Impacts of Climate Change on Coral reefs in the Caribbean Mrs. Marcia Creary
Impacts of Climate Change on coral reefs in the Caribbean Climate Change: Impacts on the Caribbean June 15-17, 2007 Faculty of Social Sciences, UWI & Caribbean Community Climate Change Centre Marcia M. Creary & Loureene Jones Caribbean Coastal Data Centre Centre for Marine Sciences University of the West Indies
What are corals? • The corals that form reefs are “hard corals” with skeletons of calcium carbonate. • These “reef-building” corals are usually composed of many polyps (colonial) and have microscopic plants (zooxanthellae) in their tissues which provide some additional food for the coral by photosynthesis – thus reef-building corals need light and so grow close to the surface of the sea.
What are coral reefs? • Coral reefs are large structures composed mainly of dead coral skeletons built up over thousands of years. • The reef maintains itself by the continued growth of living corals
Climate change factors that affect coral reefs • Sea level rise • Increased sea surface temperature • Reduced calcification rates • Altered circulation patterns • Increased frequency of sever weather events
Why do coral bleach? • Corals go pale or white as a result of stress • Prolonged elevated sea surface temperatures. • High levels of UV light • Low light conditions • High turbidity, sedimentation • Disease • Variable salinity • Pollution
Mass Bleaching – a recent phenomenon • 1997-1998 • Mass mortality of corals • 16% of worlds reef destroyed • 2002 • Great Barrier Reef and SW Pacific • 2005 • Caribbean and Western Atlantic Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005 and 2006. Special Report by GCRMN
Bleaching study in Jamaica • August - October 2005 Jamaica and other Caribbean nations experienced prolonged high sea surface temperatures • Jamaica experienced 5-6 weeks of exposure to higher than normal temperatures which resulted in widespread bleaching • Funding was received from Reef Check International though NOAA to document the event. • November 2005 to May 2006 , Reef Check surveys with an additional bleaching component were conducted. • Sites located in Negril, Discovery Bay, Portland, Port Royal and Portland Bight Protected Area were assessed twice. First to determine the extent of bleaching and second to assess level of recovery.
Observed bleaching • Bleaching was first noted on the north coast of the island late August to early September and later manifested on the south coast in late September to early October. • The effects of the bleaching episode were more pronounced on the south coast than on the north.
Thermal Stress(Degree heating weeks map – NOAA) Number of weeks of exposure to higher than normal temperatures.
Bleached coral populations at various sites around Jamaica Bleaching was observed at most sites. Sites exhibited varying degrees of bleaching from10 % to 95%. On the resurvey, up to 50% of the bleached corals had recovered.
Bleached corals • Coral species bleached • Montastrea annularis • Montastrea faveolata • Montastrea cavernosa • Siderastrea siderea • Diploria strigosa • Agaricia spp. • Millepora complanata • Porites porites
Hurricanes • Major hurricanes that have impacted Jamaica’s reefs include Hurricane Allen in 1980, Hurricane Gilbert in 1988 and Hurricane Ivan in 2004. • Hurricane Ivan caused visible damage to coastal areas. Variable levels of damage were noted on the north and south coasts. • In 2004 and 2005 (Dennis, Emily and Wilma) hurricanes passed south of Jamaica, as such reefs on the south coast have been hardest hit.
Other threats to Caribbean Reefs • Coastal development • Inland activities • Over-fishing • Destructive fishing practices • Waste disposal • Ship-based activities • Physical damage
Can coral adapt to climate change? • Adaptation • Genetic variability • Acclimatization • Biochemical or physiological • Range shift • Expand to the sub-tropics
What does this mean for the tourism and insurance industries? • Shoreline protection • Sand replenishment • Water sport activities • Diving • Snorkeling • Swimming • Food source • Aesthetic, biodiversity