The Great Barrier Reef is the world's largest coral reef system, composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres (1,400 mi) 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, Australia, separated from the coast by a channel 160 kilometres (100 mi) wide in places and over 61 metres (200 ft) deep. The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms. This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. It supports a wide diversity of life and was selected as a World Heritage Site in 1981. CNN labelled it one of the Seven Natural Wonders of the World in 1997. Australian World Heritage places included it in its list in 2007. The Queensland National Trust named it a state icon of Queensland in 2006.
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 bleaching is the process when corals become white due to loss of symbiotic algae and photosynthetic pigments. This loss of pigment can be caused by various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae that live inside their tissue, causing the coral to turn white. The zooxanthellae are photosynthetic, and as the water temperature rises, they begin to produce reactive oxygen species. This is toxic to the coral, so the coral expels the zooxanthellae. Since the zooxanthellae produce the majority of coral colouration, the coral tissue becomes transparent, revealing the coral skeleton made of calcium carbonate. Most bleached corals appear bright white, but some are blue, yellow, or pink due to pigment proteins in the coral.
The Mesoamerican Barrier Reef System (MBRS), also popularly known as the Great Mayan Reef or Great Maya Reef, is a marine region that stretches over 1,126 kilometres (700 mi) along the coasts of four countries – Mexico, Belize, Guatemala, and Honduras – from Isla Contoy at the northern tip of the Yucatán Peninsula south to Belize, Guatemala and the Bay Islands of Honduras. It is the second-longest reef system in the world.
The Great Barrier Reef is the world's largest reef systems, stretching along the East coast of Australia from the northern tip down at Cape York to the town of Bundaberg, is composed of roughly 2,900 individual reefs and 940 islands and cays that stretch for 2,300 kilometres (1,616 mi) and cover 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 northeast Australia. A large part of the reef is protected by the Great Barrier Reef Marine Park.
Ove Hoegh-Guldberg, is a biologist and climate scientist specialising in coral reefs, in particular bleaching due to global warming and climate change. He has published over 500 journal articles and been cited over 50,000 times.
Cetoscarus bicolor, also known as the bicolour parrotfish or bumphead parrotfish, is a species of fish belonging to the family Scaridae. It is found only in the Red Sea. Being from the Scaridae family of huge, vividly colored fish, which is well known as a main contributor of marine ecosystems, especially coral reefs by maintaining them.
Coral reef protection is the process of modifying human activities to avoid damage to healthy coral reefs and to help damaged reefs recover. The key strategies used in reef protection include defining measurable goals and introducing active management and community involvement to reduce stressors that damage reef health. One management technique is to create Marine Protected Areas (MPAs) that directly limit human activities such as fishing.
Nancy Knowlton is a coral reef biologist and a former Sant Chair for Marine Science at the Smithsonian National Museum of Natural History.
Human activities have substantial impact on coral reefs, contributing to their worldwide decline. 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. 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.
The resilience of coral reefs is the biological ability of coral reefs to recover from natural and anthropogenic disturbances such as storms and bleaching episodes. Resilience refers to the ability of biological or social systems to overcome pressures and stresses by maintaining key functions through resisting or adapting to change. Reef resistance measures how well coral reefs tolerate changes in ocean chemistry, sea level, and sea surface temperature. Reef resistance and resilience are important factors in coral reef recovery from the effects of ocean acidification. Natural reef resilience can be used as a recovery model for coral reefs and an opportunity for management in marine protected areas (MPAs).
Tourism is one of the major industries in the Great Barrier Reef region. Approximately 2.19 million people visit the Great Barrier Reef each year. According to the WWF, tourism of the area contributes $5.89 billion a year to the Australian economy, and employs approximately 69,000 people. Ove Hoegh-Guldberg sees the key competitive advantage of the Great Barrier Reef as opposed to other, closer, reef tourism destinations is the region's reputation as being "the most pristine coral reef on the planet". The GBRMPA states that careful management, which includes permits for camping and all commercial marine tourism within the Great Barrier Reef Marine Park, seeks to ensure that tourists have minimal impact on the reef. However, rising incidences of widespread coral bleaching, coastal development, and tourism impacts have taken a toll the biodiversity of the reef.
Ocean acidification threatens the Great Barrier Reef by reducing the viability and strength of coral reefs. The Great Barrier Reef, considered one of the seven natural wonders of the world and a biodiversity hotspot, is located in Australia. Similar to other coral reefs, it is experiencing degradation due to ocean acidification. Ocean acidification results from a rise in atmospheric carbon dioxide, which is taken up by the ocean. This process can increase sea surface temperature, decrease aragonite, and lower the pH of the ocean. The more humanity consumes fossil fuels, the more the ocean absorbs released CO₂, furthering ocean acidification.
Ruth Deborah Gates was the Director of the Hawaiʻi Institute of Marine Biology and the first woman to be President of the International Society for Reef Studies. Her research was dedicated to understanding coral reef ecosystems, specifically coral-algal symbiosis and the capacity for corals to acclimatize under future climate change conditions. Doctor Gates is most accredited with looking at coral biology and human-assisted coral evolution, known as super corals, as notably seen in the documentary Chasing Coral, available on Netflix.
A marine heatwave is a period of abnormally high sea surface temperatures compared to the typical temperatures in the past for a particular season and region. Marine heatwaves are caused by a variety of drivers. These include shorter term weather events such as fronts, intraseasonal events, annual, and decadal (10-year) modes like El Niño events, and human-caused climate change. Marine heatwaves affect ecosystems in the oceans. For example, marine heatwaves can lead to severe biodiversity changes such as coral bleaching, sea star wasting disease, harmful algal blooms, and mass mortality of benthic communities. Unlike heatwaves on land, marine heatwaves can extend over vast areas, persist for weeks to months or even years, and occur at subsurface levels.
Kimberly B. Ritchie is an American marine biologist. She is an Associate Professor in the Department of Natural Sciences at the University of South Carolina Beaufort. Her research is focused on marine microbiology and how microbes affect animal health in hosts such as corals and sharks.
Joan Ann ("Joanie") Kleypas is a marine scientist known for her work on the impact of ocean acidification and climate change on coral reefs, and for advancing solutions to environmental problems caused by climate change.
Janice Lough is a climate scientist at the Australian Institute of Marine Science (AIMS) at James Cook University, researching climate change, and impacts of temperature and elevated CO2 on coral reefs. She was elected to the Australian Academy of Science in 2022 for her research in climate change, coral reefs, and developing high resolution environmental and growth histories from corals, particularly the Great Barrier Reef.
Flinders Reef or Flinders Reefs is an isolated oceanic coral reef in the Coral Sea of the western Pacific Ocean. It lies east of Australia and the extensive Great Barrier Reef. Due to its remote location, it remains poorly studied. However, this isolation has also made it a potential site to mark the beginning of the Anthropocene.
Emma Frances Camp is an English Australian marine biologist, Coral Expert, and National Geographic Explorer who researches the mechanisms of stress tolerance in corals. She is the Team Leader of the Future Reefs Team at the University of Technology Sydney. She is also the co-founder and lead scientist of Coral Nurture Program. In addition to her research, she promotes the retention of females in STEM fields.
