Nitrogen Transformation Rates Research Articles

Soil dissolved organic matters mediate bacterial taxa to enhance nitrification rates under wheat cultivation

Studies have shown that dissolved organic matters (DOMs) may affect soil nutrient availability to plants due to their effect on microbial communities; however, the relationships of soil DOM-bacterial community-N function in response to root exudates remains poorly understand. Here, we evaluated the DOM composition, bacterial taxonomic variation and nitrogen transformation rates in both acidic and alkaline soils, with or without the typical nitrate preference plant (wheat, Triticum aestivum L.). After 30 days' cultivation, DOM compositions such as sugars, amines, amino acids, organic acid, and ketone were significantly increased in soil with wheat vs. bare soil, and these compounds were mainly involved in nitrogen metabolism pathways. Soil core bacterial abundance was changed while bacterial community diversity decreased in response to wheat planting. Function prediction analysis based on FAPROTAX software showed that the bacterial community were significantly (p < 0.05) affiliated with nitrification and organic compound degradation. Additionally, db-RDA and VPA analysis suggested that the contribution of soil DOM to the variance of bacterial community was stronger than that of soil available nutrients. Furthermore, the N-transformation related bacteria like Burkholderiales and ammonia-oxidizing bacteria (AOB) were positively correlated with soil gross nitrification rate, confirming that the soil N transformation was enhanced in both acidic and alkaline soils. Our results provide insight into how soil DOM affects the community structure and function of bacteria to regulate the process of nitrogen transformation in plant-soil system.

Dominant tree mycorrhizal associations affect soil nitrogen transformation rates by mediating microbial abundances in a temperate forest

Dominant tree mycorrhizal associations affect soil nitrogen transformation rates by mediating microbial abundances in a temperate forest

Are nitrogen and carbon cycle processes impacted by common stream antibiotics? A comparative assessment of single vs. mixture exposures.

A variety of antibiotics are ubiquitous in all freshwater ecosystems that receive wastewater. A wide variety of antibiotics have been developed to kill problematic bacteria and fungi through targeted application, and their use has contributed significantly to public health and livestock management. Unfortunately, a substantial fraction of the antibiotics applied to humans, pets and livestock end up in wastewater, and ultimately many of these chemicals enter freshwater ecosystems. The effect of adding chemicals that are intentionally designed to kill microbes, on freshwater microbial communities remains poorly understood. There are reasons to be concerned, as microbes play an essential role in nutrient uptake, carbon fixation and denitrification in freshwater ecosystems. Chemicals that reduce or alter freshwater microbial communities might reduce their capacity to degrade the excess nutrients and organic matter that characterize wastewater. We performed a laboratory experiment in which we exposed microbial community from unexposed stream sediments to three commonly detected antibiotics found in urban wastewater and urban streams (sulfamethoxazole, danofloxacin, and erythromycin). We assessed how the form and concentration of inorganic nitrogen, microbial carbon, and nitrogen cycling processes changed in response to environmentally relevant doses (10 μg/L) of each of these antibiotics individually and in combination. We expected to find that all antibiotics suppressed rates of microbial mineralization and nitrogen transformations and we anticipated that this suppression of microbial activity would be greatest in the combined treatment. Contrary to our expectations we measured few significant changes in microbially mediated functions in response to our experimental antibiotic dosing. We found no difference in functional gene abundance of key nitrogen cycling genes nosZ, mcrA, nirK, and amoA genes, and we measured no treatment effects on NO3- uptake or N2O, N2, CH4, CO2 production over the course of our seven-day experiment. In the mixture treatment, we measured significant increases in NH4+ concentrations over the first 24 hours of the experiment, which were indistinguishable from controls within six hours. Our results suggest remarkable community resistance to pressure antibiotic exposure poses on naïve stream sediments.

Effects of water content on gross nitrogen transformation rates in forest land and grassland soils

Soil water content is an important factor driving microbial activities related to soil nitrogen (N) transformation. In this study, 15N pair tracing technique combined with the numerical model FLUAZ was used to investigate the gross N mineralization, immobilization, nitrification, and denitrification rates in grassland and forest land soils from Beian City, Heilongjiang Province, China under laboratory condition [60% or 100% water holding capacity (WHC)]. The responses of soil gross N transformation rates to soil water content changes, and the mechanisms of N production, consumption, and conservation in soil under different water conditions and its environmental effects were elucidated. The results showed that changes of soil water content did not affect gross rates of N mineralization and NH4+ immobilization in the forest land and grassland soils. Increasing soil water content from 60% WHC to 100% WHC significantly increased soil gross nitrification rate in forest land soil, but not affect that in grassland soil. Gross denitrification rates in grassland and forest land soils were close to zero under 60% WHC, and significantly increased under 100% WHC. The rate in grassland soil was significantly lower than that in forest land soil. In forest land soil, the ratio of gross nitrification to NH4+ immobilization rates (gn/ia) and N2O emissions under 100% WHC were significantly higher than that under 60% WHC. N2O emission from grassland soil under 100% WHC was significantly higher than that under 60% WHC, but without significant difference in gn/ia between the two water conditions. Our results indicated that increasing soil water content in the short-term may increase the negative environmental effects of nitrogen cycling in grassland and forest land soils, especially in forest land soil.

Prescribed Fire in Karst Regions Lowers Soil Gross Nitrogen (N) Transformation Rates and N-Turnover

Prescribed Fire in Karst Regions Lowers Soil Gross Nitrogen (N) Transformation Rates and N-Turnover

Porewater exchange drives nutrient cycling and export in a mangrove-salt marsh ecotone

Coastal wetlands regulate nutrient fluxes from the continents to the oceans. Salt marshes are rapidly encroaching into mudflat area in mangrove wetlands, shaping a mangrove-salt marsh ecotone, with unknown implications to coastal biogeochemical cycles. Here, we hypothesized that nitrogen and phosphorus cycling varied in mangrove and salt marsh, having significant implication on coastal waters. We investigated a tidal creek with a marked mangrove-salt marsh gradient in China using high-frequency time-series sampling of dissolved nutrients and observations of porewater exchange rate across the sediment–water interface over a spring-neap tidal cycle. The nitrogen transformation rates and microbiological activities were also investigated to explain the variability in nitrogen concentrations. The mangrove had net groundwater outflow rates of 3.6–4.3 mm d-1 while the salt marsh had net infiltration of surface water with rates of 0.5–2.9 mm d-1. Salt marsh had less capacity for ammonium (NH4-N) production (mineralization and dissimilatory nitrate reduction to ammonium DNRA) than mangrove. Denitrification dominated nitrogen removal reaching 97% and 83% in mangrove and salt marsh, respectively. Microbe distributions were consistent with nitrogen transformations with larger nirS and nrfA abundances for denitrification and DNRA in the mangrove than salt marsh. The mangrove had a net export of NH4-N but a net import of NOx-N (sum of nitrate and nitrite) and dissolved inorganic phosphorus (DIP) during the monitoring period. In contrast, the salt marsh had lower efflux of nutrient than influx leading to a net nutrient import during the monitoring period. Porewater released from the mangrove had a large DIN:DIP mole ratio (706 ± 236) due to high NH4-N concentrations, while NH4-N in the salt marsh were lower than in the mangrove. Overall, this study revealed that mangrove-salt marsh ecotone will push the native mangrove wetlands from being a source towards a sink of NH4-N to coastal waters by decreasing porewater exchange, modifying the nutrients stoichiometry, and ultimately alleviating the potential of N-associated eutrophication in nearby coastal waters.

Advanced tool for analysing 15N tracing data

Ntrace is a family of tools for the analysis of 15N tracing data sets, to quantify the simultaneous gross nitrogen (N) transformation rates in terrestrial ecosystems. Starting with the original publication of Ntrace in 2007, a number of specialised tools have been developed that cover a range of applications such as nitrite and gaseous N dynamics. While the capability of the tool has been extended to cover a range of applications, the underlying parameter optimisation algorithm, based on the Metropolis MCMC algorithm, has remained unchanged. However, in more computational demanding applications, this algorithm turned out to be very time consuming, and in some cases it was not even able to identify unambiguous parameter sets. The aim of this study was, to test a new global optimisation algorithm (GlobalSearch), by re-analysing some of the published datasets. In the evaluation, the speed of finding a suitable solution but in particular the accuracy of the new algorithm to obtain an adequate fit to the observations was taken into account. A new uncertainty calculation for the optimised parameters, based on the Levenberg-Marquardt method, has also been implemented. The new Ntrace tool was able to find an adequate fit for all tested datasets, in often a fraction of the time compared to the original MCMC algorithm. For all test cases the accuracy of the fit was at least as good as with the original model. This is partly due to a new algorithm's option to vary the initial pool size. In summary, the new Ntrace tool is quicker in finding suitable parameters for 15N tracing data sets. The fit to measured data is often improved over the original tool. Thus, we recommend the use of the new Ntrace tool for analysing 15N tracing data. The new tool is programmed in MATLAB and can easily be adapted to new applications.

Effect of tree species and seasons on soil nitrogen transformation rates in the semi-arid forest of Delhi, India

Effect of tree species and seasons on soil nitrogen transformation rates in the semi-arid forest of Delhi, India

Soil net nitrogen transformation rates are co-determined by multiple factors during the landscape evolution in Horqin Sandy Land

Vegetation restoration affects soil N cycling, which in turn strongly affects ecosystem functions, such as plant productivity and N availability. The soil N availability is a major limiting factor for restoring vegetation in semiarid grasslands and affects landscape evolution. However, few studies have focused on how landscape evolution caused by vegetation restoration affects soil N availability and transformation in semiarid sandy grasslands. Here, we conducted a 5-year field experiment from 2015 to 2019 to evaluate the growth season (May–August) changes in soil inorganic N pools and net N transformation rates along a landscape evolution gradient caused by vegetation restoration: mobile dunes, semi-fixed dunes, fixed dunes, and dune grasslands. We examined the relationship between climate factors, vegetation characteristics, soil properties, and soil net N transformation rates in different landscape types through multivariate analyses. The landscape type, sampling time, interannual variation, and their interactive effects significantly affected the soil inorganic N pool and net N transformation rate. Soil nitrate N concentration accounted for 68% of the total inorganic N, and soil nitrification dominated the soil N transformation during landscape evolution. Redundancy analysis revealed that the changes in net N nitrification and mineralization rates during the growing season were closely correlated with climate factors, vegetation characteristics, and soil properties. Variation partitioning analysis showed that the soil net N transformation rate during the growing season was mainly affected by soil properties, whereas soil net N transformation in August for all years was mainly affected by climate factors. These results suggest that soil N availability and transformation during landscape evolution caused by vegetation restoration were co-determined by climatic factors, vegetation characteristics, and soil properties. Therefore, long-term field monitoring should be considered to improve our exploration of soil N transformation changes and their underlying mechanisms in semiarid grassland ecosystems.

Effects of experimental warming on soil nitrogen transformation in alpine scrubland of eastern Qinghai-Tibet Plateau, China

We investigated the effects of warming on soil nitrogen cycling process in alpine scrub ecosystem, with an in-situ simulated warming experiment at Sibiraea angustata alpine scrubland on the eastern Qinghai-Tibet Plateau, China. We examined the responses of soil nitrogen transformation rate to warming in three critical periods (the early, late, and non-growing seasons). The results showed that warming increased soil temperature by 1.2 ℃, but decreased soil moisture by 2.5%. The soil net nitrogen mineralization rates (i.e., ammonification and nitrification) in the growing season were significantly higher than those in the non-growing season. The rates of soil net nitrogen fixation in the non-growing season were significantly higher than that in the growing season. Soil nitrification was the major process of soil nitrogen transformation in the early growing season, while soil ammonification was the major one in the late growing season and non-growing season. The effects of experimental warming on soil nitrogen transformation differed among those three periods. Experimental warming significantly increased soil net ammonification, nitrification, nitrogen mine-ralization and fixation in the early growing season, and enhanced soil net nitrification and nitrogen mineralization in the non-growing season. However, warming significantly decreased soil net nitrification, nitrogen mineralization and fixation in the late growing season and soil net ammonification in the non-growing season. Moreover, warming did not affect soil net nitrogen fixation rates in the non-growing season and soil net nitrification rates in the late growing season. Future climate warming would significantly change soil nitrogen transformation by accelerating soil nitrogen cycling in the alpine scrub ecosystem on the eastern Qinghai-Tibet Plateau.

Decentralized Domestic Sewage Treatment Using an Integrated Multi-Soil-Layering and Subsurface Wastewater Infiltration System

In this study, an integrated multi-soil-layering and subsurface wastewater infiltration (MSL-SWI) system was developed for decentralized domestic sewage treatment under high hydraulic loading rates (HLRs). To improve sustainable nitrogen removal, the influence of intermittent operation and shunt distributing wastewater on the performance of MSL-SWI systems was investigated. The optimal performance—with removal efficiencies of 93.41% for chemical oxygen demand, 97.91% for total phosphorus, 74.02% for ammonia nitrogen, and 73.56% for total nitrogen—was achieved using both intermittent operation and shunt distributing wastewater under an HLR of 0.3 m3 m−2 d−1. The activity of microbial nitrogen functional genes (i.e., amoA, nirK, nirS, nosZ, and anammox 16S rRNA) and their relationships with nitrogen transformation rates were further analyzed in different layers of the system. The results imply that nitrification and anaerobic ammonium oxidation in the MSL section coupled with nitrification and denitrification in the SWI section contribute to main the mechanisms of sustainable nitrogen removal. In summary, MSL-SWI systems not only operate with high efficiency under high HLRs, but the contaminant removal is also stable and sustainable, which are promising properties for domestic sewage treatment in areas where land resources are limited.

Manure-based biochar decreases heterotrophic respiration and increases gross nitrification rates in rhizosphere soil

This study hypothesized that pyrolyzed manure pellet (biochar) reduces heterotrophic respiration and N2O emissions from wheat (Triticum aestivum L.) rhizosphere soil by affecting net and gross nitrogen (N) transformation rates and the effects differ between rhizosphere and bulk soils. The biochar significantly decreased heterotrophic respiration but not N2O emissions, while unpyrolyzed manure pellets (feedstock) increased both of them, in both the rhizosphere and bulk soils. The biochar increased gross nitrification rate by 32.9% in the rhizosphere but decreased it by 19.4% in the bulk soil while the feedstock increased gross N transformation (mineralization and nitrification) rates in both soil zones. The biochar decreased the % recovery of 15NH4+ in the NH4+-N pool in the rhizosphere but increased it in the bulk soil, as a result of biochar's contrasting effects on gross nitrification rates in the respective soil zones. It can be concluded that biochar had similar effects on heterotrophic respiration and N2O emissions but had contrasting effects on gross nitrification rates between rhizosphere and bulk soils, supporting part of the hypothesis and highlighting the importance of studying gross N transformation processes in understanding rhizosphere-biochar interactions.

Effect of Filter Medium on the Enhancement of Complete Autotrophic Nitrogen Removal over Nitrite Process in a Tidal Flow Constructed Wetland

This study attempted to shorten the time wasted at the startup of a complete autotrophic nitrogen removal over nitrite (CANON) process in a tidal flow constructed wetland (TFCW) to achieve higher nitrogen removal rates. Thus, the starting performance and the related microbiological characteristics of different kinds of filter media filling the TFCW were explored at an appropriate drainage rate. The results showed that the physicochemical properties of the filter medium could significantly affect the quantity and activity of the functional microbes (especially ANAMMOX bacteria) enriched in the TFCWs, leading to fluctuations of the starting time and nitrogen transformation rates of the systems filled with five different kinds of filter media. Compared with that of gravel, the quantity and activity of ANAMMOX bacteria in the bed could be enhanced to different degrees as the TFCW was filled with ceramsite, zeolite, broken bricks, and lobster shells. Correspondingly, the starting times of the TFCWs with the CANON process were shortened, and their nitrogen removal performances could also be optimized. When the hydraulic loading rate of the TFCW was 0.96 m3·(m2·d)-1, the initiation of the CANON process could be accomplished successfully in the system filled with lobster shells within 300 cycles, since AOB and ANAMMOX bacteria could become dominant quickly in the packing bed. Moreover, the TN and NH4+-N removal rates could reach up to (88.37±1.19)% and (91.03±0.66)%, respectively, followed by those of broken bricks, zeolite, ceramsite, and gravel.

Effects of different straw returning amount on the potential gross nitrogen transformation rates of fertilized Mollisol.

Straw returning is one of the important measures for improving soil fertility. It is unclear, however, whether the regulation function of soil on nitrogen (N) cycle after fertilization is sustainable and the relationship between the regulation function and the amount of straw returned to the field. In this study, a 3-year straw returning field trial was set up in a field had been carried out straw returning of all the havested straw for nine years. The amount of straw returned was 100%, 67%, 33% and 0 of the average annual straw yield (7500 kg·hm-2) to identify the effects of different straw returned amount on N transformation in the fertilized soil (0-10 cm). Results showed that the amount of straw returning affected the production and consumption of NH4+-N and NO3--N by affecting the potential gross N transformation rate. When the amount of straw returning was less than 67%, the production rate of NH4+-N significantly reduced and the consumption rate significantly increased, and thus led to the decrease in soil NH4+-N retention capacity. The NO3--N production rate increased and the retention capacity decreased, and the NO3--N accumulation and leaching loss risk increased. Therefore, returning more than 67% of harvested straw was necessary to maintain the function of soil N conservation.

Assessing the impact of long-term soil phosphorus on N-transformation pathways using 15N tracing

A laboratory incubation study was conducted on a temperate grassland soil to quantify the main mineral nitrogen (N) transformation rates and pathways via a15N tracing approach. Soil samples were taken from a long-term phosphorus (P) trial to investigate the effects on gross N-transformations under high and low phosphorus amendment. The soils were incubated over a 2-week period and treated with ammonium-nitrate (NH4NO3) which was applied to the soil both with and without a glucose amendment and labelled with 15N either on the ammonium (NH4+) or nitrate (NO3−) moiety at 50% atom enrichment. The results showed immobilisation to greatly outweigh mineralisation and that NO3− was predominantly produced via heterotrophic nitrification. Individual pathways for NO3− production were quantified including oxidation of NH4+, recalcitrant and labile organic N. Oxidation of labile organic N to NO3−, a newly considered pathway, accounted for between 63 and 83% of total NO3− production across the various treatments and P levels. This process was significantly higher in the low-P rather than the high-P soils (p < 0.05), highlighting the effect of soil P on the microbial community.

Gross rates of nitrogen transformation in soils of a global biodiversity hotspot (Western Ghats, India)

AbstractBackground: Being one of the important nutrients required by plants during photosynthesis, nitrogen (N) exerts a significant control on primary productivity and carbon dioxide sequestration. Therefore, it is essential to quantify the rates of N cycling processes, such as gross N mineralization and nitrification, to understand the flow and availability of N in different ecosystems. Lack of such data in tropical regions, particularly the Indian subcontinent, has constrained our understanding of N dynamics in soils of the subcontinent.Aims: Here, we report the results of gross N transformation rates from the hot and humid tropical forest soils of the Western Ghats, one of the global biodiversity hotspots located in India.Results: The experiments conducted using the 15N isotope dilution technique showed higher average gross N mineralization (2.6 ± 1.1 mg N kg−1 d−1) and gross nitrification (1.7 ± 1.1 mg N kg−1 d−1) rates in the top soil layers (0–20 cm), which decreased significantly with depth (20–40 cm) indicating potential for higher microbial activity in the top soils. The overall consumption rate of mineral N exceeded its production rate with higher consumption of ammonium () than nitrate () suggesting as a preferred N source for microbes. The consumption of was higher through immobilization than nitrification indicating active N conservation mechanism and an efficient microbial adaptation.Conclusion: Despite high rates of consumption, accumulation of and in soils of the Western Ghats suggested additional sources of mineral N other than internal recycling of N. Long residence time of and in soils implied longer availability of unutilized mineral N leading to high soil acidity and potential for loss of N through leaching and denitrification.

Nitrogen transformation rates in the Himalayan soils at different temperature and elevation conditions

Vast expanses of climatically sensitive ecosystems, such as tropical montane, remain unstudied in terms of factors controlling nitrogen (N) availability and in turn productivity. Temperature and elevation are two important, yet understudied, factors which decide the fate of N in montane ecosystems. Therefore, the present study aimed to quantify and understand changes in rates of N transformation processes in tropical montane soils of the Himalayas under different temperature-elevation conditions. The 15N isotope dilution technique was employed to quantify the rates of gross N transformations in soils collected at two depth intervals (0–20 cm and 20–40 cm) from five elevations (3000 m, 2500 m, 2000 m, 1500 m, and 1000 m above sea level) of the Garhwal Himalayas. The rates were measured at low (10 °C) and high temperature (23 °C) conditions to decipher the effect of temperature change on N cycling in montane soils. The results indicated a significant increase in gross N mineralization rates under the high temperature condition compared to the low. Interestingly, gross nitrification rates remained unaffected of temperature change. Increase in gross N mineralization at high temperature condition was accompanied with increased ammonium (NH4+) consumption, which was largely in the form of NH4+ immobilization. In general, gross N transformation rates in the top soils showed higher response to change in temperature and elevation conditions than the bottom soils. Increase in rates of N mineralization and other soil N cycling processes at higher temperature suggests potential acceleration in N turnover due to warming in the Himalayan soils. Increased NH4+ immobilization and poor sensitivity of nitrification to temperature are likely to increase soil N conservation at higher temperature. The inconsistent variation in N transformation rates with elevation suggested higher control of edaphic factors on soil N cycling at a particular elevation.

The effects of silver nanoparticles on the microbial nitrogen cycle: a review of the known risks.

The nitrogen cycle is an integral biogeochemical function for maintaining healthy environments. Nitrogen is a key nutrient that must be continuously replenished through recycling mechanisms to sustain ecosystems, disruption to which can result in compromised ecosystem functioning. Certain stages in the microbial conversion of nitrogen compounds are performed by a limited range of micro-organisms making these key functional species in ecosystems. The growing industrial use of silver nanoparticles (AgNPs) potentially poses significant risks for microbial nitrogen cycling species. AgNPs possess potent antimicrobial properties and are expected to reach a range of natural environments through several routes of exposure. Certain functional nitrogen cycling microbes have been shown to be highly susceptible to AgNP toxicity. The current literature indicates that AgNPs can negatively affect certain nitrogen fixing, nitrifying and denitrifying microbes in vitro. In vivo studies investigating the effect of AgNPs on nitrogen cycling microbial communities and nitrogen transformation rates in soil, sediment and sludge environments have also indicated disruption of these functional processes. This review provides a comprehensive description of the current state of knowledge regarding the toxicity of AgNPs to nitrogen cycling communities. The aim of the review is to highlight the most susceptible stages in the nitrogen cycle and the implications for the affected ecosystems.

Nutrient removal from human fecal sludge digestate in full-scale biological filters

There is a great need for simple methods for digestate management for potential household sanitation systems based on anaerobic digestion of minimally diluted fecal waste in countries that lack safe sanitation. Herein, a full-scale three-stage filter for nitrogen and phosphorus removal from anaerobic digester effluent was implemented in Madagascar. It included a trickling filter with crushed charcoal (for aerobic nitrification), a submerged anaerobic filter with bamboo chips (for denitrification), and a submerged filter with scrap iron (for phosphorus removal). All filter materials were sourced locally. Three parallel replicate systems were operated in two sequential 8-week phases for a total of 16 continuous weeks. Though the influent feed was not as expected, with much of nitrogen in the feed coming in as organic N and not as NH3–N, the filters still removed 38–49% of total incoming nitrogen. The filters achieved high rates of nitrogen transformation along with removing solids (73–82% turbidity removal), chemical oxygen demand (67–75% removal), and phosphorus (31–50% removal). Overall, the reaction rates from this full-scale study were in line with previous lab-scale investigations with scaled-down systems, supporting their application in real-world scenarios. Based on this study, simple effluent filters can support nutrient removal for small-scale and onsite fecal sludge treatment systems.

Could Cryoturbic Diapirs Be Key for Understanding Ecological Feedbacks to Climate Change in High Arctic Polar Deserts?

AbstractHigh Arctic polar deserts cover 26% of the Arctic. Increasing temperatures are predicted to significantly alter polar desert freeze‐thaw and biogeochemical cycles, with important implications for greenhouse gas emissions. However, the mechanisms underlying these changing cycles are still highly uncertain. Cryoturbic, carbon‐rich Bhy horizons (diapirs) in frost boils are key nutrient sources for Salix arctica. We hypothesized that diapirism leads to organic carbon characteristics that alter microbial pathways, which then control root foraging and greenhouse gas production. During July and August 2013, we characterized soil properties and examined gross nitrogen transformation rates in frost boils both with and without diapirs in two High Arctic polar deserts (dolomite and granite) near Alexandra Fjord (78°51′N 75°54′W), Ellesmere Island, Nunavut, Canada. Diapiric frost boils had 18% higher soil organic carbon in the dolomitic and 9% higher in the granitic deserts, and 29% higher total dissolved nitrogen in the dolomitic desert. However, diapirs decreased gross nitrogen mineralization rates by 30% in the dolomitic and by 48% in the granitic deserts. Attenuated total reflectance Fourier transformed mid‐infrared spectroscopy revealed greater concentrations of polysaccharides and recalcitrant carbon in diapiric versus nondiapiric frost boils. These increased polysaccharide concentrations likely facilitate diapirism as soil viscosity increases with polysaccharides. Lower microbial activity or ectomycorrhizae that are known to colonize S. arctica may accumulate total dissolved nitrogen in diapirs. Our results suggest geomorphologic‐plant‐microbe interactions may underlie important patterns of geochemical cycling in arctic systems. Thus, polar desert frost boils should represent a key focus of future investigations of climate change in arctic systems.