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THE
EFFECTS OF TEMPERATURE AND UV ON THE BIOMASS PARAMETERS OF AIPTASIA
PALLIDA
AND ITS SYMBIOTIC ALGAE
By Jason Berger and Troy Markus
under the advisement of Gisele Muller-Parker
Western Washington University, Shannon
Point Marine Center, SEARUN Program
INTRODUCTION
Anemone biomass
parameters include: total protein content of the anemone over time, algal
density, and the percentage of algae expelled by the anemone. Zooxanthellae
biomass parameters include: cell size and mitotic index (the percent of
algae in the process of dividing).
Algal density
and percent expulsion are the parameters used to assess if “bleaching”
(loss of zooxanthellae) took place during the course of the experiment.
Protein content of the anemone over time was used to gain insight of any
treatment effects on the anemone (animal partner of the symbiosis).
Mitotic index and cell size were used to appraise the overall health of
the algae.
METHODS
Protein content
was measured by the method of Lowery et. al. (1951).
Bovine serum albumin was used as the standard. Algal densities, percent
expulsion, and mitotic index were determined by cell counts using a hemacytometer.
Image analysis equipment was used to determine cell size.
RESULTS
-
Anemones exposed to high temperature
alone did not change protein biomass. Those exposed to UV as well
as anemones placed into recovery (27 °C) decreased in protein biomass
over time (Figure 1).
-
Algal density declined with high temperature
and UV only after 96hrs. At 27 °C, algal density in recovery
anemones increased in both –UV and +UV treatments (Figure
2).
-
Higher expulsion rates of zooxanthellae
were obtained with anemones in the +UV treatment. A decline in expulsion
of zooxanthellae took place with anemones exposed to high temperature alone
(Figure 3).
-
In both UV and high temperature treatments,
expelled algae had a larger volume compared to algae retained by the animal.
Algae which experienced UV and were placed into recovery conditions continued
to increase in volume over time (Figure
4).
-
Mitotic index of the algae was uniform
between UV treatments and between EZ and AZ samples (Figure
5) indicating that growth of zooxanthellae did not vary among the experimental
treatments.
SUMMARY
Bleaching of
the anemones was not observed during our experiments. Adverse effects
from UV exposure were obtained. Anemones in the +UV treatment decreased
in biomass and expelled more algae the longer they were in the presence
of UV light. The increased cell size of the expelled zooxanthellae
suggests these algae differ from those remaining within the anemone host.
Either the anemone selectively expels larger cells or the algae undergo
changes in size after they leave the anemone. Our work will continue
to focus on comparisons of these two populations of symbiotic algae.
ACKNOWLEDGMENTS
The authors
would like to thank the National Science Foundation (grant DBI-9711075)
for funding, PIs Gisele Muller-Parker, Suzanne Strom, and Jack Hardy,
the staff at Shannon Point Marine Center, Gabrielle Mowlds, David Leaf,
and Clay Cook for providing us with anemones.
REFERENCES
Lowery, O.H., N.J. Rosebrough, H.L.
Farr, and R.J. Randell. 1951. Protein measurement with the Folin phenol
reagent. Jour. Biol. Chem. 193: 265-275.
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