The 14th annual State of the River Report stresses a need for concern in several areas when it comes to the health of the St. Johns River, despite some positive developments. The city of Jacksonville commissions the academic research document each year.
For one thing, a trend in rising total phosphorus levels that began in 2016 is continuing. That’s helping to fuel another problem: harmful freshwater algal blooms, which are driven by nutrient pollution (including phosphorus and nitrogen), in addition to natural changes in the ecosystem and climate change. Nitrogen in the river’s tributaries remains at an “unsatisfactory” level.
Researchers say rising salinity continues to be of concern as well, despite storms over the past four years that have added significant amounts of freshwater to the river’s system. Increases in salinity are contributing to yet another problematic development: the amount of submerged aquatic vegetation is declining in several regions of the Lower St. Johns River Basin, the Jacksonville area. The plant die-offs are also being driven by sea level rise and the ongoing St. Johns River dredging. These aquatic plants support fisheries, help prevent erosion and even provide flood protection.
Wetlands, another extremely beneficial natural feature, are also being lost throughout the river basin due to development. Additionally, the number of invasive species found in the river basin rose from 90 to 92.
Fecal bacteria like E. coli also continue to be found at high levels in several tributaries, though the report says a new biennial assessment plan that was recently adopted by the state’s Department of Environmental Protection should help speed up the process of identifying issues and restoring water quality.
On the other hand, dissolved oxygen levels in the mainstem of the river are “satisfactory,” according to the report, but levels occasionally dip to low levels in some of the tributaries, which can have negative impacts on aquatic life. And total nitrogen levels are improving in the river.
Scientists are also keeping an eye on nasty chemicals called per- and polyfluoroalkyl, or PFAS, which are considered an “emerging” contaminant in the St. Johns River. These man-made chemicals are used in stain and water repellents, and they don’t easily break down, so they can accumulate not only in the environment but also in the human body. Exposure to PFAS can lead to health issues.
The annual State of the River report is written collaboratively by a team of researchers from Jacksonville University, the University of North Florida, Florida Southern College in Lakeland, and West Chester University in Pennsylvania, with support from the city of Jacksonville’s Environmental Protection Board.
