Relationship Between Amounts of Zooxanthellae and
Intertidal Zone Distribution in Anthopleura
xanthogrammica
Bi 3B
Patricia Seabourne
Department of Biological Sciences
Saddleback College
Mission Viejo, California 92692
Patricia Seabourne
Introduction
Zooxanthellae are photosynthetic algae that inhabit the endodermal tissues of their
hosts (Weiss 10996). Anthopleura xanthogrammica is common in the lower and middle
intertidal zones in the west coast of North America, and it forms symbiotic relationships
with photosynthetic algae. The color of the algae makes the anemone brownish grenn
green. Anemones with Zooxanthellae can be found throughout the intertidal zone, but
favor the upper levels (Bates, 2000; second et al. 2000). Bates explains that high-shore
individuals of A. xanthogrammica tend to have predominantly Zooxanthellae and are
brownish-green in color. Zooxanthellae favours favors higher temperatures and higher
light conditions.
In order to determine the relationships between amounts of
Zooxanthellae present and intertidal zone distribution, I developed the hypothesis that A.
xanthogrammica living in the middle intertidal zone, contain higher amounts of
Zooxanthellae.
Methods
Six tentacles were collected at Aliso Creek Beach, Laguna Beach, California, and
six tentacles were collected at Woods Cove, Palos Verdes, California. I wane to Aliso
Creek Beach during the lowest tide (Lowest tide=1.2) and started collecting tentacles at
the lowest point of the intertidal zone. I walked toward the bottom of the lower zone,
found an animal. And cut a tentacle. . Then, I continued walking until I found another
animal and I cut another tentacle. It was difficult to cut tentacles from anemones that
were contracted, thus I avoided those. I also avoided anemones I found in crevices, and
under rocks. I continued walking the lower intertidal zone until I collected six tentacles
from six different A. xanthogrammica. Then, I moved to the middle zone and I began
collecting six tentacles in the same manner. Collection at the Palos Verdes location was
carried in the same way with a low tide of -0.6. I placed the samples in plastic containers
and immediately froze them. Tips of A. xanthogrammica were used for analysis. All
tentacles were cut into the same volune volume (0.2 grams), placed in an Eppendorf tube
and dipped in a 15 ul µL of distilled water. The tentacles mixture was homogenized
using a glass rod, and the density was calculated. The mixture was placed in an
hemacytometer under a light microscope.
The number of Zooxanthellae was were
counted in eight squares. Then, the cell concentration was calculated by dividing the
average cells in the eight squares by the volume of a square. The final Zooxanthellae
volume was calculated by dividing the obtained density musltiplied multiplied by the
initial value by the recommended cell density.
Results
Anemones with a higher concentration of Zooxanthellae were observed in the
higher intertidal zone, or middle zone, while the anemones with the lower concentration
of Zooxanthellae were observed in the lower intertidal zone.
8000
14000
7000
Lower Zone
5000
Series1
4000
Middle Zone
12000
6000
10000
8000
Series1
6000
3000
4000
2000
2000
1000
0
1
2
3
4
0
1
2
3
4
5
6
Amount of Zooxanthellae
Zooxanthellae Count
-
5
6
Figure 1. Amount of Zooxanthellae in Lower Intertidal Zone and Middle Intertidal Zone.
Correlation between amount of Zooxanthellae and tidal zone distribution was clear. The
mean amount of Zooxanthellae present in anemones from the middle intertidal zone was
higher. (Figure 1).
Discussion
The location in the intertidal zone seems to affect the number of Zooxanthellae
present in the anemone; the anemones with a higher number of Zooxanthellae seem to
prefer locations in the middle intertidal zone, and the anemones with lower numbers of
Zooxanthellae are more likely to be found in the lower intertidal zone. As Bates (2000)
mentioned, anemones with Zooxanthellae are usually found in the higher intertidal zones.
Higher numbers of Zooxanthellae are found in anemones further from the water ay and?
help anemones survive better. Also, anemones can always find a crevice or shaded area
where to hide. These shaded microhabitats may help the Zooxanthellae survive. While
collecting specimens of A. xanthogrammica, I only chose specimens exposed to the sun
and light, thus, my results indicate the amounts of Zooxanthellae found in anemones
which are exposed. If tentacles were collected from anemones found in shaded areas, the
results may differ. The amount of Zooxanthellae seems to be directly correlated to the
amount of Zooxanthellae present in the anemone. Figure 1 suggests that the standard
deviation and mean standard error is also lower for anemones found in the middle
intertidal zone. Figure 1 also indicates that middle zone anemones have the higher mean.
This result supports my hypothesis that anemones with higher concentrations of
Zooxanthellae are more likely to be found in higher intertidal zones. Even thought my
results support my hypothesis, some points should be mentioned. All the results are based
in on samples collected from anemones exposed to sunlight. If the tentacles would have
been collected from specimens living in shaded areas or crevices, the results might have
been different. Also, counting Zooxanthellae cells using an hemacytometer needs to be
done very precisely. Counting errors can alter the results significantly. There is still a lot
to learn about the relationship between tidal zone distribution and amounts of
Zooxanthellae.
Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s):__Patricia Seabourne
Title:_Relationship Between Amounts of Zooxanthellae and Intertidal Zone Distribution
in Anthopleura xanthogrammica
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
The author looked at the correlation between the amount of zooanthellae found in
tenacles of sea anemones living in the lower intertidal and middle intertidal zone. It was
hypothesized that the middle zone would have anemones with greater amounts of
zooanthellae when compared to the lower zone. The author stated that the mean number
was higher for the middle zone when compared with the lower zone. This could be due to
the zooanthellae helping the anemones to survive in this zone via a symbiotic
relationship. Apparently, zooanthellae also survive better in shaded areas but the author
only collected samples from light areas.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our
current state of knowledge.
The research idea is very interesting and the author has a descriptive method. It is a good
project idea there just needs to be more detail behind things. Statistics need to be run to
determine if there was a significant difference between the groups being compared. Say
more specifically if you are comparing middle to low. Explain the mechanism a little
more in detail about what zooanthellae actually do for the sea anenome and why you
hypothesize that the sea anenome would have more in the middle zone. Maybe discuss
more the importance as for how the sea anenome affects other species, and how this
research topic is relevant. Put the graph of middle zone and low zone together so they can
be compared. Cite more literature and put a literature cited section as well as an abstract
in the paper.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical
errors, and minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the
manuscript.
This paper was a final version
This paper was a rough draft
-Do not use first person
-Organize your thoughts better so it flows
-Spell check
-Some single sentences could be put together to make it less choppy
-Sometimes a point would be made and a few lines later the importance of that
point would be given. Maybe reorganize that?
-Clarify more throughout paper what you are discussing
-Check font size, single spaced, justify, and bold the title and abstract, italicize
figure caption
-Italicize genus and class in paper
Recommendation
 This paper should be published as is
 This paper should be published with revision
 This paper should not be published