Coral reefs of the Virgin Islands

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Corals picture taken from Brewers Bay on St. Thomas Corals 2.jpg
Corals picture taken from Brewers Bay on St. Thomas
Formation of fringing reefs (top), barrier reefs (middle) and atolls (bottom). Formation of coral.jpg
Formation of fringing reefs (top), barrier reefs (middle) and atolls (bottom).

One of the marine ecosystems found in the Virgin Islands are the coral reefs. These coral reefs can be located between the islands of St. Croix, St. Thomas, and St. John. These coral reefs have an area of 297.9 km2, along with other marine habitats that are in between. [2] The way these coral reefs grow are by coral larvae swimming freely and attaching themselves to hard surfaces around the islands and start to develop a skeleton on the outside of their skin to protect themselves from predators but also allow a new place for other coral larvae to attach to and grow on. [3] These corals can form into three different structures; fringing reefs, which are reefs that are close to the shore, barrier reefs, which are reefs that are alongside the shore and is separated by deep water, and an atoll reef which is a coral reef that circles a lagoon or body of water. [1]

Contents

Distribution

As stated, the coral reefs such as fringing reefs, deep reefs, patch reefs and spur and groove formation are distributed over three islands in the Virgin Islands which are St. Croix (Salt River Bay National Historical Park and Ecological Preserve, Buck Island Reef National Monument), St. Thomas, and St. John (Virgin Islands Coral Reef National Monument). The coral reefs found offshore of St. Thomas and St. John are distributed patchily around the islands. Additionally, a developed barrier reef system surrounds St. Croix along its eastern and southern shores.

Corals picture taken from Brewers Bay on St. Thomas. Corals 4.jpg
Corals picture taken from Brewers Bay on St. Thomas.

Ecology

The coral reefs as well as hard-bottom habitat accounts for 297.9 km2. [2] The coral reefs are home to diverse species. There are over 40 species of scleractinian corals and three species of Millepora. [4] Live scleractinian species are found throughout the Virgin Islands, but mainly around Buck Island, St. Croix and St. John. [2] More specifically based on a survey from 2001-2006, listed are a total of 215 fishes from St. John and 202 from St. Croix. [4] Four species of sea turtles are found within the Virgin Islands. [4] The coral reefs are impacted by freshwater environments from the Amazon and Orinoco River in the form of anticyclonic rings which are rich in nutrients. [4]

Hazards

This marine environment has been degraded in a variety of ways. One of the ways in which the corals have been affected is by the dust from Africa. [4] This dust might be affected the corals by causing degradation. [4] Apart from the dust, the corals also experience a few diseases. There is black-band disease which infects major coral reefs such as Montastraea annularis. [4] The most severe diseases are the white-band and white plague disease. [4] The branching acroporid have been influenced the most. [2]

Corals picture taken from Brewers Bay on St. Thomas Corals 5.jpg
Corals picture taken from Brewers Bay on St. Thomas

Other than the few diseases listed, other ways in which the corals have been affected are by natural disasters such as hurricanes, human influence such as fishing and pollution, and global warming. [2]
The Coral reefs are also being degraded by many other factors:

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<span class="mw-page-title-main">Southeast Asian coral reefs</span> Marine ecosystem

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<span class="mw-page-title-main">White band disease</span> Disease affecting marine corals

White band disease is a coral disease that affects acroporid corals and is distinguishable by the white band of exposed coral skeleton that it forms. The disease completely destroys the coral tissue of Caribbean acroporid corals, specifically elkhorn coral and staghorn coral. The disease exhibits a pronounced division between the remaining coral tissue and the exposed coral skeleton. These symptoms are similar to white plague, except that white band disease is only found on acroporid corals, and white plague has not been found on any acroporid corals. It is part of a class of similar disease known as "white syndromes", many of which may be linked to species of Vibrio bacteria. While the pathogen for this disease has not been identified, Vibrio carchariae may be one of its factors. The degradation of coral tissue usually begins at the base of the coral, working its way up to the branch tips, but it can begin in the middle of a branch.

<i>Diadema antillarum</i> Species of sea urchin

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<span class="mw-page-title-main">Marine ecosystem</span> Ecosystem in saltwater environment

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<span class="mw-page-title-main">Elkhorn coral</span> Species of coral

Elkhorn coral is an important reef-building coral in the Caribbean. The species has a complex structure with many branches which resemble that of elk antlers; hence, the common name. The branching structure creates habitat and shelter for many other reef species. Elkhorn coral is known to grow quickly with an average growth rate of 5 to 10 cm per year. They can reproduce both sexually and asexually, though asexual reproduction is much more common and occurs through a process called fragmentation.

<span class="mw-page-title-main">Fringing reef</span> Type of coral reef

A fringing reef is one of the three main types of coral reef. It is distinguished from the other main types, barrier reefs and atolls, in that it has either an entirely shallow backreef zone (lagoon) or none at all. If a fringing reef grows directly from the shoreline, then the reef flat extends to the beach and there is no backreef. In other cases, fringing reefs may grow hundreds of yards from shore and contain extensive backreef areas within which it contains food and water, examples are Philippines, Indonesia, Timor-Leste, the western coast of Australia, the Caribbean, East Africa, and Red Sea. Charles Darwin believed that fringing reefs are the first kind of reefs to form around a landmass in a long-term reef growth process. The largest fringing coral reef in the world is the Ningaloo Reef, stretching to around 260 km (160 mi) along the coastline of Western Australia.

<span class="mw-page-title-main">Wild fisheries</span> Area containing fish that are harvested commercially

A wild fishery is a natural body of water with a sizeable free-ranging fish or other aquatic animal population that can be harvested for its commercial value. Wild fisheries can be marine (saltwater) or lacustrine/riverine (freshwater), and rely heavily on the carrying capacity of the local aquatic ecosystem.

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The Coral Triangle (CT) is a roughly triangular area in the tropical waters around the Philippines, Indonesia, Malaysia, Papua New Guinea, the Solomon Islands and Timor-Leste. This area contains at least 500 species of reef-building corals in each ecoregion. The Coral Triangle is located between the Pacific and Indian oceans and encompasses portions of two biogeographic regions: the Indonesian-Philippines Region, and the Far Southwestern Pacific Region. As one of eight major coral reef zones in the world, the Coral Triangle is recognized as a global centre of marine biodiversity and a global priority for conservation. Its biological resources make it a global hotspot of marine biodiversity. Known as the "Amazon of the seas" (by analogy to the Amazon rainforest in South America), it covers 5.7 million square kilometres (2,200,000 sq mi) of ocean waters. It contains more than 76% of the world's shallow-water reef-building coral species, 37% of its reef fish species, 50% of its razor clam species, six out of seven of the world's sea turtle species, and the world's largest mangrove forest. In 2014, the Asian Development Bank (ADB) reported that the gross domestic product of the marine ecosystem in the Coral Triangle is roughly $1.2 trillion per year and provides food to over 120 million people. According to the Coral Triangle Knowledge Network, the region annually brings in about $3 billion in foreign exchange income from fisheries exports, and another $3 billion from coastal tourism revenues.

<span class="mw-page-title-main">Environmental issues with coral reefs</span> Factors which adversely affect tropical coral reefs

Human activities have substantial impact on coral reefs, contributing to their worldwide decline.[1] Damaging activities encompass coral mining, pollution, overfishing, blast fishing, as well as the excavation of canals and access points to islands and bays. Additional threats comprise disease, destructive fishing practices, and the warming of oceans.[2] Furthermore, the ocean's function as a carbon dioxide sink, alterations in the atmosphere, ultraviolet light, ocean acidification, viral infections, the repercussions of dust storms transporting agents to distant reefs, pollutants, and algal blooms represent some of the factors exerting influence on coral reefs. Importantly, the jeopardy faced by coral reefs extends far beyond coastal regions. The ramifications of climate change, notably global warming, induce an elevation in ocean temperatures that triggers coral bleaching—a potentially lethal phenomenon for coral ecosystems.

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<span class="mw-page-title-main">Mesophotic coral reef</span>

A Mesophotic coral reef or mesophotic coral ecosystem (MCE), originally from the Latin word meso (meaning middle) and photic (meaning light), is characterised by the presence of both light-dependent coral and algae, and organisms that can be found in water with low light penetration. Mesophotic Coral Ecosystem (MCEs) is a new, widely-adopted term used to refer to mesophotic coral reefs, as opposed to other similar terms like "deep coral reef communities" and "twilight zone", since those terms sometimes are confused due to their unclear, interchangeable nature.

The St. Croix East End Marine Park (STXEEMP) was established to "protect territorially significant marine resources, and promote sustainability of marine ecosystems, including coral reefs, sea grass beds, wildlife habitats and other resources, and to conserve and preserve significant natural areas for the use and benefit of future generations." It is the U.S. Virgin Islands’ first territorially designated and managed marine protected area (MPA).

The Virgin Islands Patch Reefs are numerous, small subtropical coral reef ecoregions. These reefs are located on all three islands; St. John, St. Thomas, and St. Croix. Of the three islands St. Croix, has an established barrier reef. It is approximately 20 meters deep and covers 485 sq km.

<span class="mw-page-title-main">Coral reefs of Jamaica</span>

Jamaica, an island located within the Caribbean Sea, known for being a popular tourist destination because of its pristine white sand beaches, is now faced with the issue of mass coral depletion. Both environmental and human factors contribute to the destruction of these corals, which inevitably affect Jamaica's environmental sustainability and economy. Actions have been put in place to counteract the negative consequences associated with the loss of the corals, which act as a symbol of hope for the revival of Jamaica's environment.

References

  1. 1 2 "Corals" NOAA National Ocean Service Education: Corals.
  2. 1 2 3 4 5 6 Catanzaro, Don, Rick Nemeth, Caroline Rogers, Zandy Hillis-Starr, and Marcia Taylor, "The Status of the Coral Reefs of The U.S. Virgin Islands"
  3. "How Coral Reefs Grow" Coral Reef Alliance.
  4. 1 2 3 4 5 6 7 8 Caldow, Chris, Barry Devine, Peter Edmunds et al. "Ecology of Coral Reefs in the US Virgin Islands" (2008)

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