What is the primary function of an echo sounder?

The primary function of an echo sounder is to determine depth by transmitting sound waves. An echo sounder operates by emitting a sound pulse into the water column. When this sound pulse encounters the seabed or any object in the water, it reflects back to the equipment. By calculating the time it takes for the sound pulse to travel to the seabed and back, the system can determine the water depth accurately. This method is essential in hydrographic surveying for mapping underwater topography and is a fundamental tool in navigation and marine resource management.

The other options, while related to marine environments, do not specifically address the primary capability of an echo sounder. For instance, measuring water temperature is more aligned with thermometers or temperature sensors. Mapping sea flora and fauna involves different techniques, such as using sonar or cameras specific for biological studies. Tracking marine traffic typically relies on radar or AIS (Automatic Identification System) technologies, which are not functions of an echo sounder.