In accordance with various aspects of the present invention, a method and system for a buoyancy engine is presented. In an exemplary embodiment, the buoyancy engine includes a divider to separate a liquid environment from a gas environment, and a reservoir aperture in the divider. A rotating element, approximately opposite the reservoir aperture, provides tension to, and helps rotate, a segmented chain. The segmented chain is configured to form a solid inner surface when transitioning between the liquid and gas environments, but separate during vertical travel. As the segmented chain travels between the liquid and gas environments, a rotary motion is created which can be captured as electrical or mechanical energy.