Seasonal Variation in Nitrate Removal Mechanisms in Coastal Stormwater Ponds

Stormwater wet ponds (SWPs) are engineered structures used to collect and retain stormwater runoff from developed areas. SWPs generally regarded as important nitrogen (N) sinks, but seasonal variation in SWP N cycling that influences pond removal has not been characterized. To inform function across seasons, we sampled the sediments water columns of three southeastern US coastal plain measured gas nutrient fluxes sediment-water interface during ambient conditions nitrate (NO3)-enriched “simulated storm” conditions. Dissolved organic (DON) was dominant form dissolved column, while + nitrite (NOx) typically below detection. sediment matter properties varied by study site had minimal impact on processes or estimated NO3 fate. functioned TN sinks NO3-enriched conditions, fate based temperature, DON concentrations, O2 uptake. These results suggest permanent (denitrification) varies seasonally, with retention NOx becoming more hotter when uptake is largest. Low concentrations rapid can host reduced may promote over denitrification. Additional research needed determine retained how might downstream quality.