Marine barriers are natural or artificial structures that protect coastal areas from the effects of waves, storms, and erosion. These barriers can include coral reefs, sand dunes, and mangroves, which help to absorb wave energy and reduce the impact of storm surges. Artificial marine barriers, such as sea walls and breakwaters, are built to safeguard coastal infrastructure and communities. They are designed to redirect wave energy and prevent flooding, but they can also alter local ecosystems and sediment transport. Proper planning and maintenance are essential to ensure their effectiveness and minimize environmental impacts.