Transcript Human Impacts on Our Coral Reefs

ARC 344
HUMAN IMPACTS ON
CORAL REEFS
Ertuğ Cemal BARUTOĞLU
1662550
OUTLINE
• Importance of Coral Reefs
• Human Impacts on Coral Reefs
– Sedimentation
– Overfishing
– Careless Recreation
– Pollution
– Climate Change
• Results of Impacts
Importance of Coral Reefs
•Corals are shelters for fishes
•Corals controls O2 and CO2 levels of sea
•Corals are natural barriers that protect nearby
shorelines from the eroding forces of the sea, thereby
protecting coastal dwellings, agricultural land and
beaches.
http://theresilientearth.com/?q=content/bleached-coral-reefs-bounce-back
http://earthobservatory.nasa.gov/Features/Paleoclimatology_CloseUp/paleocl
imatology_closeup_2.php
Importance of Coral Reefs
•With growth rates of 0.3 to 2 centimeters per year
for massive corals, and up to 10 centimeters per
year for branching corals, it can take up to 10,000
years for a coral reef to form from a group of larvae
•Depending on their size, barrier reefs and atolls
can take from 100,000 to 30,000,000 years to fully
form.
Human Impacts on Coral
Reefs
Sedimentation
Over-Fishing
Careless Recreation
Pollution
Climate Change
Sedimentation
What is sedimentation?
Sedimentation occurs when sediments found
on land (soil, silt, & sand) enter the ocean
and cause the water to become very murky
Sedimentation
How does sediment travel?
http://www.maricopa.gov/aq/divisions/compliance/dust/dust_sources/photos.aspx
Wind
Natural
Impacts
Runoff
http://en.wikipedia.org/wiki/Surface_runoff
Sedimentation
What are human causes
of sedimentation?
• Clearing land for homes, resorts, & other
buildings
• Harbor construction
• Agriculture
• Dredging
http://www.opencell.us/dutchharbor.html
http://www.dredgingtoday.com/2012/04/25/usa-bayou-verdine-dredging-begins-in-august/
Sedimentation
How does sedimentation threaten
the coral reef habitat?
• Smothering coral when particles settle out
• Reducing light availability which reduces
coral photosynthesis and growth
• Sedimentation increases nutrients which
allow algae overgrowth on coral
http://coralreef-keaneandcedric.blogspot.com/2008/08/negative-impacts-on-sedimentation.html
Over-Fishing
Over-fishing is when people take more fish
from the ocean than the ocean can produce
• Smothering coral when particles settle out
• Reducing light availability which reduces
coral photosynthesis and growth
• Sedimentation increases nutrients which
allow algae overgrowth on coral
http://seawayblog.blogspot.com/2009/03/overfishing-doom-of-our-oceans.html
Over-Fishing
How do people over-fish?
longlines
gillnets
dynamite & poisons
Over-Fishing
Over-fishing threatens the coral reef
habitat
• Fish caught too young cannot grow
old to reproduce and contribute to
fish population
• Fewer fish are available to provide
food for other marine organisms
• Some fish eat algae and where there
are less of these fish, algae grows
too thick and smothers the reef
Careless Recreation
How do people use the reef
for recreation?
diving
boating
snorkeling
surfing
fishing
Careless Recreation
How are people careless
with the reef?
• Kicking, touching, or
standing on coral
• Boats can drop anchor or
drive across shallow coral
• Abandoning fishing gear
http://theintelligentcruiser.com/are-snorkelers-killing-the-reef/man-standing-on-coral/
https://cabrillo.edu/~ncrane/Clipperton/clippertonlog8.html
https://cabrillo.edu/~ncrane/Clipperton/clippertonlog8.html
Careless Recreation
What can you do to protect the reef?
• Don’t touch the
coral or any other
animals
• Do not drive your
boat over coral
• Only drop anchors
in sand or other
non-coral
sediment
• Educate others!
Pollution
Raw sewage
Trash that settles on coral will kill it
• Human’s cause many forms of
pollution that harms or kills coral.
Lost fishing gear (ghost gear)
Oil can kill all forms of sea life
Climate Change
What is climate change?
Climate change is the increase in the temperature of the Earth’s air and oceans.
Climate Change
What causes climate change?
Climate Change happens when more carbon dioxide enters the
atmosphere than can be removed by plants
Human sources of climate change
Climate Change
many types of
transportation
factories
deforestation
anything that uses fossil fuels!
Climate Change
How does climate change affect the
coral reef habitat?
Bleaching is a result of warm sea-surface temperatures
http://www.scubaboard.com/forums/socal/427334-sharing-photos-my-trip-frenchpolynesia.html
healthy coral
http://feww.wordpress.com/2008/05/26/oceans-where-life-started-are-dying-part-iv/
bleached coral
Increases in water temperature can kill marine
organisms not adapted to the warmer temperatures
The Big Picture
Human Impacts on the Ocean
Results of Impacts
•Susceptible species die as a result of bleaching
•Significant declines occur in coral genetic and species diversity
when corals die as a result of bleaching
•Change in the size structure of the reef fish populations and
assemblages when corals die as a result of bleaching
•Bio-erosion and collapse of structural complexity of the reef will
accelerate changes in reef communities, erosion of beaches, and
loss of coral islands
•With the corals absent, fish and invertebrates that rely on the
coral for food and habitat leave
Conclusion
• In conclusion, these behaviours of human cause
bleaching and extinction of one of the most
beautiful visual exhibitions in the world and the
sea life accordingly.
• To prevent this extinction, people should be
more awared and educated not only giving up
from doing personal damage on them but also
stopping the activities causing climate change
like deforestation or air pollution.
References
• G. Hodgson, (1999), A global assessment of human effects on coral
reefs. Marine Pollution Bulletin (vol. 38, pp. 345-355)
• B.S. Haplern, S. Walbridge, (2008), A global map of human impact
on marine ecosystems (vol. 319, pp. 948-951)
• Nystrom, M., Falke, c., and Moberg, F. (2000). Coral reef
disturbance and resilience in a human-dominated environment.
Trends in Ecologly and Evolution 15, pp. 413-417.
• T.P.Hughes, A.H. Baird, (2003), Climate change, human impacts
and resiliance of coral reefs (vol. 301, pp. 929-932)
• http://www.reefresilience.org/Toolkit_Coral/C7a_Importance.html
The End
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