Marine Science 2016 Edition

Page 154 Chapter 6 Temperature and sea water Ocean surface temperatures vary from 28 o C in the tropics to below zero at the poles. Figure 154.1A shows the surface temperatures in the Pacific Ocean. Figure 154.1B shows the temperatures of the Pacific depths (photographs courtesy NOOA). The ocean surface can be heated by radiation from the sun, conduction of heat from the atmosphere or condensation of water vapour. The sea surface can be cooled by radiation back from the sea to the atmosphere, conduction of heat back to the atmosphere or evaporation. Ocean currents can also transfer heat from one place to another. Biological significance of temperature Animal migrations occur due to temperature. Whales migrate to warmer waters to calf. Corals spawn at certain temperatures and the composition and texture of marine animals and plants is governed by temperature. Animals that live on the rocky shore also develop protective coverings to compensate for temperature changes. In recent times, coral bleaching (see Chapter 11) has been blamed on increased temperature changes. Figure 154.1 Pacific Ocean potential temperatures. (Illustration A courtesy Commonwealth bureau of meteorology Illustration B courtesy NOOA) B Colour references Try the following words in your search engine: Pacific Ocean surface sea temperature Can you see the thermocline? See chapter 3 for more information on temperatures and currents. Depth A