<P> The pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea . The benthic zone is the ecological region at the very bottom of the sea . It includes the sediment surface and some subsurface layers . Marine organisms living in this zone , such as clams and crabs , are called benthos . The demersal zone is just above the benthic zone . It can be significantly affected by the seabed and the life that lives there . Fish that live in the demersal zone are called demersal fish , and can be divided into benthic fish , which are denser than water so they can rest on the bottom , and benthopelagic fish , which swim in the water column just above the bottom . Demersal fish are also known as bottom feeders and groundfish . </P>
<P> The pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea . The benthic zone is the ecological region at the very bottom of the sea . It includes the sediment surface and some subsurface layers . Marine organisms living in this zone , such as clams and crabs , are called benthos . The demersal zone is just above the benthic zone . It can be significantly affected by the seabed and the life that lives there . Fish that live in the demersal zone are called demersal fish , and can be divided into benthic fish , which are denser than water so they can rest on the bottom , and benthopelagic fish , which swim in the water column just above the bottom . Demersal fish are also known as bottom feeders and groundfish . </P>
the bottom environments of the oceans are referred to as the
the bottom environments of the oceans are referred to as the
benthic and demersal zones
benthic and demersal zones