57 research outputs found

    A Standardized Ecosystem Classification for the Coordination and Design of Long-term Terrestrial Ecosystem Monitoring in Arctic-Subarctic Biomes

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    A Canadian Arctic-Subarctic Biogeoclimatic Ecosystem Classification (CASBEC) is proposed as a standardized classification approach for Subarctic and Arctic terrestrial ecosystems across Canada and potentially throughout the circumpolar area. The CASBEC is grounded in long-standing terrestrial ecosystem classification theory and builds on concepts developed for ecosystems in British Columbia, Quebec, and Yukon. The fundamental classification unit of the CASBEC, the plant association, is compatible with the lower-level classifications of the Arctic Vegetation Classification (AVC), the Canadian National Vegetation Classification (CNVC), and the United States National Vegetation Classification (USNVC) and is used to generate a classification and nomenclature for Arctic and Subarctic terrestrial ecological communities. The use of a multi-scalar ecosystem framework, such as that developed by the British Columbia Biogeoclimatic Ecosystem Classification, provides an ecological context to use classified plant associations to delineate and define climatically equivalent regional scale climate units (biogeoclimatic subzones) and ecologically equivalent local-scale site units within biogeoclimatic subzones. A standardized framework and taxonomy of ecosystem classification for Subarctic and Arctic terrestrial ecological communities will facilitate the planning, coordination, and applicability of terrestrial ecological monitoring and research. The CASBEC classification and high-resolution ecosystem mapping are being used to develop an effective experimental design, to select ecosite types for long-term monitoring, and to extrapolate results to landscape scales in the Experimental and Reference Area of the Canadian High Arctic Research Station (CHARS) in Cambridge Bay. Widespread adoption of the CASBEC could provide a spatial and functionally scalable framework and a common language for interpreting, integrating, coordinating, and communicating Arctic and Subarctic monitoring, research, and land management activities across the Canadian North and around the circumpolar area.Une classification biogĂ©oclimatique arctique et subarctique canadienne (Canadian Arctic-Subarctic Biogeoclimatic Ecosystem Classification, ou CASBEC) est proposĂ©e en tant que mĂ©thode de classification standardisĂ©e pour les Ă©cosystĂšmes terrestres arctiques et subarctiques pancanadiens, et peut-ĂȘtre mĂȘme pour les Ă©cosystĂšmes de la rĂ©gion circumpolaire. CASBEC s’appuie sur une thĂ©orie de classification des Ă©cosystĂšmes terrestres de longue date et sur des concepts mis au point pour les Ă©cosystĂšmes de la Colombie-Britannique, du QuĂ©bec et du Yukon. L’unitĂ© de classification fondamentale de CASBEC, soit l’association vĂ©gĂ©tale, est compatible avec les classifications de niveau infĂ©rieur de la classification de la vĂ©gĂ©tation de l’Arctique (Arctic Vegetation Classification, ou AVC), de la Classification nationale de la vĂ©gĂ©tation du Canada (CNVC) et de la classification nationale de la vĂ©gĂ©tation des États-Unis (USNVC). Elle permet de produire une classification et une nomenclature pour les communautĂ©s Ă©cologiques terrestres arctiques et subarctiques. Le recours Ă  un cadre Ă©cosystĂ©mique multiscalaire, comme celui Ă©laborĂ© par la classification Ă©cosystĂ©mique biogĂ©oclimatique de la Colombie-Britannique, fournit un contexte Ă©cologique permettant d’utiliser les associations vĂ©gĂ©tales classifiĂ©es pour dĂ©limiter et dĂ©finir les unitĂ©s climatiques rĂ©gionales Ă  l’échelle climatiquement Ă©quivalentes (sous-zones biogĂ©oclimatiques) et les unitĂ©s Ă©cologiquement Ă©quivalentes de sites d’envergure locale Ă  l’intĂ©rieur des sous-zones biogĂ©oclimatiques. La mise en place d’une taxonomie et d’un cadre standardisĂ©s de classification des Ă©cosystĂšmes des communautĂ©s Ă©cologiques terrestres arctiques et subarctiques facilitera la planification, la coordination et l’applicabilitĂ© des travaux de surveillance et de recherche Ă©cologique terrestre. La classification CASBEC et la cartographie des Ă©cosystĂšmes en haute rĂ©solution sont employĂ©es pour mettre au point une conception expĂ©rimentale efficace, pour sĂ©lectionner des types d’écosites Ă  des fins de surveillance Ă  long terme ainsi que pour extrapoler les rĂ©sultats Ă  l’échelle des paysages dans la zone d’expĂ©rimentation et de rĂ©fĂ©rence de la Station canadienne de recherche dans l’ExtrĂȘme-Arctique (SCREA) Ă  Cambridge Bay. L’adoption de CASBEC Ă  grande Ă©chelle pourrait fournir un cadre spatial et fonctionnellement extensible de mĂȘme qu’un langage commun pour interprĂ©ter, intĂ©grer, coordonner et communiquer les activitĂ©s de surveillance, de recherche et de gestion des terres arctiques et subarctiques Ă  la grandeur du Nord canadien et de l’ensemble de la rĂ©gion circumpolaire

    Geochemistry of small Canadian Arctic rivers with diverse geological and hydrological settings

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    Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 125(1), (2020): e2019JG005414, doi:10.1029/2019JG005414.A survey of 25 coastal‐draining rivers across the Canadian Arctic Archipelago (CAA) shows that these systems are distinct from the largest Arctic rivers that drain watersheds extending far south of the Arctic circle. Observations collected from 2014 to 2016 illustrate the influences of seasonal hydrology, bedrock geology, and landscape physiography on each river's inorganic geochemical characteristics. Summertime data show the impact of coincident gradients in lake cover and surficial geology on river geochemical signatures. In the north and central CAA, drainage basins are generally smaller, underlain by sedimentary bedrock, and their hydrology is driven by seasonal precipitation pulses that undergo little modification before they enter the coastal ocean. In the southern CAA, a high density of lakes stores water longer within the terrestrial system, permitting more modification of water isotope and geochemical characteristics. Annual time‐series observations from two CAA rivers reveal that their concentration‐discharge relationships differ compared with those of the largest Arctic rivers, suggesting that future projections of dissolved ion fluxes from CAA rivers to the Arctic Ocean may not be reliably made based on compositions of the largest Arctic rivers alone, and that rivers draining the CAA region will likely follow different trajectories of change under a warming climate. Understanding how these small, coastal‐draining river systems will respond to climate change is essential to fully evaluate the impact of changing freshwater inputs to the Arctic marine system.This work was only possible through a network of enthusiastic and devoted collaborators. Partners included Polar Knowledge Canada and the Canadian High Arctic Research Station, the Arctic Research Foundation, the Kugluktuk Angoniatit Association, and the Canadian Arctic GEOTRACES Program. We acknowledge support from the Department of Fisheries and Oceans Canada, the Woods Hole Oceanographic Institution Coastal Ocean Institute, The G. Unger Vetlesen Foundation, Jane and James Orr, and the Woods Hole Research Center. Many thanks go to Austin Maniyogena, Angulalik Pedersen, Adrian Schimnowski, JS Moore, Les Harris, Oksana Schimnowski, as well as Barbara Adjun, Amanda Dumond, and Johnny Nivingalok, and the captains and crew of the research vessels CCGS Amundsen and R/V Martin Bergmann, all of whom supported our research and helped with sample collection. Special thanks also go to Valier Galy, Zhaohui “Aleck” Wang, Marty Davelaar, Michiyo Yamamoto‐Kawai, Hugh McLean, Mike Dempsey, Baba Pedersen, Maureen Soon, Katherine Hoering, Sean Sylva, Ekaterina Bulygina, and Anya Suslova for their invaluable contributions during field program planning, preparations, and laboratory analyses. Robert Max Holmes is thanked for many fruitful discussions. We also thank several anonymous reviewers for their helpful comments on the paper's content and structure. All of the data presented in this paper can be found at https://doi.org/10.1594/PANGAEA.908497

    Curation and Analysis of Global Sedimentary Geochemical Data to Inform Earth History

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    Large datasets increasingly provide critical insights into crustal and surface processes on Earth. These data come in the form of published and contributed observations, which often include associated metadata. Even in the best-case scenario of a carefully curated dataset, it may be non-trivial to extract meaningful analyses from such compilations, and choices made with respect to filtering, resampling, and averaging can affect the resulting trends and any interpretation(s) thereof. As a result, a thorough understanding of how to digest, process, and analyze large data compilations is required. Here, we present a generalizable workflow developed using the Sedimentary Geochemistry and Paleoenvironments Project database. We demonstrate the effects of filtering and weighted resampling on Al2O3 and U contents, two representative geochemical components of interest in sedi-mentary geochemistry (one major and one trace element, respectively). Through our analyses, we highlight several methodological challenges in a "bigger data" approach to Earth science. We suggest that, with slight modifications to our workflow, researchers can confidently use large collections of observations to gain new insights into processes that have shaped Earth's crustal and surface environments

    Cohort profile for the STratifying Resilience and Depression Longitudinally (STRADL) study:A depression-focused investigation of Generation Scotland, using detailed clinical, cognitive, and neuroimaging assessments

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    Grant information: STRADL is supported by the Wellcome Trust through a Strategic Award (104036/Z/14/Z). GS:SFHS received core support from the CSO of the Scottish Government Health Directorates (CZD/16/6) and the Scottish Funding Council (HR03006). ADM is supported by Innovate UK, the European Commission, the Scottish Funding Council via the Scottish Imaging Network SINAPSE, and the CSO. HCW is supported by a JMAS SIM Fellowship from the Royal College of Physicians of Edinburgh, by an ESAT College Fellowship from the University of Edinburgh, and has received previous funding from the Sackler Trust. LR has previously received financial support from Pfizer (formerly Wyeth) in relation to imaging studies of people with schizophrenia and bipolar disorder. JDH is supported by the MRC. DJM is an NRS Clinician, funded by the CSO. RMR is supported by the British Heart Foundation. ISP-V and MRM are supported by the NIHR Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol. The views expressed in this publication are those of the author(s) and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health; and MRM is also supported by the MRC MC_UU_12013/6). JMW is supported by MRC UK Dementia Research Institute and MRC Centre and project grants, EPSRC, Fondation Leducq, Stroke Association, British Heart Foundation, Alzheimer Society, and the European Union H2020 PHC-03-15 SVDs@Target grant agreement (666881). DJP is supported by Wellcome Trust Longitudinal Population Study funding (216767/Z/19/Z) the Eva Lester bequest to the University of Edinburgh. AMM is additionally supported by the MRC (MC_PC_17209, MC_PC_MR/R01910X/1, MR/S035818/1), The Wellcome Trust (216767/Z/19/Z ), The Sackler Trust, and has previously received research funding from Pfizer, Eli Lilly, and Janssen. Both AMM and IJD are members of The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology, part of the cross council Lifelong Health and Wellbeing Initiative (MR/K026992/1); funding from the BBSRC and MRC is gratefully acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscriptPeer reviewedPublisher PD

    Protocol for a randomized controlled trial of a specialized health coaching intervention to prevent excessive gestational weight gain and postpartum weight retention in women: the HIPP study

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    BackgroundPregnancy is a time of significant physiological and physical change for women. In particular, it is a time at which many women are at risk of gaining excessive weight. We describe the rationale and methods of the Health in Pregnancy and Post-birth (HIPP) Study, a study which aims primarily to determine the effectiveness of a specialized health coaching (HC) intervention during pregnancy, compared to education alone, in preventing excessive gestational weight gain and postpartum weight retention 12 months post birth. A secondary aim of this study is to evaluate the mechanisms by which our HC intervention impacts on weight management both during pregnancy and post birth.Methods/DesignThe randomized controlled trial will be conducted with 220 women who have a BMI &gt; 18.5 (American IOM cut-off for normal weight), are 18 years of age or older, English speaking, no history of disordered eating or diabetes and are less than 18 weeks gestation at recruitment. Women will be randomly allocated to either a specialized HC intervention group or an Education Alone group. Our specialized HC intervention has two components: (1) one-on-one sessions with a Health Coach, and (2) two by two hour educational group sessions led by a Health Coach. Women in the Education Alone group will receive two by two hour educational group sessions with no HC components. Body Mass Index, waist circumference, and psychological factors including motivation, readiness to change, symptoms of depression and anxiety, and body dissatisfaction will be assessed at baseline (14-16 weeks gestation), and again at follow-up: 32 weeks gestation, 6 weeks, 6 months and 12 months postpartum.DiscussionOur study responds to the urgent need to design effective interventions in pregnancy to prevent excessive gestational weight gain and postpartum weight retention. Our pregnancy HC intervention is novel and innovative and has been designed to be easily adopted by health professionals who work with pregnant women, such as obstetricians, midwives, allied health professionals and health psychologists. <br /

    Growth and nutrient relations in black cottonwood in South-Coastal British Columbia

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    Initially, the study examined within and among site temporal and spatial variation of foliar nutrients, and spatial variation of soil nutrients to assess the sampling methods employed, and to provide background for the interpretation of nutrient-site index interactions. The study then examined relationships between the growth of black cottonwood, expressed as site index, and site units, under story vegetation, soil nutrient contents, and foliar nutrient concentrations in29 black cottonwood stands in south-coastal British Columbia. The final phase of the study was a fertilizer trial in three juvenile black cottonwood stands, with treatments based on used DRIS diagnosis of limiting nutrients. Significant levels of variability in foliar nutrient concentrations were identified within tree canopies, and from tree-to-tree within stands. A protocol was suggested to standardize sampling procedures to reduce spatial variability. Sample size requirements for different levels of accuracy and precision were presented. Important variation in foliar nutrient concentrations was also recorded seasonally, and from year to year, in foliage samples collected according to the same protocol. It was shown that the temporal variability was sufficient to alter the interpretation of foliar nutrient concentrations for the stands. Spatial variation in soil nutrient concentrations was high and was attributed to order-of-magnitude concentration differences between soil strata in each pedon. Spatial variation of soil nutrient contents (expressed in kg/ha over a 1 m sampling depth) was generally higher than soil nutrient concentrations, because of factors such as bulk density and percent coarse fragments that were used to calculate soil contents, and that are themselves subject to variation. It was shown that the compositing procedure used to reduce costs approximately doubled the variability seen in the intensively sampled sites, and alterations to the compositing procedure were suggested. It was also argued that sampling over a depth of 1 m, and not over the main rooting depth, provided the most biologically meaningful estimates of soil nutrients available to black cottonwood. The ANOVA comparing black cottonwood growth within site units was highly significant (p < .001), and explained 87% of the variance in site index within the 29 study sites. This general result suggests that, relative to the ecological requirements of black cottonwood, the site classification provided an ecologically-meaningful differentiation of the edatopic gradients sampled. For operational purposes, this result predicts that black cottonwood site index can be estimated with considerable accuracy by identifying the site unit on which a stand is located. Growth was best on the high bench of alluvial floodplains (Ss-Salmonberry site association), and on moist upland sites with seepage (Cw-Foamflower site association). Growth was poorest on the low bench of alluvial floodplains (Ac-Willow site association), and on gleyed, marine site units (Cw-Salmonberry and Cw-Black twinberry site associations). About 50% of the variation in site index could be accounted for using understory vegetation from within the stands as predictors. This relatively low explanatory power was attributed to the fact that black cottonwood site index changed significantly across the indicative range of many of the understory plants. All methods of analysis revealed consistent relationships between measures of site nutrient status and site index. Sample stands with high pH, high levels of exchangeable Ca and Mg, and low levels of soil N, P, and K, had foliar concentrations of N, P, and K diagnosed as limiting to black cottonwood growth, and had the lowest site index. High site index was recorded in stands with more or less opposite soil and foliar properties. Site index was seen to decrease in site units with increasing flooding frequency and duration on alluvial floodplains. The decrease was attributed to the negative impact of flooding on the rate of organic matter mineralization, on nutrient uptake, and on the negative effect of high levels of soil Ca and high soil pH on the availability of soil P. On upland sites, soil gleying and prolonged rooting zone flooding during the growing season was correlated with low site index. Using DRIS analysis based on foliar norms from the 25 fastest-growing, fertilized trees at the Squamish 23 site, it was concluded that black cottonwood stands in the high site index class were limited by K, and then P. In three juvenile black cottonwood stands, the application of fertilizer based on diagnosis of foliar nutrient concentration using DRIS norms had the following 3 year responses - basal area increment increased by 65%, and height growth increment by 15% at the Squamish 23 site; basal area increment increased by 65% and height growth increment increased by 30% at the Strawberry site; and basal area increment increased by 27% without a significant height growth response at the Soowahlie site. At the Squamish 23 and Soowahlie trials, response was attributed to fertilization with K and P, as suggested from the foliar nutrient diagnosis of the fast-growing group. Given that relatively low dosages (ca. 100 kg/ha) of P were required to achieve a significant growth response, and acknowledging that, in many forest fertilization programs response to P fertilization occurs for a considerable period of time, the results suggest that the fertilization of fast-growing, juvenile black cottonwood stands in coastal British Columbia may be economically justified. Significant correlations between measures of foliar response and wood production were not seen in the study, and this finding limits the usefulness of the graphical procedure for interpretation of the experimental results. Foliar concentrations from the 25 fastest-growing black cottonwoods at the Squamish 23 site are presented as DRIS standards that will be useful in the diagnosis of the nutrient status of black cottonwood stands in coastal British Columbia.Forestry, Faculty ofGraduat
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