Coral bleachingMuhammad Hafiz bin ZulkifiliUK 25364
What is coral bleaching?• Loss of important cell (zooxanthellae ) inside the coral.• Zooxanthellae contribute coloration for coral.• Factors that cause this cell to loss caused the coral’s color to become white. (bleached)
Zooxanthellea• Lives in the coral, as the coral act as its shield or protective home.• It helps to provide nutrients and oxygen during photosynthesis.• Provide 90% of energy to the coral to grow.
What are the factors?1. Increase/decrease of water temperature.2. Change in water chemistry.3. Bacteria infection.4. Increase in sea level.5. Herbicides.6. Cyanide fishing.7. Low tide8. Shipping accidents.
Increase of water temperature. (global warming)• Extreme hot sea water disrupt the nature of coral.• Coral cannot adapt the fast changing climate temperature.• Sudden change of temperature caused the expulsion of zooxanthellea• Temperature increases of only 1.5 –2°C lasting for six to eight weeks are enough to trigger bleaching. Microdocs project. (2012). Coral Bleaching. Retrieved from http://www.stanford.edu/group/microdocs/coralbleaching.html
Increase in sea level. (global warming)• Sea level increases due to melting of ice caps as resulted from greenhouse effect, coral will be deeper thus prevent coral to get enough sunlight.The Coral Reef Alliance. (2005). CORAL REEFS & GLOBAL CLIMATE CHANGE: Rising tides, temperaturesand costs to reef communities. Retrieved from http://www.icran.org/pdf/ClimateChangeIssueBriefs.pdf
Change in water chemistry.• Related to the acidity of sea water.• CO2 increases, sea water acidity increases.• Coral act as a shield for zooxanthellae. High water acidity disturb the formation of coral.New England Aquarium. (2012). Climate change and the oceans. Retrieved fromhttp://www.neaq.org/conservation_and_research/climate_change/climate_change_and_the_oceans.php
Low tide and exposure• Cause coral at shallow region to be exposed to excessive ultraviolet sunlight that may dried up the coral and trigger stress to cause the expulsion of zooxanthellea.National Oceanic and Atmospheric Administration. (2012). Hazards to Coral Reefs. Retrieved fromhttp://coris.noaa.gov/about/hazards/
Bacteria infection.• Vibrio shiloi is a type of bacterium that being released by fireworms (Hermodice carunculata).• V.shiloi becomes more effective as a bleaching agent when the temperature of sea water rises.Lynn Dicks. (2003). Coral bleaching caused by "malaria of the oceans“. Retrieved fromhttp://www.newscientist.com/article/dn3606-coral-bleaching-caused-by-malaria-of-the-oceans.html
Herbicides• Mass usage of herbicides on plant by farmers being absorbed by the soil.• Rain will wash away the chemical in the soil to the sea.• Hazardous chemicals cause the coral to bleach. Dr Heok Hee Ng. (2009). Herbicide threat to coral reefs. Retrieved from http://www.practicalfishkeeping.co.uk/content.php?sid=2075
Cyanide fishing.• Cyanide is poisonous to coral.• Fishers use cyanide to stun the fish and make it easy to catch alive. (fresh)
Shipping accidents• groundings, vessels sinking, illegal and accidental oil and diesel spills, and litter overboard can pollute coral reefs.