The primary cause of ocean tides on Earth is the gravitational pull exerted by the Moon, with a lesser influence from the Sun. The Moon's gravity pulls water toward it, creating a bulge, or high tide, on the side of the Earth facing the Moon. Conversely, on the opposite side, another high tide occurs due to the inertia of water. As the Earth rotates, different areas experience these high and low tides. The regular cycle of tides affects marine ecosystems and coastal processes.