Tides in the oceans are caused by the gravitational pull of the Moon and the Sun on Earth. The Moon's gravity has the strongest effect because it's closer to Earth, and it pulls water towards it, creating a "bulge" in the ocean. As the Earth rotates, different areas pass through this bulge, causing the water level to rise and fall. The Sun also affects tides, but its influence is weaker than the Moon's.
These tidal movements have a big impact on coastal ecosystems. High tides bring in more water, which can flood areas and provide nutrients for plants and animals. Low tides expose parts of the shoreline, creating a habitat for species like crabs, mussels, and seaweed. The regular ebb and flow of tides help keep the ecosystem healthy by moving nutrients around and supporting a wide variety of life in these areas. However, if tides are disrupted by human activities, it can harm these ecosystems and the animals that depend on them.