Nitrogen turnover rates in a riparian fen determined by 15N dilution |
| |
Authors: | Per Ambus Arvin Mosier Søren Christensen |
| |
Institution: | (1) Institute of Population Biology, Copenhagen University, DK-2100 Copenhagen, Denmark;(2) Agricultural Research Service, United States Department of Agriculture, P.O. Box E, 80522 Fort Collins, CO, USA |
| |
Abstract: | 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. |
| |
Keywords: | N mineralization Assimilation Nitrification NO
in3
sup-
reduction Riparian fen 15N substrates |
本文献已被 SpringerLink 等数据库收录! |
|