Smithsonian reports regional sea temperature rise and coral bleaching event in Western Caribbean

Oct 12, 2010
This graphic displays sea surface temperatures in September 2009. Credit: NOAA

The Smithsonian Tropical Research Institute's Bocas del Toro Research Station and Galeta Point Marine Laboratory are reporting an anomalous sea temperature rise and a major coral bleaching event in the western Caribbean. Although the U.S. National Oceanic and Atmospheric Administration, NOAA, issued an advisory in July announcing above-average sea surface temperatures in the wider Caribbean region, there had been no clear indication of increased sea temperatures in Panama and the western Caribbean until late August-early September.

Scientists and local dive operators first noticed in the waters surrounding Isla Colon in Panama's Bocas del Toro province in July. Smithsonian staff scientist Nancy Knowlton and colleagues documented an extensive bleaching event in late September. Station personnel recorded an extreme sea water temperature of 32 degrees C. Normal temperatures at this time of year are closer to 28 degrees C. This warming event currently affects the entire Caribbean coast of Panama from Kuna-Yala to Bocas del Toro and has also been reported at sites in Costa Rica.

Abnormal sea temperatures not only affect corals, but also affect other reef organisms like these sponges. Credit: Arcadio Castillo

An extensive coral reef monitoring network in Panama, established over a decade ago by staff scientist Héctor M. Guzmán of STRI and partially funded by the Nature Conservancy, consists of 33 sites along both the Pacific and Atlantic coasts of the Isthmus, with 11 sites in the Bocas del Toro area. As of Oct. 3, 95 percent of the seafloor at the Bocas del Toro sites had been checked for bleaching. Coral mortality was limited to shallow areas near Isla Colon and a semi-lagoon area in Bocas del Toro, which is considered to be particularly vulnerable to bleaching as water circulation there is slow and temperatures tend to rise quickly. Researchers expect to have a complete report of the state of the coral reefs in several weeks.

Coral polyps, the tiny organisms that make up a coral reef, contain photosynthetic algae called zoxanthellae. Coral bleaching occurs when corals lose their color as a result of the loss of their algal component, which is caused by increased water temperature or other stress factors. Bleaching impairs vital functions of the coral such as reproduction and growth.

This graphic displays sea surface temperatures in September 2010. Credit: NOAA

With prolonged warming, corals begin to die releasing great quantities of mucous resulting in increasingly turbid waters. Oxygen levels may fall as bacteria and fungi proliferate. Anoxic conditions affect fish and coastal productivity. STRI has monitored the water column to a depth of 20 meters at 23 sites. "Dissolved oxygen dropped to less than 3 milligrams per liter at 10 meters and nearly zero milligrams per liter at the bottom," said STRI technician Plinio Gondola, who recorded the measurements. It is still not clear if temperature rise is directly related to bleaching and anoxia at this site.

The images show ocean temperatures in September 2009 and in 2010. Increasing intensity of orange towards red indicates warming on a regional scale. The final outcome of this event is uncertain. A similar event in 2005 in the wider Caribbean included intense bleaching in Panama. However, mortality was less that 12 percent in this zone and reefs have been relatively resilient. In Guzman's opinion, hurricane season may be enhancing the current problem, resulting in low water circulation in the Southwestern Caribbean and thus creating a "warm pocket" of water along the coasts of Panama and Costa Rica.

Explore further: US delays decision on Keystone pipeline project

Provided by Smithsonian Tropical Research Institute

3.7 /5 (3 votes)
add to favorites email to friend print save as pdf

Related Stories

Fears mount of massive Caribbean coral bleaching: study

Sep 23, 2010

Above-average temperatures this year could spark massive coral bleaching in the Caribbean basin region, experts with the National Oceanic and Atmospheric Administration (NOAA) warned Wednesday after a major ...

Caribbean, Gulf spared widespread coral damage

Nov 06, 2009

(AP) -- Lower-than-feared sea temperatures this summer gave a break to fragile coral reefs across the Caribbean and the central Gulf of Mexico that were damaged in recent years, scientists said Thursday.

Coral bleaching increases chances of coral disease

Oct 01, 2009

Mass coral bleaching has devastated coral colonies around the world for almost three decades. Now scientists have found that bleaching can make corals more susceptible to disease and, in turn, coral disease ...

Recommended for you

US delays decision on Keystone pipeline project

Apr 18, 2014

The United States announced Friday a fresh delay on a final decision regarding a controversial Canada to US oil pipeline, saying more time was needed to carry out a review.

New research on Earth's carbon budget

Apr 18, 2014

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...