Why does a dive computer keep track of a diver's nitrogen absorption levels?

A dive computer tracks a diver's nitrogen absorption levels primarily to stay within the no-decompression limits on each dive. As divers descend and ascend, the pressure changes affect how nitrogen from the breathing gas is absorbed and released by the body. The dive computer calculates how much nitrogen is being absorbed and estimates how long a diver can stay at a particular depth without needing to decompress on ascent. This is critical for diver safety to prevent decompression sickness, commonly known as "the bends," which can occur if a diver ascends too quickly or stays too long at depths that exceed the no-decompression limits.

Monitoring nitrogen levels helps divers plan their ascents and any deeper dives they may wish to conduct later in their dive session, ensuring they remain within safe operational guidelines. This function of a dive computer is vital for divers to execute safe diving practices and mitigate risks associated with nitrogen narcosis and other pressure-related issues.