JU, UNF researchers give St. Johns River's health mixed reviews

Elevated levels of dissolved salt and fecal bacteria among study's concerns

JACKSONVILLE, Fla. – When it comes to the health of the St. Johns River, the latest checkup offers yet another mixed bag.

On one hand, the 11th annual State of the River report, compiled by Jacksonville University and the University of North Florida, found that dissolved oxygen levels in the tributaries are the best they’ve been in years. Not to mention phosphorus levels are showing signs of improvement downstream.

On the other hand, there are plenty of reasons for concern – rising levels of dissolved salt, a growing number of non-native species, and levels of fecal bacteria that are “significantly above both previously used and newly developed water quality-criteria” – all of which can disrupt plant and marine life.

“Improvement in dissolved oxygen in the tributaries is encouraging,” said Dr. Radha Pyati, a former UNF chemistry chair and professor who is part of the research team that produced the report. “But the severity of this year’s algal blooms tells us that nutrient levels remain too high.”

Though phosphorus levels are improving, Pyati said, there’s still potential for algae growth, which is a major concern for researchers studying the river’s health. They also found “elevated and widespread” levels of chlorophyll a, which can point to “harmful algal blooms,” the schools said in a joint statement. 

The schools said the number of non-native species has risen to 86 total species, compared to 80 in 2017 and 57 in 2008. The key concern lies with the spread of the lionfish and Cuban tree frogs, whose presence could have a negative impact on the native ecosystem.

Researchers will present their findings on Friday during an environmental symposium held in the Grand Banquet Hall of the Adam W. Herbert Center on UNF’s campus. A copy of the report will also be made available to the public online at SJRReport.com.

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