Soldier stationed at Atlantis Base in the Pegasus Galaxy, sent to provide backup to Colonel John Sheppard's unit while investigating Major Leonard's team on M1B-129. An altered Leonard, believing the new arrivals to be the enemy, shot Barroso in the shoulder before escaping back into the woods.
Unlike Kagan, who was exposed point-blank to an explosive device, Barroso was able to walk to the source of unusual electromagnetic interference on the planet. He concealed himself inside a cave while the others continued to search for the missing personnel. Here, on the wall of the interior of the cave, he died of internal bleeding.
The source of the electromagnetic interference was a Wraith mind manipulator. This device, active and pulsating, affected Dr. Carson Beckett, who had been tending to Barroso. In his imaginings, Beckett believed Barroso to be alive for at least three hours after his death when rigor had set in.
Phantoms - Barroso accompanies Sheppard's unit for backup on M1B-129, but is shot almost immediately by the team leader of the group they had come to help.