The temperature of ocean water does not change with depth very much for about 300 m, and then as depth increases to about 1000 m, it decreases rapidly. Below 1000 m the temperature decreases very slowly with depth. A typical middle latitude approximation would be T = 22°C for the first 300 m of depth, then T decreases to 5°C at 1000 m, and then to 2°C at a depth of 5000 m. Graph T as a function of the depth d, assuming linear changes.