Which term refers to a device used to collect sediment samples by clamshell action?

• A. Grab Sampler
• B. Push Core
• C. Clamshell Sampler
• D. Box Core

Answer: (C)

The clamshell sampler is the device described. It uses two hinged jaws that open and then snap shut like a clamshell to scoop and trap sediment as the instrument is lowered and retrieved. This clamshell action specifically identifies the method as a discrete surface-sediment sampler.

Push cores and box cores are designed to take undisturbed vertical columns: push cores drive a hollow tube into the sediment to preserve layering, while box cores collect a square, larger block of sediment. A grab sampler is a broader term for devices that grab sediment, but the description calling out clamshell action points to the clamshell sampler.