Hard bottom habitats refers to areas of rock or onsolidated sediments, which can be distinguished from surrounding unconsolidated sediments, and it is generally located in the ocean rather than in the estuarine system. The topography of these habitats can vary from a relatively flat, smooth surface to a scarped ledge with stepped relief. Examples of hard bottom habitats include shallow kelp-covered areas in rocky headlands, rock outcrops, submarine canyon walls, and the deep-water plateau. Hard bottom habitat also consist of man made structures such as artificial reefs, outfall pipes, breakwaters, wrecks, and jetties, which provide substrate for the establishment and development of hard bottom communities.
Hard bottom habitats are also called “live bottom” because of the abundance of plants and invertebrates that attach to or bore into these hard substrates. Hard bottom surfaces can be colonized by algae, sponges, soft coral, hard coral, bryozoans, polychaete worms, and tunicates. The extent and diversity of colonization, however, changes according to topography, habitat diversity, currents, light availability, and location on the shelf. Hard bottom habitats provide food, shelter, and spawning and nursery areas to a wide variety of fish and shellfish species, and many other organisms. |
