Final answer:
Bryozoans are called fouling organisms because they attach to surfaces, obstructing movement and interfering with man-made structures. They are filter feeders that extract food particles from the water. Their small size and ability to colonize various surfaces make them efficient fouling organisms.
Step-by-step explanation:
Bryozoans are called fouling organisms because they often encrust surfaces and grow branching structures, which can obstruct the movement of ships, clog pipes, and interfere with other man-made structures. They attach themselves to the substrate and form colonies that produce hard calcium carbonate skeletons, which can accumulate and cause problems for humans. Bryozoans are filter feeders, extracting food particles from the water using their tentacles. Their small size and ability to colonize various surfaces make them efficient fouling organisms.