Coral Reefs

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Importance of Coral Reefs: 0.2% of world’s ocean. Habitat for 1/3 of marine fishes. Habitat for tens of thousands of other animals. The rainforests of the oceans. Destruction of other ecosystems upon which coral reefs depend. Possible disruption of reproduction and recruitment.

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Nội dung Text: Coral Reefs

Coral Reefs http://tools.coralreef.org/content/ http://ourworld.compuserve.com/homepages/ objects/view.acs?object_id=545 mccarty_and_peters/coral/Cintro.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/ florida2/background/coralspawning.html
$375 billion in environmental goods and services Reefs at Risk 1998 (http://www.wri.org/powerpoints/reefswww/sld011.htm
Caribbean reef values (annual net benefits in 2000) • Fisheries: $310 million • Dive tourism: $2.1 billion • Shoreline protection: $0.72.2 billion Total: $4.14.6 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 •1970s: ~50% coral cover •Present: ~10% coral cover •=80% reduction in coral cover over last 30 years Gardner et al. 2003 Science 301: 958960
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/ 1989hugo.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/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/ cotstarfish/pages/cotq07.html http://www.sanctuaries.nos.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 http://ourworld.compuserve.com/homepages/ mccarty_and_peters/coral/Bleach.htm – heavy UV light exposure