What instrument is used to measure dissolved oxygen in water?

The correct choice involves the dissolved oxygen meter, which is specifically designed to measure the amount of oxygen that is present in water. This measurement is crucial for assessing water quality, particularly in aquatic environments, since dissolved oxygen is vital for the survival of fish and other aquatic organisms. The dissolved oxygen meter typically employs sensors that can provide real-time measurements, allowing for accurate monitoring of oxygen levels in various water sources.

Other instruments mentioned serve different purposes: a pH meter measures the acidity or alkalinity of a solution, a conductivity meter assesses the ability of water to conduct electricity (which can indicate the concentration of ions), and a turbidimeter quantifies the turbidity of a liquid by measuring the cloudiness caused by suspended particles. While all these instruments are important in water quality analysis, only the dissolved oxygen meter is specifically tailored to measure dissolved oxygen concentrations.