What is used to get samples from specified depths?

• A. The DPD kit
• B. The DR 900
• C. Kemmerer bottles
• D. Bacon bombs

Answer: (C)

Collecting water samples from a specified depth requires a device that traps water from that exact layer during retrieval, without mixing with water above or below. The Kemmerer bottle is designed for this purpose. It is lowered to the chosen depth and its internal valves/opening mechanism seals the sample at that depth as the bottle is brought back up, preserving a true vertical snapshot of water quality for later analysis. This makes it ideal for creating depth profiles of parameters like nutrients, dissolved gases, or contaminants. Other tools listed serve different tasks: a DPD kit is for on-site chemical testing (like chlorine) rather than sampling by depth; the DR 900 is a field instrument for analyzing water quality data, not a depth-specific sampler; Bacon bombs are an older or alternative sampler but not the standard option for precise depth sampling.