Even though today remote-operated machines perform many deep underwater tasks, these robots can't completely replace human deep sea divers. Exploring the unknown depths of the sea is not for the faint of heart. Divers need to be in top physical shape, able to remain completely calm in the face of danger, and (obviously) have excellent swimming skills. You'll also need certification in various kinds of diving, like closed bell, surface, and SCUBA [source: National Careers Service].
Deep sea divers perform many different types of jobs, depending on where they're working. Divers work deep underwater for many industries, including: offshore gas and oil pipelines, scientific research, filmmaking or stunt work, forensic work for law enforcement, archaeology, civil engineering or leading recreational dives. In the case of offshore saturation diving, a deep sea diver might live for up to 28 days in an underwater pressure chamber to get his or her body adjusted to the water pressure of the ultra deep sea.