Superstorm Sandy left destruction across Long Island a decade ago, but it also helped clean up the Great South Bay.

The storm ripped through a part of Fire Island, causing a breach west of Smith Point Park that let water flow from the ocean into Bellport Bay.

Initially there was serious concern, but soon experts realized the storm was actually helping the bay heal.

"The increased exchange with the ocean cleaned the bay," says Stony Brook University Research Professor Charlie Flagg.

Flagg started documenting rising salinity levels, cleaner water and a rebirth of marine life in parts of the Great South Bay

However, the breach has mostly closed at this point.

The Stony Brook professor says breaches and shore lines are constantly changing, but he worries there will be a return of high nitrogen levels and reduced marine life.

"The not so good phytoplankton are gonna reestablish themselves because they take advantage of the higher neutrian loads," Flagg says.

He says a big storm could open up another breach but doesn't know exactly when or where it could happen.

Until more ocean water is infused into the bay it's up to people to help protect the waters.

Flagg says that can be done by modernizing septic systems and reducing nitrogen runoff into the bay.