The City Treasurer may appoint an Assistant City Treasurer who shall hold office at the pleasure of the City Treasurer, and whose compensation shall be fixed by the Board of Aldermen. The Assistant City Treasurer shall render such service to the City Treasurer as he or she may require and in the absence or inability of the City Treasurer to perform his or her duties, the Assistant City Treasurer shall have the same powers, be subject to the same liabilities, and perform all of the duties of the City Treasurer.