[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,
Arthur
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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