The city council shall appoint a city clerk who shall have custody of and shall be responsible for the official seal and records of the city. The city clerk shall act as secretary of the city council and all other boards, commissions and agencies of the city. The city council shall prescribe the qualifications additional duties and compensation of the city clerk. The city clerk shall appoint subject to the civil service provisions of this Charter, such deputies and employees as the council may by resolution prescribe.