Is the well built lad below with the gun on his hip a Marine or Seal? I don't remember too many Marine with battle hair like his.
He's most likely neither. I would say he's a member of the ship's Visit, Board, Search and Seizure (VBSS) team, which also provide security for these Noncombatant Evacuation Operations.
I think it's likely he's a Navy MA - a relatively new rating which signifies 'master-at-arms'. In other words, a Navy ship-board cop. Once upon a time (i.e., back in my day) 'MAA's were typically pulled from the deck ratings (Bos'n, Gunner's mate, etc.) for temporary duty as MAA. We called them 'hall-monitors' behind their back - but not so's one of them could hear you; they could make life hell for you in a NY minute.