High sulfate concentrations maintain low methane emissions at a constructed fen over the first seven years of ecosystem development.

Wetlands comprise a large expanse of the pre-disturbance landscape in the Athabasca Oil Sands Region (AOSR) and have become a focus of reclamation in recent years. An important aspect of wetland reclamation is understanding the biogeochemical functioning and carbon exchange, including methane (CH4) emissions, in the developing ecosystem. This study investigates the drivers of CH4 emissions over the first seven years of ecosystem development at a constructed fen in the AOSR and looks towards future CH4 emissions from this site. Specifically, the objectives were to: 1) investigate the environmental controls on CH4 emissions measured using manual static chambers between 2013 and 2019 and 2) investigate the relationship between water table depth, sulfate (SO42-) concentrations and CH4 emissions during the 2019 growing season. Methane emissions remained low throughout the majority of the measurement period; however, in later years, a small but significant increase became apparent. High levels of SO42- are likely the cause of the low CH4 emissions, despite the high-water tables and dominance of vegetation with aerenchyma such as Carex aquatilis and Typha latifolia in later years. Although low CH4 emissions may be beneficial from a climate warming perspective, the results also suggest that this constructed peatland is not functioning similarly to regional reference fens. Future climate scenarios across Western Boreal Canada could lead to higher air temperatures and changing precipitation patterns, influencing the direction of future CH4 emissions from this site. However, given the likelihood of this site maintaining extremely high SO42- concentrations over the next decade, it is expected that CH4 emissions will remain low.

Methane emissions dynamics from a constructed fen and reference sites in the Athabasca Oil Sands Region, Alberta.

Recently, fen construction projects on surface mines in northeastern Alberta have been attempted as a reclamation strategy to reintroduce peatlands into the region where industry disturbs a substantial amount of wetland ecosystems. Knowledge of carbon cycling and greenhouse gas (GHG) dynamics, including methane (CH4), is one way to understand the biogeochemical function of newly constructed fen ecosystems. In this study we monitored CH4 emissions and CH4 pore water concentration, as well as ecological and soil chemistry controls on CH4 emissions and pore water concentration, from a constructed fen. The same variables were also monitored at two natural reference fens that had similar vascular vegetation to the constructed fen. Methane emissions were lower at the constructed fen compared to the reference poor fen, but similar to the reference saline fen. However, CH4 concentration in pore water at 0.2m and 0.7m depth was lower at the constructed fen than either of the natural reference sites. The supply rate of sulfur (all mobile forms) was the most dominant control on CH4 emission and CH4 pore water concentration. While low CH4 emissions may be beneficial for constructed fens from a GHG perspective, this condition indicates that peat and carbon accumulation at these reclaimed sites may ensue slowly. Therefore, a clear statement of goals is required to determine how CH4 dynamics from constructed fen ecosystems relate to the reclamation outcome.

Normobaric hyperoxia training in elite female hockey players.

BACKGROUND: Supplemental oxygen use may offer recovery benefits to team sport athletes both in training and match play. A blinded independent measures study was used to investigate the effect of supplementary oxygen use during recovery from high-intensity exercise on performance. METHODS: Fifteen female international hockey players underwent a 6 week running based training program with a 2:1 work to rest ratio. The subjects were split into 3 groups; normobaric hyperoxia (HXA), normoxia (NXA) and control (CTR). In between exercise sets HXA received 100% oxygen for 1 minute whilst NXA received a placebo in the same manner. CTR received no treatment and were not supervised. Maximal aerobic speed (MAS) was measured pre and post. Distance covered was measured along with peak heart rate (HRpeak), peak blood lactate concentration ([La-]peak) and rate of perceived exertion (RPE). RESULTS: MAS improved in HXA, NXA and CTR. However, distance ran in training was not different between groups. There was a likely positive effect on HRpeak in HXA (lower in HXA). RPE and [La-]peak response was not different between groups. CONCLUSIONS: Inhaling supplementary oxygen during recovery between high-intensity intervals did not improve physiological performance of high-level team sport players. The normobaric hyperoxia treatment had no effect on maximal aerobic (distance covered), metabolic ([La-]peak), and perception (RPE) parameters. It is not recommended as an ergogenic aid to training at sea level.