 | |  | | : Coral Monitoring Project | 
 | | | Coral Factfile | |
| | | | | Coral: | a colony of tiny coral polyps | | Coral species: | 35-60,000 recorded (probably 4% of actual number) | | Coral Groups: | hard corals (brain) & soft corals (sea fan) | | Diversity: | 2nd most species rich ecosystem on planet | | Distribution: | Indo-Pacific & Atlantic Ocean in tropical, clear, shallow waters | | Medical importance: | compounds found for treatment of HIV, cancer, heart disease | | Why in danger: | acutely sensitivity to human & natural impacts | | Destroyed reefs: | in 25 years 35 million acres were lost |
|  |
| | | | | | : Biology | | Coral is a colony of individual animals called polyps. Inside most of these polyps are Zooxanthellae, tiny algal cells that photosynthesise, providing polyps with sugars. Reefs are formed by species that use calcification to form their rock-like skeletons. Coral can grow in temperate water but cannot calcify to build reefs. | |
| : Controls on the Reef |
 Light - provides energy to drive photosynthesis, therefore limiting reefs to shallow waters.
Sedimentation - reduces light and smothers coral.
Hyper-Nutrification – causes an increase in algae.
Salinity – influxes of freshwater kills coral, as does increased salinity.
Water movement – strong wave action breaks coral, low movement cause stagnant areas.
Temperature – changes growth rates.
Disease & Predation
Competition – between and within coral species. | |
| : Socio-Economics of Coral Reefs | | Most commercial fish spend part of their life cycle in coral reefs. Fishing provides employment and is an essential source of protein in poor areas. Reefs provide coastal protection against floods and erosion by decreasing wave action and enabling the formation of sea grass beds and mangroves. Through tourism coral generates $1 billion p.a. in Australia. It’s estimated the loss of coral reefs would cost $375 billion p.a. | |
| | | : Global Threats to Coral Reefs | Sedimentation: Dissolved sediments from dredging, runoff, sewage and forested mangroves (which entraps sediment) cuts out light and suffocates the coral. Productivity therefore lowers and with that so does calcification. This causes two shifts; coral starts growing in shallower water and the species that reject sediment more efficiently increase in number.
Nutrient Enrichment: When sewage and agriculture outputs are released into sensitive areas, often lagoons, the high nutrient levels cause an increase in algae that suffocates coral. Sometimes algal blooms occur, which raises toxicity, in particular phosphate that inhibits calcification.
Sea Level Rise: Predominantly caused by thermal expansion, melting of glaciers and tectonic effects. If predicted rates of sea level rise are correct, branching coral [the fastest growers] will be the only coral able to keep up.
Coral Bleaching: When symbiotic algae, or their pigment, leave the host marine invertebrate. Increased sea temperatures are a very likely cause of mass bleaching as well as an increased UV radiation and abnormal salinity. Bleaching is highly associated with global climate change.
Climate Change: As levels of CO2 in the sea rise so does acidity. This reduces argonite levels needed for calcification weakening coral skeletons at a time when the frequency of storms is increasing. Survival is down to whether coral can acclimatise or adapt as fast as the climate is changing. | |
| : Local Threats | | El Nino in 1998 caused isolated bleaching in some areas of the Quirimbas Archipelago. Destructive fishing techniques are still used by local fisherman. | |
|
| | | | | |
|
| |
