Layang2 massive coral bleach?

[opalobsidian]

Hello!

Im currently in Layang-Layang, having to sit out my second dive due to clogged sinuses...sigh...

my question is....is there really massive coral bleaching going on here? On our first dive the reef looked pretty skeletal and dead...this must be fairly recent?

I did see a turtle tho

Shivaya

 

[Quero]

There has been widespread bleaching in the region. Layang Layang is deep, though, so I would expect the deeper parts to have suffered less damage than the shallower areas because the surface water temps have been significantly warmer than those at depth. Bleached coral doesn't necessarily look skeletal--it just looks white. I've seen lots and lots of still-living bleached coral up here in Thailand. The polyps come out, but they're white instead of brown or green or whatever other color. Other things we normally expect to have some color are also white, such as sea anemones. You can see where the effects are being most felt in the region on this NOAA Coral Bleaching Hotspots map.

 

[Zippsy]

My dive computer has been recording the temeratures for dives in South East Asia for the past 15 years. I can easily sort the data by the 'lowest temperature recorded' during a dive. With nearly 1,000 dives in the time, out of the 25 hottest 'lowest temperature recorded', 22 were recorded this year since late March. That includes dives in the Similans, Layang Layang (in mid-May) and around peninsular Malaysia. The coldest parts of those dives ranged from a steamy 29.2C up to 31.2C. Normal in these areas is around 27.5C.

Yeah, it is hot and recent. I saw no bleached coral in Layang Layang 6 weeks ago.

 

[OnTheSpot]

I don't think the polyps come out of the coral...its the release of the symbiotic coloured algae like protozoa normally living within coral animals, which occurs when coral animals are stressed (by high temperatures, for example). This makes the coral appear white. I think the coral can survive for a short time without the algae (zooxanthellae).

 

[Quero]

Yes, the polyps do come out to feed, even in bleached coral. You are correct that the elevated temperatures cause the coral to expel the zooxanthallae algae (which is typicially brown in color). The algae seem to remain in the vicinity for a while. The coral can live for a time without the algae, and the algae can return to the coral to resume residence in some cases.

Hard coral feeds both on the fixed carbon compounds (products of photosynthesis) produced by the algae as well as on plankton in the water. Corals feed by day by photosynthesis and by night by predation, filtering out plankton from the water with their polyps extended. The plankton is enough to keep the coral alive for a short time, but without the added nutrition from the products of algae photosynthesis, the coral slowly weakens and dies. Thus, yes, the polyps do come out to feed, and what is more disturbing, we can see them coming out during the daytime, which would seem to indicate that they are in desperate need of food.

 

[OnTheSpot]

Oh, OK I get it now....come out to feed.

 

[Travelnsj]

I was there for 10 days of diving in 2008....Sorry I am not a fan of Malaysia diving....kinda fished out and the corals well you can see them....go to Borneo and do the land tours...Next time head to Palau or Raja Ampat...my 2psi!

 

[opalobsidian]

Thanks for the fascinating yet sad info everyone!

The sinuses have cleared enough to go down and yup, everything is sort of a uniform cream color down there. Highlights have been a thresher shark and those crazy Jimmy Durante schnozzed fish. The other dive group reports having seen schools of hammerheads, maybe they just want to make us jealous