WELLINGTON, New Zealand » Sometimes the object spotted in the water is a snarled fishing line. Or a buoy. Or something that might once have been the lid to an ice box. Not once — not yet at least — has it been a clue.

Anticipation has repeatedly turned into frustration in the search for signs of Flight 370 as objects spotted from planes in a new search area west of Australia have turned out to be garbage. It’s a time-wasting distraction for air and sea crews searching for debris from the Malaysia Airlines flight that vanished March 8.

It also points to wider problems in the world’s oceans.

"The ocean is like a plastic soup, bulked up with the croutons of these larger items," said Los Angeles captain Charles Moore, an environmental advocate credited with bringing attention to an ocean gyre between Hawaii and Cali­for­nia known as the Great Pacific Garbage Patch.

The world’s oceans have four more of these flotsam-collecting vortexes, Moore said, and the searchers, in an area about 1,150 miles west of Perth, have stumbled onto the eastern edge of a gyre in the Indian Ocean.

"It’s like a toilet bowl that swirls but doesn’t flush," said Moore.

Most of the trash is composed of tiny bits of plastic bobbing just below the surface. Larger items also tend to be plastic and are often fishing-related, Moore said. Though, he added, he has come across light bulbs, a toilet seat and a refrigerator.

Seattle oceanographer Curtis Ebbesmeyer has been studying the phenomena of ocean debris for years. He said there are smaller collections of garbage within the gyres.

"If you go into a house, you’ll find dust bunnies," he said. "The ocean has a mass of dust bunnies, each moving about 10 miles a day."

Ebbesmeyer said he’s fascinated by what happens to the trash that spews from the hundreds of shipping containers lost overboard from cargo ships each year. He said there’s one that keeps belching out Lego pieces onto the beaches of Cornwall, England. Another spilled 2,000 computer monitors. Another released thousands of pairs of Nike sneakers.

Sometimes, he said, the containers themselves can become hazards as they float around for months, buoyed by plastic objects inside or the air trapped behind watertight doors.

Trash also gets into the ocean after being washed down rivers or swept up in tsunamis, Ebbesmeyer said.

Wing Cmdr. Andy Scott, of New Zealand’s defense force, said the crew in a P-3 Orion scouring the ocean for Flight 370 on Saturday spotted about 70 objects in four hours.

Three were deemed worthy of further investigation, he said, but none turned out to be from the missing plane. One was probably a fishing line, he said, another was the suspected ice box lid, and a third was some unidentified brown and orange material.

A cluster of orange-colored items spotted Sunday from an Australian search plane and thought to be a promising lead also turned out to be fishing equipment.

"From my experience, it can be quite a roller coaster," he said. "You sight these search objects and think you’ve made a breakthrough, and then you have to get back to your routine."

Scott said that over time, small pieces of debris can tangle together to make something larger. Such rafts will eventually attract sea life, he said, which can stir up the water and make it appear to be more important than it is.

"A lot of the stuff we are seeing," he said, "is basically rubbish."

Nick Perry, Associated Press