Modeling increased riverine nitrogen export: Source tracking and integrated watershed-coast management

Abstract

The global NEWS model was calibrated and then used to quantify the long term trend of dissolved inorganic nitrogen (DIN) export from two tributaries of Jiulong River (SE China). Anthropogenic N inputs contributed 61-92% of river DIN yield which increased from 337 in 1980s to 1662 kg N km −2 yr −1 in 2000s for the North River, and from 653 to 3097 kg N km −2 yr −1 for the West River. North River and West River contributed 55% and 45% respectively of DIN loading to the estuary. Rapid development and poor management driven by national policies were responsible for increasing riverine N export. Scenario analysis and source tracking suggest that reductions of anthropogenic N inputs of at least 30% in the North River (emphasis on fertilizer and manure) and 50% in the West River (emphasis on fertilizer) could significantly improve water quality and mitigate eutrophication in both river and coastal waters.

Biogeochemical Dynamics in a Eutrophic Tidal Estuary Revealed by Isotopic Compositions of Multiple Nitrogen Species

“…In this study, we select the Jiulong River Estuary (JRE) as an architype of macrotidal subtropical estuary to explore the dynamics of N processes along the salinity gradient and to examine to what degree various N transformations interact during downstream transport. The Jiulong River is characterized by approximately tenfold higher areal yield rate of NO 3 -(>1,000 kg N km 2 year −1 ) than that of the Amazon River (Yan et al, 2012) as a result of intensive agriculture and pig/poultry farming (Chen & Hong, 2012;Yu et al, 2015).…”

“…In this study, we select the Jiulong River Estuary (JRE) as an architype of macrotidal subtropical estuary to explore the dynamics of N processes along the salinity gradient and to examine to what degree various N transformations interact during downstream transport. The Jiulong River is characterized by approximately tenfold higher areal yield rate of NO 3 – (>1,000 kg N km 2 year −1 ) than that of the Amazon River (Yan et al, ) as a result of intensive agriculture and pig/poultry farming (Chen & Hong, ; Yu et al, ). Although the spatial and temporal distributions of DIN (the sum of NO 3 – , NO 2 – , and NH 4 + ) have been archived since the 1990s (Chen, ; Wu et al, ; Yan et al, ; Zhang et al, ), no previous isotopic study in the JRE has been conducted.…”

El Niño‐Driven Dry Season Flushing Enhances Dissolved Organic Matter Export From a Subtropical Watershed

“…Watershed land cover is dominated by forests (69.4%) (Yang et al, 2012). Mean population density is >200 persons per km 2 , with intensive human activities (e.g., sewage discharge, agriculture, and animal husbandry) affecting water quality (Yu et al, 2015). Over 100 hydropower stations are distributed within the watershed, thus increasing the water residence time especially during the low flow period (Gao et al, 2018).…”

A Pilot Study of an Online Intelligent Environmental Observation System for Monitoring and Evaluating Public Health Hazard from Indoor and Outdoor Pollutants

“…The majority of the methods reviewed in the present study refer to monitoring, sampling and measuring of fertilizers, pesticides, insecticides [3, 37, 52-54, 57, 60, 61] as is presented in Table 2. There are also scientific articles and research data which make reference to industrial effluents, waste water and solid waste treatment monitoring [39][40][41][42][43][44][45][46][47][48][49][50][71][72][73][74][75][76][77]. Other methods of sampling techniques and analysis for the monitoring of water bodies focus on the chemical elements (Emergent Contaminants ECs) [3, 4, 50-61, 65-70, 78-81].…”