Grand Canyon And Great Barrier Reef

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The Grand Canyon (Hopi: Ongtupqa; Yavapai: Wi:kaʼi:la) is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is contained within and managed by Grand Canyon National Park, the Hualapai Tribal Nation, and the Havasupai TribeSony VAIO VPCF24Q1E battery. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery. It is considered one of the Seven Natural Wonders of the World.[1]

The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,000 feet / 1,800 metres) Sony VAIO VPCF13M1E/H battery Nearly two billion years of the Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted.[3] While the specific geologic processes and timing that formed the Grand Canyon are the subject of debate by geologists, Sony VAIO VPCF12Z1E/BI battery recent evidence suggests the Colorado River established its course through the canyon at least 17 million years ago. Since that time, the Colorado River continued to erode and form the canyon to its present-day configuration.[7]

For thousands of years, the area has been continuously inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon ("Ongtupqa" in Hopi language) Sony VAIO VPCF12S1E/B battery a holy site and made pilgrimages to it.[8] The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540.


The Grand Canyon is a huge fissure in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and is also one of the 19 distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world (Kali Gandaki Gorge in Nepal is far deeper) Sony VAIO VPCF13Z8E/BI battery, nor the widest (Capertee Valley in Australia is about 0.6 mi/1 km wider and longer than Grand Canyon); however, the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically it is significant because of the thick sequence of ancient rocks that are beautifully preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continentSony VAIO VPCF13Z8E battery.

A map of the Grand Canyon and surrounding areas, circa 1908.

Uplift associated with mountain formation later moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has also resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid. The uplift of the Colorado Plateau is uneven,Sony VAIO VPCF13M1E/B battery and the Kaibab Plateau that Grand Canyon bisects is over a thousand feet higher at the North Rim (about 1,000 ft/300 m) than at the South Rim. Almost all runoff from the North Rim (which also gets more rain and snow) flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon (following the general tilt) Sony VAIO VPCF1318E/H battery. The result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side.

Temperatures on the North Rim are generally lower than the South Rim because of the greater elevation (averaging 8,000 ft/2,438 m above sea level).[10] Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (State Route 67) is limited during the winter season due to road closuresSony VAIO VPCF13J0E/H battery.


Main article: Geology of the Grand Canyon area

Diagram showing the placement, age and thickness of the rock units exposed in the Grand Canyon.

Rockfalls in recent times, along with other mass wasting, have further widened the canyon.

The Colorado River basin (of which the Grand Canyon is a part) has developed in the past 40 million years. A recent study places the origins of the canyon beginning some 17 million years agoSony VAIO VPCF13E8E battery. Previous estimates had placed the age of the canyon at 5 to 6 million years. The study, which was published in the journal Science in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon.[11] There is a substantial amount of controversy because this research suggests such a substantial departure from prior widely supported scientific consensus. Sony VAIO VPCF13E4E battery

The result of all this erosion is one of the most complete geologic columns on the planet.

The major geologic exposures in the Grand Canyon range in age from the 2 billion year old Vishnu Schist at the bottom of the Inner Gorge to the 230 million year old Kaibab Limestone on the Rim. There is a gap of about one billion years between the stratum that is about 500 million years old and the lower levelSony VAIO VPCF12M1E/H battery, which is about 1.5 billion years old. This large unconformity indicates a period of erosion between two periods of deposition.

Many of the formations were deposited in warm shallow seas, near-shore environments (such as beaches), and swamps as the seashore repeatedly advanced and retreated over the edge of a proto-North America. Major exceptions include the Permian Coconino Sandstone, which contains abundant geological evidence of aeolian sand dune depositionSony VAIO VPCF12F4E/H battery. Several parts of the Supai Group also were deposited in non–marine environments.

The great depth of the Grand Canyon and especially the height of its strata (most of which formed below sea level) can be attributed to 5,000 to 10,000 feet (1500 to 3000 m) of uplift of the Colorado Plateau, starting about 65 million years ago (during the Laramide Orogeny) Sony VAIO VPCF12E1E/H battery. This uplift has steepened the stream gradient of the Colorado River and its tributaries, which in turn has increased their speed and thus their ability to cut through rock (see the elevation summary of the Colorado River for present conditions).

Weather conditions during the ice ages also increased the amount of water in the Colorado River drainage system. The ancestral Colorado River responded by cutting its channel faster and deeperSony VAIO VPCF11Z1E/BI battery.

The base level and course of the Colorado River (or its ancestral equivalent) changed 5.3 million years ago when the Gulf of California opened and lowered the river's base level (its lowest point). This increased the rate of erosion and cut nearly all of the Grand Canyon's current depth by 1.2 million years ago. The terraced walls of the canyon were created by differential erosionSony VAIO VPCF24M1E battery.

Between three million and 100,000 years ago, volcanic activity deposited ash and lava over the area which at times completely obstructed the river. These volcanic rocks are the youngest in the canyon.

Human history

Main article: History of the Grand Canyon area

Grand Canyon from the South Rim, near the NPS Visitor Center

Ancestral Puebloan granaries at Nankoweap Creek.

Eagle Rock (located at Eagle Point) on the west rim, aptly named for its shape, is considered sacred by the Hualapai IndiansSony VAIO VPCF23S1E battery.

[edit]Native Americans

Main article: Ancient Pueblo Peoples

The Ancient Pueblo People were a Native American culture centered on the present-day Four Corners area of the United States. The Ancient Puebloans were the first people to live in the Grand Canyon area. The cultural group has often been referred to in archaeology as the Anasazi, although the term is not preferred by the modern Puebloan peoplesSony VAIO VPCF231S1E battery. The word "Anasazi" is Navajo for "Ancient Ones" or "Ancient Enemy".[14]

Archaeologists still debate when this distinct culture emerged. The current consensus, based on terminology defined by the Pecos Classification, suggests their emergence around 1200 BC, during the archaeologically designated Basketmaker II Era. Beginning with the earliest explorations and excavationsSony VAIO VPCF23Q1E battery, researchers have believed that the Ancient Puebloans are ancestors of the modern Pueblo peoples.[14]

In addition to the Ancestral Puebloans, a number of distinct cultures have inhabited the Grand Canyon area. The Cohonina lived to the west of the Grand Canyon, between 500 and 1200 AD. The Cohonina were ancestors of the Yuman, Havasupai, and Walapai peoples who inhabit the area todaySony VAIO VPCF23M1E battery.

The Sinagua were a cultural group occupying an area to the southeast of the Grand Canyon, between the Little Colorado River and the Salt River, between approximately 500 AD and 1425 AD. The Sinagua may have been ancestors of several Hopi clans.

By the time of the arrival of Europeans in the 16th century, newer cultures had evolved. The Hualapai inhabit a 100-mile (160 km) Sony VAIO VPCF22S8E battery stretch along the pine-clad southern side of the Grand Canyon. The Havasupai have been living in the area near Cataract Canyon since 1200 AD, occupying an area the size of Delaware.[18] The Southern Paiutes live in what is now southern Utah and northern Arizona. The Navajo or Diné, live in a wide area stretching from the San Francisco Peaks eastwards towards the Four CornersSony VAIO VPCF22S1E battery. Archaeological and linguistic evidence suggests the Navajo descended from the Athabaskan people near Great Slave Lake, Canada, who migrated after 1000 AD.[19][not in citation given]

European arrival and settlement

Spanish explorers

In September 1540, under orders from the conquistador Francisco Vázquez de Coronado to search for the fabled Seven Cities of Cibola, Captain Garcia Lopez de Cardenas, along with Hopi guides and a small group of Spanish soldiersSony VAIO VPCF22M1E battery, traveled to the South Rim of the Grand Canyon between Desert View and Moran Point. Pablo de Melgrossa, Juan Galeras, and a third soldier descended some one third of the way into the Canyon until they were forced to return because of lack of water. In their report, they noted that some of the rocks in the Canyon were "bigger than the great tower of Seville." Sony VAIO VPCF22L1E battery It is speculated that their Hopi guides must have been reluctant to lead them to the river, since they must have known routes to the canyon floor. Afterwards, no Europeans visited the Canyon for over two hundred years.

Fathers Francisco Atanasio Domínguez and Silvestre Vélez de Escalante were two Spanish priests who, with a group of Spanish soldiersSony VAIO VPCF22J1E battery, explored southern Utah and traveled along the North Rim of the Canyon in Glen and Marble Canyons in search of a route from Santa Fe to California in 1776. They eventually found a crossing, formerly known as the "Crossing of the Fathers," that today lies under Lake Powell.

Also in 1776, Fray Francisco Garces, a Franciscan missionary, spent a week near Havasupai, unsuccessfully attempting to convert a band of Native Americans to ChristianitySony VAIO VPCF11S1E/B battery. He described the Canyon as "profound".[20]

American exploration

This section needs additional citations for verification. (February 2011)

James Ohio Pattie, along with a group of American trappers and mountain men, may have been the next European to reach the Canyon in 1826.[21]

Jacob Hamblin, (a Mormon missionary), was sent by Brigham Young in the 1850s to locate easy river crossing sites in the CanyonSony VAIO VPCF11M1E/H battery. Building good relations with local Native Americans Hualapai Nation and white settlers, he discovered the Crossing of the Fathers, Lee's Ferry in 1858 and Pierce Ferry (later operated by, and named for, Harrison Pierce) – the latter two the only two sites suitable for ferry operation.[citation needed] He also acted as an advisor to John Wesley Powell before his second expedition to the Grand CanyonSony VAIO VPCF11D4E battery, serving as a diplomat between Powell and the local native tribes to ensure the safety of his party.

William Bell's photograph of the Grand Canyon, taken in 1872 as part of the Wheeler expedition

In 1857, Edward Fitzgerald Beale was superintendent of an expedition to survey a wagon road along the 35th parallel from Fort Defiance, Arizona to the Colorado River. He led a small party of men in search of water on the Coconino Plateau near the Canyon's South RimSony VAIO VPCF11C5E battery. On September 19, near present day National Canyon, they came upon what May Humphreys Stacey described in his journal as "...a wonderful canyon four thousand feet deep. Everyone (in the party) admitted that he never before saw anything to match or equal this astonishing natural curiosity."

Also in 1857, the U.S. War Department asked Lieutenant Joseph Ives to lead an expedition to assess the feasibility of an up-river navigation from the Gulf of CaliforniaSony VAIO VPCF11C4E/B battery. Also in a stern wheeler steamboat "Explorer", after two months and 350 miles (560 km) of difficult navigation, his party reached Black Canyon some two months after George Johnson.[citation needed] The "Explorer" struck a rock and was abandoned. Ives led his party east into the Canyon — they may have been the first Europeans to travel the Diamond Creek drainage and traveled eastwards along the South RimSony VAIO PCG-31114V battery. In his "Colorado River of the West" report to the Senate in 1861 he states that "One or two trappers profess to have seen the canon."

Noon rest in Marble Canyon, second Powell Expedition, 1872

According to the San Francisco Herald, in a series of articles run in 1853, they give this honor to Captain Joseph R. Walker, who in January 1851 with his nephew James T. Walker and six menSony VAIO PCG-31114M battery, traveled up the Colorado River to a point where it joined the Virgin River and continued east into Arizona, traveling along the Grand Canyon and making short exploratory side trips along the way.

Walker said he wanted to visit the Moqui Indians, as the Hopi were then called by whites. He had met these people briefly in previous years, thought them exceptionally interesting and wanted to become better acquainted. The Herald reporter took it from there, writing: "We believe that Capt. Joe Walker is the only white man in this country that has ever visited this strange peopleSony VAIO PCG-31113M battery."

In 1858, John Strong Newberry became probably the first geologist to visit the Grand Canyon.

In 1869, Major John Wesley Powell led the first expedition down the Canyon. Powell set out to explore the Colorado River and the Grand Canyon. Gathering nine men, four boats and food for 10 months, he set out from Green River, Wyoming on May 24Sony VAIO PCG-31112M battery. Passing through dangerous rapids, the group passed down the Green River to its confluence with the Colorado River, near present-day Moab, Utah and completed the journey with many hardships through the Grand Canyon on August 13, 1869.[22] In 1871 Powell first used the term "Grand Canyon"; previously it had been called the "Big Canyon"Sony VAIO PCG-31111M battery.

In 1889, Frank M. Brown wanted to build a railroad along the Colorado River to carry coal. He, his chief engineer Robert Brewster Stanton, and 14 others started to explore the Grand Canyon in poorly-designed cedar wood boats, with no life preservers. Brown drowned in an accident near Marble Canyon: Stanton made new boats and proceeded to explore the Colorado all of the way to the Gulf of CaliforniaSony VAIO PCG-41112M battery.

In 1908, the Grand Canyon[25] became an official national monument and became a national park in 1919.

[edit]Settlers in and near the canyon

Miners: "Captain" John Hance, William W. Bass, Louis Boucher "The Hermit", Seth Tanner, Charles Spencer, D. W. "James" Mooney

Lees Ferry: John Doyle Lee, Emma Lee French (17th of John Lee's 19 wives), J. S. Emmett, Charles SpencerSony VAIO PCG-41111M battery

Phantom Ranch: David Rust, Mary Colter

Grand Canyon Village: Ralph H. Cameron, Emery & Ellsworth Kolb,

[edit]Federal protection

U.S. President Theodore Roosevelt visited the Grand Canyon in 1903. An avid outdoorsman and staunch conservationist, he established the Grand Canyon Game Preserve on November 28, 1906. Livestock grazing was reduced, but predators such as mountain lions, eagles, and wolves were eradicatedSONY VAIO PCG-21212M battery. Roosevelt added adjacent national forest lands and redesignated the preserve a U.S. National Monument on January 11, 1908. Opponents such as land and mining claim holders blocked efforts to reclassify the monument as a U.S. National Park for 11 years. Grand Canyon National Park was finally established as the 17th U.S. National Park by an Act of Congress signed into law by President Woodrow Wilson on February 26, 1919. SONY VAIO PCG-21211M battery

The federal government administrators who manage park resources face many challenges. These include issues related to the recent reintroduction into the wild of the highly endangered California condor, air tour overflight noise levels, water rights disputes with various tribal reservations that border the park, and forest fire managementSONY VAIO PCG-51212M battery. The Grand Canyon National Park superintendent is Steve Martin. Martin was named superintendent on February 5, 2007, to replace retiring superintendent Joe Alston. Martin was previously the National Park Service Deputy Director and superintendent of several other national parks, including Denali and Grand Teton.[26] Federal officials started a flood in the Grand Canyon in hopes of restoring its ecosystem on March 5, 2008SONY VAIO PCG-51211M battery. The canyon's ecosystem was permanently changed after the construction of the Glen Canyon Dam in 1963.[27]

Between 2003 and 2011, 2,215 mining claims have been requested that are adjacent to the Canyon, including claims for uranium mines. Mining has been suspended since 2009, when U.S. Interior Secretary Ken Salazar temporarily withdrew 1 million acres (4,000 km2) from the permitting processSONY VAIO PCG-51112M battery, pending assessment of the environmental impact of mining. Critics of the mines are concerned that, once mined, the uranium will leach into the water of the Colorado River and contaminate the water supply for up to 18 million people.[28]

South Rim buildings

There are several historical buildings located along the South Rim with most in the vicinity of Grand Canyon VillageSONY VAIO PCG-51111M battery.

Desert View Watchtower in 2004

Buckey O'Neill Cabin was built during the 1890s by William Owen "Buckey" O'Neill. He built the cabin because of a copper deposit that was nearby. He had several occupations such as miner, judge, politician, author and tour guide. This cabin is the longest continually standing structure in the South Rim. It is currently used as a guest house; booking is required well in advanceSONY VAIO PCG-81212M battery.

Kolb Studio was built in 1904 by brothers Ellsworth and Emery Kolb. They were photographers who made a living by photographing visitors walking down the Bright Angel Trail. In 1911, the Kolb brothers filmed their journey down the Green and Colorado Rivers. Emery Kolb showed this movie regularly in his studio until 1976, when he died at the age of 95. Today the building serves as an art gallery and exhibitSony VAIO PCG-81112M battery.

The El Tovar Hotel was built in 1905 and is the most luxurious lodging on the South Rim. The hotel consists of 4 stories with a rustic chalet appearance. It was designed by Charles Whittlesley. A gift shop and restaurant are located inside the hotel.

Hopi House was built by Mary Jane Colter in 1905. It is based on structures that were built in an ancient Hopi settlement called Old Oraibi, located on the Third Mesa in eastern ArizonaSONY VAIO PCG-71111M battery. It served as a residence for the Hopi Indians who sold arts and crafts to visitors in the South Rim.

Verkamp's Curios, which stands next to the Hopi House, was built by John Verkamp in 1905. He sold arts and crafts as well as souvenirs. Until September 2008, it was run by his descendants; in November 2008 the building reopened as a visitor center focusing on the history of the Grand Canyon Village communitySONY VAIO PCG-7196M battery.

Locomotive No. 4960

Grand Canyon Railway Depot was built in 1909 and contains 2 levels. Gordon Chappell, Regional Historian for the Park Service, claims that this depot building is one of only three log-cabin-style train stations currently standing, out of fourteen ever built in the U.S.[29] The depot is the northern terminus of the Grand Canyon Railway which begins in Williams, ArizonaSONY VAIO PCG-7195M battery.

Lookout Studio was built in 1914 and is another structure that was designed by Mary Colter. Photography, artwork, books, souvenirs, and rock and fossil specimens are sold here. A great view of Bright Angel Trail can be seen here.

Desert View Watchtower, one of Mary Colter's best-known works, was built in 1932. Situated at the far eastern end of the South Rim, 27 miles (43 km) SONY VAIO PCG-7194M battery from Grand Canyon Village, the tower stands 70 feet (21 m)tall. The top of the tower is 7,522 feet (2,293 m)above sea level, the highest point on the South Rim. It offers one of the few full views of the bottom of the Canyon and the Colorado River. It was designed to mimic an Anasazi watchtower, though it is significantly taller than existing ones. SONY VAIO PCG-7192M battery

Bright Angel Lodge was built of logs and stone in 1935. Mary Colter designed the lodge and it was built by the Fred Harvey Company. Inside the lodge is a small museum honoring Fred Harvey (June 27, 1835–February 9, 1901), who played a major role in popularizing the Grand Canyon. In the History Room is a stone fireplace layered crin the same sequence as in the canyonSONY PCG-8113M battery.


A storm over the Grand Canyon

Weather in the Grand Canyon varies according to elevation. The forested rims are high enough to receive winter snowfall, but along the Colorado River in the Inner Gorge, temperatures are similar to those found in Tucson and other low elevation desert locations in Arizona. Conditions in the Grand Canyon region are generally drySONY PCG-8112M battery, but substantial precipitation occurs twice annually, during seasonal pattern shifts in winter (when Pacific storms usually deliver widespread, moderate rain and high-elevation snow to the region from the west) and in late summer (due to the North American Monsoon, which delivers waves of moisture from the southeast, causing dramatic, localized thunderstorms fueled by the heat of the day). SONY PCG-7134M battery  Average annual precipitation on the South Rim is less than 16 inches (35 cm), with 60 inches (132 cm) of snow, the higher North Rim usually receives 27 inches (59 cm) of moisture, with a typical snowfall of 144 inches (317 cm), and Phantom Ranch, far below the Canyon's rims along the Colorado River at 2,500 feet (762 m) gets just 8 inches (17.6 cm) of rain, and snow is a rarity. The weather is different on the north rim and south rimSONY PCG-7131M battery.

Grand Canyon covered with snow

Temperatures vary wildly throughout the year, with summer highs within the Inner Gorge commonly exceeding 100 °F (37.8 °C) and winter minimum temperatures sometimes falling below zero degrees Fahrenheit (−17.8 °C) along the canyon's rims.[31] Visitors are often surprised by these potentially extreme conditions, and thisSONY PCG-7122M battery, along with the high altitude of the canyon's rims, can lead to unpleasant side effects such as dehydration, sunburn, and hypothermia.

Weather conditions can greatly affect hiking and canyon exploration, and visitors should obtain accurate forecasts because of hazards posed by exposure to extreme temperatures, winter storms and late summer monsoonsSONY PCG-7121M battery. While the park service posts weather information at gates and visitor centers, this is a rough approximation only, and should not be relied upon for trip planning. For accurate weather in the Canyon, hikers should consult the National Weather Service's NOAA weather radio or the official National Weather Service website. SONY PCG-7113M battery

The National Weather Service has had a cooperative station on the South Rim since 1903. The record high temperature on the South Rim was 105°F on June 26, 1974, and the record low temperature was −20°F on January 1, 1919, February 1, 1985, and December 23, 1990.

Air pollution

Smoke from prescribed fires on the south rim, as seen from Yavapai Point, April 2007SONY PCG-7112M battery .

The Grand Canyon has suffered some problems with air pollution, attributed to the nearby Navajo Generating Station, a coal-burning power plant. In 1991 an agreement was reached with the Navajo Generating Station in Page, Arizona, to add air pollution control devices to their smokestacks. SONY PCG-8Z3M battery

Biology and ecology

There are approximately 1,737 known species of vascular plants, 167 species of fungi, 64 species of moss and 195 species of lichen found in Grand Canyon National Park.[38] This variety is largely due to the 8,000 foot elevation change from the Colorado River up to the highest point on the North Rim.[38] Grand Canyon boasts a dozen endemic plants SONY PCG-8Z2M battery (known only within the Park's boundaries) while only ten percent of the Park's flora is exotic.[38] Sixty-three plants found here have been given special status by the U.S. Fish and Wildlife Service.[38]

The Mojave Desert influences the western sections of the canyon, Sonoran Desert vegetation covers the eastern sections, and ponderosa and pinyon pine forests grow on both rims. SONY PCG-8Z1M battery

Natural seeps and springs percolating out of the canyon walls are home to 11% of all the plant species found in the Grand Canyon.[39] The Canyon itself can act as a connection between the east and the west by providing corridors of appropriate habitat along its length.[39] The canyon can also be a genetic barrier to some species, like the Tassel-eared squirrel. SONY PCG-8Y3M battery

The aspect, or direction a slope faces, also plays a major role in adding diversity to the Grand Canyon. North-facing slopes receive about one-third the normal amount of sunlight, so plants growing there are similar to plants found at higher elevations, or in more northern latitudes. SONY PCG-8Y2M battery The south-facing slopes receive the full amount of sunlight and are covered in vegetation typical of the Sonoran Desert.


Of the 34 mammal species found along the Colorado River corridor, 15 are rodents and eight are bats.

Life zones and communities

The Park contains several major ecosystems.[10] Its great biological diversity can be attributed to the presence of five of the seven life zones and three of the four desert types in North America. SONY PCG-7Z1M battery The five life zones represented are the Lower Sonoran, Upper Sonoran, Transition, Canadian, and Hudsonian.[10] This is equivalent to traveling from Mexico to Canada. Differences in elevation and the resulting variations in climate are the major factors that form the various life zones and communities in and around the canyon. Grand Canyon National Park contains 129 vegetation communitiesSONY PCG-6W2M battery, and the composition and distribution of plant species is influenced by climate, geomorphology and geology.[38]

Lower Sonoran

A bighorn ewe at the Grand Canyon, 2008

The Lower Sonoran life zone spans from the Colorado River up to 3500 feet. Along the Colorado River and its perennial tributaries, a riparian community exists.[38] Coyote willow, arrowweed, seep-willow, western honey mesquite, catclaw acacia, and exotic tamarisk (saltcedar) are the predominant species. SONY PCG-5J5M batteryHanging gardens, seeps and springs often contain rare plants such as the white-flowering western redbud, stream orchid, and McDougall's flaveria.[38] Endangered fish in the river include the humpback chub and the razorback sucker.[41]

The three most common amphibians in these riparian communities are the canyon tree frog, red-spotted toad, and Woodhouse’s Rocky Mountain toad. SONY PCG-5K2M battery Leopard frogs are very rare in the Colorado River corridor, and are known to exist at only a few sites.[42] There are 33 crustacean species found in the Colorado River and its tributaries within Grand Canyon National Park. Of these 33, 16 are considered true zooplankton organisms.[43]

Only 48 bird species regularly nest along the river, while others use the river as a migration corridor or as overwintering habitatSONY PCG-5K1M battery. The bald eagle is one species that uses the river corridor as winter habitat.

River otters may have disappeared from the park in late 20th century, and muskrats are extremely rare. Beavers cut willows, cottonwoods, and shrubs for food, and can significantly affect the riparian vegetation. Other rodents, such as antelope squirrels and pocket mice, are mostly omnivorous, using many different vegetation types. SONY PCG-5J4M battery  Grand Canyon bats typically roost in desert uplands, but forage on the abundance of insects along the river and its tributaries.[40] In addition to bats, coyotes, ringtails, and spotted skunks are the most numerous riparian predators and prey on invertebrates, rodents, and reptiles.[40]

Raccoons, weasels, bobcats, gray foxes, and mountain lions are also presentSONY PCG-5J1M battery, but are much more rare.[40] Mule deer and desert bighorn sheep are the ungulates that frequent the river corridor. Since the removal of 500 feral burros in the early 1980s, bighorn sheep numbers have rebounded.[40] Mule deer are generally not permanent residents along the river, but travel down from the rim when food and water resources there become scarce. SONY PCG-5G2M battery

The insect species commonly found in the river corridor and tributaries are midges, caddis flies, mayflies, stoneflies, black flies, mites, beetles, butterflies, moths, and fire ants.[45] Numerous species of spiders and several species of scorpions including the bark scorpion and the giant desert hairy scorpion inhabit the riparian zone. Sony VAIO PCG-8131M battery

Eleven aquatic and 26 terrestrial species of mollusks have been identified in and around Grand Canyon National Park.[46] Of the aquatic species, two are bivalves (clams) and nine are gastropods (snails).[46] Twenty-six species of terrestrial gastropods have been identified, primarily land snails and slugs. Sony VAIO PCG-8152M battery

There are a approximately 47 reptile species in Grand Canyon National Park. Ten are considered common along the river corridor and include lizards and snakes.[47] Lizard density tends to be highest along the stretch of land between the water's edge and the beginning of the upland desert community. The two largest lizards in the Canyon are gila monsters and chuckwallasSony VAIO PCG-31311M battery. Many snake species, which are not directly dependent on surface water, may be found both within the inner gorge and the Colorado River corridor. Six rattlesnake species have been recorded in the park.[47]

Above the river corridor a desert scrub community, composed of North American desert flora, thrives. Typical warm desert species such as creosote bush, white bursage, brittlebush, catclaw acacia, ocotillo, mariola, western honey mesquiteSony VAIO PCG-31111M battery, four-wing saltbush, big sagebrush, blackbrush and rubber rabbitbrush grow in this community.[38] The mammalian fauna in the woodland scrub community consists of 50 species, mostly rodents and bats.[40] Three of the five Park woodrat species live in the desert scrub community.[40]

Except for the western (desert) banded geckoSony VAIO PCG-8112M battery, which seems to be distributed only near water along the Colorado River, all of the reptiles found near the river also appear in the uplands, but in lower densities. The desert gopher tortoise, a threatened species, inhabits the desert scrublands in the western end of the park.

Some of the common insects found at elevations above 2,000 feet are orange paper wasps, honey bees, black flies, tarantula hawks, stink bugs, beetlesSony VAIO PCG-7186M battery, black ants, and monarch and swallowtail butterflies. Solpugids, wood spiders, garden spiders, black widow spiders and tarantulas can be found in the desert scrub and higher elevations.

Upper Sonoran and Transition

A California Condor in flight, photographed from Navajo Bridge at Marble Canyon, 2008. Wild condors are numbered to aid wildlife researchers. As of April 2009, there were 172 wild California condors knownSony VAIO PCG-7171M battery.

The Upper Sonoran Life Zone includes most of the inner canyon and South Rim at elevations from 3,500 to 7,000 feet.[39] This zone is generally dominated by blackbrush, sagebrush, and pinyon-juniper woodlands. Elevations of 3,500 to 4,000 feet are in the Mojave Desert Scrub community of the Upper SonoranSony VAIO PCG-9Z1M battery. This community is dominated by the four-winged saltbush and creosote bush; other important plants include Utah agave, narrowleaf mesquite, ratany, catclaw, and various cacti species.[39]

Approximately 30 bird species breed primarily in the desert uplands and cliffs of the inner canyon.[44] Virtually all bird species present breed in other suitable habitats throughout the Sonoran and Mohave deserts. Sony VAIO PCG-9Z1M batteryThe abundance of bats, swifts, and riparian birds provides ample food for peregrines, and suitable eyrie sites are plentiful along the steep canyon walls. Also, several critically endangered California Condors that were re-introduced to the Colorado Plateau on the Arizona Strip, have made the eastern part of the Park their home. Sony VAIO PCG-5P1M battery

The conifer forests provide habitat for 52 mammal species.[40] Porcupines, shrews, red squirrels, tassel eared Kaibab and Abert's squirrels, black bear, mule deer, and elk are found at the park's higher elevations on the Kaibab Plateau.[40]

Above the desert scrub and up to 6,200 feet is a pinyon pine forest and one seed juniper woodland.[38] Within this woodland one can find big sagebrush, snakeweed, Mormon teaSony VAIO PCG-5N2M battery, Utah agave, banana and narrowleaf Yucca, winterfat, Indian ricegrass, dropseed, and needlegrass.[38] There are a variety of snakes and lizards here, but one species of reptile, the mountain short-horned Lizard, is a particularly abundant inhabitant of the piñon-juniper and ponderosa pine forests.

Ponderosa pine forests grow at elevations between 6,500 feet and 8,200 feet, on both North and South rims in the Transition life zone. Sony VAIO PCG-3C2M batteryThe South Rim includes species such as gray fox, mule deer, bighorn sheep, rock squirrels, pinyon pine and Utah juniper.[39] Additional species such as Gambel oak, New Mexico locust, mountain mahogany, elderberry, creeping mahonia, and fescue have been identified in these forests.[38] The Utah tiger salamander and the Great Basin spadefoot toad are two amphibians that are common in the rim forests. Sony VAIO PCG-8161M battery Of the approximately 90 bird species that breed in the coniferous forests, 51 are summer residents and at least 15 of these are known to be neotropical migrants.[44]

Canadian and Hudsonian

Elevations of 8,200 to 9,000 feet are in the Canadian Life Zone, which includes the North Rim and the Kaibab Plateau.[39] Spruce-fir forests characterized by Englemann spruce, blue spruce, Douglas fir, white fir, aspenSony VAIO PCG-8141M battery, and mountain ash, along with several species of perennial grasses, groundsels, yarrow, cinquefoil, lupines, sedges, and asters, grow in this sub-alpine climate.[38] Mountain lions, Kaibab squirrels, and northern goshawks are found here.[39]

Montane meadows and subalpine grassland communities of the Hudsonian life zone are rare and located only on the North Rim.[38] Both are typified by many grass species. Some of these grasses include blue and black grama, big galletaSony VAIO PCG-3J1M battery, Indian ricegrass and three-awns.[38] The wettest areas support sedges and forbs.[38]

Grand Canyon tourism

Grand Canyon National Park is one of the world’s premier natural attractions, attracting about five million visitors per year. Overall, 83% were from the United States: California (12.2%), Arizona (8.9%), Texas (4.8%), Florida (3.4%) and New York (3.2%) represented the top domestic visitors. Seventeen percent of visitors were from outside the United StatesSony VAIO PCG-3H1M battery; the most prominently represented nations were the United Kingdom (3.8%), Canada (3.5%), Japan (2.1%), Germany (1.9%) and The Netherlands (1.2%).


Further information: Grand Canyon travel guide from Wikitravel

Rafters in the Grand Canyon pass one of the rapids of the (mud-)"colored" Colorado River

Aside from casual sightseeing from the South Rim (averaging 7,000 feet [2,100 m] above sea level), rafting, hiking, running and helicopter tours are especially popularSony VAIO PCG-3F1M battery. In October 2010 the North Rim is the host to an ultramarathon. The Grand Canyon Ultra Marathon is a 78-mile (126 km) race over 24 hours. The floor of the valley is accessible by foot, muleback, or by boat or raft from upriver. Hiking down to the river and back up to the rim in one day is discouraged by park officials because of the distance, steep and rocky trails
Sony VAIO PCG-3C1M battery
, change in elevation, and danger of heat exhaustion from the much higher temperatures at the bottom. Rescues are required annually of unsuccessful rim-to-river-to-rim travelers. Nevertheless, hundreds of fit and experienced hikers complete the trip every year.

Camping on the North and South Rims is generally restricted to established campgrounds and reservations are highly recommended, especially at the busier South RimSony VAIO PCG-9Z2L battery. There is at large camping available along many parts of the North Rim managed by Kaibab National Forest. Keep in mind North Rim campsites are only open seasonally due to road closures from weather and winter snowpack. All overnight camping below the rim requires a backcountry permit from the Backcountry Office (BCO). Each year Grand Canyon National Park receives approximately 30,000 requests for backcountry permitsSony VAIO PCG-9Z1L battery. The park issues 13,000 permits, and close to 40,000 people camp overnight.[49] The earliest a permit application is accepted is the first of the month, four months before the proposed start month.

A 6 minute video of a flight over the Grand Canyon (view in high quality)

Tourists wishing for a more vertical perspective can board helicopters and small airplanes in Las VegasSony VAIO PCG-9131L battery, Phoenix and Grand Canyon National Park Airport (seven miles from the South Rim) for canyon flyovers. Scenic flights are no longer allowed to fly within 1500 feet of the rim within the national park because of a late 1990s crash. Maverick Helicopter offers a tour that descends and lands 3,500 feet into the Grand Canyon in Hualapai Indian Territory. Sony VAIO PCG-8161L battery The last aerial video footage from below the rim was filmed in 1984. However, some helicopter flights land on the Havasupai and Hualapai Indian Reservations within Grand Canyon (outside of the park boundaries). Recently, the Hualapai Tribe opened the glass-bottomed Grand Canyon Skywalk on their property, Grand Canyon West. The Skywalk has seen mixed reviews since the site is only accessible by driving down a 10-mile (16 km) dirt roadSony VAIO PCG-8152L battery, costs a minimum of $85 in total for reservation fees, a tour package and admission to the Skywalk itself and the fact that cameras or other personal equipment are not permitted on the Skywalk at any time due to the hazard of damaging the glass if dropped. The Skywalk is some 24 miles (39 km) west of Grand Canyon Village at the South Rim.

Viewing the canyonSony VAIO PCG-8141L battery

Guano Point - a popular vantage point for tourists, situated on the West Rim of the Grand Canyon

Lipan Point is a promontory located on the South Rim. This point is located to the east of the Grand Canyon Village along the Desert View Drive. There is a parking lot for visitors who care to drive along with the Canyon's bus service that routinely stops at the pointSony VAIO PCG-8131L battery. The trailhead to the Tanner Trail is located just before the parking lot. The view from Lipan Point shows a wide array of rock strata and the Unkar Creek area in the inner canyon.

Aerial view of the less-visited lower Grand Canyon, down river from (west of) Toroweap Overlook

The canyon can be seen from the Toroweap (or Tuweep) Overlook situated 3000 vertical feet above the Colorado RiverSony VAIO PCG-81312L battery, about 50 miles downriver from the South Rim and 70 upriver from the Grand Canyon Skywalk. This region — "one of the most remote in the United States" according to the National Park Service — is reached only by one of three lengthy dirt tracks beginning in from St. George, Utah, Colorado City or near Pipe Spring National Monument (both in Arizona) Sony VAIO PCG-81214L battery. Each road traverses wild, uninhabited land for 97, 62 and 64 miles respectively. The Park Service manages the area for primitive value with minimal improvements and services.

Grand Canyon fatalities

Grand Canyon rescue Helicopter, 1978

About 600 deaths have occurred in the Grand Canyon since the 1870s. Some of these deaths occurred as the result of overly zealous photographic endeavors, some were the result of airplane collisions within the canyonSony VAIO PCG-81115L battery, and some visitors drowned in the Colorado River. Many hikers overestimate their fitness level, become dehydrated and confused, and must be rescued. The Park Service now posts a picture of an attractive and fit young man at several trailheads with the caption "Every year we rescue hundreds of people from the Canyon. Most of them look like him", in an attempt to discourage hikers from feats which are beyond their abilitiesSony VAIO PCG-81114L battery.

Of the fatalities, 53 have resulted from falls; 65 deaths were attributable to environmental causes, including heat stroke, cardiac arrest, dehydration, and hypothermia; 7 were caught in flash floods; 79 were drowned in the Colorado River; 242 perished in airplane and helicopter crashes (128 of them in the 1956 disaster mentioned below) Sony VAIO PCG-81113L battery; 25 died in freak errors and accidents, including lightning strikes and rock falls; 48 committed suicide; and 23 were the victims of homicides.[51]

1956 air disaster

Main article: 1956 Grand Canyon mid-air collision

In 1956 the Grand Canyon was the site of the deadliest commercial aviation disaster in history at the time.

On the morning of June 30, 1956, a TWA Lockheed Super Constellation and a United Airlines Douglas DC-7 departed Los Angeles International Airport within three minutes of one another on eastbound transcontinental flightsSony VAIO PCG-7142L battery. Approximately 90 minutes later, the two propeller-driven airliners collided above the canyon while both were flying in unmonitored airspace.

The wreckage of both planes fell into the eastern portion of the canyon, on Temple and Chuar Buttes, near the confluence of the Colorado and Little Colorado rivers. The disaster killed all 128 passengers and crew members aboard both planes.

This accident led to the institution of high-altitude airways and positive control by en route ground controllersSony VAIO PCG-7141L battery.


Canyon tourists and residents of Supai, a town located in the bottom of the canyon, were evacuated from the Supai area on August 17–18, 2008[52] due to a break in the earthen Redlands Dam, located upstream of Supai, after a night of heavy rainfall. Evacuees were taken to Peach Springs, Arizona. Sony VAIO PCG-71111L battery More heavy rains were expected and a flash flood warning was put into effect, necessitating the evacuation, according to the Grand Canyon National Park Service.[54] The floods were significant enough to attract coverage from international media.

The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs[3] and 900 islands stretching for over 2,600 kilometres (1,600 mi) Sony VAIO PCG-61411L battery over an area of approximately 344,400 square kilometres (133,000 sq mi). The reef is located in the Coral Sea, off the coast of Queensland in north-east Australia.

The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms.[6] This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. Sony VAIO PCG-61112L battery It supports a wide diversity of life and was selected as a World Heritage Site in 1981. CNN labeled it one of the seven natural wonders of the world.[8] The Queensland National Trust named it a state icon of Queensland.[9]

A large part of the reef is protected by the Great Barrier Reef Marine Park, which helps to limit the impact of human use, such as fishing and tourismSony VAIO PCG-61111L battery. Other environmental pressures on the reef and its ecosystem include runoff, climate change accompanied by mass coral bleaching, and cyclic population outbreaks of the crown-of-thorns starfish.

The Great Barrier Reef has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples, and is an important part of local groups' cultures and spiritualitySony VAIO PCG-5T4L battery. The reef is a very popular destination for tourists, especially in the Whitsunday Islands and Cairns regions. Tourism is an important economic activity for the region, generating $1 billion per year.

Geology and geography

Satellite image of part of the Great Barrier Reef adjacent to the Queensland coastal areas of Airlie Beach and Mackay.

The Great Barrier Reef is a distinct feature of the East Australian Cordillera division. It includes the smaller Murray Islands. Sony VAIO PCG-5T3L battery It reaches from Torres Strait (between Bramble Cay, its northernmost island, and the south coast of Papua New Guinea) in the north to the unnamed passage between Lady Elliot Island (its southernmost island) and Fraser Island in the south. Lady Elliot Island is located 1,915 km (1,190 mi) southeast of Bramble Cay as the crow flies. Sony VAIO PCG-5T2L battery

Australia has moved northwards at a rate of 7 cm (2.8 in) per year, starting during the Cainozoic.[13] Eastern Australia experienced a period of tectonic uplift, which moved the drainage divide in Queensland 400 km (250 mi) inland. Also during this time, Queensland experienced volcanic eruptions leading to central and shield volcanoes and basalt flows.Sony VAIO PCG-5S3L battery Some of these granitic outcrops have become high islands.[15] After the Coral Sea Basin formed, coral reefs began to grow in the Basin, but until about 25 million years ago, northern Queensland was still in temperate waters south of the tropics—too cool to support coral growth.[16] The Great Barrier Reef's development history is complex; after Queensland drifted into tropical watersSony VAIO PCG-5S2L battery, it was largely influenced by reef growth and decline as sea level changed.[17] Reefs can increase in diameter by 1 to 3 centimetres (0.39 to 1.2 in) per year, and grow vertically anywhere from 1 to 25 cm (0.39 to 9.8 in) per year; however, they grow only above a depth of 150 metres (490 ft) due to their need for sunlight, and cannot grow above sea level. Sony VAIO PCG-5S1L battery When Queensland edged into tropical waters 24 million years ago, some coral grew,[19] but a sedimentation regime quickly developed with erosion of the Great Dividing Range; creating river deltas, oozes and turbidites, unsuitable conditions for coral growth. 10 million years ago, the sea level significantly lowered, which further enabled sedimentationSony VAIO PCG-5R2L battery. The reef's substrate may have needed to build up from the sediment until its edge was too far away for suspended sediments to inhibit coral growth. In addition, approximately 400,000 years ago there was a particularly warm interglacial period with higher sea levels and a 4 °C (7 °F) water temperature change. Sony VAIO PCG-5R1L battery

The Great Barrier Reef is clearly visible from aircraft flying over it.

Heron Island, a coral cay in the southern Great Barrier Reef

The land that formed the substrate of the current Great Barrier Reef was a coastal plain formed from the eroded sediments of the Great Dividing Range with some larger hills (some of which were themselves remnants of older reefs[21] or volcanoes[15]). The Reef Research Centre, a Cooperative Research CentreSony VAI

O PCG-5P4L battery, has found coral 'skeleton' deposits that date back half a million years.[22] The Great Barrier Reef Marine Park Authority (GBRMPA) considers the earliest evidence of complete reef structures to have been 600,000 years ago.[23] According to the GBRMPA, the current, living reef structure is believed to have begun growing on the older platform about 20,000 years ago. Sony VAIO PCG-5P2L batteryThe Australian Institute of Marine Science agrees, placing the beginning of the growth of the current reef at the time of the Last Glacial Maximum. At around that time, sea level was 120 metres (390 ft) lower than it is today.

From 20,000 years ago until 6,000 years ago, sea level rose steadily. As it rose, the corals could then grow higher on the hills of the coastal plain. By around 13,000 years ago the sea level was only 60 metres (200 ft) lower than the present daySony VAIO PCG-5N4L battery, and corals began to grow around the hills of the coastal plain, which were, by then, continental islands. As the sea level rose further still, most of the continental islands were submerged. The corals could then overgrow the hills, to form the present cays and reefs. Sea level here has not risen significantly in the last 6,000 years.[21] The CRC Reef Research Centre estimates the age of the present, living reef structure at 6–8,000 years old. Sony VAIO PCG-5N2L battery

The remains of an ancient barrier reef similar to the Great Barrier Reef can be found in The Kimberley, a northern region of Western Australia.[24]

The Great Barrier Reef World Heritage Area has been divided into 70 bioregions,[25] of which 30 are reef bioregions.[26][27] In the northern part of the Great Barrier Reef, ribbon reefs and deltaic reefs have formed; these structures are not found in the rest of the reef system.[22] There are no atolls in the system,[28] and reefs attached to the mainland are rare. Sony VAIO PCG-51513L battery

Fringing reefs are distributed widely, but are most common towards the southern part of the Great Barrier Reef, attached to high islands, for example, the Whitsunday Islands. Lagoonal reefs are found in the southern Great Barrier Reef, and further north, off the coast of Princess Charlotte Bay. Cresentic reefs are the most common shape of reef in the middle of the systemSony VAIO PCG-51511L battery, for example the reefs surrounding Lizard Island. Cresentic reefs are also found in the far north of the Great Barrier Reef Marine Park, and in the Swain Reefs (20–22 degrees south). Planar reefs are found in the northern and southern parts, near Cape York Peninsula, Princess Charlotte Bay, and Cairns. Most of the islands on the reef are found on planar reefs. Sony VAIO PCG-51412L battery


A variety of colourful corals on Flynn Reef near Cairns

The Great Barrier Reef supports a diversity of life, including many vulnerable or endangered species, some of which may be endemic to the reef system.[30][31]

Green sea turtle on the Great Barrier Reef

Thirty species of whales, dolphins, and porpoises have been recorded in the Great Barrier Reef, including the dwarf minke whale, Indo-Pacific humpback dolphinSony VAIO PCG-51411L battery, and the humpback whale. Large populations of dugongs live there. More than 1,500 fish species live on the reef, including the clownfish, red bass, red-throat emperor, and several species of snapper and coral trout.[32] Forty-nine species mass spawn, while eighty-four other species spawn elsewhere in their range.[34] Seventeen species of sea snake live on the Great Barrier Reef in warm waters up to 50 metres (160 ft) Sony VAIO PCG-51312L battery deep and are more common in the southern than in the northern section. None found in the Great Barrier Reef World Heritage Area are endemic, nor are any endangered.[35]

Six species of sea turtles come to the reef to breed – the green sea turtle, leatherback sea turtle, hawksbill turtle, loggerhead sea turtle, flatback turtle, and the olive ridley. The green sea turtles on the Great Barrier Reef have two genetically distinct populationsSony VAIO PCG-51311L battery, one in the northern part of the reef and the other in the southern part.[36] Fifteen species of seagrass in beds attract the dugongs and turtles,[32] and provide fish habitat.[37] The most common genera of seagrasses are Halophila and Halodule.

Saltwater crocodiles live in mangrove and salt marshes on the coast near the reef.[39] Nesting has not been reported, and the salt water crocodile population in the GBRWHA is wide-ranging but low density.[35] Around 125 species of shark, stingraySony VAIO PCG-51211L battery, skates or chimaera live on the reef.[40][41] Close to 5,000 species of mollusc have been recorded on the reef, including the giant clam and various nudibranchs and cone snails.[32] Forty-nine species of pipefish and nine species of seahorse have been recorded.[35] At least seven species of frog inhabit the islands. Sony VAIO PCG-41112L battery

215 species of birds (including 22 species of seabirds and 32 species of shorebirds) visit the reef or nest or roost on the islands,[43] including the white-bellied sea eagle and roseate tern.[32] Most nesting sites are on islands in the northern and southern regions of the Great Barrier Reef, with 1.4–1.7 million birds using the sites to breed. Sony VAIO PCG-3A4L battery The islands of the Great Barrier Reef also support 2,195 known plant species; three of these are endemic. The northern islands have 300–350 plant species which tend to be woody, whereas the southern islands have 200 which tend to be herbaceous; the Whitsunday region is the most diverse, supporting 1,141 species. The plants are propagated by birds. Sony VAIO PCG-3A3L battery

A Striped Surgeonfish amongst the coral on Flynn Reef

There are at least 330 species of ascidians on the reef system with the diameter of 1–10 cm (0.4–4 in). Between 300–500 species of bryozoans live on the reef.[41] Four hundred coral species, both hard corals and soft corals inhabit the reef.[32] The majority of these spawn gametes, breeding in mass spawning events that are triggered by the rising sea temperatures of spring and summerSony VAIO PCG-3A2L battery, the lunar cycle, and the diurnal cycle. Reefs in the inner Great Barrier Reef spawn during the week after the full moon in October, while the outer reefs spawn in November and December.[46] Its common soft corals belong to 36 genera.[47] Five hundred species of marine algae or seaweed live on the reef,[32] including thirteen species of genus HalimedaSony VAIO PCG-3A1L battery, which deposit calcareous mounds up to 100 metres (110 yd) wide, creating mini-ecosystems on their surface which have been compared to rainforest cover.[48]

Environmental threats

Main article: Environmental threats to the Great Barrier Reef

Sea temperature and bleaching of the Great Barrier Reef

Climate change, pollution, crown-of-thorns starfish and fishing are the primary threats to the health of this reef system. Other threats include shipping accidents, oil spills, and tropical cyclones.[49] Skeletal Eroding Band, a disease of bony corals caused by the protozoan Halofolliculina corallasia, affects 31 coral species. Sony VAIO PCG-394L battery

Climate change

The Great Barrier Reef Marine Park Authority considers the greatest threat to the Great Barrier Reef to be climate change, causing ocean warming which increases coral bleaching. Mass coral bleaching events due to elevated ocean temperatures occurred in the summers of 1998, 2002 and 2006,[54] and coral bleaching is expected to become an annual occurrence. Sony VAIO PCG-393L battery As global warming continues due to anthropogenic causes, corals will not be able to keep up with increasing ocean temperatures. Coral bleaching events lead to increased disease susceptibility, which causes detrimental ecological effects for reef communities.[56] Climate change has implications for other forms of reef life—some fish's preferred temperature range leads them to seek new habitatSony VAIO PCG-391L battery, thus increasing chick mortality in predatory seabirds. Climate change will also affect the population and sea turtle's available habitat.[57]

Bleaching events in benthic coral communities (deeper than 20 metres / 66 feet) in the Great Barrier reef are not as well documented as those at shallower depths, but recent research has shown that benthic communities are just as negatively impacted in the face of rising ocean temperaturesSony VAIO PCG-384L battery. Five Great Barrier Reef species of large benthic corals were found bleached under elevated temperatures, affirming that benthic corals are vulnerable to thermal stress.[58]


Another key threat faced by the Great Barrier Reef is pollution and declining water quality. The rivers of north eastern Australia pollute the Reef during tropical flood events. Over 90% of this pollution comes from farm runoff.[59] Farm run-off is caused by overgrazing, excessive fertiliser use, and pesticide useSony VAIO PCG-383L battery.

The runoff problem is exacerbated by the loss of coastal wetlands which act as a natural filter for toxins and help deposit sediment. It is thought that the poor water quality is due to increased light and oxygen competition from algae.[63]

Crown of thorns

Crown-of-thorns starfish

The crown-of-thorns starfish preys on coral polyps. Large outbreaks of these starfish can devastate reefs. In 2000, an outbreak contributed to a loss of 66% of live coral cover on sampled reefs in a study by the RRC (Reefs Research Centre.) Sony VAIO PCG-382L battery Outbreaks are believed to occur in natural cycles, worsened by poor water quality and overfishing of the starfish's predators.[64][65]


The unsustainable overfishing of keystone species, such as the Giant Triton, can disrupt food chains vital to reef life. Fishing also impacts the reef through increased water pollution from boats, by-catch of unwanted species (such as dolphins and turtles) Sony VAIO PCG-381L battery and habitat destruction from trawling, anchors and nets.[66] As of the middle of 2004, approximately one-third of the Great Barrier Reef Marine Park is protected from species removal of any kind, including fishing, without written permission.[67]


The Shen Neng 1 aground on the Great Barrier Reef, 5 April 2010.

Shipping accidents are a pressing concern, as several commercial shipping routes pass through the Great Barrier Reef.Sony VAIO PCG-7185L battery Although the route through the Great Barrier Reef is not easy, reef pilots consider it safer than outside the reef in the event of mechanical failure, since a ship can sit safely while being repaired.[69] There have been over 1,600 known shipwrecks in the Great Barrier Reef region.[70] On 3 April 2010, bulk coal carrier Shen Neng 1 ran aground on Douglas Shoals,[71] spilling up to four tonnes of oil into the water and causing extensive damage to the reef. Sony VAIO PCG-7184L battery

Human use

The Great Barrier Reef has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples. Aboriginal Australians have been living in the area for at least 40,000 years,[73] and Torres Strait Islanders since about 10,000 years ago.[74] For these 70 or so clan groups, the reef is also an important cultural feature. Sony VAIO PCG-7183L battery

In 1768, Louis de Bougainville found the reef during an exploratory mission, but did not claim the area for the French.[76] On 11 June 1770, the HM Bark Endeavour, captained by explorer James Cook, ran aground on the Great Barrier Reef, sustaining considerable damage. Lightening the ship and re-floating it during an incoming tide eventually saved it. Sony VAIO PCG-7182L batteryOne of the most famous wrecks was the HMS Pandora, which sank on 29 August 1791, killing 35 men. The Queensland Museum has led archaeological digs to the Pandora since 1983.[78] Because the reef had no atolls, it was largely unstudied in the 19th century.[28] During this time, some of the reef's islands were mined for deposits of guano, and lighthouses were built as beacons throughout the system. Sony VAIO PCG-7181L battery as in Raine Island, the earliest example.[80] In 1922, the Great Barrier Reef Committee began carrying out much of the early research on the reef.[81]

Starfish on coral. Tourists often photograph the natural beauty of the reef.


Main article: Great Barrier Reef Marine Park

Royal Commissions disallowed oil drilling in the Great Barrier Reef, in 1975 the Government of Australia created the Great Barrier Reef Marine Park and prohibited various activities.[82] The Great Barrier Reef Marine Park does not include the entire Great Barrier Reef Province. Sony VAIO PCG-7174L battery The park is managed, in partnership with the Government of Queensland, through the Great Barrier Reef Marine Park Authority to ensure that it is used in a sustainable manner. A combination of zoning, management plans, permits, education and incentives (such as eco-tourism certification) are employed in the effort to conserve the reef. Sony VAIO PCG-7173L battery

In 1999, the Australian Parliament passed the Environment Protection and Biodiversity Conservation Act which improved the operation of national environmental law by providing guidance about regional biodiversity conservation priorities. The marine bioregional planning process came from the implementation of this lawSony VAIO PCG-7172L battery. This process conserves marine biodiversity by considering the whole ecosystem a species is in and how different species interact in the marine environment.

There are two steps to this process. The first step is to identify regional conservation priorities in the five (currently) different marine regions. The second step is to identify marine reserves (protected areas or marine parks) to be added to Australia’s National Representative System of Marine Protected AreasSony VAIO PCG-7171L battery. Like protected areas on land, marine reserves are created to protect biodiversity for generations to come. Marine reserves are identified based on criteria written in a document created by Australian and New Zealand Environment and Conservation Council entitled ‘Guidelines for establishing the national representative system of marine protected areas,’ also known as just “the Guidelines.” Sony VAIO PCG-7162L battery These guidelines are nationally recognised and implemented at the local level based on the Australian policy for implementation outlined in the “Goals and Principles for the Establishment of the National Representative System of Marine Protected Areas in Commonwealth Waters.” These policies are in place to make sure that a marine reserve is only added to the NRSMPA after careful evaluation of different dataSony VAIO PCG-7161L battery.

The priorities for each region are created based on human and environmental threats and the Marine Bioregional Plans are drafted to address these priorities. To assess different region’s priorities, three steps are taken, first, a bioregional profile is created, second, a bioregional plan is drafted and third, the plan is finalised. After the plan is finalizedSony VAIO PCG-7154L battery, activity in different bioregions may become limited based on particular threats an activity may pose.[84]

In 2001, the GBRMPA released a report about the declining water quality in the Great Barrier Reef and detailed the importance of this issue. In repose to this report a joint initiative between the governments of Australia and Queensland to improve the water quality of the Great Barrier ReefSony VAIO PCG-7153L battery. In 2003, the Australian and Queensland governments launched a joint initiative to improve the quality of water entering the Great Barrier Reef. The decline in the quality of water over the past 150 years (due to development) has contributed to coral bleaching, algal blooms and pesticide pollution. These forms of pollution have made the reef less resilient to climate changeSony VAIO PCG-7152L battery. When the plan was introduced in October in 2003, it originally contained 65 actions built on previous legislation. Their immediate goal was to halt and reverse the decline in water quality entering the reef by 2013. By 2020, they hope that the quality of the water entering in the reef improves enough so that it doesn't have a detrimental impact on the health of the Great Barrier ReefSony VAIO PCG-7151L battery. To achieve these goals they decided to reduce pollutants in the water entering the reef and to rehabilitate and conserve areas of the reef that naturally help reduce water pollutants. In order to achieve the objectives described above, this plan focuses on non-point sources of pollution, which cannot be traced to a single source such as a waste outlet
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The plan specifically targets nutrients, pesticides and sediment that make their way into the reef as a result of agricultural activities. Other non-point sources of pollution that are attributed to urban areas are covered under different legislation. In 2009 the plan was updated. The updated version states that to date, none of the efforts undertaken to improve the quality of water entering the reef has been successfulSony VPCW21M2E/WI battery. The new plan attempts to address this issue by “targeting priority outcomes, integrating industry and community initiatives and incorporating new policy and regulatory frameworks (Reef Plan 5).” This updated version has improved the clarity of the previous plan and targets set by that plan, have improved accountability and further improved monitoring and assessmentSony VPCW21C7E battery. The 2009 report found that 41 out of the 65 actions met their original goals, however, 18 were not progressing well according to evaluation criteria as well as 6 were rated as having unsatisfactory levels of progress. Some key achievements made since the plan’s initial passing in 2003 were the establishment of the Reef Quality Partnership to set targetsSony VPCW12S1E/WZ battery, report findings and monitor progress towards targets, improved land condition by landowners was rewarded with extended leases, Water Quality Improvement Plans were created to identify regional targets and identified management changes that needed to be made to reach those targets, Nutrient Management Zones have been created to combat sediment loss in particular areasSony VPCW12S1E/W battery, education programs have been started to help gather support for sustainable agriculture, changes to land management practices have taken place through the implementation of the Farm Management Systems and codes of practice, the creation of the Queensland Wetland program and other achievements were made to help improve the water quality flowing into the coral reefsSony VPCW12S1E/T battery.

A taskforce of scientists was also created to assess the impact of different parts of the plan on the quality of water flowing into the coral reefs. They found that many of the goals have yet to be reached but found more evidence that states that improving the water quality of the Great Barrier Reef will improve its resilience to climate change. The Reefocus summit in 2008, which is also detailed in the report, came to similar conclusionsSony VPCW12S1E/P battery. After this, a stakeholder working group was formed that worked between several groups as well as the Australian and Queensland governments to update reef goals and objectives. The updated version of the plan focuses on strategic priority areas and actions to achieve 2013 goals. Also quantitative targets have been made in order to critically assess whether targets are being metSony VPCW11S1E/W battery. Some examples of the water quality goals outlined by this plan are that by 2013, there will be a 50% reduction in nitrogen and phosphorus loads at the end of catchments and that by 2020, there will be a reduction in sediment load by 20%. The plan also outlines a number of steps that must be taken by landholders to help improve grazing, soil, nutrient and chemical management practicesSony VPCW11S1E/T battery. There are also a number of supporting initiatives to take place outlined in the plan to help create a framework to improve land use practices which will in turn improve water quality.

Through these means the governments of Australia and Queensland hope to improve water quality by 2013. The 2013 outlook report and revised water quality plan will assess what needs to be done in the future to improve water quality and the livelihoods of the wildlife that resides there. Sony VPCW11S1E/P battery

In July 2004, a new zoning plan took effect for the entire Marine Park, and has been widely acclaimed as a new global benchmark for marine ecosystem conservation.[86] The rezoning was based on the application of systematic conservation planning techniques, using MARXAN software.[87] While protection across the Marine Park was improvedSony VPCYA1S1E/B battery, the highly protected zones increased from 4.5% to over 33.3%.[88] At the time, it was the largest marine protected area in the world, although in 2006, the new Northwestern Hawaiian Islands National Monument became the largest.[89]

In 2006, a review of the Great Barrier Reef Marine Park Act 1975 recommended are that there should be no further zoning plan changes until 2013Sony VPCYA1V9E/B battery, and that every five years, a peer-reviewed Outlook Report should be published, examining the reef's health, management, and environmental pressures.[5][90] In each outlook report, several assessments are required. Each assessment has a set of assessment criteria that allows for better presentation of available evidence. Each assessment is judged by these criteria and given a gradeSony VPCY21S1E/SI battery. Every outlook report follows the same judging and grading process so that information can be tracked over time. No new research is done to produce the report. Only readily available information goes into the report so little of what is known about the Reef is actually featured in each outlook report. Sony VPCY21S1E/L battery


Due to its vast biodiversity, warm clear waters and accessibility from the tourist boats called 'live aboards', the reef is a very popular destination, especially for scuba divers. Tourism on the Great Barrier Reef is concentrated in the Whitsundays and Cairns due to their accessibility. These areas make up 7% of the Park's area. Sony VPCY21S1E/G batteryThe Whitsundays and Cairns have their own Plans of Management.[92] Many cities along the Queensland coast offer daily boat trips. Several continental and coral cay islands are now resorts, including the pristine Lady Elliot Island. As of 1996, 27 islands on the Great Barrier Reef supported resorts. Sony VPCY11S1E/S battery

A scuba diver looking at a giant clam on the Great Barrier Reef

Domestic tourism made up most of the tourism in the region as of 1996, and the most popular visiting times were in the Australian winter. It was estimated that tourists to the Great Barrier Reef contributed A$776 million per annum at this time. Sony VPCY11S1E battery

As the largest commercial activity in the region, it was estimated in 2003 that tourism in the Great Barrier Reef generates over A$4 billion annually.[94] (A 2005 estimate puts the figure at A$5.1 billion.[92]) Approximately two million people visit the Great Barrier Reef each year.[95] Although most of these visits are managed in partnership with the marine tourism industrySony VPCZ11X9E/B battery, there is a concern amongst the general public that tourism is harmful to the Great Barrier Reef.[49]

A variety of boat tours and cruises are offered, from single day trips, to longer voyages. Boat sizes range from dinghies to superyachts.[96] Glass-bottomed boats and underwater observatories are also popular, as are helicopter flights. By far, the most popular tourist activities on the Great Barrier Reef are snorkelling and diving, for which pontoons are often usedSony VPCZ11Z9E/B battery, and the area is often enclosed by nets. The outer part of the Great Barrier Reef is favoured for such activities, due to water quality.

Management of tourism in the Great Barrier Reef is geared towards making tourism ecologically sustainable. A daily fee is levied that goes towards research of the Great Barrier Reef.[92] This fee ends up being 20% of the GBRMPA's income. Sony VPCZ12M9E/B battery Policies on cruise ships, bareboat charters, and anchorages limit the traffic on the Great Barrier Reef.[92]

The problems that surround ecotourism in the Great Barrier Reef revolve around permanent tourism platforms. Platforms are large, ship-like vessels that act as a base for tourists while scuba diving and snorkeling in the Great Barrier Reef. Seabirds will land on the platforms and defecate which will eventually be washed into the seaSony VPCZ12X9E/X battery. The feces carry nitrogen, phosphorus and oftentimes DDT and mercury which cause aspergillosis,yellow band disease and black band disease. Areas without tourism platforms have 14 out of 9,468 (1.1%) diseased corals versus areas with tourism platforms that have 172 out of 7,043 (12%) diseased corals.[100] Tourism is a major economic activity for the regionSony VPCZ12Z9E/X battery. Thus, while non-permanent platforms could be possible in some areas, overall, permanent platforms are likely a necessity. Solutions have been suggested to siphon bird waste into gutters connecting to tanks helping lower runoff that causes coral disease.[101]


The fishing industry in the Great Barrier Reef, controlled by the Queensland Government, is worth A$1 billion annually.[10] It employs approximately 2000 peopleSony VPCZ138GA battery, and fishing in the Great Barrier Reef is pursued commercially, for recreation, and as a traditional means for feeding one's family.

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