Response to Dr. Amoz

[James M. Cervino]

Dear Maoz,

Bacterial infection alone cannot account for the spatial or temporal
pattern of these mass bleaching events.  They have always been correlated
with HIGH sea surface temps. I have also seen, in vitro and in situ, corals
expel there symbioant ( zoox.) under temperature decrease.Steen and
Muscatine published a paper regarding "low temperature evokes rapid
exocytosis of symbiotic algae by sea anemone" 1987 in the Biological
Bulletin 172,246-263.

We have seen in countless lab experiments exposing corals to temp increase
and decrease, causing the corals expel the symbioant. Under high
temperature stress the mitotic division rate speeds up as the temperature
rises, and the host starts to expel there symbioant. There seems to be a
host influence on division rates of the cnidarian,  Len Muscatine has shown
us this during a lab experiments in Woods Hole a couple of years ago. He
and colleagues have published a few papers regarding this physiological
response:  One example, Suharsono & BE Brown, J.Exp. Mar. Biol. Ecol., 158
(1992) 179-188.

Coral Reef Bleaching episodes between 1983 & 1991 followed positive
anomalies more than 1C above long term monthly averages "(hot spots)"
during the proceeding warm season  (Goreau, Hayes Ambio Vol. 23 no.3 May
94). Al Strong of NOAA has been watching SST closely. He is comparing the
rise above the norm for that region with EARLY SIGNS of bleaching in the
tropics.

We are seeing more and more bleaching events in the past 2 decades, this is
lowering the metabolic activity (DEFENSES!) of the corals. Areas that are
under stress from pollution, sewage (excess nutrients leading to
eutrophication) and sedimentation, will exhibit longer if no recovery rates
at all.

Deforestation causing the uplifting of the soil is unleashing a wide
variety of microbial communities into the oceans, from rivers.
Aspergillosis is a soil based fungi found in the soil in South American
rain forests, could it be that the microbial loads coming from land are
increasing at such high concentrations be responsible for wide scale
bleaching events? It is possible that  this can be linked to the seafan
mortality, and inducing other coral diseases,  but bleaching??


Yes if there is a high microbial population in the water during the time of
mass bleaching events, the mucus from the corals will be utilized as a food
source by bacteria or fungi. High numbers of gram negs (-) can become
pathogenic, especially if the metabolic activity of the corals is lowered
by stressful conditions like high temps. One of the triggering mechanisms
for zoox. expulsion are the result of: a reduced supply of nutrients
available to the algae from the stressed coral host (Muscatine,
1971;decreased space availability caused by atrophied host tissues, and
secretion of substances by the coral host that produce a hostile
environment around the algae (Jaap, W.C. 1979 Bull. Mar. Sci. 29:414-422.
Could the Vibro AK1 that was identified in that paper increase mitosis thus
causing expulsion as in increased temperature stress during bleaching
events? Reading the paper published in Nature makes no mention, or
comparison of division rates of the zooxanthellae observed in Oculina
patagonica. Vibrios will utilize the mucus that is produced as a definite
nutrient source during increased seas surface temperatures, however, the
responsibility for MASS BLEACHING??

The recovery rates of corals in areas where there is minimal stress from
anthropogenic sources are higher, much higher. After the 95 bleaching event
that hit New Britain (PNG), the corals were in full recovery 8 to 9 months
after the bleaching event. Kimbe Bay is under minimal stress from man.  Has
anyone published a paper comparing undisturbed areas to disturbed?

Good Luck with the experiments!


*******************************
James M. Cervino
Marine Biologist
Global Coral Reef Alliance
124-19 9th ave. College Point
New York, NY 11356
Phone/Fax (718) 539-8155
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