Instrument that every oceanographer uses

An instrument that every oceanographer could use would be a thermometer. It is important to geological and geophysical oceanographers when studying the physical features of the ocean currents and ocean floor. Thermometers are important for biological oceanographers when they are studying where both flora and fauna live among each other. Based on temperature in accordance to their discoveries of different flora or fauna that could only survive in certain temperatures of water. This is equally important with both physical and chemical oceanographers. Although physical oceanographers study the waves, tides, and currents, where as chemical oceanographers study the composition of the water. Because of this it is important for both physical and chemical oceanographers to understand the temperatures of the water at different locations and how it responds in accordance to their studies or the water.