As the heavier materials from the mountains make their way through the Plateau and Piedmont in the streams, creeks and rivers of the click image for more... (photo: Gray's Reef NMS)

The sand makes a temporary rest in the broad deltas that form where the out flowing fresh water collides head on with the incoming salt at flood click image for more...(photo: Gray's Reef NMS)

Planktonic (drifting) and necktonic (swimming) invertebrates are found in the waters above the Gray's Reef. Planktonic species include click image for more...(photo: Gray's Reef NMS)

Horizontal reef tops provide habitat for sessile (attached) benthic (bottom dwelling) invertebrates, which rely upon ocean currents for food, gas exchange, waste removal, and egg dispersal. Examples include hard corals, soft corals, sponges, and hydroids. (photo: Karen Angle)

Little sediment accumulates on the vertical reef surface know as scarps. As a result, the bare sandstone substrate supports colonies of encrusting sponges and bryozoans. Barnacles, tunicates, and sea anemones are also found on these exposed surfaces. (photo: Karen Angle)

Both predators and prey seek good hiding places such as ledges and overhangs of Gray's Reef like this loggerhead sea turtle (Caretta caretta) resting under a ledge. (photo: Gray's Reef NMS)

Diurnal (active at day) species find refuge within the reef during the night. Nocturnal (active at night) species seek to conceal themselves click image for more... (photo: Gray's Reef NMS)

Shifting sands and a lack of firm substrate preclude most sessile forms from settling along slopes and in sandy areas of the reef. click image for more... (photo: Gray's Reef NMS)

The invertebrates of the reef have adapted to the different habitats found within the reef. The ability to adapt to different, specific resources helps to decrease competition for click image for more... (photo: Alessandra Score)