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DOI | 10.2489/jswc.71.3.167 |
Regional patterns of total nitrogen concentrations in the National Rivers and Streams Assessment | |
Omernik, J.1; Paulsen, S.2; Griffith, G.1; Weber, M.2 | |
发表日期 | 2016-05-01 |
ISSN | 0022-4561 |
卷号 | 71期号:3页码:167-181 |
英文摘要 | Patterns of nitrogen (N) concentrations in streams sampled by the National Rivers and Streams Assessment (NRSA) were examined semiquantitatively to identify regional differences in stream N levels. The data were categorized and analyzed by watershed size classes to reveal patterns of the concentrations that are consistent with the spatial homogeneity in natural and anthropogenic characteristics associated with regional differences in N levels. Ecoregions and mapped information on human activities including agricultural practices were used to determine the resultant regions. Marked differences in N levels were found among the nine aggregations of ecoregions used to report the results of the NRSA. We identified distinct regional patterns of stream N concentrations within the reporting regions that are associated with the characteristics of specific Level III ecoregions, groups of Level III ecoregions, groups of Level IV ecoregions, certain geographic characteristics within ecoregions, and/or particular watershed size classes. We described each of these regions and illustrated their areal extent and median and range in N concentrations. Understanding the spatial variability of nutrient concentrations in flowing waters and the apparent contributions that human and nonhuman factors have on different sizes of streams and rivers is critical to the development of effective water quality assessment and management plans. This semi quantitative analysis is also intended to identify areas within which more detailed quantitative work can be conducted to determine specific regional factors associated with variations in stream N concentrations. |
英文关键词 | ecoregions;environmental sampling;nitrogen;nutrients;water quality;watersheds |
语种 | 英语 |
WOS记录号 | WOS:000376220800005 |
来源期刊 | JOURNAL OF SOIL AND WATER CONSERVATION
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来源机构 | 美国环保署 |
文献类型 | 期刊论文 |
条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/58038 |
作者单位 | 1.US Geol Survey, Corvallis, OR USA; 2.US EPA, Corvallis, OR USA |
推荐引用方式 GB/T 7714 | Omernik, J.,Paulsen, S.,Griffith, G.,et al. Regional patterns of total nitrogen concentrations in the National Rivers and Streams Assessment[J]. 美国环保署,2016,71(3):167-181. |
APA | Omernik, J.,Paulsen, S.,Griffith, G.,&Weber, M..(2016).Regional patterns of total nitrogen concentrations in the National Rivers and Streams Assessment.JOURNAL OF SOIL AND WATER CONSERVATION,71(3),167-181. |
MLA | Omernik, J.,et al."Regional patterns of total nitrogen concentrations in the National Rivers and Streams Assessment".JOURNAL OF SOIL AND WATER CONSERVATION 71.3(2016):167-181. |
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