Rivers Reveal Hidden Information About the Entire Ecosystem

CONCORD, N.H. — Rivers are the one place scientists can get a full picture of what’s happening in the landscape, a scientific paper published in Frontiers in Water this week found.

In New Hampshire, there are about 19,000 miles of streams and rivers that offer important information about water quality, pollution, and the impact of climate change, according to N.H. scientist Adam Wymore.

Wymore, who was one of the paper’s authors, is an assistant research professor at UNH’s Department of Natural Resources and the Environment, and he works at the New Hampshire Agricultural Experiment Station, the University of New Hampshire’s first research organization.

He said rivers offer important clues about what’s happening in the entire ecosystem that can inform both scientists and members of the public.

A river collects rainfall after it’s made its way across the landscape, bringing with it chemical signatures that can reveal what’s happening there. Plus, Wymore said, it’s also integrating the groundwater moving underneath the trees and soil. That’s why rivers and streams reveal so much about the broader environment, even though they only account for a small amount of earth’s surface.

Nitrogen pollution is one example of how this works. Human development adds a lot of nitrogen to the soil, which then shows up in rivers around the state. Scientists like Wymore can track where pollution is coming from and how it’s changing over time by studying rivers.

“It’s the only real way to take a whole-ecosystem approach,” he said. That’s a growing movement in the scientific community that aims to study the environment as an interconnected system. That also means reevaluating the role humans play as a part of that system, rather than separate from it.

Humans have been manipulating streams and rivers for centuries, but that’s only now starting to be explicitly acknowledged in science, according to Wymore.

Waterways can also help scientists understand when a system has been disrupted. Take extreme weather, like the recent flooding New Hampshire experienced this summer or the droughts of 2016 and 2020. Wymore said those disturbances will often show up in the chemistry of surface water.

The cycles between drought and extreme rain raise questions about how this will affect water resources. Studying streams and rivers is one way to learn how the ecosystem is responding. That’s also true when it comes to what may be the greatest disruption of all: climate change.

“In terms of water quality and freshwater resources, I think one of the big questions out there is how is the hydrologic cycle going to respond to climate change?” Wymore said.

For now, that’s an open question.

Source : Boston Globe


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