Nitrogen Removal and Recycling by Sediments in the Lower Great Miami River, Ohio
Year: 2016
Type: article
Abstract: The Lower Great Miami River (LGMR) has recently experienced algal blooms due to excess nitrogen (N) and phosphorus (P). Some Ohio water treatment plants were ordered to reduce the amount of P that they release into the river, but N also can stimulate eutrophication and algal blooms, either alone or in combination with P. In this study, LGMR sediment N transformations and effects of river impoundments on N cycling were compared with external N loads during different flow conditions to determine the extent to which N is removed or recycled within the system. Sediment nutrient fluxes, sediment N sinks and sources (denitrification/anammox and N fixation, respectively), and potential dissimilatory nitrate reduction to ammonium (DNRA) were evaluated. Results suggest that LGMR sediments were a net N sink, with high rates of denitrification during spring and summer. In contrast, LGMR sediments were a source of NH4+ and o-PO43-, which may support algal blooms. LGMR sediments removed between 8 and 33% of N loads via denitrification/anammox, but can also return nutrients to the water column, where they might fuel additional production and eutrophication. River impoundments had inconsistent effects on N cycling along the LGMR during the study period. While LGMR sediments can remove a large percentage of N load, at least 67% of N is exported, lending support to the need for watershed control of N to protect downstream systems.
Author: Lee A. Slone
Institution: Wright State University
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2597203571