CTD sensors are instruments used to measure the conductivity, temperature, and depth of water. These sensors are essential for understanding oceanographic and environmental conditions, as they help scientists gather data about water properties in various aquatic environments. Typically deployed on research vessels or buoys, CTD sensors collect data that can be used to study ocean currents, salinity, and the overall health of marine ecosystems. The information gathered is crucial for climate research, fisheries management, and understanding the impacts of pollution in water bodies.