[Coral-List] Giant barrel sponges taking over Florida's reefs!
Dennis Hubbard
dennis.hubbard at oberlin.edu
Tue Sep 8 15:28:03 EDT 2015
I agree with Mike which is why I discuss the question, "What is a reef?"
only with close friends.
Dennis
On Tue, Sep 8, 2015 at 2:05 PM, Risk, Michael <riskmj at mcmaster.ca> wrote:
>
> 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
> rat."
>
> 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
> biology.
>
> 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.
>
> Mike
>
> On Sep 4, 2015, at 4:46 PM, Douglas Fenner <[1]
> douglasfennertassi at gmail.com>
> wrote:
>
> Vassil,
> 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
> living
> 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
> people
> with different specialties, because as Mike rightly points out, coral
> reefs
> 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
> a
> 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
> is
> 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
> of
> calcium carbonate. The geological structure of carbonate is still
> there,
> but the reef flat is almost completely covered with mud that has
> eroded
> off
> 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>
> wrote:
>
> 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.
> Best,
> Vassil
> 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
> reefs!
> 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<
> [7]https://mail.uncw.edu/owa/UrlBlockedError.aspx>
> PDFs: [8]http://people.uncw.edu/pawlikj/pubs2.html<
> [9]https://mail.uncw.edu/owa/UrlBlockedError.aspx>
> **************************************************************
> ________________________________
> 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
> reefs!
> Dear Coral-Listers,
> Prof. Pawlik offered interesting paper “Population dynamics of giant
> barrel
> 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†?
> Cheers,
> Vassil
> 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
> becoming
> the dominant inhabitants of modern Caribbean reefs. The article can
> be
> downloaded for free:
> [13]http://authors.elsevier.com/a/1RcjD51aUK0hE
> 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:
> https://youtu.be/qdjhm7ojGJk
> You can see how large these sponges get in this video from the
> Bahamas:
> https://youtu.be/8WaWVuGE-LM
> 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.
> Regards,
> **************************************************************
> 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
> <tel:%28910%29232-3579>
> 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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> --
> 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/
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> [15]
> http://www.nature.com/nature/journal/v525/n7567/full/nature14876.html?
>
> WT.ec_id=NATURE-20150904&spMailingID=49465812&spUserID=MjA1NTA3MjA0OQS2&sp
> JobID=760401953&spReportId=NzYwNDAxOTUzS0
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> ear-record/
> 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
>
> References
>
> 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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--
Dennis Hubbard
Chair, Dept of Geology-Oberlin College Oberlin OH 44074
(440) 775-8346
* "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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