Hydrology of a Moderate–Rich Fen Watershed Prior to, and Following Wildfire in the Western Boreal Plain, Northern Alberta, Canada,

Peatlands are a dominant land feature in the Athabasca Oil Sands Region (AOSR) of the Western Boreal Plain (WBP), northern Alberta, Canada, comprising >50% of the total land area, many of which are moderate–rich fens. The carbon stocks of moderate–rich fens in the WBP are susceptible to degradation through anthropogenic– and climate–related factors; yet, few studies have aimed to understand their hydrologic function. In addition, low relief and subtle topographic gradients allow for the expanse of peatland development along the margins between fen and upland. Few studies have explored the hydrologic role of fen margins, despite their typically lower water tables and therefore increased susceptibility to drying. This seven–year (2011–17) study explores the hydrologic function of fen and margin areas in a moderate–rich fen watershed, and how this function changes following wildfire. The study site (Poplar Fen; 56°56′N; 111°32′W) is located in a meltwater channel belt characterized by relatively thin outwash sand and gravel (mean thickness = 6 m) underlying the peat. The watershed is underlain by a thick (~16 m) and shallow (~7 m below ground surface) aquitard, restricting hydrological connectivity between the fen and underlying regional aquifers. Vertical hydraulic gradients between peat and the underlying outwash aquifer and horizontal hydraulic gradients between fen and upland varied in correspondence with diurnal and seasonal precipitation trends. Groundwater discharge to the fen was enhanced during wet periods characterized by high rainfall. Conversely, flow reversals (groundwater recharge; fen to underlying aquifer and upland), and subsequently, enhanced fen water table drawdown persisted during extended dry periods. Results suggest the dominance of a local flow–system influencing the recharge/discharge patterns at Poplar Fen, with hydraulic head in the underlying outwash aquifer highly susceptible to fluctuations in the presence and absence of precipitation–driven recharge from adjacent uplands. Contrary to fen areas, which received groundwater discharge from the underlying outwash aquifer during wet periods, and were prone to vertical flow reversals during dry periods, margins acted as permanent vertical recharge zones, providing groundwater to the underlying outwash aquifer. Furthermore, margins acted as large facilitators of lateral groundwater flow between upland and fen, and high pH and base cation concentrations allowed for the unique assemblage of upland and fen vegetation communities. Therefore, margins act as distinct ecohydrological units, which influence the hydrologic function of Poplar Fen watershed. In May of 2016, Poplar Fen was impacted by the ~590 000 ha Horse River wildfire, which spread into the city of Fort McMurray and subsequently advanced across the boreal mosaic of mixedwood uplands and peatlands. The destructive nature of the fire motivated the investigation of the hydrometeorological conditions that preceded the fire. Field hydrometeorological data from Poplar Fen between 2015–2016 confirmed the presence of cumulative moisture deficits prior to the fire. The susceptibility of fen and upland areas to water table and soil moisture decline over rain–free periods (including winter) was enhanced by the reliance on supply from the localized flow systems which originate in adjacent topographic highs. Subtle changes in topographic position were also found to influence groundwater connectivity, leading to greater organic soil consumption by fire in wetland margins and at high elevations. It was ultimately the accumulated moisture deficits, dating back to the summer of 2015, which led to the dry conditions that preceded the fire. To address the potential changes in the hydrologic function of the uplands at Poplar Fen, differences in water repellency and hydrophysical properties were measured for burned and unburned upland duff and mineral soils. Samples were taken in the fall of 2017, the year after the watershed had burned (May 2016). Study locations included burned and unburned jack pine–dominated brunisol, and black spruce–dominated riparian uplands. Results illustrated significantly lower water repellency and higher infiltration on burned uplands at both upland types. This was due primarily to the destruction of naturally occurring hydrophobic substances by the fire. Furthermore, no significant differences were detected in duff moisture retention in brunisol uplands; however, burned duff samples had significantly lower water retention in riparian uplands. It is postulated that the lower water retention in riparian uplands was due to the greater organic layer thickness there, thus greater fuel load and potential for exceeding the temperature threshold of repellency destruction. Following retention, all soil cores exhibited high hysteresis, with differences in volumetric moisture content averaging 0.38 and 0.34 m3 m–3 at –10 cm pressure for brunisol and riparian uplands, respectively. A net gain in upland water table recharge is anticipated at Poplar Fen following wildfire, which will help in sustaining recharge to the local flow systems which discharge to lower–lying fen areas and prevent water table drawdown, thus accelerating the fen moss recovery process. In conclusion, Poplar Fen, and watersheds with a similar hydrogeologic setting, will become increasingly susceptible to drying in the future due to anticipated changing climate scenarios. This will likely lead to enhanced water table drawdown, peat oxidation and subsequent decomposition, as well as seral succession to a more ombrogenous peatland system, rendering them more vulnerable to wildfire. However, base–rich fens are typically understudied in the WBP. It is recommended that similar hydrological methods are applied to other base–rich systems (including extreme–rich fens) throughout the WBP, which will improve our understanding of how these systems will respond to disturbance. Poplar Fen may also serve as an appropriate analogue for oil sands reclamation. Results from this thesis suggest that the hydrologic function of natural fen systems (i.e. moderate–rich fens) in the AOSR can be replicated. However, considering the susceptibility of this system to drying over regional climate cycles, fen reclamation should focus on specific engineering of the landscape to provide the necessary hydrological conditions for minimizing fen recharge conditions, water loss, and susceptibility to carbon degradation from enhanced decomposition and/or wildfire.

Hydrologic function of a moderate-rich fen watershed in the Athabasca Oil Sands Region of the Western Boreal Plain, northern Alberta

The final publication is available at Elsevier via https://doi.org/10.1016/j.jhydrol.2018.12.043 © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Peatlands are a dominant land feature in the Athabasca Oil Sands Region (AOSR) of the Western Boreal Plain (WBP), comprising >50% of the total land area, many of which are moderate-rich fens. The carbon stocks of moderate-rich fens in the WBP are susceptible to degradation through anthropogenic- and climate-related factors, yet, few studies have aimed to understand their hydrologic function. This study, located in a meltwater channel belt characterized by relatively thin outwash sand and gravel (∼6 m) underlying the peat, provides the first hydrological assessment of a moderate-rich fen in the AOSR. The lithology, hydrological function and groundwater geochemistry all point to the dominance of a local flow system supplying groundwater to the fen areas, evidenced by a thick (∼16 m) and shallow (∼7 m below ground surface) aquitard underlying the outwash, restricting hydrological connectivity between the fen and underlying regional aquifers. Vertical hydraulic gradients between the peat and underlying outwash aquifer, and horizontal hydraulic gradients between the fen and upland varied in response to both short-term and seasonal precipitation trends. Groundwater discharge to the fen was enhanced during wet periods characterized by high rainfall. Conversely, flow reversals (groundwater recharge; fen to underlying aquifer and upland), and subsequently, enhanced fen water table drawdown persisted during extended dry periods. This local groundwater flow-system influences recharge/discharge patterns at Poplar Fen, with hydraulic head in the underlying outwash aquifer highly susceptible to fluctuations in the presence and absence of precipitation-driven recharge from adjacent uplands. Moderate-rich fens similar to that studied here will likely become more susceptible to drying in the future due to a changing climate, leading to enhanced water table drawdown, peat oxidation and subsequent decomposition, vulnerability to wildfire, and seral succession to a more ombrogenous peatland system.We gratefully acknowledge funding from a grant to Jonathan S. Price from the National Science and Engineering Research Council (NSERC) of the Canada Collaborative Research and Development Program, co–funded by Suncor Energy Inc., Imperial Oil Resources Limited, and Shell Canada Energy

The Effects of Prenatal Protein Restriction on β-Adrenergic Signalling of the Adult Rat Heart during Ischaemia Reperfusion

A maternal low-protein diet (MLP) fed during pregnancy leads to hypertension in adult rat offspring. Hypertension is a major risk factor for ischaemic heart disease. This study examined the capacity of hearts from MLP-exposed offspring to recover from myocardial ischaemia-reperfusion (IR) and related this to cardiac expression of β-adrenergic receptors (β-AR) and their associated G proteins. Pregnant rats were fed control (CON) or MLP diets (n = 12 each group) throughout pregnancy. When aged 6 months, hearts from offspring underwent Langendorff cannulation to assess contractile function during baseline perfusion, 30 min ischemia and 60 min reperfusion. CON male hearts demonstrated impaired recovery in left ventricular pressure (LVP) and dP/dtmax (P < 0.01) during reperfusion when compared to MLP male hearts. Maternal diet had no effect on female hearts to recover from IR. MLP males exhibited greater membrane expression of β2-AR following reperfusion and urinary excretion of noradrenaline and dopamine was lower in MLP and CON female rats versus CON males. In conclusion, the improved cardiac recovery in MLP male offspring following IR was attributed to greater membrane expression of β2-AR and reduced noradrenaline and dopamine levels. In contrast, females exhibiting both decreased membrane expression of β2-AR and catecholamine levels were protected from IR injury

The effect of maternal dietary fat content and omega-6 to omega-3 ratio on offspring growth and hepatic gene expression in the rat

© The Authors 2020. Omega-6 fatty acids have been shown to exert pro-adipogenic effects whereas omega-3 fatty acids work in opposition. Increasing intakes of LA (linoleic acid; omega-6) vs ALA (alpha-linolenic acid; omega-3) in Western diets has led to the hypothesis that consumption of this diet during pregnancy may be contributing to adverse offspring health. This study investigated the effects of feeding a maternal dietary LA:ALA ratio similar to that of the Western diet (9:1) compared to a proposed 'ideal' ratio (∼1:1.5), at two total fat levels (18% vs 36% fat w/w), on growth and lipogenic gene expression in the offspring. Female Wistar rats were assigned to one of the four experimental groups throughout gestation and lactation. Offspring were culled at 1 and 2 weeks of age for sample collection. Offspring of dams consuming a -36% fat diet were ∼20% lighter than those exposed to a 18% fat diet (

Exposure to maternal obesity during suckling outweighs in utero exposure in programming for post-weaning adiposity and insulin resistance in rats

Exposure to maternal obesity during early development programmes adverse metabolic health in rodent offspring. We assessed the relative contributions of obesity during pregnancy and suckling on metabolic health post-weaning. Wistar rat offspring exposed to control (C) or cafeteria diet (O) during pregnancy were cross-fostered to dams on the same (CC, OO) or alternate diet during suckling (CO, OC) and weaned onto standard chow. Measures of offspring metabolic health included growth, adipose tissue mass, and 12-week glucose and insulin concentrations during an intraperitoneal glucose tolerance test (ipGTT). Exposure to maternal obesity during lactation was a driver for reduced offspring weight post-weaning, higher fasting blood glucose concentrations and greater gonadal adiposity (in females). Males displayed insulin resistance, through slower glucose clearance despite normal circulating insulin and lower mRNA expression of PIK3R1 and PIK3CB in gonadal fat and liver respectively. In contrast, maternal obesity during pregnancy up-regulated the insulin signalling genes IRS2, PIK3CB and SREBP1-c in skeletal muscle and perirenal fat, favouring insulin sensitivity. In conclusion exposure to maternal obesity during lactation programmes offspring adiposity and insulin resistance, overriding exposure to an optimal nutritional environment in utero, which cannot be alleviated by a nutritionally balanced post-weaning diet

The impact of exposure to cafeteria diet during pregnancy or lactation on offspring growth and adiposity before weaning

Exposure to maternal obesity during early-life can have adverse consequences for offspring growth and adiposity. We aimed to assess the relative contributions of exposure to maternal obesity, induced by a highly varied cafeteria diet, during pregnancy and lactation on these measures in rat offspring prior to weaning. Female Wistar rats were fed either a control (C) or cafeteria diet (O) for 8 weeks before mating, throughout pregnancy and lactation. Offspring were cross-fostered at birth to a dam on the same (CC,OO) or alternate diet prior to birth (CO,OC). Feeding a cafeteria diet based on 40 different foods, was associated with a sustained period of elevated energy intake before birth and during lactation (up to 1.7-fold), through increased sugar, total fat and saturated fat intake, and lower protein consumption. Cafeteria fed dams sustained greater weight than animals fed a control chow diet and greater perirenal adiposity by the end of lactation. Exposure to obesity during pregnancy was associated with lower offspring birth weight and body weight in early-postnatal life. In contrast, exposure during lactation alone reduced offspring weight but increased adiposity in male CO offspring before weaning. This research highlights that exposure to maternal obesity during lactation alone can programme adiposity in a sex specific manner

Acute changes to breast milk composition following consumption of high-fat and high-sugar meals

© 2021 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd. Breast milk composition is influenced by habitual diet, yet little is known about the short-term effects of changes in maternal diet on breast milk macronutrient concentrations. Our aim was to determine the acute effect of increased consumption of sugar/fat on breast milk protein, lactose and lipids. Exclusively breastfeeding women (n = 9) were provided with a control, higher fat (+28 g fat) and higher sugar (+66 g sugar) diet over three separate days at least 1 week apart. Hourly breast milk samples were collected concurrently for the analysis of triglycerides, cholesterol, protein, and lactose concentrations. Breast milk triglycerides increased significantly following both the higher fat and sugar diet with a greater response to the higher sugar compared to control diet (mean differences of 3.05 g/dL ± 0.39 and 13.8 g/dL ± 0.39 in higher fat and sugar diets, respectively [P < 0.001]). Breast milk cholesterol concentrations increased most in response to the higher sugar diet (0.07 g/dL ± 0.005) compared to the control (0.04 g/dL) and the higher fat diet (0.05 g/dL) P < 0.005. Breast milk triglyceride and lactose concentrations increased (P < 0.001, P = 0.006), whereas protein decreased (p = 0.05) in response to the higher fat diet compared to the control. Independent of diet, there were significant variations in breast milk composition over the day; triglycerides and cholesterol concentrations were higher at end of day (P < 0.001), whereas protein and lactose concentrations peaked at Hour 10 (of 12) (P < 0.001). In conclusion, controlled short-term feeding to increase daily sugar/fat consumption altered breast milk triglycerides, cholesterol, protein and lactose. The variations observed in breast milk protein and lactose across the 12 h period is suggestive of a circadian rhythm

Inhibition of Fatty Acid Binding Proteins Elevates Brain Anandamide Levels and Produces Analgesia

The endocannabinoid anandamide (AEA) is an antinociceptive lipid that is inactivated through cellular uptake and subsequent catabolism by fatty acid amide hydrolase (FAAH). Fatty acid binding proteins (FABPs) are intracellular carriers that deliver AEA and related N-acylethanolamines (NAEs) to FAAH for hydrolysis. The mammalian brain expresses three FABP subtypes: FABP3, FABP5, and FABP7. Recent work from our group has revealed that pharmacological inhibition of FABPs reduces inflammatory pain in mice. The goal of the current work was to explore the effects of FABP inhibition upon nociception in diverse models of pain. We developed inhibitors with differential affinities for FABPs to elucidate the subtype(s) that contributes to the antinociceptive effects of FABP inhibitors. Inhibition of FABPs reduced nociception associated with inflammatory, visceral, and neuropathic pain. The antinociceptive effects of FABP inhibitors mirrored their affinities for FABP5, while binding to FABP3 and FABP7 was not a predictor of in vivo efficacy. The antinociceptive effects of FABP inhibitors were mediated by cannabinoid receptor 1 (CB1) and peroxisome proliferator-activated receptor alpha (PPARα) and FABP inhibition elevated brain levels of AEA, providing the first direct evidence that FABPs regulate brain endocannabinoid tone. These results highlight FABPs as novel targets for the development of analgesic and anti-inflammatory therapeutics

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries