UW News

Jennifer Ruesink


September 10, 2019

Tides don’t always flush water out to sea, study shows

Dawn in Willapa Bay in 2015, showing oysters on a tidal flat.

Researchers at the University of Washington and the University of Strathclyde report that, in Willapa Bay in Washington state, the water washing over the tidal flats during high tides is largely the same water that washed over the flats during the previous high tide. This “old” water has not been mixed in with “new” water from deeper parts of the bay or the open Pacific Ocean, and has different chemical and biological properties, such as lower levels of food for creatures within the tide flats.