Sediment Corers are used to sample the organisms that live on or just below the surface of the ocean floor (the benthos), while displaying the structure of the sediment which sledges are not designed to achieve. Sediment Corers work by boring a large tube into the benthos and then bringing up a column, or core, of sediment intact within the tube. Caps can automatically seal off the ends of the core after it has pulled up a sample, protecting the sample and its structure intact. Different sizes and approaches work with different organisms and sediment types. With benthic corers, scientists obtain samples containing organisms (including the very small ones, microbes) found in the benthos, as they are found naturally. Scientists can then identify what species are in the sediment as well as how abundant they are. Other information can also be gained, such as how and at what level organisms live and move in the sediment. This technology minimizes injury to potentially delicate organisms whether from shallow coastal waters or from abyssal depths.
A large sediment corer being recovered after collecting a sample of the ocean floor. (NOAA Ocean Explorer)
A core of seafloor sediment being collected by the mechanical arm of a manned submersible. (NOAA Ocean Explorer)
Samples taken by a boxcore, showing the details of sediment layers preserved using this technique. (J.E. Broda, Woods Hole Oceanographic Institute)
An intact core sample taken by hand during a coastal biodiversity survey. (NaGISA)