Castleland 9 - The glowing pond

You come to a pond and decide to fill your canteen. As you fill your canteen you notice a glow of light appear at the bottom of the pond and go completely from one end to the other. A second and third glow of light do the same thing. You also notice a moss covered crate on the opposite shore. Do you dive into the pond to see what the glows of lights are? Or do you go search the crate to see if there is anything useful?