Aquatic Biology and Ecology »
Total Dissolved Gases
The entrainment and supersaturation of dissolved atmospheric gases (TDGS) as a result of spillway operation at hydroelectric generating stations may result in uncompensated hyperbaric pressure of gases in fish exposed to TDGS for an extended time. When these fish enter shallower water, ambient pressure drops and gases will be released from solution in body fluids to form emboli and/or emphysema, a condition known as gas-bubble disease (GBD). NSC has worked with the hydroelectric sector to measure and profile total dissolved gas pressure in the vicinity of generating stations and spillways to evaluate the potential for TDGS and GBD in fish.