High Arctic polar deserts cover 26% of the Arctic. Climate change is expected to increase cryoturbation in these polar deserts, including frost boils and diapirs. Diapirism—cryoturbic intrusion into the overlying horizon—creates subsurface nutrient patches with low biodegradability and is thought to regulate greenhouse gas emissions, including the potent nitrous oxide. Although nitrous oxide emissions have been observed in polar deserts at a rate comparable to vegetated tundra ecosystems, the underlying mechanism by which nitrous oxide is produced in these environments remains unclear. In this study, we investigated ammonia-oxidizing archaea, which were detected in a previous study, and used stable isotope techniques to characterize the pattern of nitrous oxide emissions from frost boils. Ammonia-oxidizing archaea would be tightly linked to nitrous oxide emissions under aerobic condition whereas low degradable diapiric nutrient would limit denitirification under wet conditions. We hypothesized that (1) diapirism (i.e. diapiric frost boil) would not primarily drive nitrous oxide emissions and therefore abundance of ammonia-oxidizing archaea would be linked to the increase in nitrous oxide emissions under dry conditions favouring nitrification, and (2) diapirism decreases nitrous oxide emissions relative to non-diapiric frost boil under wet conditions that favour denitrification because of the recalcitrant nature of diapiric organic carbon. We used soil samples collected from two High Arctic polar deserts (dolomite and granite) near Alexandra Fjord (78°51′N, 75°54′W), Ellesmere Island, Nunavut, Canada from July–august 2013. Ammonia-oxidizing archaea did not differ in abundance between diapiric and non-diapiric frost boils within the dolomitic desert; however, within the granitic desert amoA abundance was 22% higher in diapiric frost boils. In both deserts, the increased abundance of archaeal amoA genes was linked to increased nitrous oxide emissions under dry conditions. Under higher soil moisture conditions favouring denitrification, diapiric frost boils emit N₂O with higher probability, but at a lower rate, than non-diapiric frost boils. For example, in the dolomitic desert, diaprism increased the probability of N₂O emissions by 104% but decreased the LS mean value of the emission rate by 36%. Similarly, diapirism increased the emission probability by 26% but decreased the LS mean value by 68% within the granitic desert. Under wet conditions, site preference values suggested that fungal and bacterial denitrification were important nitrous oxide emission processes. Our study shows that diapirism is a key cryoturbation process for nitrous oxide emissions in polar deserts primarily through diapirism's alteration of emission probability and the magnitude of the emissions.

高北极极地沙漠覆盖了北极地区的26％。预计气候变化将增加这些极地沙漠的冻土扰动，包括霜冻和di。Diapirism（向上层地平线灌入turyoturbic气体）会形成生物降解性较低的地下营养斑块，并被认为可以调节温室气体的排放，包括潜在的一氧化二氮。尽管在极地沙漠中观测到的一氧化二氮排放量与植被苔原生态系统的排放速度相当，但在这些环境中产生一氧化二氮的潜在机制仍不清楚。在这项研究中，我们调查了先前研究中检测到的氨氧化古细菌，并使用了稳定的同位素技术来表征霜冻中一氧化二氮排放的模式。氨氧化古细菌在有氧条件下将与一氧化二氮排放紧密相关，而可降解的二元养分含量低将限制在潮湿条件下的反硝化作用。我们假设（1）透水作用（即二apiros霜煮）不会主要驱动一氧化二氮的排放，因此，氨氧化古细菌的大量存在与干旱条件下有利于硝化作用的一氧化二氮排放量的增加有关，以及（2）透水作用减少在潮湿的条件下，相对于非二氧化氮霜沸腾产生的一氧化二氮排放量会增加反硝化作用，因为二api有机碳具有顽固性。我们使用了从2013年7月至8月加拿大埃勒斯米尔岛亚历山德拉峡湾（北纬78°51′，北纬75°54′）附近的两个极地极地沙漠（白云岩和花岗岩）收集的土壤样本。氨氧化古细菌在白云质沙漠中的二尖峰和非二尖峰霜沸腾之间的丰度没有差异。然而，在花岗沙漠中diapiric霜煮的amoA丰度高出22％。在这两个沙漠中，古细菌amoA基因的丰度增加与干旱条件下一氧化二氮排放的增加有关。在有利于反硝化作用的较高土壤湿度条件下，二尖峰霜沸腾散发N ₂ O的概率要高于非尖峰霜冻沸腾。例如，在白云质沙漠中，非自然因素增加了N ₂的可能性O排放降低了104％，但排放率的LS平均值降低了36％。同样，二叠纪在花岗岩沙漠中使发射概率增加了26％，但使LS平均值降低了68％。在潮湿条件下，部位偏爱值表明真菌和细菌的反硝化作用是重要的一氧化二氮排放过程。我们的研究表明，透水现象是极地沙漠中一氧化二氮排放的关键低温扰动过程，这主要是由于透水现象改变了排放概率和排放量。