line of attack, the player whose piece is pinned may move other pieces to defend the pinned piece, but the pinning player may yet attack with even more pieces, etc. Using a battery of doubled rooks with a queen behind them to this end is known as Alekhine's gun.

A pinned piece can usually no longer be counted on as a defender of another friendly piece (that is out of the pinning line of attack) or as an attacker of an opposing piece (out of the pinning line). A pinned piece can still check the opposing king, however, and therefore can still defend friendly pieces against captures made by the enemy king.

Unpinning
The act of breaking a pin is unpinning. This can be executed in a number of ways: the piece creating the pin can be captured or chased away; another unit can be moved onto the line of the pin; the unit to which a piece is pinned can be moved; or, a relatively pinned piece can be moved despite the pin, such as in the Légal Trap and the Elephant Trap.

Pins commonly seen in gameplay
A pinning move that often occurs in openings is Bb5 which, if Black has moved ...Nc6 and ...d6 or ...d5, pins the knight on c6, since moving the knight would expose the king on e8 to check. (The same may, of course, occur on the other, with a bishop on g5; or by Black on White, with a bishop on b4 or g4.)

Examples from games
The diagram shows Vladimir Lenin–Maxim Gorky, Capri 1908, with White to move. Black is threatening the following rook sacrifice and :
 * 27...Rh1+ 28.Kxh1 Qh2

White cannot play 27.gxh3, because the queen on g3 is pinning the pawn to the g-file. The only move that postpones the mate is 27.Nf4, which temporarily blocks Black's bishop from protecting his queen, but to no avail as Black can simply play 27...Bxf4 renewing the mate threat. Or, Black can respond by mating a different way:
 * 27.Nf4 Qh2+ 28.Kf2 Rhxf3#

In this case, White cannot capture 29.gxf3 because the queen now on h2 pins the pawn to the 2nd rank. With mate being inevitable, White resigned after move 26.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Pin (chess)


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SUV

A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive.

There is no commonly agreed-upon definition of an SUV and usage of the term varies between countries. Thus, it is "a loose term that traditionally covers a broad range of vehicles with four-wheel drive." Some definitions claim that an SUV must be built on a light truck chassis; however, broader definitions consider any vehicle with off-road design features to be an SUV. A crossover SUV is often defined as an SUV built with a unibody construction (as with passenger cars); however, the designations are increasingly blurred because of the capabilities of the vehicles, the labelling by marketers, and electrification of new models.

The predecessors to SUVs date back to military and low-volume models from the late 1930s, and the four-wheel-drive station wagons and carryalls that began to be introduced in 1949. Some SUVs produced today use unibody construction; however, in the past, more SUVs used body-on-frame construction. During the late 1990s and early 2000s, the popularity of SUVs greatly increased, often at the expense of the popularity of large sedans and station wagons. SUVs accounted for 45.9% of the world's passenger car market in 2021.

SUVs have been criticized for a variety of environmental and safety-related reasons. They generally have poorer fuel efficiency and require more resources to manufacture than smaller vehicles, contributing more to climate change and environmental degradation. Between 2010 and 2018 SUVs were the second-largest contributor to the global increase in carbon emissions worldwide. Their higher center of gravity increases their risk of rollovers. Their higher front-end profile makes them at least twice as likely to kill pedestrians they hit. Additionally, the psychological sense of security they provide influences drivers to drive less cautiously.

Definitions
There is no universally accepted definition of the sport utility vehicle. Dictionaries, automotive experts, and journalists use varying wordings and defining characteristics, in addition to regional variations of usage by both the media and the general public. The auto industry also has not settled on one definition of the SUV.

The actual term "Sport Utility Vehicle" did not come into wide popular usage until the late 1980s. Before then, such vehicles were marketed as four-wheel drives, jeeps, station wagons, or other terms.

American English
Automotive websites' descriptions of SUVs range from specifically "combining car-like appointments and wagon practicality with steadfast off-road capability" with "chair-height seats and picture-window visibility" to the more general "nearly anything with available all-wheel drive and raised ground clearance". It is also suggested that the term "SUV" has replaced "jeep" as a general term for off-road vehicles.

American dictionary definitions for SUVs include:
 * "rugged automotive vehicle similar to a station wagon but built on a light-truck chassis"
 * "automobile similar to a station wagon but built on a light truck frame"
 * "large vehicle that is designed to be used on rough surfaces but that is often used on city roads or highways"
 * "passenger vehicle similar to a station wagon but with the chassis of a small truck and, usually, four-wheel drive"

British English
In British English, the terms "4x4" (pronounced "four-by-four"), "jeep", four wheel drive, or "off-road vehicle" are generally used instead of "sport utility vehicle". The derogatory term "Chelsea tractor" is also commonly used, due to the perceived popularity of the vehicles with urban residents of Chelsea, London, and their likeness to vehicles used by farmers. However, in the 2020s, the term SUV has entered usage in the United Kingdom

The Collins English Dictionary defines a sport utility vehicle as a "powerful vehicle with four-wheel drive that can be driven over rough ground. The abbreviation SUV is often used."

Other countries
In Europe, the term SUV is generally used for road-oriented vehicles, described as "J-segment" by the European Commission. "Four-by-four" or the brand name of the vehicle is typically used for off-road-oriented vehicles. Similarly, in New Zealand, vehicles designed for off-road use are typically referred to as "four-wheel drives" instead of SUVs.

Government regulations
In the United States, many government regulations simply have categories for "off-highway vehicles" which are loosely defined and often result in SUVs (along with pick-up trucks and minivans) being classified as light trucks. For example, corporate average fuel economy (CAFE) regulations previously included "permit greater cargo-carrying capacity than passenger carrying volume" in the definition for trucks, resulting in cars with removable rear seats, like the PT Cruiser, being classified as light trucks.

This classification as trucks allowed SUVs to be regulated less strictly than passenger cars under the Energy Policy and Conservation Act for fuel economy, and the Clean Air Act for emissions. However, from 2004 onwards, the United States Environmental Protection Agency (EPA) began to hold sport utility vehicles to the same tailpipe emissions standards as cars for criteria pollutants, though not greenhouse gas emissions standards as they were not set until 2010. In 2011, the CAFE regulations were changed to classify small, two-wheel-drive SUVs as passenger cars.

However, the licensing and traffic enforcement regulations in the United States vary from state to state, and an SUV may be classified as a car in some states but as a truck in others. For industry production statistics, SUVs are counted in the light truck product segment.

In India, all SUVs are classified in the "Utility Vehicle" category per the Society of Indian Automobile Manufacturers (SIAM) definitions and carry a 27% excise tax. Those that are 4 m long, have a 1500 cc engine or larger, along with 170 mm of ground clearance, are subject to a 30% excise duty.

In Australia, SUV sales were helped by having lower import duties than passenger cars. Up until January 2010, SUVs were subject to a 5% import tariff, compared with 10% for passenger cars.

Higher parking fee
In February 2024, voters in Paris mandated a triple parking charge rate for SUVs, citing environmental impact and street capacity; this followed similar decisions in Lyon and Tübingen with similar ordinances being considered by London, Brussels and Amsterdam.

Chassis
Many years after most passenger cars had transitioned to unibody construction, most SUVs continued to use a separate body-on-frame method, due to being based on the chassis from a light truck, commercial vehicle, pickup truck, or off-road vehicle.

The first mass-produced unibody four-wheel-drive passenger car was the Russian 1955 GAZ-M20 Pobeda M-72, which could be considered the first crossover car. The 1977 Lada Niva was the first off-road vehicle to use both a unibody construction and a coil-sprung independent front suspension. The relatively compact Niva is considered a predecessor to the crossover SUV and combines a hatchback-like passenger car body with full-time four-wheel drive, low-range gearing, and lockable center differential.

Nonetheless, unibody SUVs remained rare until the 1984 Jeep Cherokee (XJ) was introduced and became a sales success. The introduction of the 1993 Jeep Grand Cherokee resulted in all Jeep SUV models using unibody construction, with many other brands following suit since the mid-1990s. Today, most SUVs in production use a unibody construction and relatively few models continue to use body-on-frame construction.

Body style
SUVs are typically of a two-box design similar to a station wagon. The engine compartment is in the front, followed by a combined passenger/cargo area (unlike a sedan, which has a separate trunk/boot compartment).

Up until approximately 2010, many SUV models were available in two-door body styles. Since then, manufacturers began to discontinue the two-door models as the four-door models became more popular.

A few two-door SUVs remain available, such as the body-on-frame Suzuki Jimny, Mahindra Thar, Toyota Land Cruiser Prado, Ford Bronco, and Jeep Wrangler as well as the Range Rover Evoque crossover SUV.

Safety

SUVs typically have high ground clearance and a tall body. This results in a high center of mass, which made SUVs more prone to roll-over accidents. In 2003, SUVs were quoted as 2.5 times more likely to roll over in a crash than regular cars and that SUV roofs were more likely to cave in on passengers than in other cars, resulting in increased harm to passengers.

Between 1991 and 2001, the United States saw a 150% increase in sport-utility vehicle rollover deaths. In 2001, though roll-overs constituted just 3% of vehicle crashes overall, they caused over 30% of occupant fatalities in crashes; and in crashes where the vehicle did roll over, SUV occupants in the early 2000s were nearly three times as likely to be killed as other car passengers. Vehicles with a high center of gravity do sometimes fail the moose test of maneuverability conducted by Swedish consumer magazine Teknikens Värld, for example, the 1997 Mercedes-Benz A-Class and 2011 Jeep Grand Cherokee.

The increasing popularity of SUVs in the 1990s and early 2000s was partly due to buyers perceiving that SUVs provide greater safety for occupants, due to their larger size and raised ride height. Regarding the safety of other road users, SUVs are exempted from U.S. regulation stating that a passenger car bumper must protect the area between 16 and 20 in above the ground. This often increases the damage to the other car in a collision with an SUV, because the impact occurs at a higher location on the other car. In 2000–2001, 60% of fatal side-impact collisions were where the other vehicle was an SUV, an increase from 30% in 1980–1981.

The introduction of electronic stability control (ESC) and rollover mitigation, as well as increased analysis of the risks of a rollover, led the IIHS to report in 2015 that "the rollover death rate of 5 per million registered vehicle years for 2011 models is less than a quarter of what it was for 2004 models. With ESC dramatically reducing rollover risk, the inherent advantages offered by SUVs' greater size, weight, and height emerge more clearly. Today's SUVs have the lowest driver death rate of any vehicle type."

The high danger for cyclists and pedestrians of being seriously injured or even killed by SUV drivers has caused some public protests against SUVs in urban areas. In 2020, a study by the U.S.-based IIHS found that, of a sample of 79 crashes from three urban areas in Michigan, SUVs caused more serious injuries compared to cars when impacts occurred at greater than 19 mph. The IIHS noted the sample size of the study was small and that more research is needed. The popularity of SUVs contributed to an increase in pedestrian fatalities in the U.S. during the 2010s, alongside other factors such as distracted and drunk driving.

A 2021 study by the University of Illinois Springfield showed that SUVs are 8 times more likely to kill children in a collision than passenger cars, and multiple times more lethal to adult pedestrians and cyclists.

Environmental impact
SUVs generally have poorer fuel efficiency than smaller cars, and thus contribute more to environmental degradation and global warming.

SUVs emit about 700 megatonnes of carbon dioxide per year, a gas that is linked to global warming. According to the International Energy Agency, from 2010 SUVs have been the second-largest contributor to the increase in global emissions, second only to the power sector.

SUVs were responsible for all of the 3.3 million barrels a day growth in oil demand from passenger cars between 2010 and 2018, whereas efficiency improvements in smaller cars saved over 2 million barrels a day, with electric cars reducing oil demand by under 100,000 barrels a day.

Whereas SUVs can be electrified, or converted to run on a variety of alternative fuels, including hydrogen, their (manufacturing) emissions will always be larger than smaller electric cars. On average, SUVs consume about a quarter more energy than medium-size cars. Furthermore, the vast majority of these vehicles are not converted to use alternative fuels.

Between 2010 and 2018 SUVs were the second largest contributor to the global increase in carbon emissions worldwide.

Crossover SUV
The "crossover SUV" segment (also known as "CUVs" or simply "crossovers") has become increasingly popular since around 2010. Crossovers are often based on a platform shared with a passenger car, as a result, they typically have better comfort and fuel economy, but less off-road capability (many crossovers are sold without all-wheel drive) than pickup truck-based SUVs.

The difference between crossovers and other SUVs is sometimes defined as a crossover being built using a unibody platform (the type used by most passenger cars), while an SUV is built using a body-on-frame platform (the type used by off-road vehicles and light trucks). However, these definitions are often blurred in practice, since unibody vehicles are also often referred to as SUVs. Also, crossover is a relatively recent term and early unibody SUVs (such as the 1984 Jeep Cherokee) are rarely called crossovers. Due to these inconsistencies, the term SUV is often used as a catch-all for both crossovers and SUVs.

Outside of the United States, the term crossover tends to be used for C-segment (compact) or smaller vehicles, with large unibody vehicles—such as the Mercedes-Benz GLS-Class, BMW X7, and Range Rover—usually referred to as SUVs rather than crossovers. In the United Kingdom, a crossover is sometimes defined as a hatchback model with raised ride height and SUV-like styling features.
 * Examples:

Mini SUV
The smallest size class of SUVs is the "mini SUV". In Japan, SUVs under 3400 mm—such as the Mitsubishi Pajero Mini—are included in the kei car category and therefore attract lower taxes.

Many recent vehicles labeled as mini SUVs are technically subcompact crossovers and are built on the platform of a subcompact (also called supermini or B-segment) passenger car.

 * Examples:

Compact SUV
The "compact SUV" is the next bigger-size class after mini SUVs.

Many recent vehicles labeled as compact SUVs are technically compact crossovers and are built on the platform of a compact (C-segment) passenger car.

 * Examples:

Mid-size SUV
The next larger size is called the "mid-size SUV". Some mid-size SUVs are based on platforms shared with passenger cars and therefore, are crossovers. Other mid-size SUVs are based on compact or mid-size pickups.

 * Examples:

Full-size SUV
Full-size SUVs are the largest size of commonly produced SUVs. Some, such as the Ford Expedition, and Chevrolet Tahoe, are marketed for their off-road capabilities, and others, such as the Lincoln Navigator and Cadillac Escalade, are marketed as luxury vehicles. While a few full-size SUVs are built on dedicated platforms; most share their platforms with full-size pickup trucks.

 * Examples:

Extended-length SUV
Some North American SUVs are available as a long-bodied version of a full-size SUV, which is called an "extended-length SUV" like the Ford Expedition EL and the Chevrolet Suburban. The additional length is used to provide extra space for rear passengers or cargo. As per the full-size SUVs they are based on, most extended-length SUVs are built on dedicated platforms, full-sized pickups (1⁄2 ton), or heavy-duty pickups (3⁄4 ton or more).

Extended-length SUVs are mostly sold in North America but may also be exported to other markets in small numbers.

 * Examples:

Coupe SUV
Some SUVs or crossovers with sloping rear rooflines are marketed as "coupe crossover SUVs" or "coupe SUVs", even though they have four side doors for passenger access to the seats and rear hatches for cargo area access.

1930s to 1948
Just before and during World War II, prototypes and low-volume production examples of military cars with sedan or station wagon-type bodies and rugged, off-road capable four-wheel drive chassis began to appear around the world. These early models included the 1936 Kurogane Type 95 from Japan, the 1938 GAZ-61 from Russia as well as the 1941 Volkswagen Kommandeurswagen and 1936 Opel Geländesportwagen from Germany. An early predecessor to the design of modern SUVs was the 1940 Humber Heavy Utility, a four-wheel-drive off-road vehicle built on the chassis of the Humber Super Snipe passenger car.

The most prohibitive initial factors to the potential civilian popularity of an SUV-like car were their cost and the availability of certain critical parts. Before the war, adding four-wheel drive to a car almost doubled its cost. Compared to a common, rear-wheel drive vehicle, any 4WD (four-wheel drive) needed many essential extra components, including a transfer case, a second differential, and constant-velocity joints for the driven front axle—which were expensive due to the precision involved in this required manufacturing gears and other specialized parts. Before World WarII, these were produced in the United States by only a few specialized firms with limited production capacity. Due to the increase in demand for parts for the war effort, in the spring of 1942 Ford, Dodge, and Chevrolet joined in fabricating these parts in mass quantities, boosting their production more than 100-fold.

An early usage of the term was the 1947 Crosley CC Four Sport Utility model, which used a convertible wagon body style and is therefore unrelated to the design of later SUVs.

1949 to 1970s
Several models of carryall wagons began to be offered with four-wheel drive, beginning in 1949 when the Willys Jeep Station Wagon introduced the option of four-wheel drive. Four-wheel-drive versions of the Chevrolet Suburban were introduced for 1955, followed by the International Harvester Travelall in 1956 (credited as being the first full-size SUV) and the Power Wagon Town Wagon in 1957.

Developed as a competitor to the Jeep CJ, the compact International Scout was introduced in 1961, offering either two- or four-wheel drive and a variety of engine options. The Harvester Scout provided many other options designed to appeal to a wide range of customers for numerous uses as well. The 1963 Jeep Wagoneer (SJ) introduced a sophisticated station wagon body design that was more carlike than any other four-wheel-drive vehicle on the market. The 1967 Toyota Land Cruiser FJ55 station wagon was the first comfort-oriented version of the Land Cruiser off-road vehicle. The two-door Chevrolet K5 Blazer (and related GMC K5 Jimmy) were introduced for 1969, and the two-door International Scout II was introduced in 1971. The first European luxury off-road vehicle was the 1970 Range Rover Classic, which was marketed as a luxury car for both on-road and off-road usage.

In 1972 Subaru Leone 4WD wagon was introduced in Japan, which was not designed as an off-road vehicle, but a version of the front-wheel-drive passenger car. Some argue that this was the first SUV. It was also classified as a commercial vehicle in the home market, just like later SUVs.

The first relevant usage of the term SUV was in advertising brochures for the full-sized 1974 Jeep Cherokee (SJ), which used the wording "sport(s) utility vehicle" as a description for the vehicle. The 1966 Ford Bronco included a "sport utility" model; however, in this case it was used for the two-door pickup truck version.

The VAZ-2121 (now designated Lada Niva Legend) was the first mass-market 4WD unibody car in some markets in 1977. The AMC Eagle introduced in the North American market in 1979, and is often called the first mass-market "crossover", although that term had not been coined at the time. In contrast to truck or utility-vehicle based designs and the Niva that was purpose-built for rural areas, American Motors Corporation (AMC) utilized a long-serving existing car platform and designed a new automatic full-time AWD system. The AMC Eagle was developed as a passenger car offering numerous comfort, luxury, and convenience features in sedan, coupe, and station wagon body styles. It was first with "SUV styling on a raised passenger-car platform combined with AWD." Four Wheeler magazine described the AMC Eagle as "the beginning of a new generation of cars".

1980s to 1990s
The compact-sized 1984 Jeep Cherokee (XJ) is often credited as the first SUV in the modern understanding of the term. The use of unibody construction was unique at the time for a four-wheel drive and also reduced the weight of the new Cherokee. It also appealed to urban families due to having a more compact size (compared to the full-size Wagoneer and previous generation Cherokee SJ models) as well as a plush interior resembling a station wagon. As the new Cherokee became a major sales success, the term "sport utility vehicle" began to be used in the national press for the first time. "The advent and immediate success of AMC/Jeep's compact four-door Cherokee turned the truck industry upside down."

The U.S. corporate average fuel economy (CAFE) standard was introduced in 1975 to reduce fuel usage, but included relaxed regulations for "light trucks" to avoid businesses paying extra taxes for work vehicles. This created a loophole that manufacturers increasingly exploited since the 1980s oil glut (which started an era of cheap gasoline), whereby SUVs were designed to be classified as light trucks despite their primary use as passenger vehicles to receive tax concessions and less stringent fuel economy requirements. This enabled manufacturers to sell more profitable, larger, more polluting vehicles, instead of the smaller, less polluting, less profitable cars, that the CAFE regulations intended.

For example, the United States Environmental Protection Agency agreed to classify the new Jeep Cherokee as a light truck following lobbying from its manufacturer; the Cherokee was then marketed by the company as a passenger vehicle. This increased the SUV boom as other manufacturers introduced their own SUVs in response to the compact Cherokee taking sales from their regular cars.

In 1994 the U.S. Environmental Protection Agency began classifying vehicles by "market class". For SUVs in 1994 they included three Jeep models, the Cherokee, Grand Cherokee and Wrangler. Two Ford models were the Bronco and the Explorer. Six General Motors models including the GMC Jimmy, the Yukon, and the Suburban 1500; the Chevrolet Suburban 1500, and the Blazer (1500 and S10); the Geo Tracker (Convertible or Van); and finally the Oldsmobile Bravada. Eleven Japanese models classified as SUVs were the Toyota 4Runner and Land Cruiser; the Honda Passport; the Nissan Pathfinder; the Mazda Navajo; the Mitsubishi Montero; the Isuzu Amigo, Rodeo, and Trooper; and the Suzuki Samurai and Sidekick. From Europe the three Land Rover models, the Range Rover, the Defender and the Discovery were classified as SUVs.

By late 1996 Consumers Digest magazine was calling the trend an "SUV craze", and by 1999 the U.S. sales of SUVs and light trucks for the first time exceeded sales of regular passenger cars.

2000s
By 2003, there were 76 million SUVs and light trucks on U.S. roads, representing approximately 35% of the vehicles on the road.

Car manufacturers were keen to promote SUV sales over other types of cars due to higher profits in the segment. An SUV could be sold with a profit margin of US$10,000 or more (US$18,000 per SUV in the case of the Ford Excursion), while compact cars were often sold at a loss of a few hundred dollars per car. As a result, several manufacturing plants were converted from car production to SUV production (such as the General Motors plant in Arlington, Texas in 1996), and many long-running U.S. sedan models were discontinued.

From the mid-2000s until 2010, U.S. sales of SUVs and other light trucks experienced a dip due to increasing fuel prices and then a declining economy. From 2008 until 2010, General Motors closed four assembly plants that were producing SUVs and trucks. Sales of SUVs and light trucks sales began to recover in 2010, as fuel prices decreased and the North American economy improved.

2010s to 2020s

In 2019, the International Energy Agency (IEA) reported that the global number of SUVs and crossovers on the road multiplied by six since 2010—from 35 million to 200 million vehicles, and their market share has grown to 40 percent of worldwide new light-vehicle sales at the end of the decade.

By 2013, small and compact SUVs had increased to become the third-largest market segment. Since the early 2000s, new versions have been introduced to appeal to a wider audience, such as crossovers and other small SUVs. Larger SUVs also remained popular, with sales of General Motors' large SUV models increasing significantly in 2013.

In 2015, global sales of SUVs overtook the "lower medium car" segment, to become the largest market segment, accounting for 22.9% of "light vehicle" sales in 2015. The following year, worldwide SUV sales experienced further growth of 22%. The world's fastest-growing SUV markets in 2014–2015 were: China (+ 47.9%), Italy (+ 48.6%), Spain (+ 42%), Portugal (+ 54.8 %), and Thailand (+ 56.4%). The SUV segment further grew to 26% of the global passenger car market in 2016, then to 36.8% of the market in Q1–Q3 of 2017.

In the U.S. at the end of 2016, sales of SUVs and light-duty trucks had surpassed traditional car sales for the year by over 3 million units. Manufacturers continued to phase out the production of sedan models, replacing them with new models of SUVs. Luxury brands have increasingly introduced SUV or crossover models in the 2010s. For example: Rolls-Royce Cullinan, Bentley Bentayga, Aston Martin DBX, Maserati Levante, Lamborghini Urus, and Ferrari Purosangue.

In 2019 SUVs made up 47.4% of U.S. sales compared to only 22.1% for sedans.

Motorsport

SUVs have competed in various off-road racing competitions, such as the Dakar Rally, Baja 1000, FIA Cross-Country Rally World Cup, King of the Hammers, and Australasian Safari. SUVs have also competed in the Trophee Andros ice-racing series.

Nicknames
Several derogatory or pejorative terms for SUVs are based on the combination of an affluent suburb name and "tractor", particularly for expensive vehicles from luxury brands. Examples include "Toorak Tractor" (Melbourne, Australia), "Chelsea Tractor" (London, England) and "Remuera Tractor" (Auckland, New Zealand). These terms relate to the theory that four-wheel drive capabilities are not required by affluent SUV owners, and that the SUV is purchased as a status symbol rather than for practical reasons.

In Norway, the term Børstraktor ('Stock Exchange Tractor') serves a similar purpose. In the Netherlands, SUVs are sometimes called "P.C. Hooft-tractors" after the exclusive P.C. Hooftstraat Amsterdam shopping street.

Commercial SUVs

A commercial SUV is an SUV or crossover, that is used for commercial purposes. The category is very similar to panel trucks since the Chevrolet Suburban (an SUV) had panel truck versions, which were used for commercial purposes.

The first SUV-like vehicle that had commercial versions was the Chevrolet Suburban panel truck. Panel trucks by American manufacturers were built until the late 1970s.

While panel trucks manufactured by European manufacturers were rare, commercial versions of off-road vehicles were very common, Land Rover manufactured commercial versions of the Land Rover and the Defender. Commercial SUVs are factory-built and most of them are not independent conversions, which means they can be bought from dealerships and showrooms.

Examples of SUVs used as commercial vehicles in Europe include: Citroen C5 Aircross Commercial SUV, the Land Rover Discovery, the Dacia Duster Flika, and the Mitsubishi Pajero.

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Timecode

A timecode (alternatively, time code) is a sequence of numeric codes generated at regular intervals by a timing synchronization system. Timecode is used in video production, show control and other applications which require temporal coordination or logging of recording or actions.

Video and film
In video production and filmmaking, SMPTE timecode is used extensively for synchronization, and for logging and identifying material in recorded media. During filmmaking or video production shoot, the camera assistant will typically log the start and end timecodes of shots, and the data generated will be sent on to the editorial department for use in referencing those shots. This shot-logging process was traditionally done by hand using pen and paper, but is now typically done using shot-logging software running on a laptop computer that is connected to the timecode generator or the camera itself.

The SMPTE family of timecodes are almost universally used in film, video and audio production, and can be encoded in many different formats, including:
 * Linear timecode (LTC), in a separate audio track
 * Vertical interval timecode (VITC), in the vertical blanking interval of a video track
 * AES-EBU embedded timecode used with digital audio
 * Burnt-in timecode, in human-readable form in the video itself
 * CTL timecode (control track)
 * MIDI timecode

Keykode, while not a timecode, is used to identify specific film frames in film post-production that uses physical film stock. Keykode data is normally used in conjunction with SMPTE timecode.

Rewritable consumer timecode is a proprietary consumer video timecode system that is not frame-accurate, and is therefore not used in professional post-production.

Other formats
Timecodes for purposes other than video and audio production include:
 * IRIG timecode is used for military, government and commercial purposes.
 * DTS timecode is used to synchronise the optical DTS timecode track from a projector to the CD-based DTS audio tracks.

Timecode generators

Depending on the environment, timecode generators can take various forms.

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Victoria Adams

Victoria Adams may refer to:

 * Victoria Adams (comics), fictional superheroine known as the Shield
 * Victoria Gray Adams (1926–2006), civil rights activist
 * Victoria Beckham (born 1974), née Adams, English pop singer and businesswoman
 * Vicki Chalmers (born 1989), née Adams, Scottish curler
 * Mickie James (born 1979), American wrestler, sometimes uses the ring name Vicki Adams

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Coral

Corals are colonial marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.

A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when mature, settles to form a new colony.

Although some corals are able to catch plankton and small fish using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates of the genus Symbiodinium that live within their tissues. These are commonly known as zooxanthellae and give the coral color. Such corals require sunlight and grow in clear, shallow water, typically at depths less than 60 m, but corals in the genus Leptoseris have been found as deep as 172 m. Corals are major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the Great Barrier Reef off the coast of Australia. These corals are increasingly at risk of bleaching events where polyps expel the zooxanthellae in response to stress such as high water temperature or toxins.

Other corals do not rely on zooxanthellae and can live globally in much deeper water, such as the cold-water genus Lophelia which can survive as deep as 3300 m. Some have been found as far north as the Darwin Mounds, northwest of Cape Wrath, Scotland, and others off the coast of Washington state and the Aleutian Islands.

Taxonomy
The classification of corals has been discussed for millennia, owing to having similarities to both plants and animals. Aristotle's pupil Theophrastus described the red coral, korallion, in his book on stones, implying it was a mineral, but he described it as a deep-sea plant in his Enquiries on Plants, where he also mentions large stony plants that reveal bright flowers when under water in the Gulf of Heroes. Pliny the Elder stated boldly that several sea creatures including sea nettles and sponges "are neither animals nor plants, but are possessed of a third nature (tertia natura)". Petrus Gyllius copied Pliny, introducing the term zoophyta for this third group in his 1535 book On the French and Latin Names of the Fishes of the Marseilles Region; it is popularly but wrongly supposed that Aristotle created the term. Gyllius further noted, following Aristotle, how hard it was to define what was a plant and what was an animal. The Babylonian Talmud refers to coral among a list of types of trees, and the 11th-century French commentator Rashi describes it as "a type of tree (מין עץ) that grows underwater that goes by the (French) name "coral."

The Persian polymath Al-Biruni (d.1048) classified sponges and corals as animals, arguing that they respond to touch. Nevertheless, people believed corals to be plants until the eighteenth century when William Herschel used a microscope to establish that coral had the characteristic thin cell membranes of an animal.

Presently, corals are classified as species of animals within the sub-classes Hexacorallia and Octocorallia of the class Anthozoa in the phylum Cnidaria. Hexacorallia includes the stony corals and these groups have polyps that generally have a 6-fold symmetry. Octocorallia includes blue coral and soft corals and species of Octocorallia have polyps with an eightfold symmetry, each polyp having eight tentacles and eight mesenteries. The group of corals is paraphyletic because the sea anemones are also in the sub-class Hexacorallia.

Systematics
The delineation of coral species is challenging as hypotheses based on morphological traits contradict hypotheses formed via molecular tree-based processes. As of 2020, there are 2175 identified separate coral species, 237 of which are currently endangered, making distinguishing corals to be the utmost of importance in efforts to curb extinction. Adaptation and delineation continues to occur in species of coral in order to combat the dangers posed by the climate crisis. Corals are colonial modular organisms formed by asexually produced and genetically identical modules called polyps. Polyps are connected by living tissue to produce the full organism. The living tissue allows for inter module communication (interaction between each polyp), which appears in colony morphologies produced by corals, and is one of the main identifying characteristics for a species of coral.

There are two main classifications for corals: hard coral (scleractinian and stony coral) which form reefs by a calcium carbonate base, with polyps that bear six stiff tentacles, and soft coral (Alcyonacea and ahermatypic coral) which are pliable and formed by a colony of polyps with eight feather-like tentacles. These two classifications arose from differentiation in gene expressions in their branch tips and bases that arose through developmental signaling pathways such as Hox, Hedgehog, Wnt, BMP etc.

Scientists typically select Acropora as research models since they are the most diverse genus of hard coral, having over 120 species. Most species within this genus have polyps which are dimorphic: axial polyps grow rapidly and have lighter coloration, while radial polyps are small and are darker in coloration. In the Acropora genus, gamete synthesis and photosynthesis occur at the basal polyps, growth occurs mainly at the radial polyps. Growth at the site of the radial polyps encompasses two processes: asexual reproduction via mitotic cell proliferation, and skeleton deposition of the calcium carbonate via extra cellular matrix (EMC) proteins acting as differentially expressed (DE) signaling genes between both branch tips and bases. These processes lead to colony differentiation, which is the most accurate distinguisher between coral species. In the Acropora genus, colony differentiation through up-regulation and down-regulation of DEs.

Systematic studies of soft coral species have faced challenges due to a lack of taxonomic knowledge. Researchers have not found enough variability within the genus to confidently delineate similar species, due to a low rate in mutation of mitochondrial DNA.

Environmental factors, such as the rise of temperatures and acid levels in our oceans account for some speciation of corals in the form of species lost. Various coral species have heat shock proteins (HSP) that are also in the category of DE across species. These HSPs help corals combat the increased temperatures they are facing which lead to protein denaturing, growth loss, and eventually coral death. Approximately 33% of coral species are on the International Union for Conservation of Nature's endangered species list and at risk of species loss. Ocean acidification (falling pH levels in the oceans) is threatening the continued species growth and differentiation of corals. Mutation rates of Vibrio shilonii, the reef pathogen responsible for coral bleaching, heavily outweigh the typical reproduction rates of coral colonies when pH levels fall. Thus, corals are unable to mutate their HSPs and other climate change preventative genes to combat the increase in temperature and decrease in pH at a competitive rate to these pathogens responsible for coral bleaching, resulting in species loss.

Anatomy
For most of their life corals are sessile animals of colonies of genetically identical polyps. Each polyp varies from millimeters to centimeters in diameter, and colonies can be formed from many millions of individual polyps. Stony coral, also known as hard coral, polyps produce a skeleton composed of calcium carbonate to strengthen and protect the organism. This is deposited by the polyps and by the coenosarc, the living tissue that connects them. The polyps sit in cup-shaped depressions in the skeleton known as corallites. Colonies of stony coral are markedly variable in appearance; a single species may adopt an encrusting, plate-like, bushy, columnar or massive solid structure, the various forms often being linked to different types of habitat, with variations in light level and water movement being significant.

The body of the polyp may be roughly compared in a structure to a sac, the wall of which is composed of two layers of cells. The outer layer is known technically as the ectoderm, the inner layer as the endoderm. Between ectoderm and endoderm is a supporting layer of gelatinous substance termed mesoglea, secreted by the cell layers of the body wall. The mesoglea can contain skeletal elements derived from cells migrated from the ectoderm.

The sac-like body built up in this way is attached to a hard surface, which in hard corals are cup-shaped depressions in the skeleton known as corallites. At the center of the upper end of the sac lies the only opening called the mouth, surrounded by a circle of tentacles which resemble glove fingers. The tentacles are organs which serve both for tactile sense and for the capture of food. Polyps extend their tentacles, particularly at night, often containing coiled stinging cells (cnidocytes) which pierce, poison and firmly hold living prey paralyzing or killing them. Polyp prey includes plankton such as copepods and fish larvae. Longitudinal muscular fibers formed from the cells of the ectoderm allow tentacles to contract to convey the food to the mouth. Similarly, circularly disposed muscular fibres formed from the endoderm permit tentacles to be protracted or thrust out once they are contracted. In both stony and soft corals, the polyps can be retracted by contracting muscle fibres, with stony corals relying on their hard skeleton and cnidocytes for defense. Soft corals generally secrete terpenoid toxins to ward off predators.

In most corals, the tentacles are retracted by day and spread out at night to catch plankton and other small organisms. Shallow-water species of both stony and soft corals can be zooxanthellate, the corals supplementing their plankton diet with the products of photosynthesis produced by these symbionts. The polyps interconnect by a complex and well-developed system of gastrovascular canals, allowing significant sharing of nutrients and symbionts.

The external form of the polyp varies greatly. The column may be long and slender, or may be so short in the axial direction that the body becomes disk-like. The tentacles may number many hundreds or may be very few, in rare cases only one or two. They may be simple and unbranched, or feathery in pattern. The mouth may be level with the surface of the peristome, or may be projecting and trumpet-shaped.

Soft corals
Soft corals have no solid exoskeleton as such. However, their tissues are often reinforced by small supportive elements known as sclerites made of calcium carbonate. The polyps of soft corals have eight-fold symmetry, which is reflected in the Octo in Octocorallia.

Soft corals vary considerably in form, and most are colonial. A few soft corals are stolonate, but the polyps of most are connected by sheets of tissue called coenosarc, and in some species these sheets are thick and the polyps deeply embedded in them. Some soft corals encrust other sea objects or form lobes. Others are tree-like or whip-like and have a central axial skeleton embedded at their base in the matrix of the supporting branch. These branches are composed of a fibrous protein called gorgonin or of a calcified material.

Stony corals
The polyps of stony corals have six-fold symmetry. In stony corals, the tentacles are cylindrical and taper to a point, but in soft corals they are pinnate with side branches known as pinnules. In some tropical species, these are reduced to mere stubs and in some, they are fused to give a paddle-like appearance.

Coral skeletons are biocomposites (mineral + organics) of calcium carbonate, in the form of calcite or aragonite. In scleractinian corals, "centers of calcification" and fibers are clearly distinct structures differing with respect to both morphology and chemical compositions of the crystalline units. The organic matrices extracted from diverse species are acidic, and comprise proteins, sulphated sugars and lipids; they are species specific. The soluble organic matrices of the skeletons allow to differentiate zooxanthellae and non-zooxanthellae specimens.

Feeding
Polyps feed on a variety of small organisms, from microscopic zooplankton to small fish. The polyp's tentacles immobilize or kill prey using stinging cells called nematocysts. These cells carry venom which they rapidly release in response to contact with another organism. A dormant nematocyst discharges in response to nearby prey touching the trigger (Cnidocil). A flap (operculum) opens and its stinging apparatus fires the barb into the prey. The venom is injected through the hollow filament to immobilise the prey; the tentacles then manoeuvre the prey into the stomach. Once the prey is digested the stomach reopens allowing the elimination of waste products and the beginning of the next hunting cycle.

Intracellular symbionts
Many corals, as well as other cnidarian groups such as sea anemones form a symbiotic relationship with a class of dinoflagellate algae, zooxanthellae of the genus Symbiodinium, which can form as much as 30% of the tissue of a polyp. Typically, each polyp harbors one species of alga, and coral species show a preference for Symbiodinium. Young corals are not born with zooxanthellae, but acquire the algae from the surrounding environment, including the water column and local sediment. The main benefit of the zooxanthellae is their ability to photosynthesize which supplies corals with the products of photosynthesis, including glucose, glycerol, also amino acids, which the corals can use for energy. Zooxanthellae also benefit corals by aiding in calcification, for the coral skeleton, and waste removal. In addition to the soft tissue, microbiomes are also found in the coral's mucus and (in stony corals) the skeleton, with the latter showing the greatest microbial richness.

The zooxanthellae benefit from a safe place to live and consume the polyp's carbon dioxide, phosphate and nitrogenous waste. Stressed corals will eject their zooxanthellae, a process that is becoming increasingly common due to strain placed on coral by rising ocean temperatures. Mass ejections are known as coral bleaching because the algae contribute to coral coloration; some colors, however, are due to host coral pigments, such as green fluorescent proteins (GFPs). Ejection increases the polyp's chance of surviving short-term stress and if the stress subsides they can regain algae, possibly of a different species, at a later time. If the stressful conditions persist, the polyp eventually dies. Zooxanthellae are located within the coral cytoplasm and due to the algae's photosynthetic activity the internal pH of the coral can be raised; this behavior indicates that the zooxanthellae are responsible to some extent for the metabolism of their host corals. Stony Coral Tissue Loss Disease has been associated with the breakdown of host-zooxanthellae physiology. Moreover, Vibrio bacterium are known to have virulence traits used for host coral tissue damage and photoinhibition of algal symbionts. Therefore, both coral and their symbiotic microorganisms could have evolved to harbour traits resistant to disease and transmission.

Reproduction
Corals can be both gonochoristic (unisexual) and hermaphroditic, each of which can reproduce sexually and asexually. Reproduction also allows coral to settle in new areas. Reproduction is coordinated by chemical communication.

Sexual
Corals predominantly reproduce sexually. About 25% of hermatypic corals (reef-building stony corals) form single-sex (gonochoristic) colonies, while the rest are hermaphroditic. It is estimated more than 67% of coral are simultaneous hermaphrodites.

Broadcasters
About 75% of all hermatypic corals "broadcast spawn" by releasing gametes—eggs and sperm—into the water where they meet and fertilize to spread offspring. Corals often synchronize their time of spawning. This reproductive synchrony is essential so that male and female gametes can meet. Spawning frequently takes place in the evening or at night, and can occur as infrequently as once a year, and within a window of 10–30 minutes. Synchronous spawning is very typical on the coral reef, and often, all corals spawn on the same night even when multiple species are present. Synchronous spawning may form hybrids and is perhaps involved in coral speciation.

Environmental cues that influence the release of gametes into the water vary from species to species. The cues involve temperature change, lunar cycle, day length, and possibly chemical signalling. Other factors that affect the rhythmicity of organisms in marine habitats include salinity, mechanical forces, and pressure or magnetic field changes.

Mass coral spawning often occurs at night on days following a full moon. A full moon is equivalent to four to six hours of continuous dim light exposure, which can cause light-dependent reactions in protein. Corals contain light-sensitive cryptochromes, proteins whose light-absorbing flavin structures are sensitive to different types of light. This allows corals such as Dipsastraea speciosa to detect and respond to changes in sunlight and moonlight.

Moonlight itself may actually suppress coral spawning. The most immediate cue to cause spawning appears to be the dark portion of the night between sunset and moonrise. Over the lunar cycle, moonrise shifts progressively later, occurring after sunset on the day of the full moon. The resulting dark period between day-light and night-light removes the suppressive effect of moonlight and enables coral to spawn.

The spawning event can be visually dramatic, clouding the usually clear water with gametes. Once released, gametes fertilize at the water's surface and form a microscopic larva called a planula, typically pink and elliptical in shape. A typical coral colony needs to release several thousand larvae per year to overcome the odds against formation of a new colony.

Studies suggest that light pollution desynchronizes spawning in some coral species. In areas such as the Red Sea, as many as 10 out of 50 species may be showing spawning asynchrony, compared to 30 years ago. The establishment of new corals in the area has decreased and in some cases ceased. The area was previously considered a refuge for corals because mass bleaching events due to climate change had not been observed there. Coral restoration techniques for coral reef management are being developed to increase fertilization rates, larval development, and settlement of new corals.

Brooders
Brooding species are most often ahermatypic (not reef-building) in areas of high current or wave action. Brooders release only sperm, which is negatively buoyant, sinking onto the waiting egg carriers that harbor unfertilized eggs for weeks. Synchronous spawning events sometimes occur even with these species. After fertilization, the corals release planula that are ready to settle.

Planulae
The time from spawning to larval settlement is usually two to three days but can occur immediately or up to two months. Broadcast-spawned planula larvae develop at the water's surface before descending to seek a hard surface on the benthos to which they can attach and begin a new colony. The larvae often need a biological cue to induce settlement such as specific crustose coralline algae species or microbial biofilms. High failure rates afflict many stages of this process, and even though thousands of eggs are released by each colony, few new colonies form. During settlement, larvae are inhibited by physical barriers such as sediment, as well as chemical (allelopathic) barriers. The larvae metamorphose into a single polyp and eventually develops into a juvenile and then adult by asexual budding and growth.

Asexual

Within a coral head, the genetically identical polyps reproduce asexually, either by budding (gemmation) or by dividing, whether longitudinally or transversely.

Budding involves splitting a smaller polyp from an adult. As the new polyp grows, it forms its body parts. The distance between the new and adult polyps grows, and with it, the coenosarc (the common body of the colony). Budding can be intratentacular, from its oral discs, producing same-sized polyps within the ring of tentacles, or extratentacular, from its base, producing a smaller polyp.

Division forms two polyps that each become as large as the original. Longitudinal division begins when a polyp broadens and then divides its coelenteron (body), effectively splitting along its length. The mouth divides and new tentacles form. The two polyps thus created then generate their missing body parts and exoskeleton. Transversal division occurs when polyps and the exoskeleton divide transversally into two parts. This means one has the basal disc (bottom) and the other has the oral disc (top); the new polyps must separately generate the missing pieces.

Asexual reproduction offers the benefits of high reproductive rate, delaying senescence, and replacement of dead modules, as well as geographical distribution.

Colony division
Whole colonies can reproduce asexually, forming two colonies with the same genotype. The possible mechanisms include fission, bailout and fragmentation. Fission occurs in some corals, especially among the family Fungiidae, where the colony splits into two or more colonies during early developmental stages. Bailout occurs when a single polyp abandons the colony and settles on a different substrate to create a new colony. Fragmentation involves individuals broken from the colony during storms or other disruptions. The separated individuals can start new colonies.

Coral microbiomes

Corals are one of the more common examples of an animal host whose symbiosis with microalgae can turn to dysbiosis, and is visibly detected as bleaching. Coral microbiomes have been examined in a variety of studies, which demonstrate how oceanic environmental variations, most notably temperature, light, and inorganic nutrients, affect the abundance and performance of the microalgal symbionts, as well as calcification and physiology of the host.

Studies have also suggested that resident bacteria, archaea, and fungi additionally contribute to nutrient and organic matter cycling within the coral, with viruses also possibly playing a role in structuring the composition of these members, thus providing one of the first glimpses at a multi-domain marine animal symbiosis. The gammaproteobacterium Endozoicomonas is emerging as a central member of the coral's microbiome, with flexibility in its lifestyle. Given the recent mass bleaching occurring on reefs, corals will likely continue to be a useful and popular system for symbiosis and dysbiosis research.

Astrangia poculata, the northern star coral, is a temperate stony coral, widely documented along the eastern coast of the United States. The coral can live with and without zooxanthellae (algal symbionts), making it an ideal model organism to study microbial community interactions associated with symbiotic state. However, the ability to develop primers and probes to more specifically target key microbial groups has been hindered by the lack of full-length 16S rRNA sequences, since sequences produced by the Illumina platform are of insufficient length (approximately 250 base pairs) for the design of primers and probes. In 2019, Goldsmith et al. demonstrated Sanger sequencing was capable of reproducing the biologically relevant diversity detected by deeper next-generation sequencing, while also producing longer sequences useful to the research community for probe and primer design (see diagram on right).

Holobionts
Reef-building corals are well-studied holobionts that include the coral itself together with its symbiont zooxanthellae (photosynthetic dinoflagellates), as well as its associated bacteria and viruses. Co-evolutionary patterns exist for coral microbial communities and coral phylogeny.

It is known that the coral's microbiome and symbiont influence host health, however, the historic influence of each member on others is not well understood. Scleractinian corals have been diversifying for longer than many other symbiotic systems, and their microbiomes are known to be partially species-specific. It has been suggested that Endozoicomonas, a commonly highly abundant bacterium in corals, has exhibited codiversification with its host. This hints at an intricate set of relationships between the members of the coral holobiont that have been developing as evolution of these members occurs.

A study published in 2018 revealed evidence of phylosymbiosis between corals and their tissue and skeleton microbiomes. The coral skeleton, which represents the most diverse of the three coral microbiomes, showed the strongest evidence of phylosymbiosis. Coral microbiome composition and richness were found to reflect coral phylogeny. For example, interactions between bacterial and eukaryotic coral phylogeny influence the abundance of Endozoicomonas, a highly abundant bacterium in the coral holobiont. However, host-microbial cophylogeny appears to influence only a subset of coral-associated bacteria.

Reefs
Many corals in the order Scleractinia are hermatypic, meaning that they are involved in building reefs. Most such corals obtain some of their energy from zooxanthellae in the genus Symbiodinium. These are symbiotic photosynthetic dinoflagellates which require sunlight; reef-forming corals are therefore found mainly in shallow water. They secrete calcium carbonate to form hard skeletons that become the framework of the reef. However, not all reef-building corals in shallow water contain zooxanthellae, and some deep water species, living at depths to which light cannot penetrate, form reefs but do not harbour the symbionts.

There are various types of shallow-water coral reef, including fringing reefs, barrier reefs and atolls; most occur in tropical and subtropical seas. They are very slow-growing, adding perhaps one centimetre (0.4 in) in height each year. The Great Barrier Reef is thought to have been laid down about two million years ago. Over time, corals fragment and die, sand and rubble accumulates between the corals, and the shells of clams and other molluscs decay to form a gradually evolving calcium carbonate structure. Coral reefs are extremely diverse marine ecosystems hosting over 4,000 species of fish, massive numbers of cnidarians, molluscs, crustaceans, and many other animals.

Evolution

At certain times in the geological past, corals were very abundant. Like modern corals, their ancestors built reefs, some of which ended as great structures in sedimentary rocks. Fossils of fellow reef-dwellers algae, sponges, and the remains of many echinoids, brachiopods, bivalves, gastropods, and trilobites appear along with coral fossils. This makes some corals useful index fossils. Coral fossils are not restricted to reef remnants, and many solitary fossils are found elsewhere, such as Cyclocyathus, which occurs in England's Gault clay formation.

Early corals
Corals first appeared in the Cambrian about. Fossils are extremely rare until the Ordovician period, 100 million years later, when Heliolitida, rugose, and tabulate corals became widespread. Paleozoic corals often contained numerous endobiotic symbionts.

Tabulate corals occur in limestones and calcareous shales of the Ordovician period, with a gap in the fossil record due to extinction events at the end of the Ordovician. Corals reappeared some millions of years later during the Silurian period, and tabulate corals often form low cushions or branching masses of calcite alongside rugose corals. Tabulate coral numbers began to decline during the middle of the Silurian period.

Rugose or horn corals became dominant by the middle of the Silurian period, and during the Devonian, corals flourished with more than 200 genera. The rugose corals existed in solitary and colonial forms, and were also composed of calcite. Both rugose and tabulate corals became extinct in the Permian–Triassic extinction event (along with 85% of marine species), and there is a gap of tens of millions of years until new forms of coral evolved in the Triassic.

Modern corals
The currently ubiquitous stony corals, Scleractinia, appeared in the Middle Triassic to fill the niche vacated by the extinct rugose and tabulate orders and is not closely related to the earlier forms. Unlike the corals prevalent before the Permian extinction, which formed skeletons of a form of calcium carbonate known as calcite, modern stony corals form skeletons composed of the aragonite. Their fossils are found in small numbers in rocks from the Triassic period, and become common in the Jurassic and later periods. Although they are geologically younger than the tabulate and rugose corals, the aragonite of their skeletons is less readily preserved, and their fossil record is accordingly less complete.

Threats
Coral reefs are under stress around the world. In particular, coral mining, agricultural and urban runoff, pollution (organic and inorganic), overfishing, blast fishing, disease, and the digging of canals and access into islands and bays are localized threats to coral ecosystems. Broader threats are sea temperature rise, sea level rise and pH changes from ocean acidification, all associated with greenhouse gas emissions. In 1998, 16% of the world's reefs died as a result of increased water temperature.

Approximately 10% of the world's coral reefs are dead. About 60% of the world's reefs are at risk due to human-related activities. The threat to reef health is particularly strong in Southeast Asia, where 80% of reefs are endangered. Over 50% of the world's coral reefs may be destroyed by 2030; as a result, most nations protect them through environmental laws.

In the Caribbean and tropical Pacific, direct contact between ~40–70% of common seaweeds and coral causes bleaching and death to the coral via transfer of lipid-soluble metabolites. Seaweed and algae proliferate given adequate nutrients and limited grazing by herbivores such as parrotfish.

Water temperature changes of more than 1–2 C or salinity changes can kill some species of coral. Under such environmental stresses, corals expel their Symbiodinium; without them, coral tissues reveal the white of their skeletons, an event known as coral bleaching.

Submarine springs found along the coast of Mexico's Yucatán Peninsula produce water with a naturally low pH (relatively high acidity) providing conditions similar to those expected to become widespread as the oceans absorb carbon dioxide. Surveys discovered multiple species of live coral that appeared to tolerate the acidity. The colonies were small and patchily distributed and had not formed structurally complex reefs such as those that compose the nearby Mesoamerican Barrier Reef System.

Coral health
To assess the threat level of coral, scientists developed a coral imbalance ratio, Log (Average abundance of disease-associated taxa / Average abundance of healthy associated taxa). The lower the ratio the healthier the microbial community is. This ratio was developed after the microbial mucus of coral was collected and studied.

Climate change impacts
Increasing sea surface temperatures in tropical regions (~1 C-change) the last century have caused major coral bleaching, death, and therefore shrinking coral populations. Although coral are able to adapt and acclimate, it is uncertain if this evolutionary process will happen quickly enough to prevent major reduction of their numbers. Climate change causes more frequent and more severe storms that can destroy coral reefs.

Annual growth bands in some corals, such as the deep sea bamboo corals (Isididae), may be among the first signs of the effects of ocean acidification on marine life. The growth rings allow geologists to construct year-by-year chronologies, a form of incremental dating, which underlie high-resolution records of past climatic and environmental changes using geochemical techniques.

Certain species form communities called microatolls, which are colonies whose top is dead and mostly above the water line, but whose perimeter is mostly submerged and alive. Average tide level limits their height. By analyzing the various growth morphologies, microatolls offer a low-resolution record of sea level change. Fossilized microatolls can also be dated using radiocarbon dating. Such methods can help to reconstruct Holocene sea levels.

Though coral have large sexually-reproducing populations, their evolution can be slowed by abundant asexual reproduction. Gene flow is variable among coral species. According to the biogeography of coral species, gene flow cannot be counted on as a dependable source of adaptation as they are very stationary organisms. Also, coral longevity might factor into their adaptivity.

However, adaptation to climate change has been demonstrated in many cases, which is usually due to a shift in coral and zooxanthellae genotypes. These shifts in allele frequency have progressed toward more tolerant types of zooxanthellae. Scientists found that a certain scleractinian zooxanthella is becoming more common where sea temperature is high. Symbionts able to tolerate warmer water seem to photosynthesise more slowly, implying an evolutionary trade-off.

In the Gulf of Mexico, where sea temperatures are rising, cold-sensitive staghorn and elkhorn coral have shifted in location. Not only have the symbionts and specific species been shown to shift, but there seems to be a certain growth rate favorable to selection. Slower-growing but more heat-tolerant corals have become more common. The changes in temperature and acclimation are complex. Some reefs in current shadows represent a refugium location that will help them adjust to the disparity in the environment even if eventually the temperatures may rise more quickly there than in other locations. This separation of populations by climatic barriers causes a realized niche to shrink greatly in comparison to the old fundamental niche.

Geochemistry
Corals are shallow, colonial organisms that integrate oxygen and trace elements into their skeletal aragonite (polymorph of calcite) crystalline structures as they grow. Geochemical anomalies within the crystalline structures of corals represent functions of temperature, salinity and oxygen isotopic composition. Such geochemical analysis can help with climate modeling. The ratio of oxygen-18 to oxygen-16 (δ18O), for example, is a proxy for temperature.

Strontium/calcium ratio anomaly
Time can be attributed to coral geochemistry anomalies by correlating strontium/calcium minimums with sea surface temperature (SST) maximums to data collected from NINO 3.4 SSTA.

Oxygen isotope anomaly
The comparison of coral strontium/calcium minimums with sea surface temperature maximums, data recorded from NINO 3.4 SSTA, time can be correlated to coral strontium/calcium and δ18O variations. To confirm the accuracy of the annual relationship between Sr/Ca and δ18O variations, a perceptible association to annual coral growth rings confirms the age conversion. Geochronology is established by the blending of Sr/Ca data, growth rings, and stable isotope data. El Nino-Southern Oscillation (ENSO) is directly related to climate fluctuations that influence coral δ18O ratio from local salinity variations associated with the position of the South Pacific convergence zone (SPCZ) and can be used for ENSO modeling.

Sea surface temperature and sea surface salinity
The global moisture budget is primarily being influenced by tropical sea surface temperatures from the position of the Intertropical Convergence Zone (ITCZ). The Southern Hemisphere has a unique meteorological feature positioned in the southwestern Pacific Basin called the South Pacific Convergence Zone (SPCZ), which contains a perennial position within the Southern Hemisphere. During ENSO warm periods, the SPCZ reverses orientation extending from the equator down south through Solomon Islands, Vanuatu, Fiji and towards the French Polynesian Islands; and due east towards South America affecting geochemistry of corals in tropical regions.

Geochemical analysis of skeletal coral can be linked to sea surface salinity (SSS) and sea surface temperature (SST), from El Nino 3.4 SSTA data, of tropical oceans to seawater δ18O ratio anomalies from corals. ENSO phenomenon can be related to variations in sea surface salinity (SSS) and sea surface temperature (SST) that can help model tropical climate activities.

Limited climate research on current species
Climate research on live coral species is limited to a few studied species. Studying Porites coral provides a stable foundation for geochemical interpretations that is much simpler to physically extract data in comparison to Platygyra species where the complexity of Platygyra species skeletal structure creates difficulty when physically sampled, which happens to be one of the only multidecadal living coral records used for coral paleoclimate modeling.

Protection
Marine Protected Areas, Biosphere reserves, marine parks, national monuments world heritage status, fishery management and habitat protection can protect reefs from anthropogenic damage.

Many governments now prohibit removal of coral from reefs, and inform coastal residents about reef protection and ecology. While local action such as habitat restoration and herbivore protection can reduce local damage, the longer-term threats of acidification, temperature change and sea-level rise remain a challenge.

Protecting networks of diverse and healthy reefs, not only climate refugia, helps ensure the greatest chance of genetic diversity, which is critical for coral to adapt to new climates. A variety of conservation methods applied across marine and terrestrial threatened ecosystems makes coral adaption more likely and effective.

To eliminate destruction of corals in their indigenous regions, projects have been started to grow corals in non-tropical countries.

Relation to humans
Local economies near major coral reefs benefit from an abundance of fish and other marine creatures as a food source. Reefs also provide recreational scuba diving and snorkeling tourism. These activities can damage coral but international projects such as Green Fins that encourage dive and snorkel centres to follow a Code of Conduct have been proven to mitigate these risks.

Jewelry
Corals' many colors give it appeal for necklaces and other jewelry. Intensely red coral is prized as a gemstone. Sometimes called fire coral, it is not the same as fire coral. Red coral is very rare because of overharvesting. In general, it is inadvisable to give coral as gifts since they are in decline from stressors like climate change, pollution, and unsustainable fishing.

Always considered a precious mineral, "the Chinese have long associated red coral with auspiciousness and longevity because of its color and its resemblance to deer antlers (so by association, virtue, long life, and high rank". It reached its height of popularity during the Manchu or Qing Dynasty (1644-1911) when it was almost exclusively reserved for the emperor's use either in the form of coral beads (often combined with pearls) for court jewelry or as decorative Penjing (decorative miniature mineral trees). Coral was known as shanhu in Chinese. The "early-modern 'coral network' [began in] the Mediterranean Sea [and found its way] to Qing China via the English East India Company". There were strict rules regarding its use in a code established by the Qianlong Emperor in 1759.

Medicine
In medicine, chemical compounds from corals can potentially be used to treat cancer, neurological diseases, inflammation including arthritis, pain, bone loss, high blood pressure and for other therapeutic uses. Coral skeletons, e.g. Isididae are being researched for their potential near-future use for bone grafting in humans. Coral Calx, known as Praval Bhasma in Sanskrit, is widely used in traditional system of Indian medicine as a supplement in the treatment of a variety of bone metabolic disorders associated with calcium deficiency. In classical times ingestion of pulverized coral, which consists mainly of the weak base calcium carbonate, was recommended for calming stomach ulcers by Galen and Dioscorides.

Construction
Coral reefs in places such as the East African coast are used as a source of building material. Ancient (fossil) coral limestone, notably including the Coral Rag Formation of the hills around Oxford (England), was once used as a building stone, and can be seen in some of the oldest buildings in that city including the Saxon tower of St Michael at the Northgate, St. George's Tower of Oxford Castle, and the medieval walls of the city.

Shoreline protection
Healthy coral reefs absorb 97 percent of a wave's energy, which buffers shorelines from currents, waves, and storms, helping to prevent loss of life and property damage. Coastlines protected by coral reefs are also more stable in terms of erosion than those without.

Local economies
Coastal communities near coral reefs rely heavily on them. Worldwide, more than 500 million people depend on coral reefs for food, income, coastal protection, and more. The total economic value of coral reef services in the United States - including fisheries, tourism, and coastal protection - is more than $3.4 billion a year.

Aquaria
The saltwater fishkeeping hobby has expanded, over recent years, to include reef tanks, fish tanks that include large amounts of live rock on which coral is allowed to grow and spread. These tanks are either kept in a natural-like state, with algae (sometimes in the form of an algae scrubber) and a deep sand bed providing filtration, or as "show tanks", with the rock kept largely bare of the algae and microfauna that would normally populate it, in order to appear neat and clean.

The most popular kind of coral kept is soft coral, especially zoanthids and mushroom corals, which are especially easy to grow and propagate in a wide variety of conditions, because they originate in enclosed parts of reefs where water conditions vary and lighting may be less reliable and direct. More serious fishkeepers may keep small polyp stony coral, which is from open, brightly lit reef conditions and therefore much more demanding, while large polyp stony coral is a sort of compromise between the two.

Aquaculture
Coral aquaculture, also known as coral farming or coral gardening, is the cultivation of corals for commercial purposes or coral reef restoration. Aquaculture is showing promise as a potentially effective tool for restoring coral reefs, which have been declining around the world. The process bypasses the early growth stages of corals when they are most at risk of dying. Coral fragments known as "seeds" are grown in nurseries then replanted on the reef. Coral is farmed by coral farmers who live locally to the reefs and farm for reef conservation or for income. It is also farmed by scientists for research, by businesses for the supply of the live and ornamental coral trade and by private aquarium hobbyists.

Gallery
Further images: commons:Category:Coral reefs and commons:Category:Corals

title: Coral