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.ht
ml

•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.noa
a.gov/reef/reef2570.ht
m

 

 

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/mari
ne/data/coral_mangrove/coral.
danger.html

http://ourworld.compuserve.com/h
omepages/mccarty_and_peters/cor
al/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/sc
ied/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