Coral starving and survival
debimack at auracom.com
Fri Mar 22 20:46:38 EST 2002
>I decided to add a little more firewood to discussion on Debbie
>McKenzie's interesting coral starving-survival hypohesis.
>Probably well fed Acropora palmata crests survived the massive
>mortality event(s) (cause unknown: coral bleaching, white band,
>patchy necrosis?) that killed the crests exposed to less nutrified
>and less productive oceanic waters.
>If so, McKenzie's hypothesis, far from be discarded prematurely,
>has to be tested because it could explain differences in the fate of
>some coral reefs at small scale, and also explain some
>mismatches at larger scale when correlating coral bleaching with
>sea surface temperature.
Thanks very much Pedro!
It is well beyond my means to do anything about testing the hypothesis, but
I really hope that someone will investigate it.
Regarding the role of high temperatures in causing mass bleaching and death
of corals, what do you make of the "Medieval Warm Period?" From what I've
read, have not Acroporas a history of dominating Caribbean reefs for many
thousands of years before the onset of their recent decline due to diseases
and bleaching? If the "mass bleaching" cause of death were strictly the
result of the recent temperature increase, should not the records from the
"Medieval warm period" (about 1000 years ago) also show a period of decline
in Acropora? Apparently today's higher temperatures are similar to what
occurred at that time (although the existence of the Medieval warm period
has been debated in some circles, there seems to be lots of evidence for
it, from diverse areas of the globe). If temperatures as high as today's
occurred a thousand years ago without causing mass mortality in corals, the
corals must have had a greater resistance to heat stress in those days...a
greater resilience attributable to what? Well, one main difference in their
environment that comes to mind is the fact that the bulk of other forms of
marine life involved in nutrient cycling was far greater 1000 years ago
than it is today. (Here's a news clip that I noticed today about the
Medieval warm period:
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