Luu,T.N.M., Garnier,J., Billen,G., Le,T.P.Q., Nemery,J., Orange,D. and Le,L.A.(2012): N, P, Si budgets for the Red River Delta (northern Vietnam): how the delta affects river nutrient delivery to the sea. Biogeochemistry, 107, 241-259.

『紅河デルタ（北部ベトナム）についての窒素・リン・ケイ素収支：デルタは海洋へ河川栄養放出にどのように影響するか』

『Abstract
　The Red River Delta (RRD) (Vietnam), a region experiencing rapid population growth, industrialization, and economic development, concentrates 54% of the population of the whole Red River watershed in less than 10% of the basin area. Our study aimed at understanding and quantifying the processes by which the delta affects the nutrient fluxes coming from the upstream watershed before they reach the sea. A comprehensive budget on nitrogen (N), phosphorus (P), and silica (Si) fluxes associated with natural and anthropogenic processes in the terrestrial and hydrological system of the delta was established for five sub-basins of the delta for the period 2000-2006, based on official statistical data, available measurements, and our own sampling campaigns and enquiries. The results show that anthropogenic inputs of N and P brought into the delta area are higher than the amounts delivered by the river from the upstream watershed. However, the amounts of these two elements ultimately delivered to the coastal zone from the delta are lower than the amounts carried by the upstream river, showing extremely efficient retention of both the soils and the delta's drainage network. For Si (taking into account both dissolved and amorphous solid forms), the retention is much lower. High retention of N and P and low retention of Si in the delta area have up to now protected the coastal zone from severe eutrophication problems.

Keywords: Red river; Delta; Nutrient budget; nitrogen; Phosphorus; Silica; Marine eutrophication; ICEP indicator

Introduction
Study site: the red river delta
　Geomorphologic and hydrologic characteristics
　Land use, social and economic conditions
　 Meteorological conditions
Minerals and methods
　Chemical analysis
　　Particles
　　Dissolved elements
　Questionnaire and statistics
　Nutrient and suspended solid flux calculations
　Nutrient and suspended solid budget for the five sub-basins
　　Budget of the soil system
　　Budget f the hydrological network
　　Sources of error and uncertainty
Results and discussion
　Nutrient budgets
　Eutrophication potential
　Comparison with other estuarine systems
Acknowledgments
Open access
References

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