Kelly Lekan

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REEFS

• Kelly Lekan

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Early Reefs

• First appearance of reefs around 570 million
  years ago.
• The first reefs formed were made of
  cyanobacteria.
• Were found living around 3.5 billion years ago
• Reefs formed by trapping in sediment, and
  secreting calcium carbonate
• Formed stromatolites
• Reefs were then formed by rugose and tabulate
  corals
• Disappeared during the Devonian

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Modern Day Reefs

• Coral reef building started during the Triassic
  period
• Bivalve reefs took over, and then corals became
  the dominate reef builders after the Cretaceous
  extinction

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Coral Reefs

• Rainforests of the Ocean
• One of the most biologically diverse regions
• Huge array of species of plant and animal life

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Formation Environment

• Form in tropical and semitropical areas
• Water temperatures between 16 and 30 degrees
  Celsius
• Exist within 30 degrees latitude north and south
  of the equator
• Shallow, clear water
• Normal salinity free of suspended matter

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Reef Formation

• Corals and zooxanthellae algae
• Work together in a symbiotic relationship to
  build reefs
• Corals live in colonies
• Polyps
• Secrete a hard exoskeleton of calcium carbonate
  which serves as a base for the reef
• Reefs build by the deposition of calcium
  carbonate
• Upper layer is the living layer of the polyps,
  and when calcium carbonate is secreted, it leaves
  behind another layer

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Types of Reefs

• Fringing Reefs
• Most common type
• Project directly offshore of islands or
  continents
• Grow in shallower waters
• Barrier Reefs
• Occur offshore
• Separated by a bay or lagoon
• Atolls
• Develop when islands, volcanic, sink and the
  surrounding reef remains

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Fringing Reef
Barrier Reef
Atoll
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Keys to the Past

• Plate tectonics
• Rise and fall of sea level
• Extinctions/Interruptive events

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Plate Movement

• Plate movement can be seen through the
  distribution of corals throughout the world
• When one super continent existed, the Tethys Sea
  ran through the middle of every continent
• After American split from Africa and Asia, the
  Atlantic Ocean formed, and two major areas of
  coral reef development were formed
• Caribbean region and the Indo-West Pacific region
• The distribution of corals today fits the idea of
  plate tectonics and continental drift

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Sea Level Rise and Fall

• Reefs only grow in warm, clear, shallow water
• Sea level fluctuation can be studied by the
  existence or non-existence of coral reefs
• The position of fossil reefs in geologic strata
  are an accurate indicator of sea level at the
  time of formation of the reef, because reefs will
  always grow to the level of low tide (Reef
  Education Network 2001)
• 17 cycles of sea level rise and fall over the
  last two million years
• Can interpret past environments by the formation
  of reefs

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Extinctions and Interruptive Events

• Reef formations altered by three major extinction
  events
• End of the Permian, Triassic, Cretaceous
• Change in global temperature and a drop in sea
  level that effected a decrease in reef
  development
• Core drilling of reefs
• Can look at fossils in reefs and determine
  periods of growth and decline of reefs

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Significance of Reefs

• Biologic significance
• Home to a huge assortment of plant and animal
  life
• Contain 25 of all marine life
• Economic significance
• Fishing
• Tourists
• 375 billion contributed to the U.S. economy
  annually
• Artificial Reefs

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Threats to Reefs

• Natural
• Weather
• Natural Disasters
• Humans
• The biggest threat to reefs!
• Fishing with explosives
• Pollution
• Global Warming
• Coral Bleaching

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References

• Adams, Chuck, Lindberg, Bill, Stevely, John.
  2006. The Economic Benefits Associated with
  Floridas Artificial Reefs. University of
  Florida, Institute of Food and Agricultural
  Sciences. http//edis.ifas.ufl.edu/FE649
• Agardy, Tundi. 2004. Americas Coral Reefs
  Awash with Problems. Issues in Science and
  Technology. http//www.findarticles.com/p/article
  s/mi_qa3622/is_200401/ai_n9371079/print
• Exploring the Environment Coral Reefs. 2004.
  Wheeling Jesuit University/NASA supported
  Classroom of the Future. http//www.cotf.edu/ete/
  modules/coralreef/CRmain.html
• Reef Education Network. 2001. Life and Times
  Origins. University of Sydney and Tech Talk
  Australia. http//www.reef.edu.au/contents/lt/fr_
  origins.html
• Solcomhouse. Coral Reefs. http//www.solcomhouse
  .com/coralreef.htm
• Thurman, H.V. 1993. Essentials of Oceanography.
  Macmillian Publishing, New York. 4th Edition,
  p. 336-341. http//www.geology.iupui.edu/academic
  s/CLASSES/g130/reefs/EO.htm
• Underwater Science Program. 2002. Artificial
  Reefs of the Florida Keys. Indiana University.
  http//www.indiana.edu/scuba/artificial.html
• United States Environmental Protection Agency.
  2007. Coral Reef Protection About Coral Reefs.
  http//www.epa.gov/owow/oceans/coral/about.html
• United States Geological Survey. 2005. Coral
  Reef Facts. http//coralreefs.wr.usgs.gov/facts1.
  html
• Weisburd, Steve. 1986. Artificial Reefs.
  Science News. http//www.findarticles.com/p/artic
  les/mi_m1200/is_v130/ai_4326693/print
• Wood, Rachel. 2002. Dodging mass extinctions
  all around, species were dying off. But in this
  Devonian reef, like went on. Why? Natural
  History. http//www.findarticles.com/p/articles/m
  i_m1134/is_01_111/ai_95357574/print

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Images

• http//www.solcomhouse.com/coralreef.htm image
  slide 1
• http//www.cotf.edu/ete/modules/coralreef/CRcoralr
  eefs.html image slide 1
• www.mbgnet.net/salt/coral/faq.htm image slide 3
• www.cdnn.info/news/article/a020412.html image
  slide 4
• http//www.solcomhouse.com/coralreef.htm image
  slide 6
• http//www.geology.iupui.edu/academics/CLASSES/g13
  0/reefs/EO.htm image slide 7
• http//www.solcomhouse.com/coralreef.htm images
  slide 8
• http//www.solcomhouse.com/coralreef.htm images
  slide 9
• www.dailycal.org/printable.php?id3993 image
  slide 14
• www.gasdetection.com/news2/health_news_digest...
  Image slide 14
• www.science.uts.edu.au/.../karin_ulstrup.html
  image slide 15