BLEACHING IS DUE TO CO2

[MARTIN PECHEUX]

Dear Coral-listers
This work was presented (and can be
quoted as "Link between CO2 rise
and bleaching proved by fast
fluorescence kinetics") at the 4th
Europ. Meet. Coral Reef, Perpignan,
France, 1-4 Sept.1998, p. 138.
I have done many bleaching
experiments on corals, anemones and
large foraminifers, short- and
long-term, with systematic light,
temperature and CO2 synergies. They
were monitored by fast kinetics of
chlorophyll fluorescence rise
(quantum efficiency of absorbtion,
trapping, transport, later
processes, i.e. photosynthesis
stress measures). I gathered more
than 100 000 data.
As I hypothesized in late 1991 (cf.
my Review on Internet), CO2 rise
and induced seawater acidification
(-0.0853 pH, 21percent more H+) is
indeed an important bleaching
factor : a) it is very complex in
details with time, synergies,
taxons, etc ; b) CO2 is as much
important as temperature for
bleaching ; c) SPECTAULARLY it has
the same physiological effect than
temperature ; one pH less is like
>>4.1 C.
Thus actual CO2 rise is a bleaching
stress exactly equivalent to at
least 0.4, surely 1.2 degree morE,
strongly synergical with increasing
light and temperature. I now
consider prooved that CO2 rise is
directly a (the) main bleaching
factor. And I have good indications
that the origin of bleaching is
impairement of electron transport
between the quinone A and B of the
D1-D2 photosystem II site
(photoinhibition s.s.).
Future CO2 level with a "business
as usual scenario" would correspond
to 5 degrees more during sunny
summer : this is an announciated
catastroph ("best guest" 90-98
percent species death ??). A
proposito, observed recent shell
abnormalities of bleaching large
forams proves that : a) mass
bleaching is a new phenomenon ; b)
it can be compared only to the
Cretaceous-Tertiary boundary : 10
millions years reef disappearence.
An article is of course in
preparation. Call me if you need
sooner more informations for your
own research, or for
vulgarization/political reasons.

Otherwise, if you have proposition
for a job, thanks.

Martin Pêcheux
IUFM Sciences Vies et Terre,
University of Nice
15 bis, rue des Roses, 06100 Nice -
France
Tel +33 492 071 079