Status of Caribbean coral reefs after bleaching and hurricanes in 2005

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Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005THERMAL STRESS AND HOTSPOTSNOAA Coral Reef Watch uses satellite sea surface temperature (SST) data to producetwice-weekly global estimates of thermal stress on corals (http://coralreefwatch.noaa.gov). Thermal stress depends on the capacity of corals in different locations to tolerateheat; corals near the equator are comfortable in temperatures that would be stressful forcorals that are used to cooler waters.Because stress thresholds are location-specific, the expected temperature for a normalsummer is determined for each location. To measure the stress level, the current SST iscompared with this normal summer temperature. The difference between these indicatesthe current level of stress experienced by corals and is called the ‘HotSpot.’Coral bleaching HotSpot maps illustrate the magnitude and distribution of HotSpots usingdifferent colors that correspond to the number of degrees by which the SST exceeds thenormal summer temperature. Examples of the maps are on pages 8 to 11)31-May-05 Reports are coming in from Colombia that they are seeing the highest sea surfacetemperature (SST) over the reefs so far this year, 29.9 o C. Thankfully, there is no bleaching there… (yet).02-Jun-05 The trade winds have begun again, mixing and cooling the waters. While this hasprovided some relief, there are still concerns about coral bleaching – and we’re only at the startof June!16-Jun-05 The first Coral-List report of bleached corals for the Caribbean has comefrom the northwest coast of Colombia at Islas del Rosario, following sustained high watertemperatures.25-Jun-05 SSTs at Culebra, Puerto Rico, have reached 30.5°C and corals are bleaching. Insome areas, 50% of corals have died. On top of this, there have been outbreaks of white plaguelikesyndrome and black band disease. The warmest temperatures here aren’t usually reacheduntil September and October.05-Jul-05 SSTs have started to cool on the Caribbean coast of Panama but the accumulatedthermal stress shown by the coral bleaching Degree Heating Week (DHW) values are still high.Corals have bleached near Bocas del Toro; hopefully this cooling will allow them to recover.Hurricane Dennis, 05 to 13 July 2005Hurricane Dennis was unusually strong for a July hurricane, reaching Category 4 status.Dennis made landfall four times; in Grenada, twice in Cuba and finally in western Florida.Wind speed is used to indicate a hurricane’s strength, from Category 1 (weakest) to Category5 (strongest) on the Saffir-Simpson scale (see Hurricane Capter).38
The 2005 Bleaching Event: Coral-List LogDEGREE HEATING WEEKSThe satellite-based coral bleaching Degree Heating Week (DHW) is an accumulationof thermal stress experienced by corals within the previous 12 consecutive weeks. ADHW value of 4°C-weeks indicates that significant coral bleaching is likely; widespreadcoral bleaching and mortality have been associated with DHW values exceeding 8°Cweeks.For each location, DHW are calculated by adding any HotSpot values greater than1°C and multiplying by the half-week time step of the NOAA Coral Reef Watch data.For example, if the HotSpot values for a particular location were [1.0, 2.0, 0.8, 1.2] thecontribution to the DHW from these four half-week values would be (1.0+2.0+1.2)*0.5= 2.1°C-weeks. Note that 0.8 is not included in the calculation as it is less than 1°C.Examples of maps derived illustrating the distribution of DHW values can be seen on thefirst page inside the front cover; the front cover is a stylized version of this map.13-Jul-05 NOAA Coral Reef Watch launches a new operational product: the Satellite BleachingAlert system.15-Jul-05 More reports of bleaching have come in, including extensive paling of corals aroundAbacos in the Bahamas. The HotSpot image on Executive Summary page 8 illustrates thedeveloping HotSpot.Hurricane Emily, 11 to 26 July 2005Hurricane Emily eclipsed the record set by Dennis, just 6 days earlier, as the strongest recordedpre-August hurricane and is the only Atlantic hurricane to have reached Category 5 statusbefore August. Emily inflicted damage on Grenada as a tropical storm before intensifying inthe western Caribbean. Emily crossed the Yucatan Peninsula (Category 4) and again madelandfall in northern Mexico (Category 3).26-Jul-05 Amazing! In the first two weeks of the Satellite Bleaching Alerts (SBA) system,emails have been sent for all 6 Caribbean/Atlantic sites. The U.S. Virgin Islands have thankfullydropped back to a condition of no thermal stress; Puerto Rico, the Bahamas, and Bermuda havegone up to Bleaching Watch, while Belize has dropped down to Bleaching Watch. There is someconcern for the Florida Keys; there is a Bleaching Warning there at the moment.02-Aug-05 Things have become worse; the National Hurricane Center has upgraded theprobability of an above-normal hurricane season to 95-100%. The prediction is now for 18-21tropical storms, including 5-7 major hurricanes.05-Aug-05 Corals have become pale and bleached in Bermuda where calm seas and clear skiesare persisting and there have been reports of unusually large numbers of nudibranchs (a typeof sea slug). Reports of sponge diseases have increased in Cozumel, Mexico; requests have goneout for more sightings. It is worse around St. Croix in the U.S. Virgin Islands where spongesappear to be absent - should we send out a search party?08-Aug-05 Elkhorn corals (Acropora palmata) in Biscayne Bay have lost tissue following thepassage of Hurricane Dennis through the Florida Keys. With the prediction of more hurricanes,will more corals lose tissue?39
Page 1 and 2: Stat u s o fCa r i b b e a nCo r a
Page 3 and 4: Dedication: This book is dedicated
Page 5 and 6: Status of Caribbean Coral Reefs aft
Page 25 and 26: Status of Coral Reefs in the Caribb
Page 35 and 36: 3. Hu r r i ca n e s a n d t h e i
Page 37 and 38: Hurricanes and their Effect on Cora
Page 39 and 40: Hurricanes and their Effect on Cora
Page 41: 4. Th e 2005 Bl e a c h i n g Ev e
Page 45 and 46: The 2005 Bleaching Event: Coral-Lis
Page 47 and 48: The 2005 Bleaching Event: Coral-Lis
Page 49 and 50: 5. Stat u s o f t h e Mesoamerican
Page 51 and 52: Status of the Mesoamerican Reef aft
Page 65 and 66: 6. Co r a l Reefs o f t h e U.S. Ca
Page 67 and 68: Coral Reefs of the U.S. Caribbean19
Page 69 and 70: Coral Reefs of the U.S. CaribbeanMe
Page 71 and 72: Coral Reefs of the U.S. Caribbeanwe
Page 73 and 74: Coral Reefs of the U.S. CaribbeanSe
Page 75 and 76: Coral Reefs of the U.S. CaribbeanBl
Page 77 and 78: 7. Th e Effects o f Co r a l Bl e a
Page 79 and 80: The Effects of Coral Bleaching in t
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Status of Caribbean Coral Reefs aft
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9. Th e Effects o f Co r a l Bl e a
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The Effects of Coral Bleaching in S
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10. Ma n ag i n g f o r Ma s s Co r
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Managing for Mass Coral Bleaching:
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Status of Caribbean coral reefs after bleaching and hurricanes in 2005

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