Organic nitrogen distribution in NOM size classes

被引:23
作者
Egeberg, PK [1 ]
Eikenes, M [1 ]
Gjessing, ET [1 ]
机构
[1] Agder Coll, Dept Nat Sci, N-4604 Kristiansand, Norway
关键词
D O I
10.1016/S0160-4120(98)00101-9
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
In Norwegian lakes, organic nitrogen typically constitutes about 60% of the total dissolved pool of nitrogen. However, evaluation of its effect on aquatic ecosystems and its role as promoter of heterotrophic growth in water distribution systems is difficult because of restricted knowledge about the various forms of organically-bound nitrogen in water. On line standard wet chemical analysis of total nitrogen was combined with high-performance size exclusion chromatographic (HPSEC) separation of natural organic matter (NOM) for investigation of the distribution of nitrogen between size classes of NOM. It was found that the high molecular weight (HMW) size fractions (humic acids) are enriched in nitrogen relative to the low molecular weight (LMW) size fractions (fulvic acids, nominal molecular weights of about 1000 Daltons) by a factor of up to 10. The low molecular weight size fractions (a few hundred Daltons) are interpreted to be of autocthonous origin based on their low C/N ratios, and correlation with the eutrophic status of the source waters. It was observed that NOM from water sources surrounded by large catchments contains relatively more nitrogen in HMW size fractions than NOM from small catchments, except that bog-derived NOM is particularly enriched in HMW nitrogen. (C) 1999 Elsevier Science Ltd.
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页码:225 / 236
页数:12
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