La Niña conditions are strengthening and looking to continue through to the middle of this year, according to the World meteorological Association. Will La Niña be able to change water temperatures significantly to prevent coral bleaching from occurring.
By Natasha Ruckel
© Green Log Home 2008
Every 3-5 years, central and east-central equatorial regions of the Pacific Ocean’s surface temperature cools by 1o to 2oC below average. This Pacific cold episode is referred to as ‘La Niña’. La Niña has been associated with an increase in Atlantic hurricanes and drier conditions, such as severe drought experienced in the southern United States seven years ago. The extreme cold weather pattern in southern and south-western parts of China, during January of this year, has also been attributed to La Niña.
While the weather outlook may be forbidding, there may be a small respite for stressed coral reefs in central and east-central equatorial regions of the Pacific.
Healthy corals become stressed if exposed to slight increases in temperature, causing ‘coral bleaching’. Sea temperatures over the past hundred years have increased by almost one degree, having a huge impact on temperature-sensitive reef-building corals.
Photosynthesizing organisms living in corals become more vulnerable to light as higher than normal water temperatures occur. As a result these damaged organisms are expelled from the coral host, leaving it a bleached white color. Bleached coral can only recover if cooler water temperatures return, allowing the photosynthesizing organisms to grow back. Coral can only survive a maximum of two years without these organisms, without them the coral starves.
Perhaps the lowering of water temperature caused by La Niña may provide a small glimmer of hope for the corals reefs in the Pacific. Sadly, it will take more than one La Niña phenomenon to secure the future of these great reefs, that not only provide a habitat for numerous plants and animals; but they also form a breakwater for adjacent coast lines, providing a natural form of storm protection.
NOTE: La Niña will cause global temperatures to drop slightly this year; however, this does not mark the end to global warming! According to data sources obtained by the World Meteorological Organization 1998-2007 has been the warmest decade on record.