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

Vassil Zlatarski vzlatarski at gmail.com
Wed Sep 2 07:19:59 EDT 2015

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 <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 <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
pawlikj at uncw.edu; Office:(910)962-2377; Cell:(910)232-3579
Website: http://people.uncw.edu/pawlikj/index.html<
PDFs: http://people.uncw.edu/pawlikj/pubs2.html<

From: Vassil Zlatarski [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”?



Vassil N. Zlatarski
D.Sc. (Biology), Ph.D. (Geology)

On Tue, Sep 1, 2015 at 10:45 AM, Pawlik, Joseph <pawlikj at uncw.edu<mailto:
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:


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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