Why does tropical ocean have a greater temperature range than temperate ocean?

Tropical oceans lie between the Tropic of Capricorn and the Tropic of Cancer and include the central parts of the Pacific Ocean and the Atlantic Ocean, as well as the Indian Ocean. Average temperatures exceed 20 degrees Celsius and remain constant throughout the year.

In the Northern Hemisphere, temperate oceans are located between the Tropic of Cancer and the Arctic Circle. In the Southern Hemisphere, temperate seas lie between the Tropic of Capricorn and the Southern Ocean. Temperatures are between 10 and 20 degrees Celsius, and fluctuate along with the seasons.

Tropical waters are crystal clear, while temperate waters are a murky blue-green color. What causes the blue-green color is plankton. The more murky the water, the more plankon it contains.

Plankton are tiny organisms that float near the ocean surface. They get their energy through photosynthesis and are eaten by many creatures low on the food chain.

The majority of fish that are served in restaurants or bought at markets to be cooked at home are caught in temperate seas. The high plankton concentration allows large schools of fish to thrive. The high concentration of fish sustains birds and mammals, as well as humans. These include Atlantic herring, abalone, cod, hake, halibut, haddock, mackerel, monkfish, sWordfish, salmon, blue mussels, northern lobsters and king crabs.

The tropical oceans play a critical role in regulating the Earth's weather patterns. The sun shines squarely on the waters around the equator all year. Warm surface water is evaporated, forming a mass of warm, humid air. This air cools as it travels north and south, condensing into clouds. The clouds grow heavy and precipitation, or rain, occurs. The rain is vital for rain forests in tropical climates and agriculture in more temperate climates.