[Coral-List] Darwin was WRONG about reef formation

Dennis Hubbard dennis.hubbard at oberlin.edu
Mon Oct 26 19:22:24 UTC 2020

Thanks David:

Going back to a thread from a couple years back, this is the reason that
extensive citing of the literature (and not just the most recent and "hot"
articles) is so important.


On Mon, Oct 26, 2020 at 10:57 AM David Blakeway <
fathom5marineresearch at gmail.com> wrote:

> The Droxler & Jorry article provides a valuable perspective but, as has
> been pointed out by others, it sells Darwin short. The article claims that
> most modern atolls have developed over flat-topped Pliocene banks, and
> therefore that Darwin’s fringing reef to barrier reef to atoll model is
> wrong. However, Darwin already knew his model did not apply to all atolls.
> For example:
> “*...if, therefore, corals were to grow up from a bank, with a level
> surface some fathoms submerged, having steep sides and being situated in a
> deep sea, a reef not to be distinguished from an atoll, might be formed..*.”
> (Darwin 1842, chapter 5)
> Furthermore, the article fails to cite a recent paper that describes a
> fringing reef to barrier reef transition at Tahiti, reconstructed from 35
> logged and dated cores (Blanchon et al. 2014; open access at
> https://www.nature.com/articles/srep04997).  Such selective citation is
> especially disappointing in a review article.
> An additional problem with the article, from my perspective, is that it
> invokes the antecedent karst hypothesis to explain the atoll rims. A more
> parsimonious explanation, developed by the first scientists to survey
> atolls in the early 17th century, is simply that corals and coralline algae
> grow better in the turbulent and well-oxygenated water on the outer edges
> of submerged structures.
> The karst hypothesis, in my opinion, is impeding coral reef science
> because it views reefs as passive structures – it denies the reef-building
> organisms any agency in creating reef form. We really need some young
> ecologists to take reef geomorphology forward!
> David Blakeway

Dennis Hubbard - Emeritus Professor: Dept of Geology-Oberlin College
Oberlin OH 44074
(440) 935-4014

* "When you get on the wrong train.... every stop is the wrong stop"*
 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"

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