What is the significance of a range marker's lower light?

The lower light of a range marker is significant because it indicates the direction in which a vessel should navigate to remain aligned with a designated channel or safe passage. Range markers are often used in conjunction with a higher light to create a visual reference for mariners, helping them understand if they are on the correct course. When both lights are visible, especially aligned vertically, it gives the navigator clear guidance on how to steer the vessel to ensure it stays in the navigable water, thus avoiding hazards and ensuring safe passage.

In this context, the other options do not accurately capture the primary function of the lower light. For instance, while it may indirectly aid in determining a safe anchorage by keeping the vessel in the channel, that is not its primary purpose. Similarly, while warnings about nearby hazards are crucial, the lower light is not designed specifically to convey that information. Lastly, the idea that it serves as a decorative feature does not align with its practical function in marine navigation.