文章基本信息

标题：Nitrogen management challenges in major watersheds of South America
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作者：Mercedes M C Bustamante ; Luiz Antonio Martinelli ; Tibisay Pérez 等
期刊名称：Environmental Research Letters
印刷版ISSN：1748-9326
电子版ISSN：1748-9326
出版年度：2015
卷号：10
期号：6
页码：065007
DOI：10.1088/1748-9326/10/6/065007
语种：English
出版社：IOP Publishing Ltd
摘要：Urbanization and land use changes alter the nitrogen (N) cycle, with critical consequences for continental freshwater resources, coastal zones, and human health. Sewage and poor watershed management lead to impoverishment of inland water resources and degradation of coastal zones. Here we review the N contents of rivers of the three most important watersheds in South America: the Amazon, La Plata, and Orinoco basins. To evaluate potential impacts on coastal zones, we also present data on small- and medium-sized Venezuelan watersheds that drain into the Caribbean Sea and are impacted by anthropogenic activities. Median concentrations of total dissolved nitrogen (TDN) were 325 μg L⁻¹ and 275 μg L⁻¹ in the Amazon and Orinoco basins, respectively, increasing to nearly 850 μg L⁻¹ in La Plata Basin rivers and 2000 μg L⁻¹ in small northern Venezuelan watersheds. The median TDN yield of Amazon Basin rivers (approximately 4 kg ha⁻¹ yr⁻¹) was larger than TDN yields of undisturbed rivers of the La Plata and Orinoco basins; however, TDN yields of polluted rivers were much higher than those of the Amazon and Orinoco rivers. Organic matter loads from natural and anthropogenic sources in rivers of South America strongly influence the N dynamics of this region.