The 30-year-old defender joined Town in the summer and has made over 300 career appearances during spells with Hereford, Leyton Orient, Millwall and Southend.
"Tam will be the team captain for the season, he's got a lot of experience," Turner told the club's official website.
"He's a good leader on the pitch and a good person in the dressing room and has a good perception of the game. He's a good talker but I want that from all of the players.
"The same attributes can be said for Dave Winfield and he was another candidate for captain but I've just gone for that little bit more experience that Tam brings."
He added: "He's played a lot of games at a good level; to play at Millwall in front of the demands of their fans on a regular basis takes a lot of character."