Is There Gravity Under the Oceans?

Yes. Gravity is a universal force between masses; water doesn't negate it. Earth's gravity pulls everything toward its center, keeping oceans from flying into space. Underwater, gravity is slightly less than at the surface because water's buoyancy exerts an upward force equal to the weight of displaced fluid. Net force on a submerged object = gravity minus buoyancy. This net force governs sediment settling, ocean currents (driven by density/gravity differences), and marine life movement. Gravity also holds the atmosphere, which in turn affects sea surface.