A new study from researchers at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science (RSMAS) details the loss of coral reef species during the 2010 cold snap. Their results are published in the August 2011 issue of PLoS ONE.
“It was a major setback,” said Diego Lirman, associate professor at RSMAS and lead author of the study. “Centuries-old coral colonies were lost in a matter of days.”
Temperatures in January caused unprecedented loss of corals in the Florida Reef Tract, which spans 160 miles from Miami to the Dry Tortugas. It is the only living barrier reef in the continental United States. Air temperatures were frequently down to 30 degrees F, with water temperatures as low as 50 degrees. Corals, like the ones found in the Florida Reef Tract, have adapted to warmer waters and they are typically not found in temperatures below 60 degrees.
“The 2010 cold-water anomaly not only caused widespread coral mortality but also reversed prior resistance and resilience patterns that will take decades to recover,” the study’s authors conclude.
The research team, which included members from the Florida Reef Resilience Program, conducted a month-long survey of 76 reef sites from Martin County to Key West, during and shortly after the cold weather. They then compared mortality rates from the cold snap to warm-water events. This allowed them to conclude that the colder temperatures caused more widespread mortality than warm-water events, such as the bleaching event in 2005.
They found that coral tissue mortality reached over 40 percent for many reef building species. Reefs of larger colonies and those located closer inland were the most damaged. The bleaching event of 2005 caused less than one percent tissue mortality. Species that were tolerant to the warming were not so fortunate in the cold.
“This was undoubtedly the single worst event on record for Florida corals,” said Lirman. “We can’t protect corals from such an extreme event but we can mitigate other stresses to help them recover.”
The paper, titled “Severe 2010 Cold-Water Event Caused Unprecedented Mortality to Corals of the Florida Reef Tract and Reversed Previous Survivorship Patterns,” was supported by the NOAA Coral Reef Conservation Program, The Nature Conservancy, and the ARRA program.
Copyright © 2011 by Marine Science Today, a publication of OceanLines LLC