[Coral-List] Giant barrel sponges taking over Florida's reefs!

Risk, Michael riskmj at mcmaster.ca
Tue Sep 8 14:05:29 EDT 2015

   Hi Doug.

   I have never had a real problem with the old "geological" definition of a
   reef as a "biologically-constructed wave-resistant structure." This would
   mean that, for example, there are no true deep-water coral reefs, nor are
   there likely to be reefs constructed by modern sponges. Of course, we have
   had  ancient  reefs  made  by  ancient  sponges  with  hard  skeletons
   (stromatoporoids), as well as brachiopods and huge oysters, and the list
   goes on.

   Where  I  might  take  issue  with you is your broad usage of the term
   "ecologist.” I consider that an ecologist is one who studies the ecosystem.
   There are many universities today at which one can obtain a PhD in "ecology"
   without ever having had a course in earth sciences or, indeed, physics or
   chemistry. I knew the biology department at my old university was in trouble
   when  they  advertised  for  an "ecologist” and the title of the first
   candidate's job seminar was “The ecology of T4 phage in the hind gut of the

   I think you were referring to people I would call "biologists." Fine people
   all, to be sure, but a real ecologist has a grasp on more things than just

   Your separation of processes into biological and geological on the basis of
   time is perhaps not a bad one, but I would point out that dead reefs already
   have been shown to lose topographical complexity. It is that mixture of
   habitats  that  allows  reefs  to support those diverse and entrancing
   communities that so fascinate us. It only takes a decade for substantive
   change to occur.


   On Sep 4, 2015, at 4:46 PM, Douglas Fenner <[1]douglasfennertassi at gmail.com>

        Good point.  The geological reef structure was built by primarily by
     corals, or at least the corals are important as baffling to hold it
     together.  Algae often are very important contributors and can contribute
     more calcium than corals.  They are coral reefs in the same sense as a
     similar structure lifted 20 feet out of the water 100,000 years ago is a
     coral reef.  But an uplifted reef above the water does not have a living
     coral reef ecosystem on the surface.  The same is true of reefs that are
     now dominated by algae, whether the algae is macroalgae (by which I mean
     frondose or fleshy algae) or turf (by which I mean filamentous algae) or
     coralline algae or mixtures or soft corals or other things.
         Sometimes people talk or write about how reefs may die in coming
     decades.  The geological structures won't die, though they have many
     things in holes in the structure, I would think.  I don't think the
     geological structures are going to disappear in a few decades, either.  I
     presume that reefs in Florida that are now sponge-dominated instead of
     being coral-dominated are not accumulating more calcium deposits, likely
     they are loosing more than gaining, bioerosion likely is greater than
     calcification (unless there are algae calcifying faster than the
     bioerosion).  But I'm not as worried about the geological structure as the
     ecosystem, in the relatively short term (decades).
          I have sympathy for Mike Risk's view of the need for something
     besides just ecologists, studying reefs.  I tend to think that with the
     vast expansion of knowledge, individuals have to specialize.  I read
     somewhere that about 1800 papers on coral reefs are being published each
     year now and the rate is increasing fast.  No one can keep up with all of
     it, and time spent outside of your specialty means less time to gain the
     knowledge to be a competitive expert in your specialty.  So trying to be a
     generalist is pretty self-defeating.  The answer is to have teams of
     with different specialties, because as Mike rightly points out, coral
     are very complex structures with many different things that require
     different specialists to study, and many reef aspects need people in
     several different specialists to study.  We already need statisticians on
     our teams.  I agree ecologists probably need to work with geologists in
     their teams more often.  I think ecologists need to consult with
     taxonomists about identifications of their favorite organisms more often,
     and geneticists need taxonomists on their teams.
          But I also think that the coral reef crisis is an ecological crisis,
     not really a geological crisis.  Oh, it will be in a few thousand years if
     we keep this up.  But we are loosing coral reef ecosystems even if we
     aren't loosing geological structures yet.  Both provide benefits for
     humans.  But the scientific community is pretty nimble at shifting towards
     the exciting parts of science, and a lot of people see the coral reef
     crisis as important and so makes for exciting science.  Easier to get
     funding on things important to society, so some of us shift to work on
     those things.  Not a bad thing.
          But I think you're right, Vassil, to be accurate, in some places,
     what was a coral reef ecosystem is now a sponge-algal ecosystem on top of
     dead coral reef.  Or something like that, I'm not sure what the best name
     is.  Likely people will continue to call them "coral reefs" because that
     a catchy name that we are all familiar with.  There is one on the south
     side of Molokai Island in Hawaii which had a wide reef flat, a reef made
     calcium carbonate.  The geological structure of carbonate is still there,
     but the reef flat is almost completely covered with mud that has eroded
     of agricultural fields on land.  A few tiny corals poke up through the
     mud.  I saw similar along the east side of Lanai Island in Hawaii a couple
     decades ago.  What should we call that?  Certainly that reef flat does not
     have a coral reef ecosystem.  Mud ecosystem on top of a dead coral reef is
     more like it.
        In truth, many of the ecosystems we call coral reef ecosystems are not
     actually dominated by corals.  Corals are an important component, but not
     dominant.  True even on many reefs with very little human influence.  Of
     course humans have caused massive losses of corals on many or most of the
     world's reefs.  Of course that's bad.
        By the way, I LIKE sponges!  Caribbean sponges are large, colorful, and
     their biology is very different and interesting.  Where I'm at in the
     Pacific, sponges are small, uncommon, and cryptic.  Nothing like the
     glorious sponges of the Caribbean.  They are not completely incompatible
     with corals.  Cozumel used to have good coral on top of the reefs, and
     fabulous sponge communities on overhangs.  Spectacular.  Wonderful part of
     the ecosystem.
         Cheers,  Doug
     On   Wed,   Sep   2,   2015   at   12:19   AM,   Vassil   Zlatarski
     <[2]vzlatarski at gmail.com>

     Well, Joseph, in such case the usage of “coral reefs” should be precised,
     for example, "coral-limestone reefs" or “dead-coral reefs” or
     “not-living-coral reefs” or in other appropriate way.
     Vassil Zlatarski
     D.Sc. (Biology), Ph.D. (Geology)
     ---------- Forwarded message ----------
     From: Pawlik, Joseph <[3]pawlikj at uncw.edu>
     Date: Wed, Sep 2, 2015 at 5:31 AM
     Subject: RE: [Coral-List] Giant barrel sponges taking over Florida's
     To: Vassil Zlatarski <[4]vzlatarski at gmail.com>
     Agreed, Vassil,
     But the reef was built by coral (it's limestone) -- they just aren't
     building it anymore!
     Joseph R. Pawlik, Professor
     Department of Biology and Marine Biology
     UNCW Center for Marine Science
     5600 Marvin K Moss Lane
     Wilmington, NC  28409   USA
     [5]pawlikj at uncw.edu; Office:(910)962-2377; Cell:(910)232-3579
     Website: [6]http://people.uncw.edu/pawlikj/index.html<
     PDFs: [8]http://people.uncw.edu/pawlikj/pubs2.html<
     From: Vassil Zlatarski [[10]vzlatarski at gmail.com]
     Sent: Wednesday, September 02, 2015 4:25 AM
     To: Coral-List Subscribers; Pawlik, Joseph
     Subject: Re: [Coral-List] Giant barrel sponges taking over Florida's
     Dear Coral-Listers,
     Prof. Pawlik offered interesting paper “Population dynamics of giant
     sponges on Florida coral reefs” and video adding to the growing evidence
     that reef-building corals are declining and sponges are becoming the
     dominant inhabitants of modern Caribbean benthic communities.  For the
     fortunate researchers of coral reefs 4-5 decades ago is strange the usage
     of “coral reefs” for the documented now-existing situation.  Is it not in
     reality a case of “sponge gardens”?
     Vassil N. Zlatarski
     D.Sc. (Biology), Ph.D. (Geology)
     On    Tue,    Sep   1,   2015   at   10:45   AM,   Pawlik,   Joseph
     <[11]pawlikj at uncw.edu<mailto:
     [12]pawlikj at uncw.edu>> wrote:
     Greetings, Colleagues,
     In a 12-year study just published in the Journal of Experimental Marine
     Biology and Ecology, we report that populations of giant barrel sponges
     have increased by 122% since 2000 on Conch Reef, off the coast of Key
     Largo,  Florida. This adds to the growing evidence that sponges are
     the dominant inhabitants of modern Caribbean reefs.  The article can be
     downloaded for free:
     Giant barrel sponges (Xestospongia muta) are found throughout the
     Caribbean, and commonly grow to the size of an oil drum or larger. Called
     the "redwoods of the reef," these sponges can live to be hundreds, even
     thousands of years old, based on earlier growth studies conducted by the
     same first author, Dr. Steven McMurray.
     A video tour of the plots on Conch Reef can be seen here:
     You can see how large these sponges get in this video from the Bahamas:
     Not only are the numbers of giant barrel sponges increasing, so is their
     volume, with a 39% increase since 2000. On average, each square meter of
     Conch Reef now has about 2 liters of barrel sponge tissue on its surface,
     more than any other organism on the reef.  And the giant barrel sponge is
     only one of many species of sponges that populate Caribbean coral reefs.
     Much of the increase in the numbers of giant barrel sponges was due to
     recruitment - the successful establishment of baby sponges. On some plots,
     the increase in the smallest-sized barrel sponges was over 600% for the
     period 2000-2012. And while the survival of larger barrel sponges was
     stable for the first half of this period, it increased during the second
     half, perhaps because of the absence of hurricanes over that time period.
     When hurricanes pass over reefs, large sponges can be damaged and
     dislodged, often resulting in mortality.
     Joseph R. Pawlik, Professor,
     Dept. of Biology and Marine Biology
     UNCW Center for Marine Science
     5600 Marvin K Moss Lane
     Wilmington, NC  28409
     Office:(910)962-2377<tel:%28910%29962-2377>; Cell:(910)232-3579
     Website: http://people.uncw.edu/pawlikj/index.html
     PDFs: http://people.uncw.edu/pawlikj/pubs2.html
     Video Channel: https://www.youtube.com/user/skndiver011
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     Coral-List at coral.aoml.noaa.gov

     Douglas Fenner
     Contractor with Ocean Associates, Inc.
     PO Box 7390
     Pago Pago, American Samoa 96799  USA
     phone 1 684 622-7084
     Join the International Society for Reef Studies.  Membership includes a
     subscription to the journal Coral Reefs, there are discounts for pdf
     subscriptions and developing countries.  [14]www.fit.edu/isrs/
     "Belief in climate change is optional, participation is not."- Jim Beever.
      "Everyone is entitled to their own opinion, but not to their own facts."-
     Daniel Patrick Moynihan.
     Energy policy: push renewables to spur carbon pricing.  (the world
     subsidizes fossil fuels a half Trillion dollars a year!)
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     website:  http://independent.academia.edu/DouglasFenner
     blog: http://ocean.si.edu/blog/reefs-american-samoa-story-hope
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   Risk, Michael
   [16]riskmj at mcmaster.ca


   1. mailto:douglasfennertassi at gmail.com
   2. mailto:vzlatarski at gmail.com
   3. mailto:pawlikj at uncw.edu
   4. mailto:vzlatarski at gmail.com
   5. mailto:pawlikj at uncw.edu
   6. http://people.uncw.edu/pawlikj/index.html
   7. https://mail.uncw.edu/owa/UrlBlockedError.aspx
   8. http://people.uncw.edu/pawlikj/pubs2.html
   9. https://mail.uncw.edu/owa/UrlBlockedError.aspx
  10. mailto:vzlatarski at gmail.com
  11. mailto:pawlikj at uncw.edu
  12. mailto:pawlikj at uncw.edu
  13. http://authors.elsevier.com/a/1RcjD51aUK0hE
  14. http://www.fit.edu/isrs/
  15. http://www.nature.com/nature/journal/v525/n7567/full/nature14876..html?WT.ec_id=NATURE-20150904&spMailingID=49465812&spUserID=MjA1NTA3MjA0OQS2&spJobID=760401953&spReportId=NzYwNDAxOTUzS0
  16. mailto:riskmj at mcmaster.ca

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