[Coral-List] Toth et al 2021

[Douglas Fenner]

    That's an amazing video all right.  The video does have a lot of live
stuff in it, and that as I gather is pretty much natural for there in
Florida (?)  I have read a statement in a published paper that confirms
what I have long thought, no surface underwater in tropical oceans goes
more than a few days without being totally covered with one kind or life or
another.  If it is natural I have no complaints, however, it sure doesn't
look like a coral reef ecosystem to me, looks like hardground which I never
expected to have coral on it.  Looks really grungy, anyone who has seen a
nice reef wouldn't find that a beautiful place.  Doesn't even have sponges,
let alone corals.  Must be 1% cover or less.  If it is natural, I have no
complaints.  I saw two sharks and at least 3 big black groupers in the
video.  That's great, in American Samoa usually you see no sharks on a
dive, and I've never seen a single big grouper alive here.  I saw one once
that a fisherman had caught and was quite dead by the time I saw it.  The
video has jillions of tiny fish, minnow size, but I saw few medium size
fish other than that big school of jacks.
     Yeah, there are tons of gorgonia and tons of algae.  Some of the very
few coral colonies I saw had disease on them.  Some people talk about the
"Florida Barrier Reef."  This video is what that looks like, I gather.  If
I look at a map of the Florida reef tract (which is what it has long been
called) I see tiny little dots that have actual living coral reef
ecosystems.  One of the reefs said to be among the nicest remaining is Looe
Key Reef.  Looked to me like it was maybe a city block square or
something.  Without GPS you could easily miss it.  Not a barrier to
anything.  Was ringed with buoys for dive boats.  Our dive boat had to wait
for another boat to untie and leave before we could tie up.
     The relict reefs and hard grounds like in this photo are interesting
both geologically and biologically.  But they are not "living coral reef
ecosystems."  They are "dead coral reef ecosystems" on geological coral
reef structures, with living benthic communities dominated apparently by
gorgonia and algae, and maybe I'm biased and I am certainly spoiled, it
isn't an attractive reef to me and for pleasure I wouldn't pay 10 cents to
dive on it.  As a biologist or geologist I might be super interested in
them.
      I think this video, along with Bruce Carlson's one from one reef in
Fiji (which is not representative of Fiji reefs) showing what it looked
like last time he surveyed it, are a warning.  People say "we need to get
used to the ecosystem changed, not the way it was."  Oh.  And this is what
they will look like???  Sorry, those are DEAD coral reef ecosystems.  This
is what I, and many, fear the future looks like for many or most coral
reefs.  And it isn't pretty and it isn't productive of ecosystem services.
No, the very last few corals are not dead yet, but if you wanted to
document that all the original coral species were still there, no local
extinctions, I think you'd have a lot of surveying and work trying to find
them.  I did not see even a single pair of living coral colonies of the
same species close enough together to be able to fertilize eggs.  I don't
even remember a pair of any kind of coral colonies next to each other.
        Sorry, I'm just NOT going to be happy with the world's reefs
looking this way and I refuse to "adapt and adjust" to reefs this way.  If
the world's reefs start looking like these it will be an unmitigated
disaster and we should call a disaster a disaster.  Over 100 million people
are going to be malnourished and on the edge of starvation if we allow this
to happen, and the best current predictions are dire indeed.
     Cheers, Doug

On Tue, Jun 22, 2021 at 9:41 AM Bruno, John via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Coral peeps: check out the interesting new paper by Toth et al "Climate
> and the latitudinal limits of subtropical reef development" -> its open
> access here:  https://doi.org/10.1038/s41598-021-87883-8
>
> What an author group! Some of the Caribbean's leading reef scientists
> teamed up to assess past accretional states and the demise of the
> high-latitude reefs of southeast Florida I grew up diving on in the 80s
> (off Jupiter and West Palm Beach). They conclude that climate variability
> (namely post-holocene thermal maximum cooling and cold fronts) and not sea
> level rise was the cause of the demise of these reefs after a period of
> accretion ~ 10,000 years ago. (I had thought they were much older),
>
> Importantly, they conclude: "Modern warming is unlikely to simply reverse
> this trend, however, because the climate of the Anthropocene will be
> fundamentally different from the HTM. By increasing the frequency and
> intensity of both warm and cold extreme-weather events, contemporary
> climate change will instead amplify conditions inimical to reef development
> in marginal reef environments such as southern Florida, making them more
> likely to continue to deteriorate than to resume accretion in the future."
>
> PS, You can see what these relic reefs look like now here:
> https://vimeo.com/177782350
> Little coral, but extraordinary fish and invert communities. If you think
> a reef with <10% living cover is "dead" you should watch this or go see for
> yourself.
>
> Cheers,
>
> JB
>
> John Bruno
> Professor, Dept of Biology
> UNC Chapel Hill
> www.johnfbruno.com
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