[Coral-List] Question concerning cold temps and coral stress.
James M. Cervino
cnidaria at earthlink.net
Wed Dec 7 08:31:25 EST 2005
Dear Melissa,
With regards to the differences between cold water coral bleaching
and thermal (expulsion) bleaching; yes they do loose their symbiotic
algae as a result of cold water stress. I have seen this in PNG along
a coral wall where deep water was being up-welling cool water
vertically for a week. The extreme cool water was brought to about 65
feet. At that point the temperatures increased and mixed with the
warmer surface water that was between 87-88F. We monitored the 70-65
feet depth range and watched the corals for that week as they were
getting the continual supply of cool 69-70F water. We noticed the
Pachyseris sp. (Tabular plate coral 12 feet wide) begin to bleach.
The algal mass was clustered around the oral disk well below the
tentacals and seemed to remain there for a few days. Eventually this
mass is slowly pushed out due to the cold shock. Where as, during
thermal expulsion the algal (zooxanthellar) mass is pushed out much
faster into the water column due to newer algae (zoox) continually
dividing within the gastroderm. This creates an over crowding
population of algae within the host and disrupts the steady state
symbiotic association between host animal and its resident symbioant.
The alga/zooxanthellae become forced out of the gastrodermal cavity
into the colenteron and then into the water column, hence "bleaching
the coral".
I also conducted this work in vitro with Len Muscatine during 1995
and then again during 2000 with Garriet Smith (with pathogens and
cool water trials). During the in vitro experiments we noticed that
the initial cold shock triggers the initial increase in division of
the algae and then sort of slows down compared to thermal shock where
division is constant until all the algae/zoox are vacant from the
gastroderm. Hence much more algal pellets were being expelled during
thermal shock compared to cold shock. Recovery was faster during
cold shock whereas during thermal stress 75% our testing corals died
and did not recover. All cold water treatments survived. Below are
my references. The observations in PNG were also positive whereas the
colonies of Pachyseris survived and fully recovered. Can anyone on
the list share similar observations in vitro and in situ?
Thanks
Steen, R.G., and L. Muscatine. 1987. Low temperature evokes rapid
exocytosis of symbiotic algae by a sea anemone. Biol. Bull.
172:246-263.
Gates RD, Baghdasarian G, Muscatine L (1992) Temperature stress
causes host cell detachment in symbiotic cnidarians: implications for
coral bleaching. Biol Bull Mar Biol Lab Woods Hole 182:324-332
Hoegh-Guldberg O, McCloskey LR, Muscatine L (1987) Expulsion of
zooxanthellae by symbiotic cnidarians from the Red Sea. Coral Reefs
5:201-204
Hoegh-Guldberg O, Smith GJ (1989) Influence of the population density
of zooxanthellae and supply of ammonium on the biomass and metabolic
characteristics of the reef corals Seriatopora hystrix and Stylophora
pistillata. Mar Ecol Prog Ser 57:173-186
Muscatine L, Pool RR (1979) Regulation of numbers of intracellular
algae. Proc R Soc Lond B 204:131-139
Titlyanov EA, Titlyanova TV, Leletkin VA, Tsukahara J, Van Woesik R,
Yamazato K (1996) Degradation of zooxanthellae and regulation of
their density in hermatypic corals. Mar Ecol Prog Ser 139:167-178
Trench RK (1979) The cell biology of plant-animal symbiosis. Ann Rev
Pl Physiol 30:485-532
>If we have a much colder than usual winter here in the Caribbean,
>how might the corals be affected? Do they stress and perhaps die
>as a result? Do they lose their Zooxanthellae as with excessive
>heat? Which corals are more sensitive to cold?
>
> Thanks in advance for any replies,
>
> Melissa Keyes
>
> independant coral reef monitoring project
>
> St. Croix, USVI
>
>
>
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--
**************************************************
Dr. James M. Cervino, MS, Ph.D.
Marine Pathology
Department of Biological & Health Sciences
Pace University New York NYC
Phone: (917) 620-5287
Web site: http://www.globalcoral.org
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