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NOAA QuickSCAT satellite image of doldrums in Central America taken on Oct. 23, 2006.Oct. 24, 2006 NOAA’s Coral Reef Watch, a part of the NOAA Coral Reef Conservation Program, now offers a satellite-based experimental low winds product that improves the ability to assess and forecast coral bleaching events, allowing managers to better plan and implement management actions that reduce the effects of bleaching and promote resilience among the nation’s coral reefs. (Click NOAA QuickSCAT satellite image for larger view of doldrums in Central America taken on Oct. 23, 2006. Please credit “NOAA.”)

Low wind conditions of less than five knots, commonly known as doldrums, can increase the temperature and light stress that contribute to coral bleaching. Winds promote mixing of the surface waters helping to cool the waters and deliver oxygen to corals and remove nutrients and waste products. Wind-generated waves also scatter light reducing incoming solar radiation to below harmful levels. During periods of sustained low winds, there is less mixing of shallow waters, higher temperatures and increased light penetration promoting environmental conditions adverse to corals, increasing the likelihood of bleaching.

Coral bleaching is associated with a variety of stresses especially high ocean temperatures. High temperatures and light cause corals to expel symbiotic micro-algae living in their tissues—algae that provide corals with food. Losing their algae leaves coral tissues devoid of color, and thus the coral appears to be bleached. Prolonged coral bleaching of more than a week can kill coral and eliminate the habitats needed for a range of marine life.

The NOAA Coral Reef Watch Program, part of the NOAA Center for Satellite Applications and Research, working in collaboration with NOAA's Coast Watch and the Southwest Fisheries Science Center - Environmental Research Division, gathers four-day mean surface wind data from the QuikSCAT satellite sensor. Persistent regions of low wind conditions are identified, and images and data are made available in a series of formats, including on Google Earth.

The potential utility of the new doldrums product was demonstrated in mid-August, when scientists witnessed the development of a large area of low winds off Florida’s west coast. Persisting for several days, the event warned of the onset of a significant warming trend over the area. After the doldrum event, this trend precipitated a bleaching warning for some areas of Florida. Other doldrums followed by subsequent warming events also have been recently observed off the south coast of Cuba and in the vicinity of Guam.

“NOAA's investment in researching new approaches to forecasting, monitoring and mediating the impacts of coral bleaching, mortality and recovery is critical in protecting these vitally important ecosystems,” said NOAA’s Timothy Keeney, deputy assistant secretary of commerce for oceans and atmosphere and U.S. Coral Reef Task Force co-chair. Keeney notes that data gathered through NOAA satellites is critical to predicting and responding to the event, and will continue to be a key component of analysis of the long-term impact of the bleaching.

"As an experimental product, we expect to further improve and refine the doldrum tool," said Dwight Gledhill of the NOAA's Coral Reef Watch Program. "However, even in its current format, NOAA’s Coral Reef Watch Program believes the experimental doldrums product will provide reef managers and the coral research community with important information on the way that wind conditions influence bleaching and coral reef communities."

NOAA’s bleaching alerts have proved useful to coral reef managers and researchers in monitoring environmental stresses impacting their reefs. With advance notice, officials can take measures to prevent human activity, such as diving, boating and recreational fishing, from adding to the stress of higher ocean temperatures already affecting the coral reefs.

The addition of the doldrum component to the coral bleaching warning system is one in a continuing series of steps NOAA and its partners have taken this year to address the growing number of bleaching incidents. In February, NOAA announced expanded regional coverage for the NOAA Coral Reef Watch Satellite Bleaching Alert monitoring system, increasing it from six Caribbean sites to a total of 24 sites throughout the U.S. and the Caribbean.

The warning system is one initiative in the Ocean Action Plan, which calls for development of new international partnerships to enhance the management of coral reefs. The expansion was made possible through collaborative efforts with NOAA, the World Bank and the Global Environment Facility. Improvements such as the doldrums product also address the U.S. Coral Reef Task Force resolution that instructs federal agencies to “Improve U.S. capabilities to forecast thermal stress and its ecosystem impacts in order to enhance management and conservation of coral reef ecosystems."

The alert system is part of a growing integrated ocean observing system, which is helping develop a coordinated ocean research plan and advancing international capacity building.

In 2007 NOAA, an agency of the U.S. Commerce Department, celebrates 200 years of science and service to the nation. Starting with the establishment of the U.S. Coast and Geodetic Survey in 1807 by Thomas Jefferson much of America's scientific heritage is rooted in NOAA. The agency is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of the nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.

Relevant Web Sites
NOAA Sea Surface Wind - Doldrums

NOAA Coral Reef Watch Program

NOAA Coral Reef Conservation Program

Media Contact:
Ben Sherman, NOAA Ocean Service, (301) 713-3066 ext. 178