Van Veen grab sampler

The Van Veen grab sampler is an instrument to sample

A draw-back of the use of this sampler is that it tends to disturb the sediments more than a box corer does.

Mechanism

While letting the instrument down into the water, the two

• 
  Van Veen grab when it is locked, ready to be lowered to the floor
• 
  It is now unlocked after hitting the floor, ready to collect sediment
• 
  When lifting it after unlocked, the jaws will close to collect sediment inside

Three small technical changes lead to variations with more mechanical parts or structure:

• The Ekman grab sampler does not close the
  shovels
  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 and has additional springs which are released upon bottom contact which might be helpful for harder surfaces.
• The Young modified grab sampler includes a metal frame for additional stability.

See also

• Epibenthic sled

References