When scientists want to sample the organisms that live on or just below the surface of the ocean floor (the benthos) they commonly use a Benthic Grab to collect a portion of the ocean floor. Benthic Grabs can take a bite out of the benthos. Various sizes and approaches work with different organisms and sediment types. The aim is to bring to the surface a complete sample of both the sediment and the organisms found there. Using these techniques, scientists describe the species found in the sediment and their abundance, even preventing some of the injury that occurs to delicate animals with other methods, such as bottom trawling.
A diagram of a small Benthic Grab detailing the major components. (NOAA Ocean Explorer)
A large Benthic Grab being hauled on deck after use. (Census of the Diversity of Abyssal Marine Life - CeDAMar. Senckenberg, Germany)