Friday, October 24, 2008

Coral Bleaching and Global Warming

by Charles Roring
Coral reefs around the world are facing the events of bleaching as a result of global warming. The burning of fossil fuels to run cars, power factories; and the burning of woods as land clearing for agriculture purposes, forest fires during long dry season increase the amount of carbon dioxide and other greenhouse gases in the atmosphere. Such increases bring side effects that are harmful to the survivability of coral reefs such as
- increase in sea surface temperatures (SSTs)
- rising sea levels
- more frequent and severe storms
Several days ago, NHK - a national Japanese TV station - aired a program which showed how teachers in Okinawa prefecture taught elementary school children the influence of climate change to coral reefs. After explaining the importance of corals to the marine environment, the teachers brought the school children to the nearby beach to measure the color of the corals using coral indicator. The indicator has color gradation ranging from D1 to D6. The D1 is white indicating bleached coral whereas the D6 which is the darkest color meaning the coral is healthy.
Over the period of three to six months, they found out that the color of corals were getting brighter. It means that the corals are dying or bleaching. The program showed the tragic event of how the symbiotic algae or zooxanthellaes were leaving the dying coral when exposed to abnormal heat, and UV lights.
NHK also showed how most corals in the southern region of the islands had died as a result of rising sea temperature. Fishermen who catch small coral fish reported that their catch was far less than the previous year. When diving among the corals to catch fish with their net, they saw how severe the bleaching was.
A Japanese professor invented a tool that helps young coral to grow in the shelves. When entering summer, coral release "eggs" that will "fly" and land on these shelves. The "eggs" are safe in the gaps of the shelves. They can grow to become young coral. After one year, the professor would dismantle the shelves with the living corals and implant each of them to places where corals had died of bleaching. This way, he hopes that the condition of the dying coral reefs will be restored.
Saving coral reefs should be the concern of everybody. We can work together to reduce the global warming. When we burn less, we have saved more corals from bleaching. A simple thing that we can do is going to work by bike, wear thicker clothes at home instead of burning woods or turning on the room heater. We can also participate in beach clean-up, plant more trees along the river banks to stop or reduce soil sediments from flooding to the sea and smother the corals.