Microbial activity is not always limited by nitrogen in Arctic tundra soils

Melle, C.; Wallenstein, Matthew D.; Darrouzet‐Nardi, Anthony; Weintraub, Michael N.

doi:10.1016/j.soilbio.2015.07.023

Cited by 22 publications

(27 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Soil N‐acquiring hydrolytic enzyme activity assays were conducted using high‐throughput microplate assays (Melle et al, ; Rinkes, Weintraub, DeForest, & Moorhead, ; Saiya‐Cork, Sinsabaugh, & Zak, ; Wallenstein, McMahon, & Schimel, ). Fluorogenic substrates at saturating concentrations (200 µM) were used to measure activities of two hydrolytic N‐acquiring enzymes: N ‐acetyl‐β‐glucosaminidase (NAG) and leucine peptidase (LAP), and one hydrolytic C‐acquiring enzyme, β‐glucosidase (BG).…”

Section: Methodsmentioning

confidence: 99%

“…Enzyme activities were expressed as nmol reaction product hr −1 g −1 dry soil. For further details on the enzymes and the procedure, see Melle et al ().…”

Section: Methodsmentioning

confidence: 99%

“…Nitrogen (N) is an essential plant macronutrient in Arctic tundra ecosystems, where it often, though not always, limits both plant production and microbial activity (Mack, Schuur, Bret‐Harte, Shaver, & Chapin, ; Melle, Wallenstein, Darrouzet‐Nardi, & Weintraub, ; Nowinski, Trumbore, Schuur, Mack, & Shaver, ; Weintraub & Schimel, ). The main source of N in Arctic soils is the large stocks of organic N, which can be mined enzymatically for amino acids and sugars, and other organic N monomers, which can ultimately be mineralized to NO 3 − or NH 4 + (McLaren, Darrouzet‐Nardi, Weintraub, & Gough, ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Limited effects of early snowmelt on plants, decomposers, and soil nutrients in Arctic tundra soils

Darrouzet‐Nardi

Steltzer

Sullivan

et al. 2019

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

In addition to warming temperatures, Arctic ecosystems are responding to climate change with earlier snowmelt and soil thaw. Earlier snowmelt has been examined infrequently in field experiments, and we lack a comprehensive look at belowground responses of the soil biogeochemical system that includes plant roots, decomposers, and soil nutrients. We experimentally advanced the timing of snowmelt in factorial combination with an open‐top chamber warming treatment over a 3‐year period and evaluated the responses of decomposers and nutrient cycling processes. We tested two alternative hypotheses: (a) Early snowmelt and warming advance the timing of root growth and nutrient uptake, altering the timing of microbial and invertebrate activity and key nutrient cycling events; and (b) loss of insulating snow cover damages plants, leading to reductions in root growth and altered biological activity. During the 3 years of our study (2010–2012), we advanced snowmelt by 4, 15, and 10 days, respectively. Despite advancing aboveground plant phenology, particularly in the year with the warmest early‐season temperatures (2012), belowground effects were primarily seen only on the first sampling date of the season or restricted to particular years or soil type. Overall, consistent and substantial responses to early snowmelt were not observed, counter to both of our hypotheses. The data on soil physical conditions, as well interannual comparisons of our results, suggest that this limited response was because of the earlier date of snowmelt that did not coincide with substantially warmer air and soil temperatures as they might in response to a natural climate event. We conclude that the interaction of snowmelt timing with soil temperatures is important to how the ecosystem will respond, but that 1‐ to 2‐week changes in timing of snowmelt alone are not enough to drive season‐long changes in soil microbial and nutrient cycling processes.

show abstract

Section: Methodsmentioning

confidence: 99%

“…Enzyme activities were expressed as nmol reaction product hr −1 g −1 dry soil. For further details on the enzymes and the procedure, see Melle et al ().…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Limited effects of early snowmelt on plants, decomposers, and soil nutrients in Arctic tundra soils

Darrouzet‐Nardi

Steltzer

Sullivan

et al. 2019

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

show abstract

“…The rate of root exudates is linked to the nutrient availability in soils, with more root exudates present in plants located in nutrient-poor wetland soils (Koelbener et al, 2010). The wetland soils in Arctic tundra are known to be nitrogen-limited (Melle et al, 2015;Gurevitch et al, 2006). The plant growth in the polygonal lowland tundra of Indigirka, Russia, is colimited by nitrogen and phosphorus, and only about 5 % of the total nitrogen soil content is active in the biological fraction (Beerman et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Process-based modelling of the methane balance in periglacial landscapes (JSBACH-methane)

et al. 2017

View full text Add to dashboard Cite

Abstract. A detailed process-based methane module for a global land surface scheme has been developed which is general enough to be applied in permafrost regions as well as wetlands outside permafrost areas. Methane production, oxidation and transport by ebullition, diffusion and plants are represented. In this model, oxygen has been explicitly incorporated into diffusion, transport by plants and two oxidation processes, of which one uses soil oxygen, while the other uses oxygen that is available via roots. Permafrost and wetland soils show special behaviour, such as variable soil pore space due to freezing and thawing or water table depths due to changing soil water content. This has been integrated directly into the methane-related processes. A detailed application at the Samoylov polygonal tundra site, Lena River Delta, Russia, is used for evaluation purposes. The application at Samoylov also shows differences in the importance of the several transport processes and in the methane dynamics under varying soil moisture, ice and temperature conditions during different seasons and on different microsites. These microsites are the elevated moist polygonal rim and the depressed wet polygonal centre. The evaluation shows sufficiently good agreement with field observations despite the fact that the module has not been specifically calibrated to these data. This methane module is designed such that the advanced land surface scheme is able to model recent and future methane fluxes from periglacial landscapes across scales. In addition, the methane contribution to carbon cycleclimate feedback mechanisms can be quantified when running coupled to an atmospheric model.

show abstract

“…Studies have shown that DON concentrations typically increase with higher flow volumes (Townsend-Small et al 2010) and in the lateseason especially following rainfall events (Townsend-Small et al 2010;Lewis et al 2012). The increases in the late-season concentration of DON and other solutes associated with summer rainfall have been attributed to the increases in rates of decomposition and weathering with increasing temperatures, and the resulting accumulation of solutes in the active layer followed by their subsequent export, as rainfall runoff reestablishes hydrological connectivity in the catchment (Weintraub and Schimel 2003;Koch et al 2007;Melle et al 2015). Therefore, the increase in DON concentration and fluxes in GS and in PT in 2012 are likely explained by the higher stormflow discharge volumes and rainfall runoff occurring later in the season in 2012 relative to 2007.…”

Section: Increases In Late-season Donmentioning

confidence: 99%

Active layer slope disturbances affect seasonality and composition of dissolved nitrogen export from High Arctic headwater catchments

2017

View full text Add to dashboard Cite

This study investigates the impacts of active layer detachments (ALDs) on nitrogen in seasonal runoff from High Arctic hillslope catchments. We examined dissolved nitrogen in runoff from an undisturbed catchment (Goose (GS)) and one that was disturbed (Ptarmigan (PT)) by ALDs, prior to disturbance (2007) and 5 years after disturbance (2012). The seasonal dynamics of nitrogen species concentrations and fluxes were similar in both catchments in 2007, but the mean seasonal nitrate concentration and mass flux from the disturbed catchment were on the order of 30 times higher relative to the undisturbed catchment in 2012. Stormflow yielded 45% and 60% of the 2012 total dissolved nitrogen flux in GS and PT, respectively, although rainfall runoff provided less than 25% of seasonal discharge. Results support that through the combined effects of increased disturbance and rainfall, climate change stands to significantly enhance the export of nitrate from High Arctic watersheds. This study highlights that the increase in the delivery of nitrate from disturbance is especially pronounced late in the season when downstream productivity and the biological demand for this often limiting nutrient are high. Our results also demonstrate that the impact of ALDs on nitrate export can persist more than 5 years following disturbance.Key words: dissolved nitrogen, active layer detachment, precipitation, nitrate, High Arctic.Résumé : Cette étude analyse les effets des détachements de la couche active (DCA) sur la teneur en azote dans l'écoulement saisonnier provenant des bassins versants des sommets du Haut-Arctique. Nous avons examiné l'azote dissous dans l'écoulement d'un bassin versant calme (Goose) (GS) et d'un bassin qui a été perturbé (Ptarmigan) (PT) par les DCA, et ce, avant la perturbation (2007) For personal use only.substance nutritive limitante sont élevées. Nos résultats démontrent aussi que l'impact des DCA sur l'exportation de nitrate peut persister plus de 5 ans après la perturbation.Mots-clés : azote dissous, détachement de la couche active, précipitation, nitrate, Haut-Arctique.

show abstract

Microbial activity is not always limited by nitrogen in Arctic tundra soils

Cited by 22 publications

References 49 publications

Limited effects of early snowmelt on plants, decomposers, and soil nutrients in Arctic tundra soils

Limited effects of early snowmelt on plants, decomposers, and soil nutrients in Arctic tundra soils

Process-based modelling of the methane balance in periglacial landscapes (JSBACH-methane)

Active layer slope disturbances affect seasonality and composition of dissolved nitrogen export from High Arctic headwater catchments

Contact Info

Product

Resources

About