Corals!

I grew up in the Virgin Islands, on a small sail boat, surrounded by stunning coral reefs. One of my earlier memories was seeing these massive structures for the first time. I was stunned by all of the colors, fish, sea fans, and depth. If I am recalling this memory correctly, the site I was snorkeling is called the Indians. So I decided to check if there were any videos of the site on YouTube. If you watch this one. You'll probably realize, just as I did, that all of that color and diversity is gone. The site is pretty bland. Seeing this in person is disturbing to say the least. Unfortunately, the future for corals does not look that great. According to the 2008 World Coral Status report by Clive Wilkinson, 20% of coral area worldwide has already been lost.

The main mechanisms by which corals die stems from bleaching events. These events are triggered by sudden changes in the corals environment (mainly temperature) and results in the breakdown of the coral's symbiotic relationship with its algae. These algae are kicked out of the corals body and leave the translucent coral behind, exposing its bright white skeleton. Thus corals that loose their symbionts appear "bleached". Bleaching events can be massive - affecting up to 99% of corals on a reef! These corals essentially starve while they are bleached, since their symbionts are not there to make sugars for them. Starving corals are very susceptible to disease outbreaks and often die, although they can recover in seemingly rare instances.

Bleaching events are a global phenomenon and are decimating global reefscapes. The Great Barrier Reef in Australia, for example, just underwent one of the most devastating bleaching events. Just watch this video! You can see the bleaching from a plane!

Eilats reefs are different though... No mass bleaching events have ever been recorded. The hypothesized reason for this? Essentially an evolutionary bottleneck that caused corals to adapt to hot, salty temperatures really quickly (on geologic timescales, that is, <6,000 years). You can read about it here in this abstract. This makes Eilat a really interesting place to study coral reefs and their symbionts.

If you're in to Netflix (let's be honest - who isn't?), there's this really cool new documentary I'm dying to watch called Chasing Corals! It's coming out super soon and after I finally get to watch it, I'll undoubtedly post again to tell you what I thought of it. :-)

Stay tuned for more!

Stephan