The diving trip descended into the turquoise waters of the Maldives with decades of experience in tow: a marine scientist, her college-age daughter, a research fellow, a former student and a diving instructor among them. They dropped into extraordinary depths, seeking to explore underwater caves where soft coral thrives and batfish take shelter. But the divers never resurfaced, in what authorities have called one of the worst diving accidents in the island nation’s recent history. Five Italian nationals died Thursday on the dive, according to Italy’s Foreign Ministry and Maldives police. They included Monica Montefalcone, a marine ecologist at the University of Genoa; her daughter Giorgia Sommacal, a biomedical engineering student at the same university; Muriel Oddenino, a research fellow; Federico Gualtieri, a former student of the ecologist; and Gianluca Benedetti, a diving instructor.…