Stable isotopic evidence of enhanced export of microbially derived $${\text{NO}}_{3}^{ - }$$ NO 3 - following active layer slope disturbance in the Canadian High Arctic

Louiseize, Nicole L.; Lafrenière, Melissa J.; Hastings, Meredith G.

doi:10.1007/s10533-014-0023-x

Cited by 34 publications

(55 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ptarmigan is drained by an incised channel that flows into mineral soils through the length of the two elongate disturbances. In Ptarmigan, disturbances are well connected to downstream; thus, the water delivered provides important information on ALD impacts on stream DOM properties and biogeochemical functioning (Lamoureux et al 2014;Louiseize et al 2014) In all catchments, river discharge typically lasts from early June until mid-to end of July. Early June, the river flow, which peaks within few days and recedes rapidly, is sustained by snowmelt from snowpacks located in channels and depression.…”

Section: Study Sitementioning

confidence: 99%

“…The methods of discharge and precipitation measurements are detailed in Louiseize et al (2014). As reported by Louiseize et al (2014), seasonal hydrographs for Goose, Caribou, ALD, and Ptarmigan were divided into nival melt (or spring freshet), baseflow, and stormflow phases depending on changes in discharge and the frequency of rainfall (Fig.…”

Section: Hydrologic Regimesmentioning

confidence: 99%

“…The sample collection and preparation are detailed in Louiseize et al (2014). Water samples were collected at stream outlets twice daily at approximately 10:00 (i.e.…”

Section: Field Samplingmentioning

confidence: 99%

“…Streams from undisturbed and recently disturbed headwater catchments were sampled to assess the impacts of ALDs on DOM composition. Although previous research from the CBAWO reports on the impact permafrost disturbance had on sediment fluxes (Lamoureux et al 2014), total dissolved solute fluxes (Lafreniere and Lamoureux 2013), and sources of dissolved nitrogen (Louiseize et al 2014), here we characterize for the first time the optical properties of DOM in four headwater catchments during an entire hydrologic season. This study makes an important contribution to our understanding of the potential for permafrost disturbance to increase the export of fresh and low molecular weight compounds from small High Arctic streams.…”

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

et al. 2017

View full text Add to dashboard Cite

Arctic landscapes are experiencing intense warming and modification of precipitation regimes with climate change. Permafrost disturbances and climate change impacts on hydrology of Arctic watersheds are likely to modify the quantity and composition of exported dissolved organic matter (DOM). In July 2007, intense rainfall and active layer thickening caused widespread active layer detachments at Cape Bounty, Melville Island (Canada). This study investigates the impacts of seasonal hydrology and permafrost disturbance on DOM composition exported from High Arctic headwater catchments. In 2012, streams were sampled from three disturbed catchments and one undisturbed catchment. The composition of DOM was characterized using absorbance and fluorescence spectroscopy. DOM was mostly exported during the spring freshet. Throughout this period, the undisturbed catchment exported humified DOM with high humic-like fluorescence that likely originated from runoff through shallow organic rich soil. In contrast, DOM exported from disturbed catchments was fresher, less humified with a high proportion of low molecular weight humic acid. We demonstrate that disturbed catchments delivered likely more labile DOM derived from either thawed permafrost or enhanced microbial activity. If this labile DOM comes from an ancient pool, as indicated by other studies at this site, disturbances may strengthen the permafrost carbon feedback on climate change.Key words: active layer detachments, dissolved organic matter, fluorescence, High Arctic, parallel factor analysis, PARAFAC.Résumé : Avec le changement climatique, les paysages arctiques connaissent un réchauffe-ment intense et une modification des régimes de précipitation. Les impacts des perturbations du pergélisol et du changement climatique sur l'hydrologie des bassins hydrographiques arctiques vont probablement modifier la quantité et la composition de matière organique dissoute (MOD) exportée. En juillet 2007, des averses intenses et l'épaississement de la couche active ont causé des décollements généralisés de la couche active à Cape Bounty, île Melville (Canada). Cette étude examine les impacts de l'hydrologie saisonnière et de la perturbation du pergélisol sur la composition de la MOD exportée des bassins versants d'amont du HautArctique. En 2012, on a échantillonné des cours d'eau de trois bassins versants perturbés et d'un bassin versant non perturbé. La composition de la MOD a été analysée en utilisant la spectroscopie à fluorescence et l'absorptiométrie. La MOD a surtout été exportée pendant la crue printanière. Pendant cette période, le bassin versant non perturbé a exporté de la MOD humifiée à haute fluorescence telle humique qui provenait probablement de ruissellement par sol riche organique mince. En revanche, la MOD exportée de bassins versants perturbés était plus fraîche, moins humifiée avec une haute proportion d'acide humique à Mots-clés : décollements de la couche active, matière organique dissoute, fluorescence, Haut-Arctique, analyse de facteurs parallèles...

show abstract

Section: Study Sitementioning

confidence: 99%

Section: Hydrologic Regimesmentioning

confidence: 99%

“…The sample collection and preparation are detailed in Louiseize et al (2014). Water samples were collected at stream outlets twice daily at approximately 10:00 (i.e.…”

Section: Field Samplingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Studies have shown that the downslope displacement of active layer soils from physical disturbances can expose soluble ions previously stored in the deep active layer (Kokelj and Lewkowicz 1999;Bowden et al 2008;Kokelj et al 2009;Lamoureux and Lafrenière 2009;Louiseize et al 2014). Ion-rich soils near the permafrost boundary have been attributed to progressive removal of solutes from the active layer by advection and convective transport of soluble materials along thermal gradients in nearsurface permafrost during the freezing process Burn 2003, 2005).…”

Section: Introductionmentioning

confidence: 99%

Multi-year impacts of permafrost disturbance and thermal perturbation on High Arctic stream chemistry

et al. 2017

View full text Add to dashboard Cite

Permafrost disturbances (such as active layer detachment (ALD) slides) and thermal perturbation (deep ground thaw from high soil temperatures) alter Arctic surface water chemistry. However, the potential multi-year impacts on water chemistry and the ultimate recovery time are not well understood. This study evaluates the impacts on surface waters and recovery following disturbance of a High Arctic catchment in 2007 from ALDs. We measured ion concentrations and stable isotopes in surface waters collected between 2006 and 2014 from paired catchments -one disturbed and the other not. The years 2007 and 2012 were exceptionally warm and represent unusual thermal perturbation for both catchments. Results indicate that the exposure and mobilization of soluble ions in near surface soil is a key control over dissolved ion concentrations and composition following ALDs. Runoff in the disturbed catchment shows increased total dissolved solute (TDS) concentrations and seasonal TDS fluxes and changes to the relative composition of individual ions in surface water. These impacts persisted for the 7 year study duration after disturbance and are consistent with the thawing of the solute-rich transient layer and upper permafrost. Thermal perturbation increased TDS concentrations and seasonal fluxes in runoff for up to 2 years, as ions released from ground thaw appear to be available for flushing in subsequent summers.Key words: permafrost disturbance, permafrost thaw, solutes, streamflow, active layer detachment.Résumé : Les perturbations du pergélisol (telles que les glissements causés par le détache-ment de la couche active (DCA)) et la perturbation thermique (le dégel du sol en profondeur causé par des températures élevées) changent l'hydrochimie des eaux de surface dans l'Arctique. Cependant, on ne comprend pas bien les impacts potentiels de plusieurs années sur l'hydrochimie ni le temps de rétablissement final. Cette étude évalue les impacts sur les eaux de surface après la perturbation For personal use only.changements de la composition relative des ions individuels dans les eaux de surface. Ces impacts ont continué pendant les sept ans de la durée de l'étude après la perturbation et sont conformes avec le dégel de la couche transitoire riche en solutés et du pergélisol supérieur. La perturbation thermique a causé l'augmentation des concentrations de SDT et des flux saisonniers du ruissellement sur une période allant jusqu'à deux ans alors que les ions émanant du dégel du sol semblent être disponibles pour lessivage au cours des étés suivants.Mots-clés : perturbations du pergélisol, dégel du pergélisol, solutés, écoulement fluvial, détachement de la couche active.

show abstract

Isotopic identification of soil and permafrost nitrate sources in an Arctic tundra ecosystem

et al. 2015

View full text Add to dashboard Cite

show abstract

Stable isotopic evidence of enhanced export of microbially derived $${\text{NO}}_{3}^{ - }$$ NO 3 - following active layer slope disturbance in the Canadian High Arctic

Cited by 34 publications

References 58 publications

Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

Multi-year impacts of permafrost disturbance and thermal perturbation on High Arctic stream chemistry

Isotopic identification of soil and permafrost nitrate sources in an Arctic tundra ecosystem

Contact Info

Product

Resources

About