Describe the relationship between oxygen toxicity and the depth of a dive.

The correct response emphasizes the direct relationship between the depth of a dive and the risk of oxygen toxicity. As the diver descends, the ambient pressure increases, which affects the partial pressure of oxygen in the breathing gas. For every 10 meters of seawater, the pressure increases by approximately one atmosphere. This increase in pressure leads to a higher partial pressure of oxygen when breathing a gas mix that includes oxygen, such as Enriched Air Nitrox.

Oxygen toxicity can occur when the partial pressure of oxygen exceeds certain thresholds, typically around 1.4 ATA (atmospheres absolute) for recreational diving. Since depth increases the pressure and therefore the partial pressure of oxygen, deeper dives pose a greater risk of experiencing oxygen toxicity. This understanding is crucial for divers using Enriched Air Nitrox because it may contain higher concentrations of oxygen than regular air, further influencing the risk if proper depth limits are not observed.

The incorrect options suggest misunderstandings about oxygen toxicity. Some imply that oxygen toxicity is less concerning at depth or that it is irrelevant to depth altogether, which overlooks the scientific principles of gas behavior under pressure. Understanding these principles helps divers manage their risks effectively while utilizing Enriched Air Nitrox during their dives.