Effect of Copper (II) Sulfate Pentahydrate on Simocephalus serrulatus Reproduction
Tyler Freeman, Brad Kroyer, Leena Rani. Baylor University Waco, TX 76798
Abstract
This experiment determined the effects copper (II) sulfate pentahydrate on Simocephalus serrulatus reproduction. Both samples of organisms and wetland water to grow them came from the Waco Wetlands.
Samples of Simocephalus serrulatus were divided among 16 containers (Three concentrations and a control). The organisms were allowed to reproduce for 20 days. Pipette sub-sampling was used to analyze the
copper’s effects on reproduction. Data did not supports our original hypothesis that increased copper has a negative effect on reproduction. Results showed that the optimal copper level for reproduction was
approximately 1.487 ppm.
Introduction
Results
Copper (II) sulfate pentahydrate is used in a variety of herbicides,
fungicides, and pesticides. Because of this widespread use, copper
leakage into the ground water, streams, and lakes occurs frequently
(Bae & Freeman, 2007). Copper in high concentrations is toxic for
most organisms because of its ability to create molecules that
damage proteins, lipids and DNA. Daphnia sp., has been used
extensively to measure aquatic population tolerance of pollutants, so
Simocephalus serrulatus, a similar organism, has been chosen to
investigate the affects of copper (II) sulfate pentahydrate on their
reproductive fitness (United, 2001).
Figure 3: Mean population of Simocephalus serrulatus at
varying concentrations of copper (II) sulfate pentahydrate after
a 20 day growth period
Materials and Methods
Organisms were placed in 16 plastic containers filled with 1.4 L of
Lake Waco Wetlands filtered water (120 micromesh), a minimal
amount of algae for food, and a count of 7 Simocephalus serrulatus
per container on a 12-12 day-night cycle at 22 C (Fig. 1). Using the
DR-890 Colorimeter, we obtained the concentration of copper in the
wetland water (Fig. 2). Control, 0.895 ppm, 1.487 ppm, and 2.975
ppm concentrations were established. Each concentration had 4
separate containers to remove outliers (Bylsma & O’Meara, 2006).
To support the growing populations with a continuous supply of
nutrients, we added 1.4 L more of filtered wetland water weekly
along with the corresponding value of copper necessary to keep a
constant concentration. After 20 days, data was obtained on the
reproductive success of each cell by pipette sub-sampling. Water
from each container was siphoned off leaving a more concentrated
150 mL sample. A 5 mL portion of that was pipetted in a petri dish
and organisms were counted.
Contrary to the initial hypothesis, populations of Simocephalus
serrulatus exhibited heightened reproductive success in increased
concentrations of copper (II) sulfate pentahydrate. In comparison
with the inversely proportional relationship between the fitness of
Daphnia sp. and increasing levels of copper concentration (Bylsma
& O’Meara, 2006), data supported the notion that Simocephalus
serrulatus prefer an environment with a slightly higher copper
concentration than that of the Waco wetlands. Further investigation
is needed to determine the tolerance of Simocephalus serrulatus in
environments of even higher copper concentrations. In regard to
the regulation of water-bourne heavy-metal pollutants (specifically
copper), slight increases may be tolerable by aquatic populations.
However, more drastic levels of heavy metal toxicity could pose a
threat to populations of Simocephalus serrulatus. Further
experimentation is necessary to determine if excessive copper
levels, far beyond those used in this experiment, have a detrimental
effect on aquatic populations; the data is insufficient in making this
assessment.
Acknowledgements
After counting Simocephalus serrulatus in each container using
pipette sub-sampling, our results showed an unexpected affinity
for higher concentrations of copper (II) sulfate pentahydrate.
While the control groups and groups with lower concentrations
of copper demonstrated moderate reproductive success, the
Simocephalus serrulatus thrived in medium-high concentrations.
Figure 2
Figure 1
Discussion & Conclusion
Marty L. Harvill, Ph.D.; Baylor University Biology
Department; Ms. Nora Schell; Lake Waco Wetlands; Baylor
University Dean of Arts and Science; URSA; Alissa Wiseman,
Statistics Graduate Student; Baoqin Ding, Laboratory Assistant
Literature Cited
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<http://www.the-macc.org/wpcontent/uploads/2009/09/2006_Effects-of-Copper-SulfateTreatments.pdf>.
United States Department of Agriculture. "Copper Sulfate."
Agricultural Marketing Service. Department of
Agriculture, 21 Sept. 2001. 1 Mar. 2012.
<http://www.ams.usda.gov>.