In the event of state ownership of any port or harbor, in its entirety, in any county which may now or hereafter be authorized by law to receive a portion of the state ad valorem tax for port or harbor purposes, such portion of the state ad valorem tax shall be paid to the state port authority and shall be used for the improvement, development, operation and expansion of such port under the provision of this chapter, and the port fund of such county to which such ad valorem tax is paid shall be subject to the requisition of the state port authority.