NOAA scientists say warm oceans pose risk to reefs
FRISCO — After reporting major coral-bleaching events in 2014, scientists with the National Oceanic and Atmospheric Administration are warning that continued warm ocean temperatures are setting the stage for a repeat in 2015.
The warning is spelled out in the most recent outlook from NOAA’s Coral Reef Watch, a weekly product that forecasts the potential for coral bleaching up to four months in the future. Just last summer, the federal government put 20 coral types on the Endangered Species List, citing climate change as a major threat.
“The new outlook gives us greater confidence in what it shows for future coral bleaching and it comes at an important time,” said Mark Eakin, NOAA Coral Reef Watch coordinator. “The outlook shows a pattern over the next four months that is similar to what we saw during global coral bleaching events in 1998 and 2010. We’re really concerned that 2015 may bring the third global coral bleaching event.”
Coral bleaching takes place when corals are stressed by changes in conditions such as temperature, light or nutrients. They expel the symbiotic algae living in their tissues, causing them to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease.
The greatest threats early this year are in the western South Pacific and Indian oceans. In the Pacific, thermal stress has already reached levels that cause bleaching in the nations of Nauru, Kiribati, and the Solomon Islands, and is expected to spread to Tuvalu, Samoa, and American Samoa in the next few months.
In the Indian Ocean, thermal stress may reach levels that cause bleaching around Madagascar, Mauritius, Seychelles, and parts of Indonesia and western Australia.
NOAA scientists in American Samoa are already seeing the start of bleaching on their shallow reefs.
“In the coming months, we will be watching to see if the model predicts conditions that can cause bleaching in Southeast Asia and the Coral Triangle region around mid-2015,” said Eakin.
In another significant advance, NOAA’s Coral Reef Watch program has refined its satellite observational capacity that provides near real-time information on coral reef environmental conditions. It now can focus on reef areas as small as five square kilometers, with an increase of as much as 50 times more data than before. This allows coral reef managers and scientists to accurately pinpoint bleaching thermal stress levels at coral reef scales and take actions to protect their coral reefs.
“Climate change and its impacts, which can include bleaching, are some of the most pressing global threats to coral reef ecosystems today,” said Jennifer Koss, acting program manager for NOAA’s Coral Reef Conservation Program. “This suite of products is vital to help scientists, coral reef managers, and decision makers in the U.S. and around the globe prepare for bleaching events.”