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the top of the coral package (with the exception
of the 11 samples from Belize and the four young
samples from Campeche Bank that plot above
present sea level). If this agreement in any way
validates the curve, then the possibility that the
difference seen in the Belize samples represents
local tectonic differences cannot be ruled out.
The point in all of this is that the actual depth
values assigned to any individual coral based
on using the 'wrong' sea-level curve might be
in error by 1-3 m. It will be left to the reader to
decide if this sort of difference could be used to
explain the lack of variability in reef accretion
seen in this compilation over a depth range of
some 22 m.
Another source of possible error is related to
the assumption that recovered corals were
either in growth position or ultimately came to
rest close to the place where they lived. This lay
at the core of the argument between Toscano &
Macintyre (2003) and Blanchon (2005) over
whether there are 'good' and 'bad' corals, and
which should and should not be used to recon-
struct sea level. The Faustian bargain of Lighty
et al.
(1982) was to lay a curve over the top of the
'coral envelope', assuming that the occasional
upward deviants represented rubble tossed up on
beaches or storm ridges. However, another reliable
independent data source (e.g. peat) is required to
support or refute this approach.
The identifi cation of basal coral attachments
strongly argues for a colony being in place. Convex
upward coral-growth bands similarly lend
credibility to a colony in growth position, albeit
with less confi dence. Unfortunately, the likelihood
of encountering either in a core with any regular-
ity is small. Coral-growth rates consistent with
the hindcast depth can be useful (Hubbard
et al
.,
1986), but this will not resolve issues related to
A. palmata
. It has been proposed that the differ-
ences between polyp structure on the top and
bottom of
A. palmata
branches can be used
to divine orientation, and that 'right-side-up'
branches refl ect colonies in growth position.
However, measurement of over 500 broken
and in-place branches from the same localities
reveals no statistical difference (D.K. Hubbard,
unpublished data).
It is necessary to consider
in situ
colonies -
those that are either in growth position or have
not moved signifi cant distances from where
they grew. While great strides have been made
in identifying taphonomic signatures associated
with different styles of coral deposition (Perry,
1999, 2000, 2001; Blanchon & Perry, 2004),
this is not yet a panacea. When available, the
greatest assurance can be derived from either
direct observation in submarine outcrop/
excavation or reconstructing topography using
multiple cores along transects. The data from
northern Florida (in Lighty
et al.
, 1982; Toscano &
Macintyre, 2003) were from excavations where
the in-place nature of the sampled corals could
be directly observed. The samples from Hess Ship
Channel (Adey
et al
., 1977) similarly benefi ted from
direct observation (W. Adey, personal communi-
cation). Samples in the parent study from Buck
Island (BI and BB in Appendix 1), Lang Bank (LB)
and SW Puerto Rico (PAR) were all collected from
cores aligned in transects where time lines could
be used to reconstruct palaeotopography. In all
these cases, the samples were recovered from
either the apex of the topographic surface or along
a broad horizontal bank. The result is that there
was no shallower site from which to derive the
samples. Also, these features were of suffi ciently
limited lateral extent that any disrupted sample
had only limited space to be moved from where
it grew. Similar reconstructions can be made
from the well-constrained transects at Galeta
Point, Panama (Macintyre & Glynn, 1976). Even
if it is assumed that all the remaining studies
suffered from dramatic downward transport of
samples, the patterns refl ected in the curves of
Lighty
et al.
(1982), Toscano & Macintyre (2003),
and Hubbard
et al.
(2005) remain.
This is not to say that any of these curves are a
perfect representations of Holocene sea-level rise.
Certainly, the package of mangrove and coral data
above the curve that fueled the debate between
Toscano & Macintyre (2003) and Gischler (2006)
cannot be ignored. However, the author has not
examined any of these samples and is, there-
fore, not in a position to comment (for example,
are the peats short-rooted? What are the species,
and what is their relationship to sea level? What
is the condition of the corals and what evidence
is there that might be used to reconstruct palaeo-
topography?). Nevertheless, the bulk of the data
available support the curve used in this paper as a
realistic approximation of sea level over the past
12,000 years. Even if this position were aban-
doned, the maximum spread among all the
curves is less than 3 m, a value that is not likely
to reconcile the trends shown in Fig. 7 with
present models based on an order-of-magnitude
decrease in reef accretion between the sea sur-
face and a depth of 20-30 m. It is worth noting
