[Coral-List] Anonymous postings and temp changes

[tomascik at novuscom.net]

Hi everyone,

I agree with Charles that we actually have an obligation to figure out  
why some coral reef sites around the world behave differently from the  
global trend if we are going to help the reefs. I am actually not  
surprised at all to hear that one particular site in PNG is bucking  
the SSTs rising global trend. What I would love to know is WHERE is  
this site that is reportedly bucking the upward SST trend located. Is  
it somewhere in the Bismarck Sea, is it along the north-west coast  
between Wewak and Jayapura (Indonesia), or was it the Solomon Sea or  
Coral Sea?

I suspect that that site is located in one of the upwelling areas of  
PNG. Coastal upwelling along the Papua New Guinea (PNG) coast and its  
effect on the SSTs during the upwelling season is well documented, for  
example see

https://journals.ametsoc.org/doi/pdf/10.1175/2010JPO4421.1

Upwelling will have moderating effects on local SST profiles, and  
therefore, it is no much of a stretch of imagination to suggest that  
areas that are affected by strong seasonal upwelling may not  
experience a noticeable rise in SSTs over the years. Many vibrant  
coral reefs in Indonesia are in fact located in well-known areas of  
strong seasonal upwelling (e.g., Banda Sea, Flores Sea and Arafura  
Sea). During my work in Indonesia I was fortunate enough to actually  
directly observe upwelling evens over coral reefs and have documented  
them in “The Ecology of Indonesian Sea”. Here is a link to some of the  
upwelling information in Indonesia (apologies for this self-promotion):

https://www.researchgate.net/publication/301883301_Chapter_Ten_Environmental_Factors

The traditional wind-induced large-scale upwelling that affects large  
regions like the Banda Sea or Sea of Bismarck is not the only  
upwelling that affects many coral reefs of the coral triangle. In  
addition to the classical upwelling generated by the monsoonal winds  
during the Southeast Monsoon (July-September) many coral reefs that we  
observed (during all seasons) are affected by daily tidally-induced  
upwelling as well. These events are significant and we described them  
as high-frequency, low-duration phenomena. Based on nutrient, salinity  
and temperature profiles we concluded that this tidally-induced  
upwelling brings up water masses from depths of 100 to 60m. On the  
coral reefs of Banda Sea the tidal upwelling will result in a drop of  
2 to 4 deg C in the SSTs over the coral reef. In Berau (Kalimantan  
Timur) we measured temperatures that were 2.5 deg C lower just over  
the coral reef than SST’s. During some tides this separation is only 2  
to 3 m. So I have no problem believing that in some areas of the  
tropical oceans, and PNG in particular, SSTs may be significantly  
different among sites, but we need to find out why instead of jumping  
to one conclusion or another.

Studies in Indonesia have shown that SSTs in upwelling regions are  
directly related to the intensity of the upwelling, which is primarily  
a function of wind strength and fetch.  Around the globe we are seeing  
intensification of tropical storms and ENSO events.  Can we therefore  
also expect an impact on the wind systems that drive these regional  
upwellings? Increased wind strength may therefore intensify these  
regional (localized) upwelling events which may result in  
local/regional cooling that may go counter to the global SST increase.

Tom


Quoting "Sheppard, Charles via Coral-List" <coral-list at coral.aoml.noaa.gov>:

> Shielding behind anonymity can perhaps be acceptable if there is  
> good cause.  Maybe this post has good cause.   This one said sea  
> temps in PNG show no upward trend and Gene added "More people should  
> look into the question the way this person did. Gene'.
>
> OK then: Of the half dozen mostly or totally complete runs that I  
> have analysed this year so far from Chagos atolls in the central  
> Indian Ocean, all show (best fit linear) rises between .21 to .52  
> deg C since 2006 depending on whether they are ocean facing reefs  
> that experience upwelling, or are in lagoons with different degrees  
> of ponding etc.  They all also document the massive marine heat  
> waves that do much of the damage.  These results have been published  
> elsewhere in fact.
>
> With those PNG results though, it was not clear whether the trends  
> derive from a series thousands of data points long, just a couple of  
> dips of a thermometer, or something between.  For PNG and parts of  
> the coral triangle, it is clear that many reefs remain vibrant, and  
> there are several ideas of differing credibility of why this is the  
> case.  While no warming for one site is lovely for that site and may  
> be perfectly correct, it does not negate the point that so many now  
> have rising temps with increasing marine heat waves.
>
> It is sad if some have been made to feel suppressed or shy about  
> reporting different trends.  I have also experienced huge pressures  
> to say what is not true about this or that site.  So I do have  
> sympathy, but where a site behaves inconveniently or differently to  
> the majority, let's hear more about it.  It might help reefs if we  
> can figure out why.
>
> Best wishes
> Charles Sheppard
>
>
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