ABSTRACT
Marine organisms can either float or swim, or they can live on, near, or within the sea bed. The entire sea-bed environment is called the benthic division and the water body forming the seas and oceans, the pelagic division. It has long been recognized that environmental factors such as soil type, temperature, salinity, and moisture are important in determining the distributions of plants and animals. For these reasons, some knowledge of the broad patterns in the physical environment of the British Isles is necessary. The coastal waters and seas around the British Isles are relatively shallow and rest on a wide continental shelf which slopes gently to the west and is in general devoid of any prominent topographical features. The southern North Sea is less saline than the other shelf seas around the British Isles and the plankton species are dominantly neritic.
