Riverine N₂O concentrations, exports to estuary and emissions to atmosphere from the Changjiang River in response to increasing nitrogen loads

Abstract

. Taken together, the findings reported here suggest that both the river N 2 O concentrations and emissions would increase in response to rising anthropogenic nitrogen loads. Our study showed that the mean emission factor based on the ratio of the total N 2 O flux to NO 3 À flux is four times greater than the value of 0.0025 obtained with the methodology recommended by the Intergovernmental Panel on Climate Change. Thus, our findings reflect the open river channel rapid exchange of gases with the atmosphere.

Spatio-Temporal Variation and Controlling Factors of Water Quality in Yongding River Replenished by Reclaimed Water in Beijing, North China

“…The availability of electrons for transfer between species was characterized by ORP, which could be measured in the field in surface water. The species of nitrogen in water were strongly affected by the redox environment [48,49]. In Figure 11, the ORP were mostly positive except for three samples, with positive values ranging from 47.4 to 214.6 mV, and the corresponding DO with variation from 7.21 to 18.0 mg/L.…”

Effect of dissolved oxygen and nitrogen on emission of N 2 O from rivers in China

“…Samples for N 2 O analysis were collected by filling 60-mL glass serum bottles from the sampler. Samples were preserved by adding a small crystal of KOH to each bottle immediately before sealing (Yan et al, 2012). All samples were collected in triplicate.…”

“…Numerous investigations have reported strong correlations between dissolved N 2 O and NO 3 -concentration in river waters (Herrman et al, 2008;Silvennoinen et al, 2008). Yan et al (2012) concluded that NO 3 -is a valid predictor of river N 2 O production in a large-deep river. However, some studies have failed to find the relationship in river waters.…”

Riverine N2O production, emissions and export from a region dominated by agriculture in Southeast Asia (Jiulong River)

“…In addition, riverine N 2 O also influences the biogeochemistry and N budget of the adjacent estuary, particularly for those river-dominated estuaries. A few studies have addressed N 2 O in China water environments (reservoirs, lakes, rivers, estuaries) which have been subject to intense anthropogenic N inputs over recent decades (Xu et al, 2005;Wang et al, 2007Wang et al, , 2009bWang et al, , 2012Chen et al, 2008a;Zhang et al, 2010;Liu et al, 2011;Yang et al, 2011;Yan et al, 2012;Xia et al, 2013). Nevertheless, very few direct observations of the two end-products (N 2 O and N 2 ) of nitrification and denitrification have been made over river networks to explore N 2 O production, emission and export to estuary.…”