[Coral-List] Re:Re: CO2 rise and bleaching

[Martin P ê cheux]

Dear List,

I am not surprised by the "amazing silence" around my disturbing hypothesis
that CO2 rise is a main factor of mass bleaching, as it goes against common
belief, although it is very natural.
Concerning the critic of John Ware that bleaching has not been observed in
experiments with elevated CO2, equivalent of "boiling water" :
- the CO2 effect is the little push throwing out of equilibrium
photosymbioses only at maximum summer stress; the CO2 effect is not exactly
the same as temperature effect, in particular, as noted, in the pattern of
relaxation in darkness (30 min for temperature, one day for pH).
- the CO2 increase in experiments, albeit important, are far from an
equivalent "boiling water". Increase from 900ppm (Leclercq et al) to 1400ppm
(Biosphere 2, Langdon) correspond to pH from 7.9 to 7.73, hence to an
equivalent temperature rise of 1.6-4.8°C to 2.4-7.2°C, according to the
range of equivalence. (Biosphere 2 climb up to 3500ppm but was buffered to
pH 7.7 with NaCO3, Nelson et al. 1993). In mine (Pêcheux, 1994, 1996), there
was bleaching in one day at 5000ppm, paling at 1000ppm.
- the temperature equivalence (0.4-1.2°C) of present CO2 rise and pH
decrease hold for the range of CO2 explored (85-1270ppm CO2, 7.8-8.7pH) and
even less, only for the range 230-570ppm CO2 (8.1-8.4pH) as seen at
500µE/s/m2. The same stepwise pattern was observed in Fv/Fm of the coral
Styllophora pistillata and the foraminifer Amphistegina gibbosa. Even more
convincing for me, I observed it also in the behaviour of the foraminifers
which move upward under CO2 rise.
I must stress that the effect of CO2 is capricious, being immediate or
delayed, sudden or progressive, depending in part on the duration of
experiments.
Cheers,

Martin Pêcheux, Nice University/Scientific Consultant/IPCC
3, allée des Elfes, 94260 Fresnes, FRANCE
martin-pecheux at wanadoo.fr

Martin Pêcheux, Nice University/Scientific Consultant/IPCC
3, allée des Elfes, 94260 Fresnes, FRANCE
martin-pecheux at wanadoo.fr