Exposure to elevated partial pressures of oxygen can lead to:

Elevated partial pressures of oxygen can significantly increase the risk of central nervous system (CNS) oxygen toxicity. At higher pressures, oxygen becomes more potent in its effects on the body. The nervous system is particularly sensitive to elevated oxygen levels, and this can lead to symptoms such as visual disturbances, muscle twitching, seizures, or even loss of consciousness. This phenomenon is important to understand for divers using enriched air nitrox, as managing oxygen exposure is critical to ensure safety during dives.

In contrast, the other options do not accurately reflect the implications of elevated partial pressures of oxygen. For instance, while diving with enriched air might indeed lead to reduced dive times due to the risks associated with oxygen toxicity, it does not have a straightforward connection to reduced dive time across the board, as dive tables usually dictate those times based on a variety of factors. Improved oxygen delivery is a benefit of enriched air in certain contexts, but it does not pertain to the dangers associated with elevated pressures. Enhanced buoyancy can result from changes in gas mixtures, but it is unrelated to the toxic effects of high partial pressures of oxygen. Understanding these distinctions can help divers make informed decisions regarding their breathing gases and manage the risks effectively during their dives.