Download Simocephalus serrulatus

Lauren Howard, Madiha German, Panna Patel. Baylor University Waco, TX 76798
ABSTRACT:
This experiment was designed to observe the reproductive capacity of Simocephalus serrulatus under the presence of Escherichia coli. The method involved the creation of two different environments based off of the Lake Waco Wetlands. One of the
environments also contained a solution of E. coli in addition to the wetland water and the Simocephalus serrulatus. Daphnia are known to be major contributors to the wetlands because they provide information on the condition of stressors in the
environment (Escher Beate, 2011). With this in mind, this research aimed to discover if the reproduction capacity of Simocephalus serrulatus , a relative of Daphnia, could indicate an increased amount of Escherichia coli. The hypothesis is that the
increased presence of Escherichia coli in the water would subsequently increase the reproduction of the Simocephalus serrulatus. This preliminary study could give rise to further research on what specific amount of E. coli could possibly be
detrimental in correlation to a range of Simocephalus serrulatus reproduced. Based on the results of the experiment the conclusion is that there is no specific correlation between the E. coli and reproduction of the Simocephalus serrulatus.
Water was collected from Cell 2 in the Lake Waco Wetlands
(Figure 4), and filtered with 120 micron mesh to create a basis
for our environment. To prepare the Escherichia coli
experimental container, 25 mL of distilled water was used to
dilute the E. coli bacteria on the tryptone agar. Ten containers
were set up representing five separate trials for our control
and experimental group (without lids, for oxygen exchange). In
our 5 variable containers 941 mL of wetland water was added,
in addition to 5 mL of e-coli concentration. In the 5 control
containers, only 946 mL of wetland water was added (Figure
2). In each container, 10 Simocephalus serrulatus were placed
(Figure 3) and a 12/12 light cycle and room temperature were
maintained throughout the experiment. After each week, a
certain method was used to count the Simocephalus
serrulatus that had reproduced. The offspring were counted
and removed to prevent them from contributing to the next
weeks population count. Each week more filtered Lake Waco
Water was added and E. Coli population was reestablished.
Results:
Discussion and Conclusion:
Averaged Number of Simocephalus serrulatus
Offspring Reproduced over three weeks with and
without additional E. Coli
The analysis of our data representing the effect of E. Coli on the
reproductive capacity of Simocephalus serrulatus required taking
a series of summations and averages of all ten trials over three
weeks to produce the graphs shown in Figure 1. Each of the
graphs produced a 6.49% percent difference to demonstrate that
there was no significant variation between the reproduction of
Simocephalus serrulatus in the control and in the experimental
group. Due to the short span of the experiment and the use of a
cultured specimen that is not directly representative of the
population, the data cannot say conclusively that E. coli
negatively affects the reproduction of Simocephalus serrulatus.
With these errors, results of both graphs indicated that the
experimental group with the additional E. coli slightly benefited
from the increased presence of the bacteria. However the
standard deviation of the control group is higher because during
the second week, reproduction of Simocephalus serrulatus was
inconsistent with this trend and more offspring on average were
produced in the control groups. With the analysis of this data,it is
likely that an increase in the reproduction of Simocephalus
serrulatus can indicate an increased presence of E. Coli, however
it is impossible to say that conclusively given the margin of error.
Therefore we fail to reject the null hypothesis.
60
Offspring
50
13.01
4.58
40
Standard Deviation
30
20
40.3
43
Control
Experimental
Averaged Number of
Offspring
10
0
Total Number of Simocephalus
serrulatus Offspring
Methods and Materials:
Averaged Number of
Escherica coli is a bacteria found in the intestines of humans
and animals. While E. coli is normally harmless it can become
harmful if it contaminates human drinking water or food. The
EnPEC strain for example is capable of causing pelvic
inflammatory disease in women (Sheldon et al. 2010). The
Lake Waco Wetlands works to filter solutes and bacteria, such
as E. coli, from the North Bosque River into Lake Waco.
However, because Lake Waco is the city of Waco’s primary
drinking source as well as a recreational location for
swimmers, the efficiency of this process is important.
Because of the wetlands ‘connection, an increase in the E. coli
concentration of the Lake Waco Wetlands would be
correlated with an increase in the concentration of E. coli in
Lake Waco. The model organism Daphnia magna (a relative of
Simocephalus serrulatus) is sensitive to changes in the
environment and therefore is known for its use in
ecotoxilogical studies and also its reproductive capabilities
(Escher Beate, 2011). Daphnia has also be proven to eat E.
coli bacteria (Vrede Tobias, 2012). This research project with
Simocephalus serrulatus aims to shed light on the effects of E.
coli on the reproduction of Simocephalus serrulatus to be
used as in indicator of an increase amount of E. coli and a
warning to the city of Waco.
Simocephalus serrulatus
Introduction:
Total Number of Simocephalus serrulatus
Offspring reproduced over three weeks with and
without
additional
E.
Coli
140
130
13.01
4.58
120
Standard
Deviation
110
100
121
129
Total Number of
Offspring
90
80
Control
Experimental
Literature Cited:
Beate I. Escher, et al. "Acute Toxicity Of Organic Chemicals To
Gammarus Pulex Correlates With Sensitivity Of Daphnia
Magna Across Most Modes Of Action." Aquatic
Toxicology 103.1/2 (2011): 38-45. Academic Search
Complete. Web. 22 Apr. 2012.
Sheldon IM, Rycroft AN, Dogan B, Craven M, Bromfield JJ, et al.
(2010) Specific Strains ofEscherichia coli Are Pathogenic
for the Endometrium of Cattle and Cause Pelvic
Inflammatory Disease in Cattle and Mice. PLoS ONE 5(2):
e9192. doi:10.1371/journal.pone.0009192
Tobias Vrede, "Survival, Growth And Reproduction Of Daphnia
Galeata Feeding On Single And Mixed Pseudomonas And
Rhodomonas Diets." Freshwater Biology 57.4 (2012): 835846. Academic Search Complete. Web. 22 Apr. 2012.
Figure 1
Acknowledgments:
Figure 2
Figure 3
Figure 4
Marty L. Harvill, Ph.D.; Baylor University Biology Department; Ms.
Nora Schell; Lake Waco Wetlands; Allisa Wiseman, Baylor University
Department of Statistics