Melting Coral Epidemic Sparked by Warming Oceans
Soft corals, unlike their hard coral brethren, lack a stony outer skeleton. As a result, when they die, they simply disappear, or "melt" away, leaving behind no remnants of their existence. According to marine biologist Hudi Benayahu, global warming has drastically accelerated this process and caused soft coral communities to vanish in large numbers by increasing the frequency and intensity of bleaching events.
Although soft corals are commonly found throughout the Indo-Pacific Ocean, many species are still relatively unknown to scientists and efforts to classify them are still ongoing. Global warming, which has been worsening the impact of bleaching events, may cause some of these undiscovered soft coral species to go extinct.
"I have observed sites before and after bleaching in Okinawa, Japan, and it was remarkable to see a massive disappearance of soft corals," said Benayahu, the head of the Porter School of Environmental Studies at Tel Aviv University. "You can't imagine this was the same site. Just two years passed and the entire area was deserted, lifeless."
While bleaching inflicts heavy damage to both hard corals and soft corals, soft corals are much more vulnerable and likely to be completely wiped out after a single event. Because hard corals retain their exoskeletons, they have the ability to regenerate if they can regain their zooxanthellae, photosynthesizing symbiotic unicellular algae that live within their tissues and feed them. On the other hand, "once soft corals disappear, the entire ecosystem is threatened," said Benayahu, adding that, "Many organisms [such as reef fish] are associated with the corals, and once the host disappears, all the associated organisms will disappear as well."
Benayahu recounted that soft coral communities once occupied close to 50 - 60% of his study sites. That number has now plummeted to a measly 5%. It's a real tragedy: though it was never assured (and, admittedly, may have never come to fruition), scientists had long hoped to discover a novel protein or gene in previously unknown marine species like soft corals that could have yielded a promising new drug or chemical. We'll never know now. As Benayahu somberly concluded: "There is such a huge gap in our knowledge of soft corals …. But it's too late, we have now actually missed the boat."