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The Effect of Shipping Activity on Growth of Lottia strigatella and Tegula funebralis (Maybe you
should also put the actual name along with the scientific name)
Alex Tran and Eric Haffner
Department of Biological Sciences
Saddleback College
Mission Viejo, CA 92692
The objective of our project was to see if the growth sizes of common tide pool animals,
such as limpets (Lottia strigatella) and turban snails (Tegula funebralis), could be affected
by human shipping activity based on competition for survival and the variances in the pH
and temperature of the water. On November 8, 2009, we measured 15 (spell out the name)
L. strigatella and T. funebralis from five different locations; starting in Long Beach harbor
then proceeding south in two miles intervals. Long Beach harbor was chosen for our
ground zero location because it was a hub of shipping activity. Traveling south, the
magnitude of activity decreased less and less. The organisms were measured length wise,
with a 12-inch ruler, on their ventral side. The lengths of (spell out the name) L. strigatella
increased and that of T. funebralis decreased as the distance from the harbor increased.
These trends were believed to be a result of the variances of competition; which were
believed to be caused by fluctuations in water pH and temperature of each location.
Introduction
This project seeks to establish a correlation between proximity to human shipping activity
and growth of tidal invertebrates, particularly L. strigatella and T. funebralis. Both species are
widespread throughout the southern California area; not only are they first-tier herbivores which
help serve as the basis of the tidal food chain, but both are important consumers of red and green
algae. Given the biological significance of these two organisms, it is important to know how they
are affected by varying levels of human activity. It has been shown that small concentrations of
metals in the water affect L. strigatella in a devastating manner (Marchan et al 1999). Variations
of factors in the water can cause fluctuations in population density, which cause ripple effects
throughout the food chain. Due to the dependence the organisms’ respective food sources have
on good water quality, we hypothesized a positive correlation between mean size and distance
from our initial location (which has the most contaminated water).
Materials and Methods
Tide pool Organisms and Locations (I don’t think you need this)
Studies were done on limpets (Lottia strigatella) and turban snails (Tegula funebralis)
at five different locations; starting in Long Beach, California, harbor then proceeding south in
two mile intervals. Long Beach harbor (latitude 33° 49' N, longitude 118° 9' W) was the first
stop and ground zero for our research since it was a hub of shipping activity. In addition, this
location was right next to the ARCO loading dock and a container ship off loading site. Fifteen
L. strigatella and T. funebralis were examined at each particular location. The second location
was at the intersection of Appian and Ravenna (latitude 33° 45' N, longitude 118° 7' W) and was
in a residential area. Our third location was at a jetty near a public beach at the intersection of 1st
Street and Ocean Avenue (latitude 33° 44' N, longitude 118° 6' W). The fourth stop was at a pier
next to 1580 Seal Way in Seal Beach, California (latitude 33° 44' N, longitude 118° 6' W). Our
fifth and final stop was at the tide pools of Crescent Bay in Laguna Beach (latitude 33° 32' N,
longitude 117° 48' W) and (intead of and maybe use which) was our control group. Traveling
south, the magnitude of shipping activity decreased.
Measurements (I don’t think you need this)
The measurement device favored for our research was a 12-inch ruler. On November 8,
2009, we measured 15 L. strigatella and T. funebralis near tide pools or rocks. At each location,
the 15 organisms were carefully extracted and measured, in centimeters, on their ventral side.
We made sure that we obtained accurate data and results by going to the tide pools
approximately around noon, so there wouldn’t (change to would not) be high tide. Our results
were compared running an Analysis of Variance (ANOVA) test, and a significant difference was
taken into account if the probability value was less than or equal to 0.05 (p≤ 0.05). If there was a
significant difference, a Post-Hoc analysis test would have to be run.
Results
The measurements of T. funebralis were first taken at Long Beach Harbor and then at
four other locations as we proceeded south in two mile intervals. The sizes of T. funebralis
significantly decreased as the distance from Long Beach increased (Figure 1).
Figure 1. Bar graph displaying the mean length, in centimeters, of turban snails. The size of the
snails significantly decreased as the distance from Long Beach increased. Error bars represent ±
standard error for each location spot. (p= 0.0001, N=13) ( You said that you guys got 15 samples
not 13)
The measurements of L. strigatella were also taken at Long Beach first and then at the other
locations as stated earlier. Lengths of L. strigatella generally increased as the distance from Long
Beach increased (Figure 2).
Figure 2. Bar graph displaying mean length, in centimeters, of limpets. The size of the limpets
increased as the distance from Long Beach increased . Error bars represent ± standard error for
each location spot. (p= 0.0001, N= 12) ( You said that you got 15 samples not 12)
After running the ANOVA test, a post-hoc analysis had to be run because of the significant
difference; f-value and p-value for both T. funebralis and L. strigatella were greater than one and
less than or equal to 0.05 (Tables 1 and 2). These tables are not necessary – delete them or The
will have a field day deducting points because you were not listening when he was bashing those
that put tables in their papers for no good reason. What do the t-values tell you?
Comparison
Significant? (P <0.05?)
t
1: Snails-Long Beach/Loc. 2
Yes
5.627
2: Snails-Long Beach/Loc. 3
Yes
8.842
3: Snails-Long Beach/Loc. 4
Yes
11.474
4: Snails-Long Beach/Loc. 5
No
2.311
Table 1. Table showing the statistical significance of turban snails. Shows if the inputted data are
significant for each comparison between Long Beach and the other locations. t-values are
included.
Comparison
Significant? (P <0.05?)
t
1: Limpets-Long Beach/Loc. 2
Yes
5.309
2: Limpets-Long Beach/Loc. 3
Yes
7.026
3: Limpets-Long Beach/Loc. 4
Yes
9.918
4: Limpets-Long Beach/Loc. 5
Yes
5.761
Table 2. Table showing the statistical significance of limpets. Shows if the inputted data are
significant for each comparison between Long Beach and the other locations. t-values are
included.
Our results indicate there was a definite (positive sounds better) correlation between shipping
activity and the growth of tide pool organisms.
Discussion (Have the paper in the same type of font)
The collected data did not conform to all of our initial expectations. We hypothesized a positive
correlation between distance from the initial location, in the middle of Long Beach harbor, and organism
size for both T. funebralis and L. strigatella.
For L. strigatella, the correlation we hypothesized was shown to be supported by the data. The
smallest mean shell sizes were found at the initial location, with successively larger specimens being
found at increased distances down the coast. We were able to establish statistical significance for the
difference between mean sizes at the first location and size at all other locations, although this was not
the case for successive locations. This correlation, in particular the results of the first location, can be
attributed to several factors. Although L. strigatella possesses some locomotion abilities, it is primarily a
stationary organism, retreating back to a “home scar” (Cook et all 1969). Ideally, the home scar is
located such that the limpet is in near constant contact with water. However, in a polluted region (as
was encountered in location 1), this ensures that the limpet is also in constant contact with any
hazardous agents in the water. Whereas snails can move in accordance with the tides, limpet
locomotion is restricted, ensuring that the limpet is either drying out in the sun, or saturated with
pollutants. This accounts for the lack of growth at location one and to a lesser extent location two. Also,
it has been demonstrated that limpets are particularly susceptible to heavy metals in the water
(Marchan et all 1999); bradycardia results from copper concentrations of 0.1g/L after one day and death
follows a few days later. In areas of heavy pollution such as location one(where was location one), this is
not unreasonable. As the water quality increases, L. strigatella does receive any penalty for being in
constant contact with the water. L. strigatella is also well suited to dealing with the increased
competition at these sites; limpets are territorial and are known to physically ram organisms out of their
designated patch (Shanks 2002). This plays a large factor in the success of L. strigatella in areas of good
water quality and high competition, found at locations 3 and beyond.
Although our expectations for L. strigatella were confirmed, we were surprised to find that T.
funebralis showed a negative correlation between size and distance, meaning the average specimen size
was largest at our initial location. We found significant differences in mean shell size between the initial
location and all four successive collection sites, and also found significant differences in size between all
successive sites ( two compared to three, three compared to four, etc), meaning that the unknown
agent responsible for the difference in sizes continued to be a factor all the way down the coast. A
number of factors may be responsible. Watanabe (1984) asserts that the highest amount of T. funebralis
predation occurs in deeper waters along the substrate bottom, with its main predators being fish and
benthic invertebrates (most notably sea-stars). At our initial site in Long Beach harbor, the water quality
could be considered noxious at best, with a noticeable oil-slick and poor light transmission qualities
caused by visible amounts of inorganic debris. Because such conditions play ill host to fish and sea-stars,
a possibility is that the proclivity of T. funebralis for this location is due to the low amounts of predation.
These conditions were replicated in less extreme fashion at location two, with water clearing up
markedly at locations three and beyond. These cleaner environs prove less hostile to T. funebralis’
predators, which may be responsible for increased predation and thus the demonstrated smaller
organism size. Similarly, toxic environments may give T. funebralis an advantage with regards to spatial
competition. As ideal vertical location with regards to the tides is a key factor in growth (Vermeij 1972),
the ability to contest the patches of tidal real estate with the correct exposure to sun, water and
nutrients becomes important, particularly for the algae-feeding snails. Because turban snails do not
attach as strongly to their substrate as mussels or limpets, they become increasingly uncompetitive as
the amount of competition for space increases (Shanks 2002). This accounts for the lower survivability
and thus smaller sizes in locations 3-5, where the cleaner water results in higher competition. However,
in areas of low nutrient availability and low competition (locations 1 and 2), T. funebralis’ mobility
becomes an advantage, allowing the turban snails to forage greater areas in search of food.
Acknowledgements
We would like to thank Professor Steve Teh for his help and wise counsel in our project.
The researchers would also like to thank Saddleback College and the Department of Biological
Sciences for allowing us to borrow equipment needed to conduct our research. The lifeguards of
Long Beach and Laguna Beach should also be acknowledged for their aid in our research.
Literature Cited
Cook, A., Bamford, O. S., Freeman, J. D., & Teideman, D. D. (1969). A Study of the Homing
Habit of the Limpet. [Electronic version]. Animal Behaviour, 17(2), 330. doi:10.1016/00033472(69)90019-0.
Marchan, S., Davies, M. S., Fleming, S., & Jones, H. D. (1999). Effects of copper and zinc on
the heart rateof the limpet Patella vulgata L. [Electronic version]. Comparative Biochemistry and
Physiology - Part A: Molecular & Integrative Physiology, 123(1), 89-93. doi:10.1016/S10956433(99)00043-4.
Steen, R.G., & Muscatine, L. (1987). Low Temperature Evokes Rapid Exocytosis of
Symbiotic Algae by a Sea Anenome [Electronic version]. Marine Biological Laboratory, 172:
246-263.
Verde, A.E., McCloskey, L.R. (2007). Seasonal effects of natural light and temperature on
photosynthesis and respiration. Development 2006 September. Marine Biology, 152: 775–792.
Watanabe, J. M. (1984). The Influence of Recruitment, Competition, and Benthic Predation on
Spatial Distributions of Three Species of Kelp Forest Gastropods. [Electronic version]. Ecology,
65(3), 920-936. <http://www.jstor.org/stable/1938065?cookieSet=1>.
Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s):_Alex Tran and Eric Haffner____________________
Title :The Effect of Shipping Activity on Growth of Lottia strigatella and Tegula funebralis
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
This paper was to see the correlation between human shipping activity and growth of tidal
invertebrates. They wanted to see if the location of human shipping activity would affect the size of tide
pool animals. The results showed that the size of the limpets increased and the size of the turban snails
decreased as the distance from the harbor increased.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our current
state of knowledge.
There discussion was very good, however I think they should add more to the introduction section. They
had great scholarly sources in the discussion and there paper flowed. Before turning in the paper they
should have looked at the font and seen that the paper is in two different types of font. Maybe at the
end of the discussion they should have a better closing sentence.
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
This paper was a rough draft. For a rough draft it is very good, they just need to go back and fix
some errors. Everything was in the correct tense and the organization was good. For the paper
to be more clearer I think throughout the discussion it is best to use the actual name instead of
the scientific because I continuously had to go back up to the materials and method to see what
each scientific word was.