Potential for Direct Nitrate-Nitrite Inhibition of Submerged Aquatic Vegetation (SAV) in Florida Springs: A Review and Synthesis of Current Literature
Todd Z. Osborne1,2*, Robert A. Mattson3, Michael F. Coveney3
1 Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL
2 Wetland Biogeochemistry Laboratory, Soil and Water Science Department, University of Florida, Gainesville, FL
3 Bureau of Environmental Sciences, St. Johns River Water Management District, Palatka, FL
*corresponding author: 9505 Ocean Shore Blvd., St. Augustine, Fl 32080 (904) 461-4000 [email protected]
Received May 7, 2015; Revised March 11, 2015; Accepted April 1, 2016; Published: March 7, 2017; Available online: March 8, 2017
Abstract
Current observations of water quality in groundwater discharge from springs in Florida show anthropogenic enrichment of nitrate plus nitrite (NOx-N) generally attributed to fertilizer application and/or wastewater or manure sources in individual spring sheds. Excessive levels of NOx-N have been implicated in eutrophication of, and observed changes in, submerged aquatic vegetation (SAV) communities in several spring runs. While the indirect effects of nitrogen (N) enrichment on SAV, are well-documented (i.e., algal productivity resulting in shading of macrophytes), there is considerably less information available concerning direct effects of NOx-N such as toxicity or inhibition of macrophyte growth. This manuscript constitutes a review of the pertinent literature and synthesis of the current understanding of elevated NOx-N in aquatic systems and the effects on SAV as viewed from the prevailing eutrophication paradigm, as well as, explores the hypothesis that NOx-N may have direct inhibitory effects on SAV growth in Florida springs.