The Young grab, or the Young modified Van Veen grab sampler is an instrument to sample

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

in the

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...

. It is a modified version of the

Van Veen grab sampler The Van Veen grab sampler is an instrument to sample sediment in water environments. Usually it is a clamshell bucket made of stainless steel. Up to 20 cm deep samples of roughly 0.1 m2 can be extracted with this instrument. It can be light-wei ...

, with a

clamshell bucket A bucket (also called a scoop to qualify shallower designs of tools) is a specialized container attached to a machine, as compared to a bucket adapted for manual use by a human being. It is a bulk material handling component. The bucket has an in ...

made out of

stainless steel Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...

mounted to a supporting frame. The sampling area extracted with this instrument can vary depending on its size. With the modifications this version of the Van Veen grab sampler is heavier than the traditional version. The frame allows for better stability and level sampling. Weights can be attached to the frame to ensure the bucket grabs sufficient sediment, or skids to ensure the gear does not sink too deep in soft sediments. A draw-back of the use of this sampler is that it tends to disturb the sediments more than a

box corer The box corer is a marine geological sampling tool for soft sediments in lakes or oceans. It is deployed from a research vessel with a wire and suitable for any water depth. It is designed for a minimum of disturbance of the sediment surface by b ...

does. This does also not allow for sampling of the water column, but only the

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

surface.

Mechanism

While letting the instrument down into the water, the two

lever A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...

s with

buckets A bucket is typically a watertight, vertical cylinder or truncated cone or square, with an open top and a flat bottom, attached to a semicircular carrying handle called the ''bail''. A bucket is usually an open-top container. In contrast, a ...

at their ends are spread like an open scissor. The levers are locked in this position, and unlock when hitting the ground. When the rope is pulled upward again, the two buckets close and grab a sample from the

sea floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

. Two small technical changes lead to variations with more mechanical parts: * The Ekman grab sampler does not close the

shovels A shovel is a tool used for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore. Most shovels are hand tools consisting of a broad blade fixed to a medium-length handle. Shovel blades are usually made o ...

instantly on ground contact, but a messenger weight has to be sent down in order to release springs and take the sample. * The Ponar type sampler is modified also has additional springs which are released upon bottom contact which might be helpful for harder surfaces.

References

{{reflist Aquatic ecology Biological oceanography Oceanography Oceanographic instrumentation