What is a physiological effect of elevated oxygen levels at depth?

Elevated oxygen levels at depth can lead to an increased risk of central nervous system oxygen toxicity. When divers use enriched air Nitrox to extend their bottom time or reduce nitrogen absorption, the higher partial pressures of oxygen at depth can result in toxic effects. Symptoms of oxygen toxicity may include visual disturbances, tinnitus, dizziness, nausea, twitching, or even seizures. This risk necessitates careful monitoring of oxygen exposure and adherence to depth and time limits specific to the blend of gas being used.

Other options, while relevant to diving concepts, do not accurately address the physiological effects related to elevated oxygen levels. For instance, buoyancy and nitrogen narcosis effects do not directly correlate with increased oxygen; buoyancy typically relates to the diver's equipment and gas densities, while nitrogen narcosis is influenced by the partial pressure of nitrogen rather than oxygen. Enhanced physical performance is also not a guaranteed result of higher oxygen levels; in fact, the opposite might occur due to the potential adverse neurological effects of oxygen toxicity. Thus, understanding the implications of oxygen at depth is critical for safe dive practices.