Somerville’s municipal election Tuesday will feature contested races for seats on the Board of Aldermen and the School Committee. Polls will be open from 7 a.m. to 8 p.m. throughout the city. Seven candidates are running for four alderman-at-large seats, including incumbents John Connolly Jr., Dennis Sullivan, and William White Jr. Challengers for the at-large Board of Aldermen seats are Carol Dempkowski, Sean Fitzgerald, William Medeiros, and Mary Jo Rossetti. There will also be several contested ward races for alderman, including in Ward 1, where Elio LoRusso will take on Matthew McLaughlin and in Ward 3 , where Suzanne Bremer is running against Robert McWatters. In Ward 5, Courtney O’Keefe is running against Mark Niedergang for a spot, and in Ward 7, Katjana Ballantyne is running against Joseph Capuano for a seat on the board. The election will also include contested School Committee races in Ward 1, where Steven Roix is running against Kenneth Salvato, and Ward 2 where Dan Futrell is running against Michael Nionakis. In Ward 5, Laura Pitone is running against Ross Richmond for a seat on the committee. Mayor Joseph Curtatone is running unopposed for his sixth term.