Caribbean reefs suffer severe coral bleaching event
Rhett A. Butler, mongabay.com
December 20, 2005
The Caribbean experienced one of the most devastating coral bleaching events on record during September and October while hurricanes battered the Gulf of Mexico. In response, NASA and National Oceanic and Atmospheric Administration (NOAA) have sent a team to assess the situation.
According to scientists in Puerto Rico, bleaching is both widespread and intense with colonies representing 42 species completely white in many reefs. Surveys show 85 to 95 percent of coral colonies were bleached in some areas, while reefs in Grenada suffered close to 70 percent bleaching in some areas.
Coral bleaching is associated with a variety of physiological stresses, the most important of which is elevated sea surface temperatures. Bleaching causes coral to expel symbiotic zooxanthellae algae living in their tissues algae that provide corals with nourishment. Losing their algae leaves coral tissues devoid of color, and thus appearing to be bleached. Corals can recover from short-term bleaching, but prolonged bleaching (over a week) can cause irreversible damage and subsequent death.
Caribbean reefs. Image by R. Butler
The NASA-NOAA team will look at reefs in Puerto Rico and the U.S. Virgin Islands, flying over affected reefs to gather digital images and visible and infrared light data.
Scientists have recently warned that the world's coral reefs face a grim future should global temperatures and atmospheric concentrations of carbon dioxide continue to rise. Higher ocean temperatures will produce increasingly severe bleaching events, while elevated levels of carbon dioxide could further acidify the world's seas.
NOAA satellite image for larger view of the regions of high thermal stress as of Oct. 25, 2005, from NOAA's Degree Heating Week (DHW) satellite-based product that accumulates high temperature events. Image courtesy of NOAA
Ove Hoegh-Guldberg, head of the University of Queensland's Centre for Marine Studies, believes that Australia's Great Barrier Reef -- the world's largest reef -- could lose 95 percent of its living coral by 2050 should ocean temperatures increase by the 1.5 degrees Celsius projected by climate scientists.
Coral reefs decimated by 2050, Great Barrier Reef's coral 95% dead November 17, 2005
Australia's Great Barrier Reef could lose 95 percent of its living coral by 2050 should ocean temperatures increase by the 1.5 degrees Celsius projected by climate scientists. The startling and controversial prediction, made last year in a report commissioned by the World Worldwide Fund for Nature and the Queensland government, is just one of the dire scenarios forecast for reefs in the near future. The degradation and possible disappearance of these ecosystems would have profound socioeconomic ramifications as well as ecological impacts.
This article used media materials provided by NOAA and NASA in addition to previously released information from mongabay.com.