Buoyancy always acts in the direction opposite to the direction of the gravitational force. We normally consider this direction as 'upward'.

Buoyancy

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Buoyancy is directly related to the density of the fluid. The more dense the fluid, the greater the buoyant force it exerts.

Buoyancy is the upward force exerted on an object immersed in a fluid (such as a liquid) due to the pressure difference between the top and bottom of the object. The magnitude of the buoyant force is equal to the weight of the fluid displaced by the object, following Archimedes' principle. Objects that are less dense than the fluid will float, while those that are denser will sink.