80-533: Lord Howe Island Marine Park is the site of Australia's and the world's most southern coral reef ecosystem . The island is 10 km in length, 2 km wide and consists of a large lagoonal reef system along its leeward side, with 28 small islets along its coast. In 1999, the waters within three nautical miles of Lord Howe Island (465.45 km) were declared a marine park under the NSW Marine Park Act 1997 to protect its unique marine biodiversity , with
160-730: A Darwin Point is reached. One such point exists at the northwestern end of the Hawaiian Archipelago; see Evolution of Hawaiian volcanoes#Coral atoll stage . However, reefs in the Persian Gulf have adapted to temperatures of 13 °C (55 °F) in winter and 38 °C (100 °F) in summer. 37 species of scleractinian corals inhabit such an environment around Larak Island . Deep-water coral inhabits greater depths and colder temperatures at much higher latitudes, as far north as Norway. Although deep water corals can form reefs, little
240-644: A continental shelf, and not around a volcanic island, Darwin's principles apply. Development stopped at the barrier reef stage, since Australia is not about to submerge. It formed the world's largest barrier reef, 300–1,000 m (980–3,280 ft) from shore, stretching for 2,000 km (1,200 mi). Healthy tropical coral reefs grow horizontally from 1 to 3 cm (0.39 to 1.18 in) per year, and grow vertically anywhere from 1 to 25 cm (0.39 to 9.84 in) per year; however, they grow only at depths shallower than 150 m (490 ft) because of their need for sunlight, and cannot grow above sea level. As
320-500: A disproportionate level of threat due to their small range and high level of endemic taxa. Even small human-induced disturbances can lead to species extinction. Key threatening processes relevant to the Lord Howe Island Marine Park include anthropogenic climate change , and entanglement in or ingestion of anthropogenic debris in marine environments. Anthropogenic climate change is listed as a Key Threatening Process under
400-440: A number of species at the limits of their distribution, reflecting the extreme latitude of the coral reef ecosystem, making Lord Howe Island Marine Park the southernmost true coral reef in the world. Lord Howe Island Marine Park is also home to a high diversity of marine benthic algae, fishes and marine invertebrates and is associated with high levels of endemicity. Lord Howe Island was only discovered by humans in 1778, consequently
480-412: A pinhead to 12 inches (30 cm) across. Reef-building or hermatypic corals live only in the photic zone (above 70 m), the depth to which sufficient sunlight penetrates the water. Coral polyps do not photosynthesize, but have a symbiotic relationship with microscopic algae ( dinoflagellates ) of the genus Symbiodinium , commonly referred to as zooxanthellae . These organisms live within
560-490: A pseudo-atoll. These can be distinguished from real atolls only by detailed investigation, possibly including core drilling. Some platform reefs of the Laccadives are U-shaped, due to wind and water flow. Atolls or atoll reefs are a more or less circular or continuous barrier reef that extends all the way around a lagoon without a central island. They are usually formed from fringing reefs around volcanic islands. Over time,
640-433: A rapidly subsiding bottom can overwhelm coral growth, killing the coral and the reef, due to what is called coral drowning . Corals that rely on zooxanthellae can die when the water becomes too deep for their symbionts to adequately photosynthesize , due to decreased light exposure. The two main variables determining the geomorphology , or shape, of coral reefs are the nature of the substrate on which they rest, and
720-504: A tool for conserving biodiversity and managing overfishing. Elsewhere, protected areas such as marine reserves have been attributed to increased species densities, biodiversity, species growth, biomass, and reproductive output. It is a similar case for the Lord Howe Island Marine Park Species habitat is typically used as the major component of designing marine parks: if a number of habitat classes are protected, so are
800-423: A zone extending from approximately 30° N to 30° S of the equator. Tropical corals do not grow at depths of over 50 meters (160 ft). The optimum temperature for most coral reefs is 26–27 °C (79–81 °F), and few reefs exist in waters below 18 °C (64 °F). When the net production by reef building corals no longer keeps pace with relative sea level and the reef structure permanently drowns
880-578: Is constantly changing. Each reef is made up of irregular patches of algae, sessile invertebrates, and bare rock and sand. The size, shape and relative abundance of these patches change from year to year in response to the various factors that favor one type of patch over another. Growing coral, for example, produces constant change in the fine structure of reefs. On a larger scale, tropical storms may knock out large sections of reef and cause boulders on sandy areas to move. Coral reefs are estimated to cover 284,300 km (109,800 sq mi), just under 0.1% of
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#1732858114317960-445: Is directly attached to a shore, or borders it with an intervening narrow, shallow channel or lagoon. It is the most common reef type. Fringing reefs follow coastlines and can extend for many kilometres. They are usually less than 100 metres wide, but some are hundreds of metres wide. Fringing reefs are initially formed on the shore at the low water level and expand seawards as they grow in size. The final width depends on where
1040-513: Is known about them. The northernmost coral reef on Earth is located near Eilat , Israel . Coral reefs are rare along the west coasts of the Americas and Africa , due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas (the Humboldt , Benguela , and Canary Currents , respectively). Corals are seldom found along the coastline of South Asia —from
1120-418: Is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae provide much of the food for other organisms. A common feature on this forereef zone is spur and groove formations that serve to transport sediment downslope. The reef flat is the sandy-bottomed flat, which can be behind
1200-419: Is remote, has a biologically diverse marine system with a high degree of endemism . Lord Howe Island Marine Park was declared after it was recognised as an area with outstanding natural values, an extraordinary array of marine habitats and biodiversity, rich maritime cultural heritage and social and economic importance to the island community, giving it both national and international importance. The marine park
1280-597: Is the carbonate equivalent of a sandstone . The term calcarenite was originally proposed in 1903 by Grabau as a part of his calcilutite , calcarenite and calcirudite carbonate classification system based upon the size of the detrital grains composing a limestone. Calcarenites can accumulate in a wide variety of marine and non-marine environments. They can consist of grains of carbonate that have accumulated either as coastal sand dunes ( eolianites ), beaches , offshore bars and shoals, turbidites , or other depositional settings. This article related to petrology
1360-1432: The Cambrian . Sometimes called rainforests of the sea , shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half the area of France, yet they provide a home for at least 25% of all marine species , including fish , mollusks , worms , crustaceans , echinoderms , sponges , tunicates and other cnidarians . Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas. Shallow tropical coral reefs have declined by 50% since 1950, partly because they are sensitive to water conditions. They are under threat from excess nutrients (nitrogen and phosphorus), rising ocean heat content and acidification , overfishing (e.g., from blast fishing , cyanide fishing , spearfishing on scuba ), sunscreen use, and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools). Coral reefs deliver ecosystem services for tourism, fisheries and shoreline protection . The annual global economic value of coral reefs has been estimated at anywhere from US$ 30–375 billion (1997 and 2003 estimates) to US$ 2.7 trillion (a 2020 estimate) to US$ 9.9 trillion (a 2014 estimate). Though
1440-494: The Galapagos shark , Carcharhinus galapagensis increased in number in sanctuary zones, while there was an increase in abundance of the endemic double header wrasse, Coris bulbifrons , bluefish, Girella cyanea and the spotted sawtail, Prionurus maculates , in sanctuary zones. Negative outcomes have shown populations of the habitat modifying urchin, Centrostaphanus rodgersii , increased threefold between 2006-2010 and densities of
1520-468: The Late Cretaceous (100–66 Ma), when reefs formed by a group of bivalves called rudists existed; one of the valves formed the main conical structure and the other, much smaller valve acted as a cap. Measurements of the oxygen isotopic composition of the aragonitic skeleton of coral reefs, such as Porites , can indicate changes in sea surface temperature and sea surface salinity conditions during
1600-699: The Mesoamerican Barrier Reef System and the New Caledonian Barrier Reef . Barrier reefs are also found on the coasts of Providencia , Mayotte , the Gambier Islands , on the southeast coast of Kalimantan , on parts of the coast of Sulawesi , southeastern New Guinea and the south coast of the Louisiade Archipelago . Platform reefs, variously called bank or table reefs, can form on the continental shelf , as well as in
1680-578: The Middle Cambrian (513–501 Ma ), Devonian (416–359 Ma) and Carboniferous (359–299 Ma), owing to extinct order Rugosa corals, and Late Cretaceous (100–66 Ma) and Neogene (23 Ma–present), owing to order Scleractinia corals. Not all reefs in the past were formed by corals: those in the Early Cambrian (542–513 Ma) resulted from calcareous algae and archaeocyathids (small animals with conical shape, probably related to sponges ) and in
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#17328581143171760-472: The class Anthozoa in the animal phylum Cnidaria , which includes sea anemones and jellyfish . Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician , displacing the microbial and sponge reefs of
1840-417: The tropics where the water is agitated, but can only live within a limited depth range, starting just below low tide . Where the level of the underlying earth allows, the corals grow around the coast to form fringing reefs, and can eventually grow to become a barrier reef. Where the bottom is rising, fringing reefs can grow around the coast, but coral raised above sea level dies. If the land subsides slowly,
1920-637: The 110 species of echinoderms are also endemic. A wide variety of seabirds roost and nest on the island but feed on schools of fish and squid. This diversity reflects the mixing of tropical species with temperate species and the range of marine environments present. It is becoming widely known that the world's marine biodiversity is under threat due to overexploitation and degrading human activities, such as pollution rapidly changing species habitat and leading to species loss. Two species of plants, nine terrestrial birds, one bat and four invertebrate species have become locally extinct . Isolated islands are under
2000-714: The Indian Ocean, for example, in the Maldives , the Chagos Islands , the Seychelles and around Cocos Island . The entire Maldives consist of 26 atolls. Coral reef ecosystems contain distinct zones that host different kinds of habitats. Usually, three major zones are recognized: the fore reef, reef crest, and the back reef (frequently referred to as the reef lagoon). The three zones are physically and ecologically interconnected. Reef life and oceanic processes create opportunities for
2080-498: The Lord Howe Island Marine Park provides various levels of biodiversity protection, regulating activities according to zones. 73.2% of the Marine Park, known as Habitat Protection Zones, allows most forms of fishing: charter boat and recreational, but excludes spearfishing. The other 26.8% of the Marine Park are zoned as seven Sanctuary Zones, where fishing, anchoring and other harmful human activities are excluded. While 0.004% (1.7ha) of
2160-612: The NSW Threatened Species Conservation (TSC) Act 1995 while loss of climatic habitat caused by anthropogenic emissions of greenhouse gases is listed under the Environmental Protection and Biodiversity Conservation (EPBC) Act . Climate change is likely to alter sea surface temperatures which can have severe consequences for seabird breeding. There has been significant growth in people pressure over time. Visitor numbers have increased significantly as has
2240-596: The UV radiation and allowing them to better adapt to warmer water temperatures. In the event of UV or thermal damage, if and when repair occurs, it will increase the likelihood of survival of the host and symbiont. This leads to the idea that, evolutionarily, clade A is more UV resistant and thermally resistant than the other clades. Clades B and C are found more frequently in deeper water, which may explain their higher vulnerability to increased temperatures. Terrestrial plants that receive less sunlight because they are found in
2320-471: The amount of available accommodation options. From 1988 to 2000 the Lord Howe Island population grew by 13%, the number of dwellings increased by 55% and the number of visitors increased by nearly 100%. Lord Howe Island has 37 km of shoreline or littoral zone , with only eight kilometres readily accessible. This eight kilometres has been most heavily impacted as most of the forest has been cleared to
2400-413: The benthic algal species are endemic to the Lord Howe Island Marine Park. Also, two species of non-endemic sea grasses are found within the marine park: Eelgrass, Zostera muelleri subsp capricorni and Paddleweed, Halophila ovalis . The marine life comprise both subtropical and temperate species due to its location and influence of the southerly flowing East Australian Current (EAC). As a consequence,
2480-402: The clarity of water in the lagoon, the impact from anchor damage (outside as well as inside the lagoon), overfishing particularly of the slower growing fish species which inhabit the drop-off, and dramatic water temperature changes causing coral bleaching and death of other marine species. To abate human influence on marine biodiversity worldwide, marine parks are becoming widely advocated as
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2560-497: The coast. The fringing reefs of the Red Sea are "some of the best developed in the world" and occur along all its shores except off sandy bays. Barrier reefs are separated from a mainland or island shore by a deep channel or lagoon . They resemble the later stages of a fringing reef with its lagoon but differ from the latter mainly in size and origin. Their lagoons can be several kilometres wide and 30 to 70 metres deep. Above all,
2640-477: The coastal plains had become continental islands . As sea level rise continued, water topped most of the continental islands. The corals could then overgrow the hills, forming cays and reefs. Sea level on the Great Barrier Reef has not changed significantly in the last 6,000 years. The age of living reef structure is estimated to be between 6,000 and 8,000 years. Although the Great Barrier Reef formed along
2720-451: The coral animals. Coral that loses a large fraction of its zooxanthellae becomes white (or sometimes pastel shades in corals that are pigmented with their own proteins) and is said to be bleached , a condition which, unless corrected, can kill the coral. There are eight clades of Symbiodinium phylotypes . Most research has been conducted on clades A–D. Each clade contributes their own benefits as well as less compatible attributes to
2800-415: The corals shelter the zooxanthellae, averaging one million for every cubic centimetre of coral, and provide a constant supply of the carbon dioxide they need for photosynthesis. The varying pigments in different species of zooxanthellae give them an overall brown or golden-brown appearance and give brown corals their colors. Other pigments such as reds, blues, greens, etc. come from colored proteins made by
2880-525: The deep sea away from continental shelves , around oceanic islands and atolls . The majority of these islands are volcanic in origin. Others have tectonic origins where plate movements lifted the deep ocean floor. In The Structure and Distribution of Coral Reefs , Charles Darwin set out his theory of the formation of atoll reefs, an idea he conceived during the voyage of the Beagle . He theorized that uplift and subsidence of Earth's crust under
2960-627: The eastern tip of India ( Chennai ) to the Bangladesh and Myanmar borders —as well as along the coasts of northeastern South America and Bangladesh, due to the freshwater release from the Amazon and Ganges Rivers respectively. Significant coral reefs include: When alive, corals are colonies of small animals embedded in calcium carbonate shells. Coral heads consist of accumulations of individual animals called polyps , arranged in diverse shapes. Polyps are usually tiny, but they can range in size from
3040-437: The edge of the beach, removing the buffer to strong prevalent winds, impacting the forest behind. The lagoon is six kilometres long and 1.5 km wide and contains the largest of Lord Howe Island's coral reef system, assessed as having World Heritage values. The main identified threats to the marine environment are the impact of water quality welling up in the lagoon from groundwater, the potential changes of turbidity affecting
3120-471: The exchange of seawater , sediments , nutrients and marine life. Most coral reefs exist in waters less than 50 m deep. Some inhabit tropical continental shelves where cool, nutrient-rich upwelling does not occur, such as the Great Barrier Reef . Others are found in the deep ocean surrounding islands or as atolls, such as in the Maldives . The reefs surrounding islands form when islands subside into
3200-401: The floor often supports seagrass meadows which are important foraging areas for reef fish. The reef drop-off is, for its first 50 m, habitat for reef fish who find shelter on the cliff face and plankton in the water nearby. The drop-off zone applies mainly to the reefs surrounding oceanic islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone
3280-403: The fringing reef, barrier reef, atoll and table reef based on Stoddart, D.R. (1969). Spalding et al. list four main reef types that can be clearly illustrated – the fringing reef, barrier reef, atoll, and "bank or platform reef"—and notes that many other structures exist which do not conform easily to strict definitions, including the "patch reef". A fringing reef, also called a shore reef,
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3360-463: The fringing reefs keep pace by growing upwards on a base of older, dead coral, forming a barrier reef enclosing a lagoon between the reef and the land. A barrier reef can encircle an island, and once the island sinks below sea level a roughly circular atoll of growing coral continues to keep up with the sea level, forming a central lagoon. Barrier reefs and atolls do not usually form complete circles but are broken in places by storms. Like sea level rise ,
3440-419: The growth of the coral. This technique is often used by climate scientists to infer a region's paleoclimate . Since Darwin's identification of the three classical reef formations – the fringing reef around a volcanic island becoming a barrier reef and then an atoll – scientists have identified further reef types. While some sources find only three, Thomas lists "Four major forms of large-scale coral reefs" –
3520-542: The history of the change in sea level relative to that substrate. The approximately 20,000-year-old Great Barrier Reef offers an example of how coral reefs formed on continental shelves. Sea level was then 120 m (390 ft) lower than in the 21st century. As sea level rose, the water and the corals encroached on what had been hills of the Australian coastal plain. By 13,000 years ago, sea level had risen to 60 m (200 ft) lower than at present, and many hills of
3600-468: The implementation of the marine bioregional planning process. This process conserves marine biodiversity by considering the whole ecosystem a species is in and how different species interact in the marine environment. This process identified the regional conservation priorities in a number of different marine regions and identified the marine reserves to be added to Australia's National Representative System of Marine Protected Areas. Lord Howe Island Marine park
3680-637: The island erodes away and sinks below sea level. Atolls may also be formed by the sinking of the seabed or rising of the sea level. A ring of reefs results, which enclose a lagoon. Atolls are numerous in the South Pacific, where they usually occur in mid-ocean, for example, in the Caroline Islands , the Cook Islands , French Polynesia , the Marshall Islands and Micronesia . Atolls are found in
3760-406: The island. Lord Howe Island's climate is moderated by oceanic air currents and mild sea temperatures. The island can be windy as the salt laden wind comes predominantly from the southeast and northeast and the mean wind speed is highest in late winter and spring. Lord Howe Island is regarded as having high geological, geomorphological and geodiversity values, many of which extend to the habitats of
3840-576: The low lying central region of the island. The sheltered lagoon contains a number of different reef habitats, dominated by sand, lagoonal corals, gravel sheets, algal flats and patch reefs. The high conservation significance of Lord Howe Island and its waters is recognised by its inclusion on the UNESCO World Heritage List in 1982. Conservation values relating to the marine park include the unique combination of tropical and temperature reef taxa, both flora and fauna . These unique taxa include
3920-418: The main reef, containing chunks of coral. This zone may border a lagoon and serve as a protective area, or it may lie between the reef and the shore, and in this case is a flat, rocky area. Fish tend to prefer it when it is present. The reef lagoon is an entirely enclosed region, which creates an area less affected by wave action and often contains small reef patches. However, the topography of coral reefs
4000-484: The mainland. Unlike fringing and barrier reefs which extend only seaward, platform reefs grow in all directions. They are variable in size, ranging from a few hundred metres to many kilometres across. Their usual shape is oval to elongated. Parts of these reefs can reach the surface and form sandbanks and small islands around which may form fringing reefs. A lagoon may form In the middle of a platform reef. Platform reefs are typically situated within atolls, where they adopt
4080-454: The marine park as it makes up the central and northern regions of the island to below sea level in several places. Calcarenite is formed through the cementing of calcareous algae, coral fragments and sand. Dating has indicated that calcarenite was deposited in the past 350,000 years during the Pleistocene period. The beach and shallow-water calcarenites indicate a sea level around 2–3 m above
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#17328581143174160-518: The marine park is considered a Special Purpose Zone used for special management needs, specifically to allow limited fish feeding. Lord Howe Island Marine park does not contain any General Use zones, like other Marine Parks in New South Wales. The zoning plan also contains regulations on specific activities and provides additional protection on species of particular importance. The zoning plan gives protection to important natural and cultural values of
4240-501: The marine park, the successes will continue to outweigh the failures until such time that equilibrium within the marine ecosystem is reached, this can take up to 20 years from the date of implementation. Coral reef A coral reef is an underwater ecosystem characterized by reef-building corals . Reefs are formed of colonies of coral polyps held together by calcium carbonate . Most coral reefs are built from stony corals , whose polyps cluster in groups. Coral belongs to
4320-418: The marine park, while allowing sustainable use including swimming, surfing, charter and recreational fishing, scuba diving, sailing, boating and research. Visitor numbers are restricted on the island to control impacts to the Marine Park. Lord Howe Island has a temperate climate, with mean water temperatures of 25 °C in summer and 18 °C in winter. Annual rainfall is 1650 mm in the lowland parts of
4400-418: The marine park. Lord Howe Island is situated at the southernmost limit of coral reef formation, receiving both tropical and temperate open ocean carbon environments. Slowly, over time Lord Howe Island is moving into reef forming seas due to the northward migration of Australia's tectonic plate, which is moving 5–6 cm north per year. A white sedimentary rock known as calcarenite is locally important within
4480-400: The name "patch reefs" and often span a diameter of just a few dozen meters. In instances where platform reefs develop along elongated structures, such as old and weathered barrier reefs, they tend to arrange themselves in a linear formation. This is the case, for example, on the east coast of the Red Sea near Jeddah . In old platform reefs, the inner part can be so heavily eroded that it forms
4560-528: The name implies, coral reefs are made up of coral skeletons from mostly intact coral colonies. As other chemical elements present in corals become incorporated into the calcium carbonate deposits, aragonite is formed. However, shell fragments and the remains of coralline algae such as the green-segmented genus Halimeda can add to the reef's ability to withstand damage from storms and other threats. Such mixtures are visible in structures such as Eniwetok Atoll . The times of maximum reef development were in
4640-415: The ocean, and atolls form when an island subsides below the surface of the sea. Alternatively, Moyle and Cech distinguish six zones, though most reefs possess only some of the zones. The reef surface is the shallowest part of the reef. It is subject to surge and tides . When waves pass over shallow areas, they shoal , as shown in the adjacent diagram. This means the water is often agitated. These are
4720-528: The oceans formed the atolls. Darwin set out a sequence of three stages in atoll formation. A fringing reef forms around an extinct volcanic island as the island and ocean floor subside. As the subsidence continues, the fringing reef becomes a barrier reef and ultimately an atoll reef. Darwin predicted that underneath each lagoon would be a bedrock base, the remains of the original volcano. Subsequent research supported this hypothesis. Darwin's theory followed from his understanding that coral polyps thrive in
4800-525: The oceans' surface area. The Indo-Pacific region (including the Red Sea , Indian Ocean , Southeast Asia and the Pacific ) account for 91.9% of this total. Southeast Asia accounts for 32.3% of that figure, while the Pacific including Australia accounts for 40.8%. Atlantic and Caribbean coral reefs account for 7.6%. Although corals exist both in temperate and tropical waters, shallow-water reefs form only in
4880-478: The offshore outer reef edge formed in open water rather than next to a shoreline. Like an atoll, it is thought that these reefs are formed either as the seabed lowered or sea level rose. Formation takes considerably longer than for a fringing reef, thus barrier reefs are much rarer. The best known and largest example of a barrier reef is the Australian Great Barrier Reef . Other major examples are
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#17328581143174960-447: The open ocean, in fact anywhere where the seabed rises close enough to the surface of the ocean to enable the growth of zooxanthemic, reef-forming corals. Platform reefs are found in the southern Great Barrier Reef, the Swain and Capricorn Group on the continental shelf, about 100–200 km from the coast. Some platform reefs of the northern Mascarenes are several thousand kilometres from
5040-460: The original flora and fauna has remained relatively untouched. Three distinct marine habitat community types have been identified within the Marine Park: coral reefs, macroalgal beds, and offshore/open coast communities. The distribution of these depends on wave exposure. The Lord Howe Island Group supports more than 305 benthic algae species, including 47 endemic species. Hence, approximately 15% of
5120-509: The park currently being managed by the New South Wales Marine Parks Authority. Both Lord Howe Island and Balls Pyramid are incorporated within the three nautical miles protected by the state marine park. Both marine parks complement the island's status as a World Heritage Site . Lord Howe Island is located approximately 643 kilometres (400 mi) northeast of Sydney , New South Wales , Australia . Lord Howe Island
5200-429: The polyps' tissues and provide organic nutrients that nourish the polyp in the form of glucose , glycerol and amino acids . Because of this relationship, coral reefs grow much faster in clear water, which admits more sunlight. Without their symbionts, coral growth would be too slow to form significant reef structures. Corals get up to 90% of their nutrients from their symbionts. In return, as an example of mutualism ,
5280-420: The precise condition under which corals flourish. The light is sufficient for photosynthesis by the symbiotic zooxanthellae, and agitated water brings plankton to feed the coral. The off-reef floor is the shallow sea floor surrounding a reef. This zone occurs next to reefs on continental shelves. Reefs around tropical islands and atolls drop abruptly to great depths and do not have such a floor. Usually sandy,
5360-446: The present level during the last interglacial period (130,000-70,000 years ago, Pleistocene). Little evidence of reefs during this time can be seen as they may have occupied locations similar to those of modern reefs or were largely destroyed following emergence once the sea level fell. The fringing reef on the windward western coastline of Lord Howe Island absorbs wave energy and acts as a breakwater preventing storm surges from eroding
5440-412: The sea bed begins to drop steeply. The surface of the fringe reef generally remains at the same height: just below the waterline. In older fringing reefs, whose outer regions pushed far out into the sea, the inner part is deepened by erosion and eventually forms a lagoon . Fringing reef lagoons can become over 100 metres wide and several metres deep. Like the fringing reef itself, they run parallel to
5520-403: The second most abundant urchin, Heliocidaris tuberculata , has doubled. If sea urchins become overpopulated, they can have major impacts on reef systems through overgrazing of important algae. Other negatives include a large and significant decline in population of bluefish within habitat protection zones. While there will continue to be both success and failures following the implementation of
5600-600: The shallow water tropical coral reefs are best known, there are also deeper water reef-forming corals, which live in colder water and in temperate seas. Most coral reefs were formed after the Last Glacial Period when melting ice caused sea level to rise and flood continental shelves . Most coral reefs are less than 10,000 years old. As communities established themselves, the reefs grew upwards, pacing rising sea levels . Reefs that rose too slowly could become drowned, without sufficient light. Coral reefs are also found in
5680-436: The species within them, hence effectively protecting and hopefully in turn increasing marine biodiversity. This is the goal of the marine park at Lord Howe Island. A study conducted in 2010, six years after the implementation of zoning showed the mean number of fish species, density and biomass of fishes is typically higher in sanctuary zones than in habitat protection zones where fishing is allowed. The mean cover of hard corals
5760-424: The survival of their coral hosts. Each photosynthetic organism has a specific level of sensitivity to photodamage to compounds needed for survival, such as proteins. Rates of regeneration and replication determine the organism's ability to survive. Phylotype A is found more in the shallow waters. It is able to produce mycosporine-like amino acids that are UV resistant , using a derivative of glycerin to absorb
5840-502: The threat to marine conservation values. The objectives of the zoning plan under the Marine Parks Act 1997 include: 1) to conserve marine biological diversity and marine habitats, 2) to maintain ecological processes, 3) where consistent with the preceding, to provide for ecologically sustainable use of fish and marine vegetation, and 4) to provide opportunities for public appreciation, understanding and enjoyment. The zoning plan for
5920-755: The undergrowth are analogous to clades B, C, and D. Since clades B through D are found at deeper depths, they require an elevated light absorption rate to be able to synthesize as much energy. With elevated absorption rates at UV wavelengths, these phylotypes are more prone to coral bleaching versus the shallow clade A. Calcarenite Calcarenite is a type of limestone that is composed predominantly, more than 50 percent, of detrital (transported) sand -size (0.0625 to 2 mm in diameter), carbonate grains. The grains consist of sand-size grains of either corals , shells , ooids , intraclasts , pellets , fragments of older limestones and dolomites , other carbonate grains, or some combination of these. Calcarenite
6000-507: The waters surrounding Lord Howe Island show rich and unique biodiversity. An extensive barrier coral reef protects a broad sheltered lagoon and sandy beach on the western side of the island, while fringing reef occurs immediately offshore of the beaches on the eastern side. The Lord Howe Island Group supports a diverse inshore fish fauna with greater than 400 species recorded. 10% of the marine inshore fish species are known to be endemic, meaning they are only found at Lord Howe Island, while 8% of
6080-404: Was also higher in sanctuary zones. Sanctuary zones have been found successful in protecting key species and biomass, though longer term datasets and further research into increasing subtidal macro algal communities in sanctuary zones is required. A review of other research following the implementation of the Marine Park has outlined a number of successes and negative outcomes. This research found
6160-509: Was collated to design the zoning plan. In August 2001 an Issues Paper was released for public comment and submissions reviewed. In June 2002, a draft zoning plan document was established outlining a number of options for zoning, incorporating the submissions gained through the public comment period, advice taken from the Lord Howe Island Marine Park Advisory Committee and a review of relevant information. This plan
6240-540: Was declared on 26 February 1999 under the Marine Parks Act 1997, with a zoning plan commencing on 1 December 2004 to protect the important natural and cultural values of the park while providing a range of sustainable uses. Due to its isolated geographic location, small size and limited access, there are a number of threats to biodiversity that require management. The marine park status helps protect marine biodiversity from fishing pressure and population pressure. A range of scientific, social, cultural and economic information
6320-464: Was identified as requiring protection. To protect the various marine conservation values associated with the waters around Lord Howe Island, the New South Wales government proclaimed the Lord Howe Island Marine Park in 1999. However, it wasn't until 2004 that a zoning scheme came into force due to lengthy negotiations with stakeholders. This zoning scheme partitioned the coastal waters of Lord Howe Island to permit different human uses, in order to minimise
6400-601: Was released for public comment in December 2003 with a finalised zoning plan and implementation of marine park zones commencing on 1 December 2004. The waters from 3–12 nautical miles were declared a federal marine park on 21 June 2000, see Lord Howe Island Marine Park (Commonwealth waters) . In 1999, the Commonwealth's Environment Protection and Biodiversity Conservation Act (EPBC) was enacted. The EPBC Act provides guidance about regional biodiversity conservation priorities through
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