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Linear disturbances are widespread in the boreal region of Alberta, Canada. Despite their ubiquitous nature, little is known about their influence on over‐winter meteorological conditions and if and how they alter the snowpack and soil temperature profiles through altered energy and water balances in the wintertime. The presence of seismic lines could affect hydrological processes in both the wintertime and warm months. This will then affect plant communities and carbon cycling on these disturbances. Thus, understanding the effect of seismic lines on meteorological conditions during cold weather conditions will be important to better understand how they alter ecosystem function. Accordingly, this study aims to assess the effect of two seismic lines with different orientations created for petroleum resource exploration on energy and meteorological variables by comparing them with the near surface conditions in the adjacent wooded peatland area from October 2022 to April 2023. We observed 1.8 times higher photon flux density of photosynthetically active radiation on the linear disturbances than in the understory of the undisturbed locations and a greater negative net radiation on the seismic lines compared with that observed off the lines. Furthermore, the average wind speed on the seismic lines were eight and seven times higher at the east–west and south–north oriented seismic lines than the adjacent wooded peatland, respectively. Together, these changes resulted in a denser snowpack on the seismic line and overall higher snow water equivalent in the pre‐melt snowpack. This provided insulation for the soil, and soil temperature on the lines stayed above freezing 7 days longer at the east–west oriented site or retained non‐freezing condition at the south–north oriented site in the upper 15 cm. This would result in more microbial activity and potential higher over‐winter carbon releases. [ABSTRACT FROM AUTHOR]

The carbon (C) dynamics of boreal coniferous swamps are a largely understudied component of wetland carbon cycling. We investigated the above‐ and below‐ground carbon stocks and growing season carbon dioxide (CO2) and methane (CH4) fluxes from a representative boreal coniferous swamp in northern Alberta, Canada in 2022. Tree inventories, understory vegetation biomass and peat cores were collected across three sub‐sites within the broader swamp, with gas flux collars placed in the dominant plant communities present. Alongside the C flux measurements, environmental variables such as water table depth, soil temperature and growing season understory green leaf phenology were measured. Our results show that these boreal coniferous swamps store large volumes of organic C in their biomass and soil (134 kg C m−2), comparable with other wetland and forest types, although 95% of the total C stock at our site was within the soil organic carbon. We also found that understory CO2 and CH4 fluxes indicated that the ground layer of the site is a source of greenhouse gases (GHGs) to the atmosphere across the growing season. However, we did not measure litterfall input, tree GHG fluxes or net primary productivity of the overstory, therefore we are not able to say whether the site is an overall source of C to the atmosphere. This study provides a much‐needed insight into the C dynamics of these under‐valued wetland ecosystems, and we highlight the need for a coordinated effort across boreal regions to try to improve inventories of C stocks and fluxes. Plain Language Summary: Compared to other wetland types across Canada, boreal conifer swamps do not receive the same level of scientific attention and therefore our understanding of how much carbon they potentially store and release is limited. To fill this knowledge gap, our study measured how much carbon was stored both in the trees and within the soil itself, alongside measurements of carbon uptake and release within a representative conifer swamp wetland in Western Canada. We found that although these wetlands may function similarly to other wetland types, by ignoring them, we are missing out on large amounts of carbon being stored in these systems. We also found that at the ground layer, these sites are a source of carbon, that is, releasing more carbon than is being taken up by the understory moss and plant layer. However, we cannot say if the site overall is a source of carbon to the atmosphere as we were unable to measure other key components of a wetland carbon cycle including litterfall input and the productivity of the trees themselves. Our findings indicate that by not including these wetlands in modeling of carbon dynamics, we are missing a substantial component of boreal carbon cycling processes. Key Points: Boreal conifer swamp wetlands are an underrepresented wetland class within wetland C cycling measurements and modelingThese swamps store large volumes of organic C in their aboveground biomass but most importantly, in their soil organic carbon stockWe also found that the ground‐layer of this site is a net source of greenhouse gases during the growing season [ABSTRACT FROM AUTHOR]

In northern Alberta, oil sands mining disturbs the boreal landscape, and reclamation to an 'equivalent land capability' is required. Industry is testing peatland construction as part of landscape reclamation. To determine if constructed peatlands can be self‐sustaining, an understanding of the cycling of solutes in pore water and their interactions with dissolved organic carbon (DOC) is needed since DOC can represent an important carbon loss from peatlands. DOC is of interest due to its biotic origin and use by the microbial community and impact on carbon budgets. Additionally, salinity as a control on DOC quantity and quality may be important in oil sands reclaimed systems due to the likelihood of elevated sodium (Na+) from saline groundwater input derived from tailings used to construct catchments, and natural sources. For this research, DOC concentration and quality, and Na+ concentration were measured in the rooting zone (10 and 30 cm depth) of Nikanotee Fen to evaluate the role of Na+ in DOC dynamics. DOC concentration and quality suggested that DOC in the fen was largely sourced from vegetation inputs, with quality also suggesting increases in vegetation inputs between years. Elevated Na+ at 30 cm below ground surface corresponded with high concentrations of labile DOC. At 10 cm below ground surface, sampling location and temperature were the best predictors of DOC concentration and quality. With expected increases in Na+, increased production of mobile and microbially active DOC may lead to higher rates of carbon export. [ABSTRACT FROM AUTHOR]

Peatland ecosystem restoration following oil mining activities in Alberta, Canada, aims at reestablishing crucial peatland functions, such as wildlife habitat, water storage and filtration, peat accumulation, and carbon sequestration. To reinstate peatland functions, characteristic hydrological conditions are necessary to support the establishment and growth of characteristic wetland vegetation. Following in situ oil sands well pad disturbances in the Peace River and Cold Lake Oil Sands regions in Alberta, we evaluated the efficiency of peatland restoration approaches including different groundwork and revegetation techniques. Groundwork techniques included the complete removal (CR) or partial removal (PR) of the former in situ well pads' mineral fill and revegetation included the spontaneous revegetation via natural ingress of diaspores from nearby peatlands, or managed revegetation via planting of Carex aquatilis, Larix laricina, and Salix lutea. We assessed the plant species composition, biochemical and hydrological properties of all study areas, including restored peatland areas, an unrestored area, and reference areas (REF) for comparison. Ten years post‐restoration, in the restored areas the mean total plant cover was 57% with an average of 35 vascular plant and bryophyte species, while in REF 68% mean total plant cover and an average of 64 plant species were recorded. Respectively, characteristic peatland species contributed to 61 and 100% of the species composition. PR and hydrological connection to the adjacent peatland resulted in near surface water table and the highest peatland plant species diversity, while CR promoted the formation of a shallow open water area. [ABSTRACT FROM AUTHOR]

We conducted a 2‐year study to examine the impacts of resource access roads on carbon (C) exchange in two forested boreal peatlands (a bog and a fen). Along six transects (perpendicular to the road), at 2, 6, and 20 m from the edge of the road on both sides of the road (RI areas), we measured understory CO2 fluxes bi‐weekly from May to August 2016 and 2017 and compared this to measurements at reference areas at least 50 m from the road. Furthermore, we estimated aboveground biomass and net primary productivity of overstory shrubs and trees and combined that with understory fluxes to estimate annual net ecosystem carbon balance, and road‐induced C emissions. Overall, at the bog, the RI areas were sources of C in both 2016 (89.9 g C m−2 y−1) and 2017 (108.9 g C m−2 y−1) while reference areas were sinks. However, at the fen, both RI areas (−744.7, −310.9 g C m−2 y−1 in 2016 and 2017, respectively) and reference areas were sinks of C. Averaged across both peatlands, the estimated road‐induced C losses were ∼7.97 and 7.40 Mg C for each km of the road in 2016 and 2017, respectively. However, areas connected by culverts showed lower road‐associated impact on C emissions. Therefore, we suggest that industries and infrastructure developers align the road parallel to the local water flow direction, when possible, consider the hydrogeological setting during road design to reduce hydrologic impacts, and increase hydrological flows between up‐ and downstream by adequate culverts. Plain Language Summary: The boreal region of Canada has significant numbers of resource access roads passing through peatlands. Undisturbed peatlands are globally important reservoirs of carbon (C, a component of carbon dioxide i.e., associated with global warming). In this study, we determined the impacts of resource access roads in two boreal forested peatlands (a bog and a fen) on C dynamics from the adjacent peatland. Our results showed that, at the bog, the road impacted areas were sources of carbon in both study years. However, in both study years, the fen was a sink of C. At both sites, the road‐impacted areas had less C uptake than undisturbed areas and this was caused by both the road affecting the wetness of the peatland and due to clearing of shrubs and trees adjacent to the road. Our study estimated road induced C losses were ∼7,970 and 7,400 kg C for each km of the road in 2016 and 2017, respectively. This study will help industries and infrastructure developers improve road construction design by considering the hydrogeological setting to reduce hydrologic impacts and increase hydrological flows between upstream and downstream areas through adequate culverts. Key Points: Access roads crossings peatlands alter carbon dynamics by disturbing local hydrology and vegetation coverEach kilometer of the road emitted a significant amount of carbon (∼7.97 and 7.40 Mg C in 2016 and 2017, respectively)To minimize road‐associated impacts, the road design should be aimed to minimize the road's hydrologic impact [ABSTRACT FROM AUTHOR]

One metric of peatland restoration success is the re‐establishment of a carbon sink, yet considerable uncertainty remains around the time‐scale of carbon sink trajectories. Conditions post‐restoration may promote the establishment of vascular plants such as graminoids, often at greater density than would be found in undisturbed peatlands, with consequences for carbon storage. Although graminoid species are often considered as a single plant functional type (PFT) in land‐atmosphere models, our understanding of functional variation among graminoid species is limited, particularly in a restoration context.We used a traits‐based approach to evaluate graminoid functional variation and to assess whether different graminoid species should be considered a single PFT or multiple types. We tested hypotheses that greenhouse gas fluxes (CO2, CH4) would vary due to differences in plant traits among five graminoid species in a restored peatland in central Alberta, Canada. We further hypothesized that species would form two functionally distinct groupings based on taxonomy (grass, sedge).Differences in gas fluxes among species primarily reflected variation in leaf physiology related to photosynthetic efficiency and resource‐use, and secondarily by plant size. Multivariate analyses did not reveal distinct functional groupings based on taxonomy or environmental preferences. Rather, we identified functional groups defined by plant traits and carbon fluxes that are consistent with ecological strategies related to differences in growth rate, resource‐acquisition and leaf economics, representing plants with either a strategy to grow quickly and invest in resource capture or to prioritize structural investment and resource conservation. These functional groups displayed larger average carbon fluxes compared to graminoid PFTs currently used in modelling.Synthesis. Existing PFT designations in peatland models may be more appropriate for pristine or high‐latitude systems than those under restoration. Although replacing PFTs with plant traits remains a challenge in peatlands, traits related to leaf physiology and growth rate strategies offer a promising avenue for future applications. [ABSTRACT FROM AUTHOR]

Northern peatlands have cooled the global climate by accumulating large quantities of soil carbon (C) over thousands of years. Maintaining the C sink function of these peatlands and their immense long‐term soil C stores is critical for achieving net‐zero global carbon dioxide (CO2) emissions by 2050 to mitigate climate warming. One‐quarter of the world's northern peatlands are in Canada, with these mostly intact ecosystems providing a global C service that is increasingly recognized as a critical part of nature‐based solutions to combat climate change. However, land‐use change and other disturbances threaten these globally important stores of "irrecoverable C" (that is, soil C lost to disturbance that will take centuries to recover). Inadequate policy safeguards to avoid conversion and degradation, and the limited quantification and reporting of peatland greenhouse‐gas emissions and removals, increase the vulnerability of these peatlands. Targeted policies from local to global scales will be needed for improved decision making and incentivizing long‐term C management of northern peatlands. [ABSTRACT FROM AUTHOR]

In this study, our goal was to adapt the moss layer transfer technique (MLTT), first developed to restore degraded Sphagnum‐dominated peatland explicitly with a bryophyte layer, to a former in‐situ oil sands well‐pad constructed with nearby mineral fill in northwestern Alberta, Canada. Mineral fill was either completely removed or partially removed with residual fill buried under excavated and decompacted peat, followed by the transfer of donor moss collected from nearby linear features with different plant communities in peatlands. Three years after MLTT, peatland vegetation covers 63% of the site. Carex spp. dominate with 36% coverage, followed by mosses at 12%, including 3% Sphagnum spp. and 8% fen mosses, and shrubs at 8%. Different substrate adjustment treatments and types of donor moss had negligible impact on vegetation development although areas without MLTT remained devoid of mosses and had the lowest peatland species cover. Instead, surface elevation, moisture conditions, and substrate chemistry played important roles in shaping the vegetation communities. The prompt introduction and establishment of peatland donor species through MLTT was crucial to the overall re‐establishment of peatland vegetation. This is the first full pad scale study to prove that a flat, moist peat surface created by the removal and/or burial of mineral fill can support peatland vegetation development, particularly ground layer bryophytes. Overall, the reclaimed well‐pad appears to be on trajectory toward becoming a functional peatland and our approaches should be considered and tested in future well‐pad reclamation trials. [ABSTRACT FROM AUTHOR]

Across Canada's boreal forest, disturbances from in situ oil sands mining, including well‐pads, significantly impact vast areas of the landscape. The creation of well‐pads requires removal of vegetation and placement of mineral fill, which essentially stops any carbon (C) sequestration on the once peatland ecosystem. It is important that, once no longer in use, these well‐pads are restored as long‐term C (peat) accumulation is what defines peatland ecosystem. However, little is known about the recovery of greenhouse gas exchange post‐restoration of these features. We studied a decommissioned well‐pad located in a treed poor fen that was restored using three soil adjustment treatments (SATs): (1) complete mineral fill removal (Peat‐Dec); (2) partial pad removal and burial under peat layer (BUPL); and (3) mixing mineral and peat by inversion (Mixed‐P‐M). The recreated peat surface was revegetated with donor peatland species using the moss layer transfer technique (MLTT). The objectives of this paper were to (1) quantify plot‐scale seasonal carbon dioxide (CO2) and methane (CH4) exchange of the SATs, 2–4 years post‐restoration compared to reference sites and (2) determine the influence of several environmental variables on CO2 and CH4 exchange. All SATs proved effective in recreating a soil surface needed to support peatland vegetation as shown by similar rates of net ecosystem exchange (NEE). Equally, both types of vegetation reintroduced led this site on a trajectory toward functioning as a net C sink. [ABSTRACT FROM AUTHOR]

Peatland degradation due to human activities is contributing to rising atmospheric CO2 levels. Restoring the carbon (C) sink function in degraded peatlands and preventing further stored C losses is a key climate mitigation strategy, given the global scale of peatland disturbance. Active restoration involving a combination of rewetting and vegetation reestablishment at a post‐extraction peatland in Canada has been shown to successfully re‐establish net CO2 uptake rates similar to undisturbed peatlands within a decade or two. However, lower than expected CH4 emissions suggest recovery of belowground C cycling processes may lag behind the recovery of the surface net flux. Using closed chamber measurements over a warm season, we determined that restored Sphagnum, which covers two thirds of the site, was a null source of CH4. Emissions from the restored site were primarily attributed to vascular plant substrate inputs, measured as acetate, and plant‐mediated transport. The C isotopic fractionation factor for CH4 and CO2 in the pore water from the restored former peat field suggested reduced hydrogenotrophic CH4 production deeper in the cutover peat profile (0.8 m depth). In contrast, isotopic fractionation in the former drainage ditches showed a balance of acetoclastic and hydrogenotrophic methanogenesis deeper in the profile, indicative of some bulk peat C turnover. This study suggests that the legacy of substrate quality in the cutover peat can reduce the climate warming impact of newly restored peatlands through a reduction in CH4 production and thus emission. Plain Language Summary: Restoration of degraded peatlands is increasingly being considered a tool to mitigate the global temperature rise associated with climate change. This study is the first to isolate methane production and emission processes to explain why methane release from post‐extraction peatlands restored by a combined rewetting and vegetation reestablishment is lower than that of undisturbed peatlands. Carbon turnover of bulk cutover peat was limited to former ditch areas in the restored peatland, which comprise less than 5% of the site. As a result, methane release from the ecosystem to the atmosphere was low and linked to vascular plant inputs and plant‐mediated transport. This study provides evidence that an active restoration method that restores the water table below the surface and aids reestablishment of Sphagnum can be an effective climate mitigation tool by bringing back endemic vegetation more quickly and avoiding large methane release often associated with unmanaged rewetting. Key Points: Restored site emissions were attributed to vascular plant‐mediated transport, while restored Sphagnum was a null source of methaneThe carbon isotopic fractionation factor for methane and CO2 indicated very little bulk peat carbon turnover beneath the restored SphagnumActive restoration (rewetting and vegetation re‐establishment) can be an effective climate mitigation strategy avoiding large CH4 release [ABSTRACT FROM AUTHOR]

Vast areas of boreal peatlands are impacted by linear disturbances known as seismic lines. Tree removal and ground disturbance alter vegetation communities and are expected to change ecosystem functioning. As boreal landscapes continue to be disturbed by linear disturbances, understanding the magnitude and mechanisms of vegetation and phenology changes is the first step toward predicting carbon cycling changes across broad spatial scales. We investigate seismic line disturbances on peatland plant community composition and phenological patterns using readily available digital photography at a bog and a fen in Alberta, Canada. Our objectives were to: (a) compare the understory peatland vegetation on seismic lines with those in adjacent undisturbed areas using two phenological metrics (green and red chromatic coordinates); (b) evaluate if vegetation greenness is directly related to vegetation community composition, and (c) determine whether plot‐scale greenness predicts plant productivity. We found that areas of peatlands intersected by seismic lines have an earlier seasonal peak (maximum greenness) compared to undisturbed areas, and vegetation communities had a stronger relationship to greenness and gross primary production (GPP) at disturbed areas relative to undisturbed areas. This change in understory vegetation results in greater CO2 uptake in disturbed areas. We demonstrate an easy‐to‐use application of digital photography that successfully quantifies phenological changes in boreal peatland vegetation. This nondestructive method for understanding vegetation phenology eliminated the need for fixed infrastructure and allowed us to expand our sampling capacity and study sites while allowing for repeated measures in the future. Plain Language Summary: Industrial activities for oil and gas mining across boreal North America can result in a vast network of linear disturbances called seismic lines. These are narrow clearings cut across peatlands and forests, resulting in the removal of trees and compaction to the soil, leading to changes in both the vegetation communities and how these ecosystems function. One such impact is how the ground‐layer vegetation communities green up over the course of the growing season and how this affects how productive they are. In this study, we investigated the greenness patterns of vegetation communities at two different peatland types impacted by seismic lines. To do this, we collect photographs using smartphones, alongside vegetation surveys and carbon exchange measurements. We found that these disturbances significantly impact the greenness of these communities, with disturbed areas becoming more productive faster. Using smartphones to collect photographs provided a quick and easy method to collect greenness data without the need for expensive equipment or fixed infrastructure. As boreal peatlands continue to be under threat from increased disturbances, this study provides a first step in understanding how greenness and productivity may change in the future. Key Points: Seismic lines cause a shift in vegetation communities and changes in green leaf phenology and greenness metricsReadily available smartphone photography successfully captured the phenological characteristics of these vegetation typesThe change in vegetation causes greater CO2 uptake in the disturbed areas and greenness metrics were good predictors of these CO2 changes [ABSTRACT FROM AUTHOR]

Peatlands after drainage and extraction are large sources of carbon (C) to the atmosphere. Restoration, through re‐wetting and revegetation, aims to return the C sink function by re‐establishing conditions similar to that of an undrained peatland. However, the time needed to re‐establish C sequestration is not well constrained due to the lack of multi‐year measurements. We measured over 3 years the net ecosystem exchange of CO2 (NEE), methane (FCH4), and dissolved organic carbon (DOC) at a restored post‐extraction peatland (RES) in southeast Canada (restored 14 years prior to the start of the study) and compared our observations to the C balance of an intact reference peatland (REF) that has a long‐term continuous flux record and is in the same climate zone. Small but significant differences in winter respiration driven by temperature were mainly responsible for differences in cumulative NEE between years. Low growing season inter‐annual variability was linked to constancy of the initial spring water table position, controlled by the blocked drainage ditches and the presence of water storage structures (bunds and pools). Half‐hour FCH4 at RES was small except when Typha latifolia‐invaded drainage ditches were in the tower footprint; this effect at the ecosystem level was small as ditches represent a minor fraction of RES. The restored peatland was an annual sink for CO2 (−90 ± 18 g C m−2 year−1), a source of CH4 (4.4 ± 0.2 g C m−2 year−1), and a source of DOC (6.9 ± 2.2 g C m−2 year−1), resulting in mean net ecosystem uptake of 78 ± 17 g C m−2 year−1. Annual NEE at RES was most similar to wetter, more productive years at REF. Integrating structures to increase water retention, alongside re‐establishing key species, have been effective at re‐establishing the net C sink rate to that of an intact peatland. We measured over 3 years the net ecosystem exchange of CO2, methane, and dissolved organic carbon (DOC) at a restored post‐extraction peatland and compared our observations to the C balance of an intact reference peatland that has a long‐term continuous flux record. The restored peatland was an annual sink for CO2, and a source of methane and DOC, resulting in a mean annual net ecosystem uptake of C. Integrating structures to increase water retention, alongside re‐establishing key species, have been effective at re‐establishing the net C sink rate to that of an intact peatland. [ABSTRACT FROM AUTHOR]

Across Canada's boreal forest, linear disturbances, including cutlines such as seismic lines and roads, crisscross the landscape to facilitate resource exploration and extraction; many of these linear disturbances cross peatland ecosystems. Changes in tree canopy cover and the compression of the peat by heavy equipment alter local thermal, hydrological, and ecological conditions, likely changing carbon exchange on the disturbance, and possibly in the adjacent peatland. We measured bulk density, water table, soil temperature, plant cover, and CO2 and CH4 flux along triplicate transects crossing a winter road through a wooded fen near Peace River, Alberta, Canada. Sample plots were located 1, 5, and 10 m from the road on both sides with an additional three plots on the road. Productivity of the overstory trees, when present, was also determined. The winter road had higher bulk density, shallower water table, higher graminoid cover, and thawed earlier than the adjacent peatland. Tree productivity and CO2 flux varied between the plots, and there was no clear pattern in relation to distance from the road. The plots on the winter road acted as a greater CO2 sink and greater CH4 source compared to the adjacent peatland with plots on the winter road emitting on average (standard error) 479 (138) compared to 41 (10) mg CH4 m−2 day−1 in the adjacent peatland. Considering both gases, global warming potential increased from 70 to 250 g CO2e m−2 year−1 in the undisturbed area to 2100 g CO2e m−2 year−1 on the winter road. Although carbon fluxes on any given cutline through peatland will vary depending on level of compaction, line width and vegetation community shifts, the large number of linear disturbances in Canada's boreal forest and slow recovery on peatland ecosites suggest they could represent an important anthropogenic greenhouse gas source. [ABSTRACT FROM AUTHOR]

Changes in atmospheric temperature and lowering in water-table (WT) are expected to affect peatland nutrient dynamics. To understand the response of peatland nitrogen (N) and phosphorus (P) dynamics to warming and drainage in a continental wooded-bog of hummock-hollow microtopography, we compared three sites: (a) control, (b) recently drained (2-3 years; experimental), and (c) older drained (12-13 years; drained), during 2013. The WT was lowered at experimental and drained sites to 74 and 120 cm, respectively, whereas a warming of ~1 °C was created at one half of the microforms using open-top chambers. Responses of peat total inorganic nitrogen (TIN = nitrate nitrogen [NO3−-N] + ammonium nitrogen [NH4+-N]) and phosphate-P (PO43−-P) pools and vegetation C:N ratio, δ13C and δ15N to the experimental treatments were investigated across sites/microforms and over time. Peat TIN available and extractable pools increased with deepening of WT and over time and were greater at hummocks relative to hollows. In contrast, the PO4 pools increased with short-term drainage but reverted to very close to their original (control) nutrient values in the longer term. The WT and warming driven change in the peat TIN pool was strongly reflected in the vascular vegetation C:N ratio and shrub δ13C and δ15N, whereas moss nutrient dynamics did not vary between sites. Therefore, we suggest that atmospheric warming combined with WT deepening can increase availability of mineral N and P, which then can be reflected in vascular vegetation and hence modify the productivity and ecosystem functioning of the northern midlatitude continental wooded bogs in the long term. [ABSTRACT FROM AUTHOR]

Recent research into the production of Sphagnum biomass in extracted peatlands, an alternative to ecological restoration as a post-industrial use of peatlands, has highlighted the need for an improved understanding of the ecohydrology of Sphagnum regenerating in these environments. Previous work suggested that limited connectivity between surficial layers and the underlying partially decomposed plant matter and peat would result in water stress and inhibited growth. This study links the soil water dynamics of regenerated layers ranging in age from 3 to 43 years and from 3 to 40 cm in thickness to the productivity of Sphagnum in order to determine the hydrological controls on productivity and the optimal range of water content for producing Sphagnum biomass. Productivity was never observed to be limited by insufficient supply of water, including during periods where water table was >40 cm below the surface and periods of 16 days without measured precipitation. While layers of different ages and thicknesses were able to sustain adequate water supply to remain productive under a range of conditions, the ability of layers to transmit water upwards differed greatly. Water content in the near-surface inhibited productivity during wetter periods, especially at newly regenerating sites where the layer was <5 cm thick. This has important implications for biomass production using the Sphagnum species studied here. Using a mixed linear modelling approach to isolate the effects of water content on variance in productivity from those of other measured variables, a volumetric water content of 0.10 is identified as optimal. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Wetlands are found extensively throughout the Western Boreal Plain, a region under pressure because of disturbance by the oil and gas industries. To understand how wetland systems may respond to disturbance and set targets for reclamation efforts, it is necessary to understand natural variability in nutrient dynamics in the landscape. The purpose of this study was to characterize spatial variability in peatland nutrient (nitrogen, N, and phosphorus, P) dynamics in the Athabasca Oil Sands (AOS) region. N and P availability and net mineralization rates in the upper 10 cm layer of peat were examined during the peak growing season in five peatlands that fell along an apparent moisture gradient. N and P dynamics within and among the sites were related to water table position, peat moisture content and temperature. Phosphorus supply rates and total inorganic N pools and supply rates were generally elevated under wetter conditions, whereas nitrate (NO3−) pools and supply rates and P pools did not vary along a moisture gradient. In general, net immobilization was observed at the wetter sites where nutrient pools were elevated and net mineralization was observed at drier sites where nutrient pools were lower. Nutrient transformation rates were most strongly driven by warmer temperatures. Nutrient availability and immobilization rates were anomalously high at one peatland (a disturbed fen with a semi-permanent road and decommissioned well pads). We suggest that reclamation and management practices should focus on regulating peatland hydrologic conditions, optimizing these for the most desirable nutrient levels for vegetation growth. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Northern peatlands are a large source of atmospheric methane (CH4) and both a source and a sink of atmospheric carbon dioxide (CO2). The rate and temporal variability in gas exchanges with peat soils is directly related to the spatial distribution of these free-phase gases within the peat column. In this paper, we present results from surface and borehole ground-penetrating radar surveys - constrained with direct soil and gas sampling - that compare the spatial distribution of gas accumulations in two raised bogs: one in Wales (UK), the other in Maine (USA). Although the two peatlands have similar average thickness, physical properties of the peat matrix differ, particularly in terms of peat type and degree of humification. We hypothesize that these variations in physical properties are responsible for the differences in gas distribution between the two peatlands characterized by (1) gas content up to 10.8% associated with woody peat and presence of wood layers in Caribou Bog (Maine) and (2) a more homogenous distribution with gas content up to 5.7% at the surface (i.e. <0.5 m deep) in Cors Fochno (Wales). Our results highlight the variability in biogenic gas accumulation and distribution across peatlands and suggest that the nature of the peat matrix has a key role in defining how biogenic gas accumulates within and is released to the atmosphere from peat soils. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Within peatland ecosystems, small deviations in surface elevation result in microforms that differ in depth to water table, plant type and rate of biogeochemical cycling, possibly leading to differences in peat physical and hydrological properties that could feed back to the whole ecosystem hydrological and biogeochemical function. However, hydrological parameters for peatland microforms have not been quantified. This study determined bulk density, pore size distribution and saturated hydraulic conductivity (Ksat) at hummocks and hollows of four, Sphagnum-dominated Canadian peatlands. Study sites included both a bog and poor fen in each of Alberta and Quebec allowing for investigation of differences in peat hydrophysical properties between microforms across a range of Sphagnum-dominated peatlands. Hydraulic conductivity was determined in the laboratory on peat from the surface (0.03-0.08 m) and the saturated zone (0.20 m below the local water table position). Peatland type, climate region, microform and depth of peat were all significant descriptors of variation in Ksat. Deeper peat was less conductive than surface peat. Hummocks generally had higher Ksat than hollows at both surface and saturated zones, although differences between microforms varied between sites. Differences in Ksat between samples were correlated with bulk density, von Post humification and macroporosity. These results indicate that there are microtopographical differences in peat hydrophysical properties; however, the strong decline in Ksat with depth indicates that differences in the local water table, resulting in a change in depth of water flow, is likely a stronger control on local Ksat than microform type. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Recently, methanotrophic members of the phylum V errucomicrobia have been described, but little is known about their distribution in nature. We surveyed methanotrophic bacteria in geothermal springs and acidic wetlands via pyrosequencing of 16 S rRNA gene amplicons. Putative methanotrophic V errucomicrobia were found in samples covering a broad temperature range (22.5-81.6° C), but only in acidic conditions ( pH 1.8-5.0) and only in geothermal environments, not in acidic bogs or fens. Phylogenetically, three 16 S rRNA gene sequence clusters of putative methanotrophic V errucomicrobia were observed. Those detected in high-temperature geothermal samples (44.1-81.6° C) grouped with known thermoacidiphilic ' M ethylacidiphilum' isolates. A second group dominated in moderate-temperature geothermal samples (22.5-40.1° C) and a representative mesophilic methanotroph from this group was isolated (strain LP2 A). Genome sequencing verified that strain LP2 A possessed particulate methane monooxygenase, but its 16 S rRNA gene sequence identity to ' M ethylacidiphilum infernorum' strain V4 was only 90.6%. A third group clustered distantly with known methanotrophic V errucomicrobia. Using pmoA-gene targeted quantitative polymerase chain reaction, two geothermal soil profiles showed a dominance of LP2 A-like pmoA sequences in the cooler surface layers and ' M ethylacidiphilum'-like pmoA sequences in deeper, hotter layers. Based on these results, there appears to be a thermophilic group and a mesophilic group of methanotrophic V errucomicrobia. However, both were detected only in acidic geothermal environments. [ABSTRACT FROM AUTHOR]

Sphagnum mosses (Sphagnum L.) are the primary peat-forming plant in northern peatlands and rely on capillary transport of water to facilitate physiological processes. The unsaturated hydraulic conductivity of the living, undecomposed, and poorly decomposed mosses is needed to estimate and model water flux to their growing upper layer. This study describes a new apparatus to measure this in the highly porous (∼90%) hummock profile where the pore sizes are large and the mosses delicate, in which established methods do not work. Independent tension disks controlled the pressure head (ψ, between 0 and -35 cm of water) and the pressure gradient and thus flow. The uppermost 5-cm layer of moss had a saturated hydraulic conductivity of 1800 μm s-1, and decreased when unsaturated (ψ = -25 cm of water) to 0.03 μm s-1. Moss 25 cm below the surface had equivalent values of 230 and 11.0 μm s-1 at moisture contents of 0.18 to 0.22 m3 m-3. The soil water retention model RETC provided a good fit for both hydraulic conductivity and water retention when fitted simultaneously, but did not perform well to predict hydraulic conductivity from water retention data alone. [ABSTRACT FROM AUTHOR]

Carbon dynamics of temperate peat swamps are a largely understudied component of wetland carbon cycling. Under a changing climate, hydrometeorological conditions may change, and understanding how peat swamps may be impacted is important. We investigated the importance of hydrogeomorphic setting on controlling soil carbon dioxide (CO2) and methane (CH4) fluxes from a temperate peat swamp in southern Ontario, Canada over a 3‐year period. We chose three different hydrogeomorphic settings: (a) a site with strong wetland‐stream interactions (i.e., an unconfined stream channel; unconfined), (b) a site with limited wetland‐stream interactions (confined), and (c) an interior site (no wetland–stream interaction). The differing hydrogeomorphic conditions between the sites resulted in differences in carbon fluxes. The unconfined site maintained a higher water table across all three study years, providing conditions that are not favourable to CO2 production. The confined and interior sites sustained a much lower water table, with conditions more conducive to CO2 efflux. The unconfined site also had the highest CH4 emissions due to the increased anoxic conditions favourable for CH4 production as a result of the higher water table position. Hydrogeomorphic setting was found to be important for understanding within site variation, suggesting the sites may respond differently to longer‐term shifts in environmental conditions. This may change relationships between sites if the responses are strong enough to significantly alter carbon fluxes, decomposition, and potential peat accumulation rates. It is important to understand the locally specific responses to environmental conditions within peat swamp ecosystems, in order to make future predictions about whole ecosystem function under changing conditions. [ABSTRACT FROM AUTHOR]

Western Boreal Canada could experience drier hydrometeorological conditions under future climatic changes, and the drying of nonpermafrost peatlands can lead to higher frequency and extent of wildfires. Despite increasing pressures, our understanding of the impact of fire on dissolved organic carbon (DOC) concentration and quality across boreal peatlands is not consistent. This study capitalizes on the rare opportunity of having 3 years of prefire and 3 years of postfire DOC data at a treed, moderate‐rich fen in the Western Boreal Plain, northern Alberta, to investigate wildfire effects on peatland DOC dynamics. We investigated whether a wildfire facilitated any changes in the pore water DOC concentration and quality. There was very little impact of the fire directly, with no significant changes in DOC concentrations postfire. We highlight that DOC patterns are more likely to be controlled by local hydrogeological factors than any effect of fire. Fall hydrological conditions and subsequent winter storage processes impose a strong control on DOC concentrations the following year. We suggest that the presence or absence of concrete ground frost in the fen (determined by fall water table position) influences overwinter storage changes, controlling the effect that DOC‐poor snowmelt may have on pore water concentrations. However, an increase in SUVA254 was found 2 years postfire, indicating an increase in aromaticity. These results highlight the need for careful consideration of the local hydrogeologic setting and hydrological regime when predicting and analysing trends in DOC concentrations and quality. [ABSTRACT FROM AUTHOR]

Northern peatlands are globally significant soil carbon sinks but contribute a significant amount of dissolved organic carbon (DOC) to streams. Climate change driven warming and drying will likely alter peatland DOC dynamics; however, few field studies have quantified the individual and interactive effects of temperature and moisture changes. Using a full factorial water table (control, drained 2 years [experimental], drained 12 years [drained]) × warming (ambient, open‐top chamber warming) × microform (hummock, hollow) study design, we monitored DOC concentration and spectrophotometric properties (specific ultraviolet absorbance [SUVA], E2/E3, E4/E6) in a wooded boreal bog in Alberta, Canada. Ecohydrological conditions including water table (WT), soil temperature, plant cover, biomass, and productivity were also measured at each plot. We observed a significant interaction between WT treatment, warming and microform for explaining variation in DOC concentrations, with the highest values at drained, warmed hummocks. Overall, drainage resulted in higher DOC concentration. DOC concentration and E2/E3 increased, whereas SUVA decreased, in response to greater plant productivity (i.e., more negative values of gross ecosystem photosynthesis). For DOC concentration and SUVA, this correlation was largely driven by drained, warmed hummocks where shrub growth increased. Moreover, redundancy analysis indicated that shrub and lichen cover, along with WT and soil temperature, were important for explaining variation in DOC concentration and quality. The results indicate that, although DOC concentrations in peatlands are likely to increase under climate change, much of this increase may be from recent carbon fixation, suggesting more rapid carbon cycling as opposed to destabilization of existing carbon stocks. [ABSTRACT FROM AUTHOR]