11. (Warm , Cool) surface temperatures and (high, low) surface densities occur in the equatorial regions. While at high latitudes, (warm , cool) surface temperatures and (high, low) surface densities are found. Circle what you think are the correct answers. 12. What is the reason for the fact that higher average surface densities are found in the Southern Hemisphere? Figure 9.14 shows how ocean water temperature varies with depth at different latitudes. Use the gure to answer questions 13-15. 13. Temperature decreases most rapidly with depth at (high , low) latitudes. Circle your answer and give the reason that the decrease with depth is most rapid at these latitudes. The layer of water where there is a rapid change of temperature with depth is called the thermocline (thermo = heat, cline = slope). The thennocline is a very important structure in the ocean because it creates a vertical barrier to many types of marine life. 14. In which of the three zones shown in Figure 9.14 does the thermocline occur? 15. Below the thermocline the temperature of ocean water (increases rapidly , remains fairly constant, decreases rapidly ). Circle what you think is the correct