Which type of ocean movement varies depending on the current moon phase

Tides.

Explanation:

Sea tides are brought about by the mind elaborate transaction of three galactic bodies: the Sun, the Earth and the Moon. Both the Sun and the Moon apply a gravitational draw on the Earth's water. The subsequent power of the Moon's gravity makes two tidal lumps on inverse sides of the Earth. Contingent upon the general situation of the Sun, the tidal lumps will change somewhat as the Moon encounters its stages