Low temperature control of soil denitrifying communities:: kinetics of N2O production and reduction
Low temperature control of soil denitrifying communities:: kinetics of N2O production and reduction
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DOI：
10.1016/s0038-0717(02)00169-4
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发表时间：
2002-11-01
影响因子：
9.7
通讯作者：
Bakken, LR
中科院分区：
文献类型：
--
作者：
Holtan-Hartwig, L;Dörsch, P;Bakken, LR
为了探讨冬季和早春温带土壤中氧化亚氮(N2O)高场通量的原因，我们研究了从芬兰到瑞典到德国的温度样带上三个农田土壤反硝化N2O产生和还原的温度响应。在0、5、10、15和20摄氏度(一次实验中30摄氏度)下，在添加或不添加N3-、N2O和C2H2的厌氧浆液中测定处理速度。这些实验是在土壤变得厌氧后立即进行的，并经过长时间(48小时)的厌氧预培养，其中含有过量的碳和电子。接受者。在厌氧开始时，所有的反硝化酶在土壤中都是活跃的。无论是在厌氧开始时还是在厌氧预培养2天后，N2O的产生和减少都发生在0℃的显著水平。N2O生成和还原的温度响应在5-20℃范围内符合Arrhenius函数，表观活化能在28-76kJ·mol(-1)之间。估算的N2O还原活化能与N2O生成活化能相近或更低。因此，冬季和早春高场N2O通量不能用这两个过程的温度敏感性来解释。然而，在接近冰点的温度下，两种土壤的正常阿累尼乌斯反应有很大的偏差。在0℃下测得的速率远低于Arrhenius函数根据5-20℃范围内的数据预测的速率。由于某些原因，低温可能对反硝化群落产生特殊的挑战，其中对N2O还原过程的影响最为严重。当这样的分解对N2O还原酶的影响比产生N2O的酶(NO3-、NO2-和NO还原酶)更大时，就像在我们的土壤中发现的那样，它将在低温下导致高N2O通量。估计的净N2O排放潜力的温度响应(基于测量的N2O产生和减少速率)在三个地点之间存在显著差异，表明它们的微生物群落之间存在内在差异。(C)2002爱思唯尔科学有限公司。保留所有权利。
To explore the reason for reported high field fluxes of nitrous oxide (N2O) from temperate soils in winter and early spring, we investigated the temperature response of denitrifier N2O production and reduction in soil from three arable field sites along a temperature transect reaching from Finland over Sweden to Germany. Process rates were determined in anaerobic slurries with or without added NO3-, N2O and C2H2 at 0, 5, 10, 15, and 20 degreesC (and 30 degreesC in one experiment). The experiments were conducted immediately after the soils had become anaerobic, and after a long (48 h) anaerobic pre-incubation with excess of carbon and electron. acceptors. All denitrifying enzymes were found to be active in the soil at onset of anaerobiosis. Significant levels of N2O production and reduction occurred at 0 degreesC, both at onset of anaerobiosis and after the 2 days anaerobic pre-incubation. Temperature response of N2O production and reduction could be fitted to an Arrhenius function in the range 5-20 degreesC, yielding apparent activation energies between 28 and 76 kJ mol(-1). The estimated activation energy of the N2O reduction was found to be similar or lower than that for N2O production. High field N2O fluxes in winter and early spring could thus not be explained by the temperature sensitivity of the two processes. However, major deviations from the regular Arrhenius response were found for two soils at near freezing temperature. The rates measured at 0 degreesC were much lower than those predicted by the Arrhenius function based on data in the temperature range 5 - 20 degreesC. Low temperature may thus exert a particular challenge to denitrifying communities for some reason, and the effect was found to be most severe for the N2O reduction process. When such a breakdown affects N2O reductase to a greater extent than the N2O producing enzymes (NO3-, NO2-, and NO reductase), as was found in our soils, it will result in high N2O fluxes at low temperature. The temperature response of the estimated net N2O emission potential (based on measured N2O production and reduction rates) differed significantly between the three sites, indicating inherent differences between their microbial communities. (C) 2002 Elsevier Science Ltd. All rights reserved.