Significant nitrate attenuation in a mangrove-fringed estuary during a flood-chase experiment.

Significant nitrate attenuation in a mangrove-fringed estuary during a flood-chase experiment. Environ Pollut. 2019 Oct;253:1000-1008 Authors: Wadnerkar PD, Santos IR, Looman A, Sanders CJ, White S, Tucker JP, Holloway C Abstract Intertidal wetlands can sequester pollutants along estuarine conduits. Here we test the effectiveness of a mangrove-dominated estuary in removing dissolved nitrogen during a rain event. We intensively and simultaneously sampled surface water nutrients upstream and downstream of an estuary before, during and after a 63 mm rain event in Coffs Creek (Australia). NOx was the main form of dissolved nitrogen upstream of the estuary (∼60%), while dissolved organic nitrogen (DON) was an important form at the downstream station (∼46%) during observations. High NOx attenuation (71%) occurred during the rain event when the loads reached 31 μmol m-2 catchment area day-1. In contrast, the estuary was found to be a source of NH4+ (∼5 μmol m-2 catchment area day-1). This implies a moderate conversion of upstream NOx into NH4+ and DON along the transport pathway, likely due to tidally-driven pore water exchange within the anoxic estuarine mangrove sediments. Overall, the mangrove-lined estuary attenuated upstream total dissolved nitrogen loads, maintaining water quality and minimizing exports to the coastal ocean even during high flow conditions. PMID: 31434177 [PubMed - in process]
Source: Environmental Pollution - Category: Environmental Health Authors: Tags: Environ Pollut Source Type: research