Water Detective

An army of 350 Watershed Watch volunteers monitor and test the water at more than 250 locations around Rhode Island. For one volunteer, who’s been tracking water quality in Narrow River for two decades, it’s a labor of love.

By Bill Ibelle

It’s early morning on Narrow River and the spring wind blows chilly from the north as Veronica Berounsky, Ph.D. ’90, lowers a Secchi disc over the side of her Carolina Skiff. The disc is a simple test of water clarity, virtually unchanged since the device was invented in 1865 by the pope’s astronomer, Angelo Secchi.

All Watershed Watch volunteers monitor water clarity, temperature, salinity, dissolved oxygen, acidity, chlorophyll, algal density, and nutrients, such as phosphorous and nitrogen. They also monitor bacteria levels.

Berounsky, who has been a volunteer with URI’s Watershed Watch for 20 years, can distinguish the black and white sections of the disc to a depth of 6 feet, which is quite good compared to the 3-foot visibility typical in midsummer. Cloudy water usually indicates excessive algae growth, which is caused by nutrients from lawn fertilizers, pet waste, and failing septic systems. As the algae die and decompose, they use dissolved oxygen in the water, leaving less for fish and other animals.

In addition to water clarity, all volunteers for the program monitor temperature, salinity, dissolved oxygen, acidity, chlorophyll, algal density, and nutrients, such as phosphorous and nitrogen. Most importantly, they also watch for elevated bacteria levels, which have kept Narrow River closed to shellfishing since 1986.

Berounsky, a coastal ecologist and coordinator of alumni relations and communications for the Graduate School of Oceanography, explains that tidal estuaries like Narrow River play an important role in New England ecology because the daily mixing of salt and fresh water provides a unique habitat for hundreds of plant and animal species.

Veronica Berounsky, Ph.D. ’90, has been a Watershed Watch volunteer for 20 years, sampling and testing the water in Narrow River.

But among these biologically diverse microenvironments, Narrow River is special.

About 4 miles up the river lie two deep-water kettle ponds carved by retreating glaciers 11,000 years ago. These ponds are protected from the full tidal surge by shallow sandbars that reduce the mixing of salt water that slides in over the bars. The result is three distinct layers of water with the bottommost devoid of oxygen. Scientists from around the world visit these ponds to study unusual microorganisms that live without oxygen and survive entirely on sulfur.

To monitor the health of this environment, Berounsky lowers an intricate glass chamber known as a Niskin bottle over the side of her boat and fills it with anoxic water—water that lacks oxygen—found at 40 to 65 feet below the surface. She then releases a pulley that caps the bottle underwater before any air can get inside. As she performs this operation, she tells the story of a strange event that occurred in this spot a few years ago.

What’s that smell?

On Friday, Oct. 12, 2017, residents noticed a strong smell of rotten eggs. The next morning, the URI women’s crew team noticed that the river’s lower pond had suddenly turned a strange milky white. Dead fish floated in the water and crabs scurried out of the pond to dig themselves into the soggy exposed mud.

The cause was an “overturn,” in which the stratified water layers of the kettle pond flipped upside down—the top layer rotating to the bottom and the anoxic bottom layer rotating to the top, bringing with it the smelly sulfur that feeds the strange lifeforms thriving in those murky depths.

An overturn is relatively rare, occurring once every decade or so. It requires a combination of several factors. The first is an exceptionally dry fall, which results in less fresh water flowing into the pond and more cold, dense ocean water coming in over the top. The result is a top-heavy pond. But this alone isn’t enough. A quick drop in temperature and a blustery wind are also required.

Berounsky emphasizes that an overturn is an entirely natural phenomenon. It’s smelly, weird, and no fun if you’re a crab—but it’s not caused by pollution.

She also notes that three decades of monitoring the Narrow River have demonstrated that conditions are improving steadily and that new municipal sewer systems, coupled with catch basins to filter road and yard runoff, are making a difference.

Although closed to shellfishing, the river has never been closed to swimming, a fact that Berounsky recently took advantage of by swimming the length of the 6-mile river to raise funds for its preservation.

“As an ecologist, it was interesting to watch the biology change as I swam down the river. It was a new perspective on a river I’ve lived on and worked to preserve for 30 years,” says Berounsky, who is co-president of the Narrow River Preservation Association and chair of the Rhode Island Rivers Council. “It’s a unique body of water and important for us to preserve its beauty and ecology.”

See related story: Rhode Island’s Water Warriors