By Henrylito D. Tacio
“In the coming months, the Philippines is set to experience another coral bleaching event as ocean temperatures continue to rise.” That’s according to Dr. Mark Eakin, coordinator of the NOAA Coral Reef Watch, a weekly product that forecasts the potential for coral bleaching up to four months in the future.
“The warm ocean temperatures in 2014, especially in the Pacific, are expected to continue to cause more coral bleaching in 2015,” said Dr. Eakin, who is with the Satellite Oceanography and Climate Division of the US National Oceanic and Atmospheric Administration (NOAA).
“The new outlook gives us greater confidence in what it shows for future coral bleaching and it comes at an important time,” said Dr. Eakin in a press statement released recently. “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.”
In fact, the NOAA scientists are warning that warm ocean temperatures in the tropical Pacific and Indian Oceans could set the stage for major coral bleaching events across the globe in 2015.
“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,” pointed out Dr. Eakin.
The Philippines is actually part of the Coral Triangle, a collective term for the marine area located in the western Pacific Ocean. It also includes the waters of Indonesia, Malaysia, Papua New Guinea, Timor Leste and Solomon Islands.
“Named for its staggering number of corals (nearly 600 different species of reef-building corals alone), the region nurtures six of the world’s seven marine turtle species and more than 2000 species of reef fish,” notes the World Wide Fund for Nature (WWF).
Over 120 million people live in the Coral Triangle and rely on its coral reefs for food, income and protection from storms, WWF added.
Marine scientists say reefs are constructed by millions of minute animals called coral polyps, each of which lives inside a protective limestone skeleton. Corals remove carbon dioxide from the ocean surface to build their skeleton of calcium carbonate, or limestone. In this way, reefs help reduce the amount of atmospheric carbon dioxide — a greenhouse gas linked to global warming.
The corals’ skeletons amass to form the foundation of a reef. Studies have shown that the stony structures grow slowly, normally at a rate of 0.25 centimeters to 0.05 centimeters a year.
The coral polyps are aided by microscopic plants (algae) which live inside them, providing food in exchange of shelter. Like any plant, the algae need sunlight to power their activities, and so coral reefs are typically found in clear, shallow water.
“Coral bleaching takes place when corals are stressed by changes in conditions such as temperature, light or nutrients,” the NOAA said. “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.”
“Bleaching is not a good thing,” explained Dr. Terry Hughes, a distinguished professor at James Cook University, who convened the International Coral Reef Symposium in 2012 at Cairns, Australia.
According to Dr. Hughes, as warm temperatures intensify, coral bleaching will also increase at an unprecedented level. “Bleaching events are expected to increase in terms of frequency,” said Dr. Hughes, who has been a Fellow of the Australian Academy of Science since 2001.
“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.
The Management of Bleached and Severely Damaged Coral Reefs traced coral bleaching as far back as 1870. However, since the 1980s, bleaching events have become more frequent, widespread and severe.
In the first months of 2002, a wave of bleaching swept coral reefs around the world with scientists linking the events to climate change. The majority of bleaching records came from the Great Barrier Reef in Australia with others from reefs in countries including the Philippines, Indonesia, Malaysia, Japan, Palau, the Maldives, Tanzania, the Seychelles, Belize, Ecuador, and off the Florida coast of the United States.
In 2010, as much as 95% of the corals in the Philippines suffered bleaching after a warming event. “The bleaching has been observed at many other sites around the Philippines featuring mass mortality of corals,” a news report said.
Marine scientists claim that recovery of severely damaged reefs caused by bleaching can take a long time, even on relatively healthy reefs. In addition, “the corals that repopulate a damaged reef may be significantly different from what existed before bleaching,” according to the Great Barrier Reef Marine Park Authority (GBRMPA), which has been recognized as a world leader in managing reefs affected by coral bleaching.
Recovery is even slower if there are other stressors like poor water quality, overfishing or disease. “Where reefs are already stressed, recovery can take many decades, or even centuries,” GBRMPA reminds. “(But) a healthy, resilient reef will recover more quickly from bleaching.”
In some instances, even if corals survived from bleaching, they are now more susceptible to diseases, according to a study which appeared in the journal Ecology. “Traditionally, scientists have attributed coral declines after mass bleaching events to the bleaching alone,” says Marilyn Brandt, the leader of the study.
Warmer water temperatures can also lead to increased incidences of coral disease, which, unlike most bleaching, can cause irreparable loss of coral tissues. In many cases, bleaching and disease occur concurrently on coral reefs. Brandt and her colleagues wondered if the occurrences of bleaching and disease were linked beyond simply occurring under the same conditions. “Coral bleaching and coral diseases are both related to prolonged thermal stress,” says Brandt.
In the Philippines, destruction of coral reefs means disaster. “Coral reefs are home to thousands of marine species, and losing them will spell disaster for our ecosystems, not to mention the thousands of Filipinos who depend on them for food and as sources of livelihood,” reminds Senator Loren Legarda, Chair of the Senate Committee on Climate Change.
Some 50 million Filipinos are dependent on the coastal ecosystem that comprises mangroves, seagrass beds, and coral reefs. Some 40 percent of the country’s coral reefs today are assessed as “poor” – up from the previous 27 percent. Only one percent is considered to be “pristine.”
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