Coral Reefs http tools coralreef orgcontent objectsview acs
Coral Reefs http: //tools. coralreef. org/content/ objects/view. acs? object_id=545 http: //ourworld. compuserve. com/homepages/ mccarty_and_peters/coral/C-intro. htm
Importance of Coral Reefs • 0. 2% of world’s oceans • Habitat for 1/3 of marine fishes • Habitat for tens of thousands of other animals • The rainforests of the oceans
Importance of Coral Reefs • PROTECTION TO COASTLINES • ECONOMIC RESOURCES • BIODIVERSITY • NATURAL BEAUTY
Importance of Coral Reefs • PROTECTION TO COASTLINES – absorb energy of ocean waves – reduce erosion of shoreline – storm damage – flooding
Importance of Coral Reefs • ECONOMIC RESOURCES – Fisheries for food – Fisheries for jobs – Tourism – Building materials – Aquarium trade
Importance of Coral Reefs • BIODIVERSITY – The rainforests of the sea – Genetic diversity – Pharmaceuticals
Importance of Coral Reefs • NATURAL BEAUTY http: //sustainableseas. noaa. gov/missions/ florida 2/background/coralspawning. html
$375 billion in environmental goods and services Reefs at Risk 1998 (http: //www. wri. org/powerpoints/reefswww/sld 011. htm
Caribbean reef values (annual net benefits in 2000) • Fisheries: $310 million • Dive tourism: $2. 1 billion • Shoreline protection: $0. 7 -2. 2 billion Total: $4. 1 -4. 6 billion
REEFS WORLDWIDE ARE THREATENED • 11% of reefs have been lost • 16% of reefs severely damaged • ~60% of studied reefs threatened by human activities • No pristine reefs left
CARIBBEAN REEFS DECLINING • 1970 s: ~50% coral cover • Present: ~10% coral cover • =80% reduction in coral cover last 30 years Gardner et al. 2003 Science 301: 958 -960
Threats to coral and coral reefs: 1) Natural 2) Anthropogenic –of human origin
Natural disturbances that affect corals and coral reefs? • Hurricanes • Tsunamis • Volcanoes • Earthquakes • Predators & competitors • Bleaching • Pathogens
Hurricanes • Physical damage • Smothering • Freshwater poisoning http: //www. nhc. noaa. gov/ 1989 hugo. html • Destruction of other ecosystems upon which coral reefs depend
Tsunamis • Physical damage • Erosion • Possible disruption of reproduction and recruitment
Volcanoes • Depends upon where volcano occurs • Heat • smothering and sedimentation http: //volcano. und. nodak. edu/vwdocs/ current_volcs/montserrat. html
Earthquakes • Little direct impact • Indirect impacts -triggers tsunamis -coastal landslides
Predators • crown of thorns starfish • snails • parrotfish • butterflyfish http: //www. aims. gov. au/pages/reflib/ cot-starfish/pages/cot-q 07. html http: //www. sanctuaries. noaa. gov/pgallery/pgflower/living/fg_living. html
Competitors • algae http: //catbert. er. usgs. gov/african_dust/algae. html
• Loss of zooxanthellae • causes – higher than usual ocean temperature – sharp changes in salinity – heavy UV light exposure http: //ourworld. compuserve. com/homepages/ mccarty_and_peters/coral/Bleach. htm
http: //orbit-net. nesdis. noaa. gov/orad/coral_bleaching_index. html
Pathogens • Diseases on the rise – new pathogens (8+) – land pathogens (Aspergillus) – occurring at all depths – More susceptible when stressed http: //ourworld. compuserve. com/ homepages/mccarty_and_peters/ coral/Bbd. htm
Threats to coral and coral reefs: 1) Natural 2) Anthropogenic –of human origin
Anthropogenic threats to coral reefs: • Overfishing • Development • Mining and dredging • Recreation
Overfishing • Ecological imbalance http: //www. photolib. noaa. g ov/reef 2570. htm http: //tools. coralreef. org/content/objects/view. acs? object_id=545
Overfishing • Ecological imbalance http: //catbert. er. usgs. gov/african_dust/events. html
Overfishing • Destructive fishing practices http: //oceanworld. tamu. edu/ students/coral 5. htm http: //www. wri. org/indictrs/rrcyanid. htm
Development • Sediment smothering • Freshwater input • Pollutants & nutrients (sewage, pesticides, fertilizer, heavy metals, pathogens)
Development http: //www. wcmc. org. uk/marine/d ata/coral_mangrove/coral. danger. h tml http: //ourworld. compuserve. com/home pages/mccarty_and_peters/coral/cintro. htm
Development http: //www. sanctuaries. noaa. gov/scied/science/habitat/influences. html
Mining for construction materials and dredging • Destruction of reef structure • stirs up sediment
Recreation Anchors, boats, flippers, hands, feet • Kill animal tissue • Skeleton breakage http: //www. sanctuaries. noaa. gov/scied/s cience/habitat/influences. html
Synergistic effects • interaction of natural changes & human activity • multiple insults
Global climate change • Reduced reef building • Increase in frequency and intensity of hurricanes • Increases in bleaching • Increased in disease
Synergistic effects CORAL DOMINATED ALGAL DOMINATED
JAMAICA OVERFISHING HURRICANE ALLEN 1980 ACROPORA DIE-OFF 1980 S DIADEMA DIE-OFF 1983
JAMAICA MORE ALGAE NO GRAZERS LESS CORAL PHYSICAL DAMAGE SYNERGISTIC EFFECTS ALGAL DOMINATED
BUCK ISLAND, ST. CROIX PROTECTION SINCE 1961 ACROPORA DIE-OFF 1980 S DIADEMA DIE-OFF 1983 HURRICANE HUGO 1989 HURRICANES MARILYN/LUIS 1995
BUCK ISLAND, ST. CROIX PROTECTION LITTLE OVERFISHING DISEASE PHYSICAL DAMAGE CORAL DOMINATED
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