Dive computers function primarily by calculating what?

Dive computers are designed to monitor and track various factors critical for safe diving, and one of their primary functions is to calculate the approximate amount of excess nitrogen present in a diver's body. When a diver descends and breathes compressed air or nitrox, the increased pressure causes nitrogen to be absorbed into the tissues. During ascent, if divers ascend too quickly, the excess nitrogen can form bubbles in the body, leading to decompression sickness or "the bends."

The dive computer continuously analyzes depth, time, and the gas mixture being used to manage the accumulation of nitrogen in the body and to provide the diver with information regarding safe ascent rates and no-decompression limits. It helps prevent situations where nitrogen levels are excessively high, ensuring efficient safety management during and after the dive.

The other options focus on parameters that are not the primary calculation function of dive computers. While monitoring optimized depth, buoyancy, and water temperature can be important for diving, the key aspect related to decompression safety is indeed the assessment of nitrogen levels in the body.