Cranberry Lake Biological Station

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Algae are photosynthetic, often single celled aquatic organisms which serve as one of the most basic prey organisms in a given ecosystem. They are susceptible to changes in the aquatic ecosystem, and when chemicals found in sunscreen are introduced, they may be affected. Based upon a previous study we hypothesize that filamentous algae will have a greater rate of photosynthesis in water where sunscreen is present as compared to water where sunscreen is not present due to the lack of UV light penetration. For this experiment, we collected algae from South Bay, and placed 4 mL samples into 118mL jars, with one control group and three experimental groups of varying sunscreen concentrate. The change in dissolved oxygen was recorded. We ran this test in outside conditions, and once under a UV and sun lamp. We then repeated the set of tests with less sunscreen to account for a potential error in light penetration, as well as a trial without UV to make sure it was in fact UV that impacted photosynthesis. Using ANOVA and Tukey statistical tests our results showed that our hypothesis was not supported, but there were other trends that were noticeable. This shows that sunscreen has a negative effect on algae photosynthesis.



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