The Effects of Hydrostatic Pressure on Toxicity

Daphnia magna is an excellent model organism to understand the environmental effects on aquatic animals. This research will help determine the effects of hydrostatic pressure on acute toxicity tests with heavy metal. After culturing isolated broods of Daphnia, we submitted them to a series of experiments. We used a Deep Water Simulator to pressurize our Daphnia at intense atmospheric pressures, such as 0.101 – 10.1 MPa. We measured toxicity by creating concentrations of toxic dissolved substances at 12.5%, 25%, 50%, and 100%. Toxicity effects on Daphnia were measured by observing movement and behaviors (i.e. swimming). Hydrostatic Pressure Tests: High levels of hydrostatic pressure will cause intense stress on the Daphnia. Daphnia show little to no movement to conserve energy. Acute Toxicity and High Hydrostatic Pressure Tests: With increased hydrostatic pressure, we also saw an increase in toxicity effects on Daphnia. As a result, Daphnia are more susceptible to the toxins at higher levels of pressure. Based on this experiment, we understand that D. magna is susceptible to heavy metals at intense pressures. Hydrostatic pressures at deep levels affect D. magna biologically, such as their membrane permeability and enzymatic activity. The results show us that high pressures can affect physiological structures on an organism. This presented the question of would D. magna be able to adapt to different atmospheric pressures to decrease susceptibility to toxins? A future study can look at how D. magna adapt to their environments to protect their physiological structures. Other experiments for this project could involve testing other organisms, such as Americamysis bahia (a saltwater organism)