The present disclosure relates to a method of oxygenating water and producing hydrogen performed by a system (4) floating on a body of water (100) and comprising a horizontal axis wind turbine (3), a propeller (105) and a hydrogen producing unit (6). The method comprises obtaining input regarding environmental conditions of the body of water for determining a direction in which the floating system (4) should be moved. The method also comprises pointing the rotor (102) of the wind turbine such that the floating system is moved in accordance with the determined direction while obtaining electricity from the rotation of the rotor. The method also comprises controlling the speed with which the floating system is moved by means of the propeller submerged in the body of water, by rotating the propeller to increase the speed when increased speed is desired, and by allowing the propeller to function as a turbine to generate electricity and reduce the speed when reduced speed is desired. The method also comprises powering the hydrogen producing unit (6) with the obtained electricity to split water molecules from the body of water (100) to produce hydrogen and oxygen. The method also comprises oxygenating the body of water by means of the produced oxygen.