SEATTLE - Researchers spent a windy week at Washington State's Willapa Bay before being blown away by an accidental discovery.
They were using infrared cameras to study how quickly seawater drained off of mud flats after the tide went out. They were operating under the common belief that the ocean gives the mud flats what they need to survive and then leaves it high and dry.
So once the flats are exposed, we would have expected, before we started this project, that nothing more is happening. Flats are dry, tide has ebbed, we're done, said University of Washington Oceanographer Jim Thomson.
But at one point, they left the camera on after the tide had gone and that's when Thompson said somebody glanced at the screen.
They said, said, 'Hey. Look at this. There's all this water coming out of here,' said Thomson.
The camera showed the water was warmer than sea water, so the team knew the mud flats weren't just shedding tidal water. They were producing their own fresh water.
Thomson and his team made a discovery. Buried within the insulating mud of the flats was a reservoir of warm, fresh water that was constantly flowing into streams and the ocean.
The discovery changes the way scientists will look at mud flats. Thomson said it could lead to changes in the way projects are built near them or how farms operate near or on them. It could also lead to a new understanding of how shellfish, salmon and the rest of the ocean depend on the mud flats for a steady supply of fresh water.