[Coral-List] Endangered species status will be considered for 82 corals

Bill Allison allison.billiam at gmail.com
Mon Feb 22 07:50:35 EST 2010

Encouraged by Jeremy's inquiry and given the Cretaceous lasted for some time
I wonder whether or not Gene's "grandest reefs" of the Cretaceous were
coincident with the very high CO2 levels he describes. The literature I have
to hand suggests that high CO2 levels occurred in the mid to late Cretaceous
with implications for skeletal development and evolution (e.g., Medina et
al., 2006; Stanley, 2003; Stanley & Fautin, 2001) and that reef communities
with important coral components waned to insignificance from the late
Jurassic to the mid-late Cretaceous (Wood, 1999; 112 & 114), apparently as
CO2 levels rose. The rudists seem to have intermittently flourished in the
face of these conditions for reasons that are debated but they may not have
formed reefs as technically defined, let alone diverse reef communities
(inferred from Wood, 1999; 114-115). With the aim of better understanding
the problem, perhaps a specialist in ancient reefs and their environments
would care to comment on my superficial presentation of the situation?

On Sat, Feb 20, 2010 at 2:04 PM, Jeremy Woodley <jdwoodley at yahoo.co.uk>wrote:

> Dear Gene,
> I’d be grateful if you could explain (to a relative ignoramus) how it could
> be that very high levels of atmospheric CO2 in the Cretaceous did not so
> reduce ocean pH as to impair coral calcification, which is a concern today?
> Were the oceans better buffered? Or must we assume that, given time,
> organisms adapted?
> Eugene Shinn wrote:
> ......................................................  Just look to the
> geologic record. The
> > grandest reefs the world has ever known grew during the Cretaceous
> > when Co2 levels were more than 7 times present levels.
> Jeremy Woodley
> Retired from the Centre for Marine Sciences, University of the West Indies,
> Jamaica.
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> Coral-List at coral.aoml.noaa.gov
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Reality, as usual, beats fiction out of sight.
Conrad, 1915

"Reality" is a dangerous word that should always be incarcerated in
quotation marks.

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