Daphnia Red Light Lab Report

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The objective of this study was to test the phototactic response of Daphnia when exposed to red (>600 nm) and white light. A 30 x 2 cm clear acrylic mesocosms with a 10 cm counting area was filled with distilled water and 10 Daphnia. We counted the number of Daphnia that traveled to the lit counting area after 10 minutes. There were twice as many Daphnia in the lit counting area for the control (white light) compared to the experimental group (red light). The results showed that red light had a negative effect on the phototaxis of Daphnia.

Introduction: Daphnia play a vital role in the ecosystem because they are an important part of the aquatic food web (Miner et al., 2012). When exposed to UV light, Daphnia swim deeper into the water (Morris et al., 1995). This natural movement is called phototaxis.

Daphnia have been utilized as test subjects due to their simplicity and how environmental disturbances have impacted their ability to survive, including UV light. Research has shown that Daphnia exhibit a positive …show more content…

Therefore, high exposure is harmful to the aquatic environment, especially for species that reside in shallow water, such as Daphnia (Rautio and Korhols, 2002). This phototactic response is attributed to Daphnia’s natural instinct to protect their internal organs and DNA (Morris et al., 1995). Visible light also aids in repairing the damaged nucleotides that are caused by over exposure of UV light (Morris et al., 1995). Even though their behavior is studied often, there is still little that is known about the physiological effect of visible light on Daphnia (Hylander and Hansson, 2010). Daphnia move away from the visible light due to the UV exposure at different rates, but as the visible light increase, so does the rate at which they move away (Storz and Paul,

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