Deep boulder reefs provide shelter for a large number of species. Encrusting sponges and coralline algae coat parts of this cobble field. Other animals seek shelter in the nooks and crannies. Colorful sea stars are found all over the globe, including the Gulf of Maine. Shell piles collect in troughs between sand waves on the top of Stellwagen Bank.
Some animals find shelter between the shells.
A smooth sun star sits on the muddy sea floor, looking much like a child's drawing of the sun in the sky.