Coral Bleaching 1 2 - UW Atmospheric Sciences

Info slide #1 • • • • • • • Coral reefs are some of the most diverse and important habitats on earth (1) (Informa8on for Ac8on.) Second only to rainforests in the number of species (2) Coral covers less than 1% of the world’s total area (1) Accoun8ng for one third of all marine life, corals and plankton with chalky skeletons serve as the founda8on of the marine food web. (3) Loss of coral reefs would result in major economic crisis for a number of small communi8es that depend on the reefs for food, medicine, and income from ac8ons such as tourism and the fishing industry. The red shows loca8ons of reef systems Coral reefs hold more than intrinsic value of humans • References 1. “Coral Reefs.” Informa8on for Ac8on. Retrieved February 23, 2009, from <hRp://www.informac8on.org/cgibin/gPage.pl?menu=menua.txt&main=coralreef_gen.txt> 2. Tacio, H. (2008, September 25). “Coral Reefs: Medicine cabinets for the 21st Century.” The Daily Guardian. Retrieved February 22, 2009, from <hRp://
www.iloiloriver.com/coral‐reefs‐medicine‐cabinets‐for‐the‐21st‐century.html> 3. Mok, K. D. (2007, October 17). “Ocean Acidifica8on.” Tree Hugger. Discovery Channel Communica8ons, LLC. Retrieved February 21, 2009, from <hRp://
www.treehugger.com/files/2007/10/ocean_acidifca8on.php> • Great Barrier Reef photo : "Climate Change Threatens UNESCO World Heritage Sites." Photograph. 30 Apr. 2007. UNESCO.20 Nov. 2008 <hRp://
unescoeduca8on.blogspot.com/>. • World Coral Distribu8on: "World Distribu8on of Coral Reefs." Map. Ichthyology. 23 Feb. 2009 <hRp://www.flmnh.ufl.edu/Fish/southflorida/coral/distribu8on.html>. • Photo on 8tle slide: NOAA, . "Coral Reef." Photograph. Solcomhouse. 23 Feb. 2009 <hRp://www.solcomhouse.com/coralreef.htm>. • Coral Photo: "Coral Reef.” Photograph. Earth First. 23 Feb. 2009 <hRp://earthfirst.com/fimh‐of‐world‐coral‐reefs‐lost‐according‐to‐new‐survey/>. Causes of
Coral Reef
Degradation
• Ocean Acidifica8on • Ocean Temperature Change • Coral Bleaching World Coral Distribu8on Source: Ichthyology Why should we
protect the reefs?
Great Barrier Reef Source: UNESCO Source: Info Slide #2 • The oceans have always been a natural check on CO2 in the atmosphere. It is a sink in the carbon cycle. (1) • The rate and quan8ty of anthropogenic CO2 emissions have exceeded the point where natural feedbacks can restore balance. (2) • This absorp8on has slowed the increase of atmospheric CO2, but has changed ocean chemistry (lowered seawater pH) (1) • Naturally, seawater is slightly alkaline (basic) at a pH level of 8.1 units. (3) • To date, the overall pH of the ocean has decreased by about 0.1 units.(4) • This decrease lowers the satura8on state for carbonate minerals like CaCO3. (1) • The pH decreases because carbonic acid is formed by the reac8on of CO2 and water. (5) • Decreased pH lowers the satura8on state for carbonate minerals (CaCO3), which are the building blocks of coral reefs and the skeletons and shells of other marine species (1) • Decreased satura8on state indicates a reduc8on in free carbonate ions in the water, to compensate; the carbonate minerals are drawn from marine organisms.(3) • Levels are expected to drop another 0.3 units by 2100 (4) • Some scien8sts believe that corals may no longer exist by the end of the century. • The IPCC climate change scenarios predict that CO2 could get as high as 600 ppm, this would decrease ocean pH by 0.1 to 0.3 units, causing aragonite satura8on to plummet. (5) • References 1. Zeebe, R. E. , Zachos, J. C., Caldeira, K., Tyrrell, Toby. (2008, July 4). “Oceans ‐ Carbon emissions and acidifica8on”. Science, 321, 51‐52. Retrieved February 21, 2008. 2. Kleypas, J.A., R.A. Feely, V.J. Fabry, C. Langdon, C.L. Sabine, and L.L. Robbins, 2006. “Impacts of Ocean Acidifica8on on Coral Reefs and Other Marine Calcifiers: A Guide for Future Research,” report of a workshop held 18–20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the U.S. Geological Survey, 88 pp. Retrieved February 22, 2009, from <hRp://www.ucar.edu/communica8ons/Final_acidifica8on.pdf> 3. Doughton, S. (2008, May 23). “Acidified seawater showing up along coast ahead of schedule.” The Sea6le Times 4. Eilperin, J. (2006, July 5). “Growing Acidity of Oceans May Kill Corals.” Washington Post. Retrieved November 4, 2008, from WashingtonPost.com database. 5. 5. Bruno, John. (2008). "Coral reefs and climate change." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Informa8on Coali8on, Na8onal Council for Science and the Environment). 6. Diagram: Hoegh‐Guldberg, O. et al. 2007. Coral reefs under rapid climate change and ocean acidifica8on. Science 318:1737‐1742. 7. Map Visual:" The Dangers of Ocean Acidifica8on”, ScoR C. Doney, Scien8fic American, March 2006 Source: Hoegh‐Guldberg et al. 2007 Acidification
• Oceans have absorbed about 40% of anthropogenic CO2 emissions over the past 200 years • Acidifica8on slows coral growth. This prevents coral from: • Compe8ng with other species • Coping with increasing sea level rise • Recovering from other climate‐
change related stressors. Info Slide #3 • • • • • CO2, CH4, and other greenhouse gases trap hear, leading to global warming. (1) Ocean temperature has increased by 1° C over the last several decades. – The small change has caused mass‐coral mortality events around the world (especially during the warm summers over the last 10 years) (1) – The intense 1998 El Niño warmed the western Pacific, and Indian Oceans. What followed was widespread coral bleaching and mass coral mortality. Ocean warming can also indirectly kill corals by magnifying the effects of infec8ous diseases, which are one of the primary causes of coral loss (1) According to the IPCC, “Observa8ons since 1962 show that the average temperature of the global ocean has increased to depth of at least 3000m and that the ocean has been absorbing more than 80% of the heat added to the climate system.” (See Table SPM.1). {5.2, 5.5} The 4th IPCC assessment predicts a 1‐4 ˚C increase in ocean temperature by 2100 Even on the low end, summer8me temperatures will be amplified beyond the tolerance of most corals causing bleaching and mass‐mortality. • References • 1. Bruno, John. Coral Reefs and Climate Change. 26 August 2008. The Encyclopedia of Earth. Retrieved February 23, 2009 from <hRp://www.eoearth.org/ar8cle/
Coral_reefs_and_climate_change> • Graph: "Global Ocean Temperature Change." Graph. 25 Feb. 2008. NOAA.20 Nov. 2008 <hRp://www.gfdl.noaa.gov/> • Coral image: "Rainbow Reef." Photograph. 31 Mar. 2006. 22 Feb. 2009 <hRp://www.ianskipworth.com/photo/pcd1742/rainbow_reef_29_3.jpg>. Temperature
Increase
• An ocean temperature increases of about 0.5‐1.5°C cause major stresses on the sea’s ecosystem. • In the past 100 years, average sea temperatures have increased by nearly 1°C • It is projected there will be about 1‐2°C temperature rise per century . • Temperature increases cause coral bleaching and death. Source: NOAA Info Slide #4 • Under stress, corals may expel their zooxantheallae, which leads to a lighter or completely white appearance (1). The phenomenon is called “coral bleaching” because the coral animal appears to turn white amer the zooxanthellae loss (2). These stressors include: – Temperature increase – Changed ocean chemistry (acidifica8on) – increased solar irradiance – Starva8on caused by the decline of zooplankton – Sea water dilu8on caused by heavy rain and increased sedimenta8on. • References • 1. Buchheim, Jason, (1998) Coral Reef Bleaching. Retrieved 16 November 2008 from Odyssey Expedi8ons‐ Marine Biology Learning Center Publica8ons. Retrieved February 21, 2009 from <hRp://www.marinebiology.org/coralbleaching.htm> • 2. Bruno, John. Coral Reefs and Climate Change. 26 August 2008. The Encyclopedia of Earth. Retrieved February 23, 2009 from <hRp://www.eoearth.org/
ar8cle/Coral_reefs_and_climate_change> • Photos 1 and 2: Reuters. "Coral Bleach and Marine Life." The above photo shows a healthy coral reef off Papua New Guinea. Photograph. Allianz. 23 Feb. 2009 <hRp://knowledge.allianz.com/en/media/galleries/biodiversity/1.html>. • Photo 3: "Bleached Coral with Damsel Fish." Photograph. ARC Centre of Excellence: Coral Reef Studies. 21 Feb. 2009 <hRp://www.coralcoe.org.au/
news_stories/buRerflyex8nc8on/imagegallery.html>. 1 Coral Bleaching
• Occurs when corals expel their zooxanthellae (algae that gives coral its color) • A few Global Warming related factors which aRribute to bleaching • Temperature increase • Changed ocean chemistry (acidifica8on) • increased solar irradiance 3 2 1. 2. 3. This photo shows a healthy coral reef in Papua New Guinea (Reuters) In contrast, this shows bleached coral off the coast of Belize (Reuters) Another example of bleached coral (ARC Centre of Excellence) • • • • • • Info Slide #5 The degrada8on of coral reefs will have direct effects on humans. Coral is a source of tourism, food, and medicines for humans. The global fishing industry would be thrown into crisis if the marine food web tumbled from the boRom up in the event that corals were degraded past the point of possible recovery. (1) Corals are being recognized as the new resource for chemicals to form medicines. Biochemicals from corals are used to make medica8ons used to fight cancer, arthri8s, heart disease, HIV/AIDS, and other viruses. (2) The Great Barrier Reef is the largest coral reef in the world (3). Tourism of the Great Barrier Reef accounts for about five billion dollars of Australia's economy. As the reefs disappear, tourism will decline. When divers and tourists disappear, it will leave some communi8es without their primary source of income. (4) On a global scale, reefs generate billions of dollars per year from tourism, recrea8onal and commercial fishing. (3) Coral reefs provide economic stability and jobs to local communi8es that depend on the fishing industry (3). If coral disappears the fish that lived in the reef habitats will be forced to dissipate. This leaves fishermen without jobs. An es8mated 10% of fish caught each year originate from coral reefs. (5) Coral reefs are home to more than just coral; they provide habitat for a number of fish species and other organisms. As reefs are lost, there will be fewer fish and other food species. These losses will cause the marine food web to topple. Coral reefs provide protec8on for coastlines from waves and storms. Degrada8on of the reefs will cause problems if sea levels con8nue to rise due to climate change. (4) The increase of category four and five weather events will reduce coral’s ability to recover between events. Amer the 2004 tsunamis in Asia, areas with healthy coral reefs suffered less damage than loca8ons with degraded reefs (6) • This exposed reef, part of the Great Barrier Reef, is an example of how living reefs provide shoreline protec8on References • 1. “Ocean Acidifica8on.” (2008, May 26). Retrieved February 23, 2009, from European Project on Ocean Acidifica8on: hRp://oceanacidifica8on.wordpress.com/ • 2. Tacio, H. (2008, September 25). “Coral Reefs: Medicine cabinets for the 21st Century.” The Daily Guardian. Retrieved February 22, 2009, from <hRp://
www.iloiloriver.com/coral‐reefs‐medicine‐cabinets‐for‐the‐21st‐century.html> • 3. “Coral Reefs.” Informa8on for Ac8on. Retrieved February 23, 2009, from <hRp://www.informac8on.org/cgibin/gPage.pl?menu=menua.txt&main=coralreef_gen.txt> • 4. Parker, B. A., Eakin, C.M. (2008, September 2). “Coral Reefs, Climate Change and Ocean Acidifica8on.” FishChannel.Com. Retrieved February 22, 2008, from <hRp://
www.fishchannel.com/fish‐magazines/freshwater‐and‐marine‐aquarium/october‐2008/coral‐reefs.aspx> • 5. Grief on the Reef." (2008, November 4) Grief on the Reef. CNN News.<hRp://edi8on.cnn.com/2008/world/americas/03/17/mexico.nature/index.html> • 6. Agence France‐Presse, (2005, January 1). “Tsunami calamity highlights key protec8ve role of coral, mangroves.” Retrieved February 22, 2098, from Terra Daily: News about Planet Earth database. • Photo fish and coral: "Hope for Corals‐Swapping Algae Improves Tolerance to Global Warming." Photograph. 12 Oct. 2006. Not Exactly Rocket Science.20 Nov. 2008 <hRp://notexactlyrocketscience.wordpress.com/>. • Snorkel: "Coral Snorkel." Photograph. Reef Encounter. 23 Feb. 2009 <hRp://www.reefencounter.com.au/Images/coral_snorkelLarge.jpg>. • Reef Photo: University of Miami Rosens8el Schoo. "John Brewer Reef." Photograph. 1981. Science Daily. 23 Feb. 2009 <hRp://www.sciencedaily.com/releases/
2006/02/060220231628.htm>. Value of Coral
Reefs
• • • • • Medicine Tourism Fishing Industry Habitat/Biodiversity Coastline protec8on from storms