[Coral-List] Mystery Event - Lankayan Island, Sulu Sea Sandakan

Arthur Webb arthur at sopac.org
Thu Aug 23 19:51:20 EDT 2007

Gene and others - thanks for your thoughts,

Gene indeed "looking up" as you indicate may be a component of the issue 
in the Maldives due to there geographic location but is highly unlikely 
re the Kiribati phenomena.  And for those that don't know these islands 
check Google Earth - 0 23'35.05" N 173 52'39.50"E (Abemama) and 0 
39'05.54"S 174 20"00.35" E (Nonouti) they're a long way from Asia and 
also "upwind" if you like.  (Incidentally, these are excellent high res. 
images and really let you get a feel for these magnificent environments).

Bob, thanks also for your comments which are instructive, again some may 
apply to Maldives event but I'll leave Don to comment further as I have 
no personal experience in the Maldives.  However, I don't know that they 
all fit with the Kiribati event.  I'm unconvinced with regards to direct 
human disturbance (these Islands must surely be some of the most 
pristine on the planet and these communities among the last on Earth who 
still live in a sustainable balance with their environment).  As for 
rainfall and tide, I've spent some 10 years working throughout these 
islands I've seen some of the highest tides on record and heaviest 
rainfall but have never heard or seen a fish kill associated with these 
natural phenomena.  Also in terms of the hydrology these floating 
freshwater lens are presumably quite restricted in the depth they can 
penetrate down since the islands are so narrow and most importantly the 
land surface is very low (on average about 1m above high tide) this 
restricts the volume of freshwater which can be "held" irrespective of 
recharge rates as heavy rain simply results in surface ponding and even 
surface runoff in extreme cases.  Additionally, I can't help but think 
we should expect to hear stories from the local communities if heavy 
rainfall and / or high tides produced fish kills as these oceanic and 
atmospheric phenomena occur relatively regularly.  Otherwise, I can't 
think what could possibly allow the quick release of sufficient volumes 
of anoxic fresh water into the neighboring marine environment which was 
adequate to cause a wide spread (several kilometers of coast) kills on 
these high energy, deep oceanic drop offs?

I guess so far, that leaves the most likely candidates as either an 
unusual deep cold / anoxic upwelling or as John McManus indicates 
perhaps the other way, an unusually warm pool of surface water forming 
around or moving past these islands (I must admit I hadn't thought it 
possible for water to heat to this extent in the deep open ocean 
environment - coral bleaching maybe but how extreme would conditions 
have to be to kill fish in such environments?! - there is obviously no 
routine direct measurement of even basic WQ parameters on these remote 
islands but if I can find time I'll see what information I can pull 
together re the regional weather and surface conditions around Dec '03 - 
perhaps our NOAA friends could help?).

Anyway it's an interesting one,

Thanks to all,


Gene Shinn wrote:
> Dear Arthur, It just may be that everyone is looking down  at the 
> "usual suspects." The cover story in the 2, August 2007 issue of 
> Nature (see 575) describes what is happening above the Maldives. Gene

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