Benthos, also known as benthon, from Greek benthos 'depth of the sea', is the community of organisms that live on, in, or near the seabed, river, lake, or stream bottom, also known as the benthic zone. This community lives in or near marine or freshwater sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths. Many organisms adapted to deep-water pressure cannot survive in the upperparts of the water column. The pressure difference can be very significant (approximately one atmosphere for each 10 metres of water depth).