Information regarding feeding

[wade1]

This is a copy of an email from a researcher at OSU:

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.

 

[SnowManSnow]

interesting.

think he just sat down and made it all up?! haha

b

 

[Meloco14]

I posted an article a month or so ago that had similar findings. That particular article was stressing that the amount of feeding that corals do does vary with conditions. It was that author's opinion that corals can and do survive bleaching events by increasing their active feeding. This article seems to agree, which gives some hope for coral reef survival over this current warming trend. I find it interesting that according to this study these corals do not feed on phytoplankton at all.

 

[Unarce]

I remember an article I read several years ago that stated the same thing. The corals that had a greater ability to feed faired much better during bleaching events.