In shallow water the colour is more intense and there are more spicules present making the external surface bright white, but at greater depths there are fewer spicules and the colour is more greyish or brownish.
In shallow water the colonies are small, the colour is more intense and there are more spicules present making the external surface bright white. At greater depths the colonies are larger, there are fewer spicules and the colour is more greyish or brownish.