What action should be taken if a diver loses communication with the surface?

When a diver loses communication with the surface, the best course of action is to follow planned signals and execute an emergency ascent if necessary. This response is critical because it maintains safety during a potentially dangerous situation. Divers are trained to use predetermined signals to convey information, and these signals help ensure that divers can effectively communicate their status or intentions even in the event of a communication breakdown.

If a diver loses communication, following planned signals allows them to attempt to regain contact or confirm their status, providing a structured way to react to the situation. If communication cannot be reestablished and the diver feels it's unsafe to remain at depth – due to factors like air supply or potential hazards – initiating an emergency ascent is the prudent choice. This approach prioritizes the diver's safety while also adhering to established diving protocols, which are designed to mitigate risks associated with diving.