Question

5. Briefly state how the following factors generate ocean currents: (a) density (b) salinity (c) temperature.
6. What is an ocean current? Why are currents called 'warm' or cold?
7. Why is salinity of oceanic water less in the polar areas and high in the tropical regions?​

Answer 1

5.density:Dense water sinks below less dense water. This is the principle that drives the deep ocean currents that circulate around the world. A combination of high salinity and low temperature near the surface makes seawater dense enough to sink into the deep ocean and flow along the bottom of the basins.

salinity:Since warmer water thus can hold more salt and other molecules than cold water; it can have a higher salinity. To relate this to ocean currents, the higher the salinity of ocean water, the more dense it becomes. When the salinity is high enough, the water will sink, starting a convection current.

temperature: The difference in density of cold water versus density of warmer water is responsible for ocean currents and upwelling. Warm seawater floats and cold (4° C), dense (1 g/cm3), seawater sinks, so ocean temperatures also vary across the surface and into the depths

6.It may be cold, warm and hot. Warm ocean currents originate near the equator and move towards the poles or higher latitudes while cold currents originate near the poles or higher latitudes and move towards the tropics or lower latitude. The current's direction and speed depend on the shoreline and the ocean floor.

7.The temperature and salinity of the sea water also help determine its density. As the temperature of sea water decreases the density also increases. ... The surface salinity is lower in the polar regions than in the tropical regions due to melting each summer.