Description Sea floor north of the South Shetland Islands: This large stone which was dropped by icebergs is covered with many organisms. Usually this site is very silty and a hardground for settlement is relatively rare. It is likely that Ctenocidaris sp. (arrow) preys on octocorals and bottle brush gorgonians.Author Lockhart, Susanne A.JPG file - 205.41 kB - 1 181 x 886 pixels