[Coral-List] [External Email] Re: Darwin was WRONG about reef formation

Lescinsky, Halard hlescinsky at otterbein.edu
Mon Oct 19 21:26:50 UTC 2020

I haven’t read Droxler’s Lit review yet, but judging from the coral list interest, it appears that it did the job of a lit review: restates and makes more appreciated what previously was substantiated in scattered scientific studies.  Of course since the turn of the last century, Daly and others argued the importance of sea level change and since then it has been widely understood that sea level is important and that the geomorphology of atolls and their lagoons are largely shaped by erosion from rainfall on the top of carbonate mounds during sea-level low stands (see Purdy and Winterer 2001).   A Geology paper by Toomey et al 2013 added some numbers showing that atolls only form when the rates of sea-level change and subsidence occurred in just the right combination within a narrow window (their so-called goldi-locks zone).  Thus the Hawaiian Islands, even though they are tropical volcanoes with reefs, are not atolls in the making because they are sinking too fast to overcome rapid sea level rise.  As a result, Hawaii preserves a series of remnant drowned reefs carried down to various depths during subsidence.  Interestingly that paper got nearly identical media hype to that reported for  Droxler’s (“ Revising Darwin’s sinking-island theory:  New study helps resolve a dispute over the origins of coral-reef formations” https://news.mit.edu/2013/revising-darwins-sinking-island-theory-0513 ), even though the importance of sea level was already well known by that time.   These studies  explain a lot about islands that aren't atolls, and about the geomorphology of the islands and lagoons, but it's worth noting, none of them even hints that Darwin's big picture of subsidence was wrong.

Its also worth clarifying, that not only did Darwin get the big picture right (subsidence was necessary), for atolls, he gave us the solution for Barrier Reef Formation as well.  While it true continents themselves don’t sink, isostatic loading on the continental edge results in subsidence that provides for more accommodation space where new reefs accrete and add more weight causing more subsidence.  Both atolls and barrier reefs reach great thicknesses due to the new accommodation space provided by continued subsidence making their origins and aspects of their geomorphology very similar (see Purdy and Winterer 2006).  I think it is pretty clear that Darwin got the big picture right for both atolls and barrier reefs, and the scientific advances over the last century suggesting that sea level change complicates the picture don't contradict Darwin’s hypothesis of subsidence; they just fill in the details, and some them are quite interesting.

From: Coral-List <coral-list-bounces at coral.aoml.noaa.gov> on behalf of Robert W Buddemeier via Coral-List <coral-list at coral.aoml.noaa.gov>
Sent: Monday, October 19, 2020 1:31 PM
To: Douglas Fenner <douglasfennertassi at gmail.com>
Cc: coral list <coral-list at coral.aoml.noaa.gov>
Subject: [External Email] Re: [Coral-List] Darwin was WRONG about reef formation

Yes, detail and precision are hallmarks of science.
Yes, science advances by the process of falsification.
Everything is uncertain, and thus, until we arrive at absolute perfection,
everything can ultimately be demonstrated to be "wrong."

In my opinion these principles can be and often are carried to
anti-intellectual extremes, to which I attribute much of the public
distrust of science.

Unashamed confession:  I haven't read the article, just Doug's summary.  I
also have not read Darwin's original work on the subject.  I have, however,
done some work on the surface and shallow subsurface of atolls.

My understanding is that Darwin set out to identify the origins of those
interesting open reef structures scattered around the Indo-Pacific.  He
came up with the NET CONTINUING growth of fringing reefs on the coasts of
subsiding volcanoes (continuing is not necessarily continuous, although
that would be a logical supposition in Darwin's time).  It was an extremely
insightful conclusion, and fundamentally correct.  Did it explain
everything we now know about atolls, almost 2 centuries later?  Of course
not -- he can't be faulted for not being prescient, any more than Wegener
can be faulted for not explicating the details of plate tectonics in
support of his continental drift conclusion.

So Darwin's theory needs refinement.  Initial theories pretty much all do.
My question is, why the big headline now?  The Eniwetok (Enewetak) drilling
project not only documented the coral-on-top-of-basalt theory; it also
demonstrated the (recognized and published at the time) existence of
unconformities, various kinds of diagenesis, and solution and erosion
effects in the carbonate column.  Read the drilling logs and articles (USGS
Prof Paper 260 & many many others).  Nobody used that to proclaim Darwin
wrong then; the real excitement was (I think appropriately) that he was
right about the basalt.

It concerns me that this title  *appears to me* to be a case of unwarranted
sensationalism, presenting the cumulative detail of 70 years of integrated
reef research as having delivered a surprising result by demonstrating that
a major scientific step forward taken over 150 years ago was not complete
or completely correct.

C'mon folks; when you are standing on the shoulders of a giant, don't
gratuitously kick him in the head.

Bob Buddemeier


On Sat, Oct 17, 2020 at 5:31 AM Douglas Fenner via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> or so says a new article:
> Popular piece:
> Study: Darwin's theory about coral reef atolls is fatally flawed
> http://news.rice.edu/2020/10/12/study-darwins-theory-about-coral-reef-atolls-is-fatally-flawed-2/
> Original review:
> The origin of Modern Atolls: Challenging Darwin's Deeply Ingrained Theory
> https://www.annualreviews.org/doi/10.1146/annurev-marine-122414-034137
> My thoughts, based on reading the popular article and the abstract for the
> review:
> Yes, if you define an "atoll" as a ring of coral at the surface, and you
> carefully ignore that it is on top of an accumulation of up to a mile of
> coral reef carbonate, which is in turn on top of a two mile tall volcano
> which all the evidence shows has indeed subsided with the ocean floor plate
> as it moves across the ocean, then yes, sea level fluctuations with the
> glaciation cycle are widely acknowledged to affect the coral reef
> structure.  It appears that maybe the new thing in this review is that the
> present ring is relatively young and built on top of the raised ring left
> from low sea level stands when rainwater was dissolving the carbonate in
> the center of the ring.  Actually, I don't think even that is new, though
> their being a flat topped bank in between time may be new.  This is a
> further embellishment on top of the Darwin theory, NOT a disproof of his
> theory, which is heavily documented.  The argument back then was whether
> there was a volcano under the carbonate, which drilling proved was correct
> and is no longer in doubt.
>      Perhaps by reading the entire review it will be clear that the review
> isn't saying that Darwin was wrong about subsidence and a volcano being
> under the carbonate, or that there was a sequence from fringing to barrier,
> to atoll, but even the title of the review implies it is.  But of course
> you attract a lot more attention saying that "Darwin was wrong."
>       What do geologists think?
> Cheers, Doug
> --
> Douglas Fenner
> Lynker Technologies, LLC, Contractor
> NOAA Fisheries Service
> Pacific Islands Regional Office
> Honolulu
> and:
> Coral Reef Consulting
> PO Box 7390
> Pago Pago, American Samoa 96799  USA
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