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Continued...
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Conclusion
The periwinkles living in the area of the North West Arm are typically smaller in shell diameter than those found in unpolluted water, indicating malnutrition or a decreased metabolic rate. However, features pertaining to appearance and function appeared to be the same as those in periwinkles from more stable ecosystems. The ability of the shell to absorb force in both sets of periwinkles was proportional to the shell's thickness. However, the shells from the North West Arm site were weaker than those from the Graves Island control site. This indicates that the material in their shells has been altered by the materials present in the polluted water. The darker color of the shells found in the North West Arm may simply relate to water turbidity, as light is not able to diffuse through water as readily in this area as at Graves Island. Increased light may simply bleach the shells. The lower turbidity at Graves Island may also account for these specimens' lack of response to light stimuli. |
I also discovered that periwinkles can survive in a polluted environment because their main source of food is algae, and in a nitrogen- and phosphorus-rich aquatic environment, algae is plentiful. The ability of periwinkles to survive in an environment with high amounts of fecal waste may indicate a high resistance to bacteria such as fecal streptococci. I cannot account for all my findings, however, as I could not find conclusive reasons why periwinkles are able to survive in a habitat with lower-than-normal levels of oxygen, as is the case in the North West Arm, as cold-blooded animals need large amounts of oxygen. To further understand this, I would like to conduct tests on the levels of oxygen a periwinkle needs to survive, and how this compares to other aquatic animals. As a result of this research I have a greater appreciation for the survival abilities of all creatures, especially periwinkles. |
