The World Conservation Union (IUCN) warned this in its report 'Coral reef resilience and resistance to bleaching', said sources here on Thursday. The report also warned that warming ocean temperatures were causing reefs to bleach and die, but marine protected areas could help it. It was key to preventing further degradation of these "underwater rainforests" by making corals more robust and helping them resist bleaching, it suggested.
According to the report, corals were animals that were usually coloured tan, green or blue due to the presence of millions of microscopic plant cells within their tissues. These tiny plants use sunlight and the coral animal's respired CO2 to produce energy rich compounds that feed the coral host and release oxygen.
When seas get too warm, the relationship collapses, the brown plant cells were ejected, the white coral skeleton becomes visible through the transparent animal tissues, and the coral slowly starves. Bleaching conditions that last longer than 10 weeks could lead to the death of the coral. In the worst ever recorded coral bleaching event in 1998, up to 90 percent of coral reefs died in some areas of the Indian Ocean.
The report recommends a strategy for the establishment of a global Marine Protected Areas network in the face of climate change, covering all important marine ecosystems, including coral reefs. Moreover, sustainable fisheries management and integrated coastal management were seen as additional valuable strategies that enable coral reefs to be more resilient to bleaching.