The search area for missing Malaysia Airlines Flight 370 has been shifted nearly 700 miles northeast, March 28, 2014. (Australian Maritime Safety Authority)

The search for debris from missing Malaysia Airlines flight 370 has not turned up any evidence of a crash, but it has trained the world's gaze on thousands of pieces of junk floating on the ocean's surface.

Much of that debris could be made up of plastics, old appliances or parts of homes that have washed away from fragile communities, and cargo containers from ships, according to ocean advocacy group One World One Ocean.

Check out some of the facts about what's really floating in our oceans:

The Pacific Garbage Patches: The most heavily-researched and well-known example of plastic pollution in the ocean is the Great Pacific Garbage Patch, made up of some 3.5 million tons of plastic beverage bottles, grocery bags, and plastic goods that have been pushed together by water currents that circulate between the west coast of North America and the east coast of China and Russia.

The Five Ocean Gyres: Pollutions can easily get caught in one of the five "gyres" of the ocean: the northern and southern Atlantic gyres, the Indian Ocean gyre, and the northern and southern Pacific gyres. The term describes water that moves in a circular, rotational current over a vast space in the ocean, pulling in stray plastics as it moves until they collide and merge with one another. B ecause these gyres are trafficked heavily by cargo ships, the garbage patches contain large objects that have gone overboard from ships, including entire cargo containers.

Indian Ocean's Plastic Problem: Researchers only began focusing on plastic pollution in the Indian Ocean in recent years, and in 2010 discovered garbage patches much like the famous Pacific Garbage Patch, according to Coastal Cares, another clean ocean advocacy group.

Plastic Breaks Down: As the garbage floats into the gyres it is broken down by salt and UV rays and begins releasing chemical properties into the water that then enter the food system, according to the Scripps Institute at the University of California San Diego. The plastics also fall into smaller pieces that can make them difficult to clean up.