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

[Arthur Webb]

It's interesting you mention an atoll event.  I was in Kiribati in the 
Central Pacific during Christmas 2003 and at that time there were 
reports of mass mortality along the ocean side coasts of at least 2 
atolls in the group (Abemama and I think Nonouti).  These atolls are 
tectonically stable and are far from any active plate boundaries and are 
thousands of kilometers from any significant land mass with surface run 
off.  Additionally, both of the islands mentioned above have small 
populations who live a traditional subsistence lifestyle (few vehicle's, 
no electricity or reticulated water, few imported products, no intensive 
agriculture, etc) in relatively pristine terrestrial and marine 
environments.

Whilst I did not witness the event I did travel to Abemama about 2 
months after and the same story was repeated time and again that there 
was so much dead marine life on the ocean side reefs (and not the lagoon 
side) that "windrows" of dead fish lined the shores (both pelagic and 
reef associated species were mentioned).  The people here too indicated 
the intolerable smell and plague of flys which followed but this seemed 
very much associated with the decaying marine life not the time of the 
event.

I must say this utterly stumped me! These atolls are ancient seamounts 
which rise steeply from 3.5 4.0 km depth and the outside living reefs 
where the dead fish were first witnessed are the very upper living rim 
of these oceanic slopes.  They are high energy environments and the 
concept of water residence times barely even applies and as mentioned 
there is no tectonic or terrigenous influence to speak of.  Last, people 
reported that some had taken and eaten fish which was sluggishly 
floating (near death I guess) immediately following the event with no 
ill effect and otherwise of those I spoke to there was no living memory 
or oral history of such an event having happen before.

My only thought was that through some freak anomaly of deep currents a 
slug of very cold and or deoxygenated water moved up the slope persisted 
for long enough to cause damage then sank again ............. anyway 
since we're on similar subjects I'd be interested if there's any similar 
stories or ideas out there.

Thanks,

**Arthur Webb
*Coastal Processes Adviser*

*/SOPAC/* **Pacific**** ****Islands**** Applied Geoscience Commission**
Postal Address: Private Mail Bag, GPO, Suva, Fiji Islands
Street Address:  241 Mead Road, Nabua, Fiji Islands
Tel: +679 338 1377 Fax: +679 337 0040
Email:** **arthur at sopac.org <mailto:herve at sopac.org>
Website:** **_<<_http://www.sopac.org <http://www.sopac.org/>_>>_



William Allison wrote:
> Several months ago something very similar was described at a Maldivian
> atoll. I'll try to track down particulars.
>
> On 8/22/07, Don Baker <reefpeace at yahoo.com> wrote:
>   
>> Dear Coral-L:
>>
>> Several months back, an event happened at Lankayan Island, north of Sandakan, Sabah, Malaysia (Sulu Sea), that resulted in the death of corals, sea cucumbers, giant clams and other marine life - from shallow water to approximately 3 meters.
>>
>> During this event, the seawater smelled putrid and noxious, whereas, it was initially assumed to be from all the dead marine life.  The water salinity was measured at or near 25ppt, and very unusually strong currents were present near the southern portion of the island's shallow reefs. Wave force was rough at about 1 to 1.5 meters.  The weather was sunny without any rainfall either at the island region nor on the North Borneo 'mainland.'
>>
>> Please refer to this publication with regards to page 9 / Sandakan Sub Basin and Sulu Sea Basin.   http://www.doe.gov.ph/ER/archives/win_opp/cd/petropot.PDF
>>
>> The nearby islands to closest to Lankayan Island are the Philippines Turtle Islands - with Buan Is. the closest and to the south west.  Buan Is. is classified as a "mud origin' type island mass, whereas, decades ago there existed active mini mud volcanoes there.
>>
>> Observation by the local fishermen in the same Turtle Island region have seen many large, upwelling mud plumes flowing from the under the sea (perhaps pushed out by the natural gas pressure in the Sandakan Basin edges near North Borneo?).
>>
>> In short, this event seems to point more so to a natural cause rather than from runoff from the N Borneo coastal regions.  The lowering of the seawater salinity was also significant as well as higher than normal water temperatures in the same area.  Could this also be a combination of 'ancient freshwater' also extruding along with the mud and perhaps natural gas?  Lastly, the seawater visibility (noted by the tour divers in their complaints) was very poor [< 3 meters at times].  The color was 'gray' the same as the mud on Buan.
>>
>> Can anyone recommend an institution to confirm the cause of this event?  Has anyone observed or know of any similar events worldwide?  What would be the best way to monitor and gather data if this event is natural and caused by the oil/gas/'old' water?   Is this event also dangerous with regards the Lankayan Island's proximity to such a event?
>>
>> Any advice, assistance, comments are welcome.
>>
>> Don Baker
>> Reef Guardian Co-Founder
>> Sabah, North Borneo
>> Malaysia
>>
>>
>> Alternate Email: donbjr95 at hotmail.com
>>
>> "Dedication and motivated direction in achieving specific goals related to the care and protection of living things is not necessarily a guaranteed formula for success.  Success is, more often than not, a direct result of a person's passion in addition to the above formula." [Don Baker, Marine Conservationist/Activist, 1998]
>>
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