why do bacteria in a biofilm have different characteristics than free-floating bacteria
Biofilm Bacteria living in a biofilm usually have significantly different properties from free-floating bacteria of the same species, as the dense and protected environment of the film allows them to cooperate and interact in various ways.[34] One benefit of this environment is increased resistance to detergents and antibiotics, as the dense extracellular matrix and the outer layer of cells protect the interior of the community. In some cases antibiotic resistance can be increased a thousandfold.[35] Lateral gene transfer is often facilitated within bacterial and archaeal biofilms[36] and leads to a more stable biofilm structure.[37] Extracellular DNA is a major structural component of many different microbial biofilms.[38] Enzymatic degradation of extracellular DNA can weaken the biofilm structure and release microbial cells from the surface.
Marine life Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry. The shapes of their bodies are adapted for maximal efficiency of water flow through the central cavity, where it deposits nutrients, and leaves through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile aquatic animals. Although there are freshwater species, the great majority are marine (salt water) species, ranging from tidal zones to depths exceeding 8,800 m (5.5 mi).