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• Between the Tropic of Cancer and Capricorn where there is warm water with temperatures between 18–27°C
• Close to the coastal areas where there is shallow water; not more than 60 metres deep so that sunlight is able to penetrate the water
• water free from sediment/clear/not polluted/clean; so that sunlight is able to penetrate the water
The map below shows where coral reefs are found.
Describe and account for the distribution of coral reefs shown in the map.
Tourism
Rich Biodiversity
Photos above taken by Pamela Tan @ Phuket, Thailand 2019
Do you know that there are some beautiful coral reefs in Singapore? Click on the images below for a the enlarged image.
How does more intensified typhoons affect coral reefs in the Phillipines?
Where is the area which the coral reefs are affected by climate change?
What other activities affect the coral reefs?
Watch the video below to see how coral reefs are in danger:
Watch the video below on the dangers to coral reefs
What is coral bleaching?
What cause coral bleaching?
How would coral bleaching affects us?
Climate change affects the growth and survival of coral reefs as it rapidly changes the sea temperature making it warmer water temperatures can result in coral bleaching. When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white.Bleaching of coral in the Seychelles archipelago says as much as 90 percent of corals in shallow waters are now bleached significantly with signs of mortality.
Rising sea level may be faster than the ability of the reefs and their associated life forms to adjust. In addition, at a local scale, rising sea level will lead to higher sedimentation of sea causing corals to be suffocated.
Read the article on the following link to find out more::
http://www.channelnewsasia.com/news/asiapacific/coral-bleaching-at/2620410.html
Threats to coral reefs https://oceanservice.noaa.gov/facts/coralreef-climate.html
Read the following article on how coral reef conservation is carried out:
Human activities bringing harm to the coral reef ecosystem
Unethical fishing methods such as blast and cyanide fishing cause the destruction and poisoning of coral reef habitats. Cyanide fishing started in the Philippines in the 1960s and although is now prohibited by law, the practice is still prevalent due to high demands for deep sea fish by the Chinese community in China and Hong Kong.
Loose construction materials from the development of infrastructure in coastal areas may be washed into coastal areas causing siltation of coral reefs, eventually suffocating them. For example, development of beachfront resorts and villas in the Maldives has put pressure on coral reef ecosystems in the region.
Untreated waste or sewage which are irresponsibly dumped in coastal areas causes corals to be killed either by the toxicity of these waste materials or when these materials affect the turbidity of water, preventing sunlight from reaching the coral polyps. For example, large volumes of raw sewage from Colombo and its suburbs in Sri Lanka are pumped into the sea daily through two 1.2 km long pipes, resulting in the deaths of marine creatures living in the coral ecosystem.
Threats to coral reefs
Physical damage or destruction from coastal development, dredging, quarrying, destructive fishing practices and gear, boat anchors and groundings, and recreational misuse (touching or removing corals).
Pollution that originates on land but finds its way into coastal waters. There are many types and sources of pollution from land-based activities, for example:
Sedimentation from coastal development, urban stormwater runoff, forestry, and agriculture
Sedimentation has been identified as a primary stressor for the existence and recovery of coral species and their habitats. Sediment deposited onto reefs can smother corals and interfere with their ability to feed, grow, and reproduce.
Nutrients (nitrogen and phosphorous) from agricultural and residential fertilizer use, sewage discharges (including wastewater treatment plants and septic systems), and animal waste
Nutrients are generally recognized as beneficial for marine ecosystems; however, coral reefs are adapted to low nutrient levels; so an excess of nutrients can lead to the growth of algae that blocks sunlight and consumes oxygen corals need for respiration. This often results in an imbalance affecting the entire ecosystem. Excess nutrients can also support growth of microorganisms, like bacteria and fungi, that can be pathogenic to corals.
Pathogens from inadequately treated sewage, stormwater, and runoff from livestock pens
Although rare, bacteria and parasites from fecal contamination can cause disease in corals, especially if they are stressed by other environmental conditions. Coral disease occurs in healthy ecosystems, but the input of pathogen-containing pollution can exacerbate the frequency and intensity of disease outbreaks.
Toxic substances, including metals, organic chemicals and pesticides found in industrial discharges, sunscreens, urban and agricultural runoff, mining activities, and runoff from landfills
Pesticides can affect coral reproduction, growth, and other physiological processes. Herbicides, in particular, can affect the symbiotic algae (plants). This can damage their partnership with coral and result in bleaching. Metals, such as mercury and lead, and organic chemicals, such as polychlorobiphenyls (PCBs), oxybenzone and dioxin, are suspected of affecting coral reproduction, growth rate, feeding, and defensive responses.
Trash and micro-plastics from improper disposal and stormwater runoff
Trash such as plastic bags, bottles, and discarded fishing gear (also called marine debris) that makes its way into the sea can snag on corals and block the sunlight needed for photosynthesis, or entangle and kill reef organisms and break or damage corals. Degraded plastics and microplastics (e.g., beads in soap) can be consumed by coral, fish, sea turtles, and other reef animals, blocking their digestive tracts and potentially introducing toxics.
Overfishing can alter food-web structure and cause cascading effects, such as reducing the numbers of grazing fish that keep corals clean of algal overgrowth. Blast fishing (i.e., using explosives to kill fish) can cause physical damage to corals as well.
Coral harvesting for the aquarium trade, jewelry, and curios can lead to over-harvesting of specific species, destruction of reef habitat, and reduced biodiversity.
Human activities protecting the coral reef ecosystem
Protection of coastal resources such as coral reefs from being exploited and destroyed. This is done through the creation of marine reserves where zones are marked off to prevent commercial fishing. For example, the setting up of the Goat Island Marine reserve in New Zealand has led to the regeneration of snapper population which is now 14 times that of areas surrounding the reserve.
Coral polyps are also cultivated in laboratories and subsequently transplanted along the coast by human means. Since 1996, the Maldives has started a coral growing programme where large construction steel rods are placed off the coast in the resort island of Ihuru. The rods are charged with low voltage electricity to hasten the growth of corals. This has resulted in a thriving marine ecosystem in the region.
An interesting case study of conservation of the coral reef where resort owner works with the local community in Tagaqe village.
https://ih-igcse-geography.wikispaces.com/2.4.%20Managing%20ecosystems
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