GEOLOGY

Detailed explanation-1: -At high latitudes, ocean waters receive less sunlight – the poles receive only 40 percent of the heat that the equator does. These variations in solar energy mean that the ocean surface can vary in temperature from a warm 30°C (86°F) in the tropics to a very cold-2°C (28°F) near the poles.

Detailed explanation-2: -The lowest ocean surface temperatures are found near the North Pole and near Antarctica (Fig. 2.8). The highest ocean surface temperatures are found near the equator. This is because, on average, the sun’s rays are most direct at the equator and less direct farther away from the equator.

Detailed explanation-3: -The surface salinity is lower in the polar regions than in the tropical regions due to melting each summer.

Detailed explanation-4: -Areas with a low salinity have the coldest water. Areas with a high density have the warmest water. Areas at high latitudes have the coldest water.

Detailed explanation-5: -Because of the heat input (from the sun) at the surface, the surface layers of the sea are warmest (> 20 degrees), and the temperature decreases with depth (to < 5 degrees). This is especially the case in the equatorial and temperate latitudes.