http://ourworld.compuserve.com/homepages/mccarty_and_peters/coral/C-intro.htm

Coral Reefs

http://tools.coralreef.org/content/objects/view.acs?object_id=545

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: $0.7-

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

•1970s: ~50% coral cover

•Present: ~10% coral cover

•=80% reduction in coral cover over 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

http://www.nhc.noaa.gov/1989hugo.html

•Destruction of other ecosystems upon which coral reefs depend

•Freshwater poisoning

•Smothering

Tsunamis

•Physical damage

•Possible disruption of reproduction and

recruitment

•Erosion

Volcanoes

•Depends upon where volcano occurs

http://volcano.und.nodak.edu/vwdocs/current_volcs/montserrat/montserrat.html

•smothering and sedimentation

•Heat

Earthquakes•Little direct impact

-coastal landslides

•Indirect impacts

-triggers tsunamis

Predators•crown of thorns

starfish •snails•parrotfish•butterflyfish

http://www.aims.gov.au/pages/reflib/cot-starfish/pages/cot-q07.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– 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 stressedhttp://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://tools.coralreef.org/content/objects/view.acs?object_id=545

http://www.photolib.noaa.gov/reef/reef2570.htm

Overfishing

•Ecological imbalance

http://catbert.er.usgs.gov/african_dust/events.html

http://oceanworld.tamu.edu/students/coral/coral5.htm

http://www.wri.org/indictrs/rrcyanid.htm

Overfishing•Destructive fishing practices

Development

• Sediment smothering• Freshwater input• Pollutants & nutrients

(sewage, pesticides, fertilizer, heavy metals, pathogens)

http://www.wcmc.org.uk/marine/data/coral_mangrove/coral.danger.html

http://ourworld.compuserve.com/homepages/mccarty_and_peters/coral/c-intro.htm

Development

Development

http://www.sanctuaries.nos.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.nos.noaa.gov/scied/science/habitat/influences.html

• interaction of natural changes & human activity

•multiple insults

Synergistic effects

Global climate change

• Reduced reef building• Increase in frequency

and intensity of hurricanes

• Increases in bleaching• Increased in disease

CORAL DOMINATED

ALGAL DOMINATED

Synergistic effects

OVERFISHINGHURRICANE ALLEN 1980

ACROPORA DIE-OFF 1980SDIADEMA DIE-OFF 1983

JAMAICA

MORE ALGAENO GRAZERSLESS CORAL

PHYSICAL DAMAGE

ALGAL DOMINATED

SYNERGISTIC EFFECTS

JAMAICA

PROTECTION SINCE 1961ACROPORA DIE-OFF 1980S

DIADEMA DIE-OFF 1983HURRICANE HUGO 1989

HURRICANES MARILYN/LUIS 1995

BUCK ISLAND, ST. CROIX

PROTECTIONLITTLE OVERFISHING

DISEASEPHYSICAL DAMAGE

CORAL DOMINATED

BUCK ISLAND, ST. CROIX