The relative importance of seasonality versus regional and network-specific properties in determining the variability of fluvial CO$$_2$$, CH$$_4$$ and dissolved organic carbon across boreal Québec

Hutchins, Ryan H. S.; Prairie, Yves T.; Giorgio, Paul A. del

doi:10.1007/s00027-021-00830-7

Cited by 3 publications

(2 citation statements)

References 68 publications

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“…Multilevel models ( lme4 package; Bates et al., 2014) were used to examine the variance explained ( variancePartition package; Hoffman & Schadt, 2016) by a series of levels (site, ecozone, month and year) and percent watershed burned, for each chemical species concentration and instantaneous runoff. Multilevel or hierarchical models are appropriate for this data set given its observational nature with the 212 observations nested in geographical areas and where responses are correlated over time and not independent (Hutchins et al., 2021). We report variance explained by each level in the multilevel models, which provides an estimate of effect size and relative importance.…”

Section: Methodsmentioning

confidence: 99%

Influence of Wildfire on Downstream Transport of Dissolved Carbon, Nutrients, and Mercury in the Permafrost Zone of Boreal Western Canada

Hutchins,

Tank,

Olefeldt

et al. 2023

JGR Biogeosciences

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Northern regions are undergoing rapid change with wildfires increasing in frequency and severity alongside thawing permafrost and altered water balance. These disturbances could cause significant change in the export of carbon, nutrients, and metals to aquatic systems, with implications for food webs and ecosystem processes. Here, we examine chemical data from a series of 52 streams and rivers that were sampled across a 250,000 km2 expanse of the Taiga Plains and Taiga Shield ecozones of the Northwest Territories, Canada. Samples were collected immediately after and for 3 years following a “megafire” that occurred in this region in 2014, and included wildfire‐affected and non‐affected catchments. While wildfire has been observed to cause significant impacts on water quality in other regions, we here report weak relationships with percent watershed burn with minor to moderate effect sizes, the greatest being a reduction in dissolved organic carbon (−32% concentration). Watershed‐specific properties were a strong driver of large spatial variability in stream water chemistry, which may overwhelm or obscure lesser wildfire effects. The watershed chemical yield‐specific response to wildfire was weaker than the response for concentrations, due to substantial variation and uncertainty in runoff among sites and years. This suggests that watershed chemical yields in this region are more sensitive to changes in water balance due to climate than to altered wildfire regimes.

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Section: Methodsmentioning

confidence: 99%

Influence of Wildfire on Downstream Transport of Dissolved Carbon, Nutrients, and Mercury in the Permafrost Zone of Boreal Western Canada

Hutchins,

Tank,

Olefeldt

et al. 2023

JGR Biogeosciences

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“…To constrain the effects of varying J CO2 , J CH4 , and stream width on upscaled efflux, we report the mean and range of upscaled fluvial J CO2 and J CH4 . These estimates do not capture fine‐scale heterogeneity in aquatic gas efflux within individual stream reaches (e.g., Crawford et al., 2017), yet our sampling across stream orders attempts to capture variability in gas concentrations across scales (e.g., Hutchins et al., 2021) and allows for a first estimate of watershed‐scale CO 2 and CH 4 efflux in western Arctic Canada. To assess how the types of carbon comprising fluvial fluxes varied among sites and regions, we calculated fluxes of individual carbon species relative to the total carbon flux at each site, henceforth termed proportional flux: p = species flux/total flux, where total flux equals the sum of efflux ( J CO2 and J CH4 ) and lateral fluxes of DIC, DOC, PIC, and POC.…”

Section: Methodsmentioning

confidence: 99%

Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change

Zolkos

Tank

Kokelj

et al. 2022

Global Biogeochemical Cycles

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Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice‐rich moraine, and organic‐rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO2 (25%) dominated. In watersheds affected by thaw‐induced mass wasting, erosion of ice‐rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw‐induced wasting was, on average, equivalent to 6%–16% of estimated net ecosystem exchange (NEE). In watersheds affected by thaw‐induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance.

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Fluvial CO2 and CH4 in a lowland agriculturally impacted river network: Importance of local and longitudinal controls

Leng

Zhao

Zhang

et al. 2022

Environmental Pollution

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The relative importance of seasonality versus regional and network-specific properties in determining the variability of fluvial CO$$_2$$, CH$$_4$$ and dissolved organic carbon across boreal Québec

Cited by 3 publications

References 68 publications

Influence of Wildfire on Downstream Transport of Dissolved Carbon, Nutrients, and Mercury in the Permafrost Zone of Boreal Western Canada

Influence of Wildfire on Downstream Transport of Dissolved Carbon, Nutrients, and Mercury in the Permafrost Zone of Boreal Western Canada

Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change

Fluvial CO2 and CH4 in a lowland agriculturally impacted river network: Importance of local and longitudinal controls

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