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 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://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

OVERFISHING

HURRICANE ALLEN 1980

ACROPORA DIE-OFF 1980S

DIADEMA DIE-OFF 1983

JAMAICA

MORE ALGAE

NO GRAZERS

LESS CORAL

PHYSICAL DAMAGE

ALGAL DOMINATED

SYNERGISTIC EFFECTS

JAMAICA

PROTECTION SINCE 1961

ACROPORA DIE-OFF 1980S

DIADEMA DIE-OFF 1983

HURRICANE HUGO 1989

HURRICANES MARILYN/LUIS 1995

BUCK ISLAND, ST. CROIX

PROTECTION

LITTLE OVERFISHING

DISEASE

PHYSICAL DAMAGE

CORAL DOMINATED

BUCK ISLAND, ST. CROIX