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Status of Caribbean coral reefs after bleaching and hurricanes in 2005

Status of Caribbean coral reefs after bleaching and hurricanes in 2005

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<strong>Status</strong> <strong>of</strong> <strong>Caribbean</strong> Coral Reefs <strong>after</strong> Bleach<strong>in</strong>g <strong>and</strong> Hurricanes <strong>in</strong> <strong>2005</strong>SATELLITE BLEACHING ALERTSSatellite Bleach<strong>in</strong>g Alerts (SBA) notify reef managers when changes occur <strong>in</strong> theenvironmental conditions relevant to <strong>coral</strong> <strong>bleach<strong>in</strong>g</strong> at or near their reef. NOAA CoralReef Watch transmits emails for 24 locations around the world, <strong>in</strong>clud<strong>in</strong>g 6 strategic <strong>reefs</strong>ites across the greater <strong>Caribbean</strong> region. SBAs are sent to registered users wheneverHotSpot <strong>and</strong> Degree Heat<strong>in</strong>g Week <strong>in</strong>dicators show that the thermal stress level haspassed a critical threshold; either <strong>in</strong>creas<strong>in</strong>g or abat<strong>in</strong>g. Subscription is free at http://<strong>coral</strong>reefwatch-satops.noaa.gov/SBA.html; additional SBA sites are under development<strong>and</strong> further locations can be requested.Bleach<strong>in</strong>g Watch: Keep an eye out! Corals are experienc<strong>in</strong>g low-level thermal stress.Temperatures have exceeded the usual summer maximum but have not yet reached theBleach<strong>in</strong>g Threshold. Degree Heat<strong>in</strong>g Weeks (DHWs) are not yet accumulat<strong>in</strong>g.Bleach<strong>in</strong>g Warn<strong>in</strong>g: Get prepared now. The HotSpot is now at least 1°C <strong>and</strong> <strong>coral</strong>sare stressed. DHWs have begun to accumulate <strong>and</strong> are at 1°C-week.Alert Level 1: Corals are probably <strong>bleach<strong>in</strong>g</strong> or will soon! DHWs have reached 4°Cweeks,signify<strong>in</strong>g that thermal stress has reached levels that cause <strong>bleach<strong>in</strong>g</strong>. Generally,<strong>coral</strong>s will respond to this level <strong>of</strong> thermal stress <strong>in</strong> the next 1-3 weeks, depend<strong>in</strong>g on thespecies <strong>and</strong> other local factors.Alert Level 2: Double trouble. At DHW <strong>of</strong> 8°C-weeks, thermal stress is widespread<strong>and</strong> you can expect to see mass <strong>coral</strong> <strong>bleach<strong>in</strong>g</strong>. Unfortunately, by this time, the thermalstress has persisted long enough that some <strong>coral</strong>s will probably die soon.No Stress: Temperatures have cooled <strong>and</strong> hopefully stressed <strong>coral</strong>s will recover.At least they are no longer under thermal stress.18-Aug-05 Extensive <strong>bleach<strong>in</strong>g</strong> has been seen <strong>in</strong> the Florida Keys, right <strong>after</strong> an SBA Alert Level1 email was sent on 13 August. SST has been around 31°C, with calm <strong>and</strong> sunny conditions.There could be more trouble <strong>in</strong> store for Florida’s <strong>reefs</strong>; a strong HotSpot is develop<strong>in</strong>g, asshown <strong>in</strong> the image on page 9.23-Aug-05 More <strong>bleach<strong>in</strong>g</strong> has been seen <strong>in</strong> Biscayne Bay, Florida Keys, <strong>and</strong> now <strong>coral</strong>s nearPalom<strong>in</strong>itos Isl<strong>and</strong>, Puerto Rico are <strong>bleach<strong>in</strong>g</strong>.Hurricane Katr<strong>in</strong>a, 23 to 30 August <strong>2005</strong>Hurricane Katr<strong>in</strong>a was one <strong>of</strong> the most devastat<strong>in</strong>g natural disasters <strong>in</strong> the United Stateshistory. Katr<strong>in</strong>a was the most costly hurricane to strike the U.S., mak<strong>in</strong>g l<strong>and</strong>fall <strong>in</strong> Florida(Category 1) <strong>and</strong> then <strong>in</strong>tensify<strong>in</strong>g to Category 5 over the Gulf <strong>of</strong> Mexico before strik<strong>in</strong>gLouisiana/Mississippi (Category 3). Katr<strong>in</strong>a was exceptionally large with hurricane-forcew<strong>in</strong>ds extend<strong>in</strong>g 170 km from the centre <strong>and</strong> storm-force w<strong>in</strong>ds out to 370 km. The 8 mstorm surge that accompanied Katr<strong>in</strong>a caused major flood<strong>in</strong>g <strong>in</strong> New Orleans <strong>and</strong> along thenorthern Gulf coast. However, Katr<strong>in</strong>a also did some good <strong>in</strong> the Florida Keys, as a Category1 hurricane, mix<strong>in</strong>g up the waters <strong>and</strong> cool<strong>in</strong>g overheated <strong>reefs</strong>.40

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