This is the twelfth in a multi-part series chronicling the 2012 trip to monitor the health of coral reefs in Raja Ampat, Indonesia. This year, Conservancy scientists are traveling to Raja Ampat alongside colleagues from CI and WWF.

This post was authored by WWF’s Helen Fox and is cross-posted on CI’s blog.

Part of the appeal of coral reefs is that they grow in warm, clear, tropical waters. But as the planet heats up from global climate change, those waters are getting a little too warm in some places, causing corals to “bleach.”

The bleaching is actually the coral’s white skeleton showing through its transparent body because the coral has lost its symbiotic algae. These algae, or “zooxanthellae,” are what give corals their colors.

In the win-win deal of symbiosis, the zooxanthellae feed coral with sugars they produce during photosynthesis. They also speed up the calcification process that creates the coral’s skeleton, which builds up the overall reef. In return, the coral provides nutrients from its waste and a safe place for the algae to live.

Safe, at least, until the water gets too hot! That’s when the algae flee. If the water cools down soon enough, the zooxanthellae often return, but if they don’t, the coral eventually dies.

Mildly Bleached seriatpora coral

As part of the reef resilience monitoring I am doing with Sangeeta, I am recording which corals have bleached and how much bleaching is found at each site. So far, bleaching appears to be quite minor in Raja Ampat, and there are no signs that this season is going to turn into a larger bleaching event. This type of very mild bleaching has been recorded in Raja Ampat by the monitoring team in previous years and has not resulted in mortality or loss of corals.

Many scientists and managers are working hard to understand what factors influence bleaching and recovery, and to what extent protecting a reef from local stressors such as overfishing or land runoff makes a reef less likely to bleach and/or more likely to recover. A few of our dives have taken place in especially spectacular, diverse stands of coral. I marvel at the diversity of shapes, sizes and colors, and hope that conservation efforts in this region can buy reefs some time as humanity tackles the larger-scale problem of global climate change.

Learn more about the Conservancy’s involvement in the game-changing Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security.

(First image: The author out on a coral monitoring excursion. First image credit: Sangeeta Mangubhai/TNC. Second image: Mildly Bleached seriatpora coral. Second image credit: Sangeeta Mangubhai/TNC.)

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