Diving to survey, sample, and manage marine life takes a great deal of skill and knowledge. This diver is sampling the seafloor, also known as the benthic zone. This kind of sampling is important for mapping and can allow scientists to draw conclusions about animal habitats and distributions. For this to work, divers must collect many samples for the data. They can use a wide variety of tools including grabs (a circular device that removes a piece of the seafloor), corers (tubes that bring up a column of sediment), and harsher methods like trawling (dragging a net behind the boat). Of course there are many other ways to sample and study benthic life. Hand collection, using quadrants, setting traps, and simply observing are other common techniques.