[Coral-List] Coral feeding

[Andréa Grottoli]

Dear Coral-listers:

There has been quite a bit of discussion about 
what corals eat, how much they eat, and what some 
of the downstream effects of feeding are.  I 
would like to point you to a few publications 
from my group involving corals studied in situ on 
the reef.  We have found that coral feeding rate 
varies among species, with depth, with 
zooplankton abundance, and with 
bleaching.  However, what they eat is always the 
same.  We have also found that of all six species 
of corals we have examined, at all depths and 
health status, that they all eat zooplankton 
predominantly in the 200-400 micron size class, 
and that their diet consists primarily of crab 
zoea, amphipods, and isopods or shrimp (corals 
studied include: Montipora capitata in Hawaii, 
Porites compressa in Hawaii, Porites lobata in 
Hawaii, Pavona clavus in the Gulf of Panama, and 
Pavona gigantea in the Gulf of Panama, and 
Pocillopora damicornis in the Gulf of 
Panama).  Other work by Ken Sebens group has 
shown the effect of flow on feeding and that 
tentacle structure affects zooplankton capture 
capability.  Others have also shown that bacteria 
and/or particles can make up a measurable amount 
of fixed carbon in the diet.  In addition, my 
group has natural abundance isotopic evidence 
that both photosynthetically and 
heterotrophically acquired fixed carbon is 
incorporated into the coral (this is from a 
combination of field and tank studies).  Our 
research strongly supports the idea that corals 
are both photoautotrophic and 
heterotrophic.  What is emerging however, is that 
the relative proportion of fixed carbon acquired 
via one mechanism or the other, varies among 
species, and with bleaching vs. healthy 
status.  In other words, there is no single 
formula that would apply to all corals, but 
rather a several alternative photo vs hetero 
combinations that can vary with bleaching.  I 
have included a list of references here for those who might be interested.

Sincerely,
Andrea Grottoli

Published papers;
1- Grottoli AG, Rodrigues LJ, Palardy JE. (2006) 
Heterotrophic Plasticity and Resilience in 
Bleached Corals.  Nature 440: 1186-1189 doi:10.1038/nature04565
2- Palardy JE, Grottoli AG, Matthews KA. (2006) 
Effect of naturally changing zooplankton 
concentrations on feeding rates of two coral 
species in the Eastern Pacific. Journal of 
Experimental Marine Biology and Ecology, 331(1):99-107
3- Palardy JE, Grottoli AG, Matthews K (2005) The 
effect of temperature, depth, morphology, and 
polyp size on feeding in three species of 
Panamanian corals.  Marine Ecology Progress Series 300:79-89
4- Rodrigues LJ, Grottoli AG (in press) 
Calcification rate and the stable carbon, oxygen, 
and nitrogen isotopes in the skeleton, host 
tissue, and zooxanthellae of bleached and 
recovering Hawaiian corals. Geochimica et 
CosmochimicaGrottoli AG, Rodrigues LJ, Juarez C 
(2004) Lipids and stable carbon isotopes in two 
species of Hawaiian corals, Porites compressa and 
Montipora verrucosa, following a bleaching event.  Marine Biology 145: 621-631
5- Grottoli AG (2002) Effect of light and brine 
shrimp levels on the skeletal d13C values of the 
Hawaiian coral Porites compressa: a tank 
experiment. Geochimica et Cosmochimica Acta  66: 1955-1967
6- Grottoli AG (1999) Variability in stable 
isotopes and maximum linear skeletal extension in 
reef corals in Kaneohe Bay, Hawaii. Marine Biology 135:437-449
7- Grottoli AG, Wellington GM (1999) Effects of 
light and zooplankton on skeletal d13C values in 
the Eastern Pacific corals Pavona clavus and P. gigantea. Coral Reefs 18:29-41

other related papers in preps include:
1- Palardy, JE, Rodrigues, LJ, Grottoli, AG. (in 
prep) Feeding behavior changes with the loss of 
facilitative interactions on coral reefs.
2- Rodrigues LJ, Grottoli AG (in prep) Energy 
reserves and metabolism in bleached and 
recovering Porites compressa and Montipora capitata corals from Hawaii.
3- Rodrigues LJ, Grottoli AG, Lesser MP (in prep) 
Long-term changes in the chlorophyll fluorescence 
of bleached and recovering corals from Hawaii.


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Andréa G. Grottoli, Assistant Professor
Ohio State University
Department of Geological Sciences
125 South Oval Mall
Columbus, OH 43210-1398
office:  614-292-5782
lab: 614-292-7415
fax: 614-292-7688
email: grottoli.1 at osu.edu
web: www.geology.ohio-state.edu/~grottoli
Office location: 329 Mendenhall Labs

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