[Coral-List] New paper: Coral colonization by Cliona delitrix excavating sponge
Andia Chaves-Fonnegra
andiachaves at gmail.com
Fri May 20 11:10:52 EDT 2011
Dear Coral-list:
The following new paper has been recently printed:
Chaves-Fonnegra, A. y S. Zea. 2011. Coral colonization by the encrusting
excavating Caribbean sponge *Cliona delitrix*. Marine Ecology 32: 162-173.
If you want a pdf, contact me (andiachaves at gmail.com) or Dr. Sven Zea (
szea at invemar.org.co)
Abstract follows:
The Caribbean sponge *Cliona delitrix *is among the strongest reef space
competitors;
it is able to overpower entire coral heads by undermining coral polyps. It
has become abundant in reefs exposed to organic pollution, such as San
Andrés
Island, Colombia, SW Caribbean. Forty-four sponge-colonized coral colonies
were followed-up for 13 months to establish the circumstances and the speed
at which this sponge advances laterally into live coral tissue and the coral
tissue
retreats. *Cliona delitrix* presence and abundance was recorded at seven
stations
to interpret current reef space and coral species colonization trends. The
spread
of *C. delitrix* on a coral colony was preceded by a band of dead coral a
few
millimeters to several centimeters wide. However, the sponge was directly
responsible for coral death only when live coral tissue was within about 2
cm
distance; coral death became sponge advance-independent at greater
distances,
being indirectly dependent on other conditions that tend to accelerate its
retreat. *Cliona delitrix *advanced fastest into recently killed clean coral
calices;
however, sponge spread slowed down when these became colonized by algae.
The lateral advance of *C. delitrix* was slower than other *Cliona* spp.
encrusting
excavating sponges, probably owing to the greater depth of its excavation
into
the substratum. *Cliona delitrix* prefers elevated portions of massive
corals,
apparently settling on recently dead areas. It currently inhabits 6–9% of
colonies
in reefs bordering San Andrés. It was found more frequently in *Siderastrea
siderea* (the most abundant local massive coral), which is apparently more
susceptible to tissue mortality than other corals. Current massive coral
mortality
caused by *C. delitrix* could initially change the relative proportions of
coral
species and in the long-term favor foliose and branching corals.
--
Andia Chaves-Fonnegra
PhD. Candidate
NOVA Southeastern University
8000 North Ocean Drive
NSU Oceanographic Center
Dania Beach, Florida, 33004
USA
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