Marine biology dredge

The marine biology dredge is used to sample organisms living on a rocky bottom or burrowing within the smooth muddy floor of the ocean (benthic) species.

This led to a mistaken impression that the deep-sea bed lacked species diversity, as theorised by Forbes in his Azoic hypothesis.

Later samplers devised by Howard L. Sanders and the Epibenthic sled designed by Robert Hessler showed that deep-sea bottoms are sometimes rich in soft-bottom benthic species.

Müller's design was modified by the Dublin naturalist Robert Ball in 1838 and at the Birmingham meeting of the British Association for the Advancement of Science in 1839 a committee was appointed for dredging research with a view to the investigation of the marine zoology of Great Britain, the illustration of the geographical distribution of marine animals, and the more accurate determination of the fossils of the Pliocene period.

The wide variety of dredges and other benthic sampling equipment makes site comparison difficult.