UNIVERSITY PARK, Pa. (WHTM) — A new study out of Penn State has found climate change could be affecting rivers even more than the oceans. This could cause problems for everything that relies on rivers — including humans.

Researchers say their findings are both surprising and disturbing. They say rivers are getting warmer and losing oxygen faster than oceans, and that could have long-term impacts.

“These are not something to be take[n] very lightly,” Penn State professor of Civil and Environmental Engineering and corresponding author on the study Dr. Li Li said.

Dr. Li said she and her group of researchers at Penn State focus on “how climate change and like human activities, influence what’s in the river,” and the results of their most recent study are troubling.

“We usually don’t expect rivers and streams to lose oxygen as much,” she said, explaining plants in rivers usually get more sunlight, making it easier to for them to produce oxygen.

Li’s group studied nearly 800 rivers going back 40 years. They found that 70% are losing oxygen and nearly 90 percent are warming up.

“If the oxygen, we’re losing oxygen enough, low enough, fish dying off is not uncommon,” Li said. The study predicts in the next 70 years, oxygen levels could get so low, some species of fish will not be able to survive at all.

Low oxygen and warmer rivers are problematic for humans too. These conditions can lead to the release of heavy metals into streams, and low oxygen can also lead to the emission of greenhouse gases like nitrous oxide and methane.

“Fisheries will be affected, tourists or will be affected, even property values will be affected along the rivers,” Li said.

In Pennsylvania, there are already many efforts to preserve water quality. As part the Fish and Boat Commission’s strategic plan, the agency tries to “Mitigate the effects of environmental and human-induced impacts” like climate change through projects like planting trees on streambanks and reducing runoff into rivers.

As for water temperature, spokesperson Mike Parker said in a statement, “Wild trout populations, which require cold and clean water year round, are a focus of our efforts.”

Li said the best thing everyone can do for rivers is to cut greenhouse gas emissions.

“We can reduce the pace of warming, and hopefully it will also affect how fast rivers are warming up,” she said.

Li said she does hope to expand this study. Her group looked at rivers in the US and Central Europe because those sites had the most data available, but looking at rivers on a global scale will help us understand how bad the problem is.