Marine scientists at Northrop Grumman Corp. are joining Raytheon BBN Technologies Corp. to investigate new ways of using sea life to detect and track potentially hostile manned submarines and unmanned underwater vehicles (UUVs) over vast areas of the world’s oceans. Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., announced a potential $5.1 million contract to the Northrop Grumman Mission Systems segment in Linthicum Heights, Md., for the Persistent Aquatic Living Sensors (PALS) program. Northrop Grumman joins Raytheon BBN Technologies in Cambridge, Mass., which won a potential $6.4 million contract for the PALS project last month. The DARPA PALS contract to Northrop Grumman is for $3.2 million, and has options to increase that to $5.1 million.