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