ISSN:
1432-0789
Keywords:
N mineralization
;
Assimilation
;
Nitrification
;
NO in3 sup- reduction
;
Riparian fen
;
15N substrates
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Gross rates of N mineralization, assimilation, nitrification, and NO in3 sup- reduction were determined in soil from a wet riparian fen by 1-day incubations of soil cores and slurries with 15N-labelled substrates. N mineralization transformed 0.1% of the total organic N pool daily in the soil cores, of which 25% was oxidized through autotrophic nitrification and 53%–70% was incorporated into microorganisms. N mineralization and nitrification were markedly inhibited below 5 cm in soil depth. At least 80% of the NO in3 sup- reduction in aerated cores occurred through dissimilatory processes. Dissimilatory reduction to NH in4 sup+ (DNRA) occurred only below 5 cm in depth. The results show that NH in4 sup+ oxidation was limited by available substrate and was itself a strong regulator of NO in3 sup- -reducing activity. NO in3 sup- reduction was significantly increased when the soil was suspended under anaerobiosis; adding glucose to the soil slurries increased NO in3 sup- reduction by 2.4–3.7 times. Between 3% and 9% (net) of the added NO in3 sup- was reduced through DNRA in the soil slurries. The highest percentage was observed in soil samples from deeper layers that were pre-incubated anaerobically.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00395457
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