74 research outputs found

    Assessment of Skill and Portability in Regional Marine Biogeochemical Models: Role of Multiple Planktonic Groups

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    Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models\u27 performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted whereby data were assimilated from one site and the resulting optimal parameters were used to generate a simulation for the second site. When a single pelagic regime is considered, the simplest models fit the data as well as those with multiple phytoplankton functional groups. However, those with multiple phytoplankton functional groups produced lower misfits when the models are required to simulate both regimes using identical parameter values. The cross-validation experiments revealed that as long as only a few key biogeochemical parameters were optimized, the models with greater phytoplankton complexity were generally more portable. Furthermore, models with multiple zooplankton compartments did not necessarily outperform models with single zooplankton compartments, even when zooplankton biomass data are assimilated. Finally, even when different models produced similar least squares model-data misfits, they often did so via very different element flow pathways, highlighting the need for more comprehensive data sets that uniquely constrain these pathways

    First circumpolar assessment of Arctic freshwater phytoplankton and zooplankton diversity : Spatial patterns and environmental factors

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    Arctic freshwaters are facing multiple environmental pressures, including rapid climate change and increasing land-use activities. Freshwater plankton assemblages are expected to reflect the effects of these stressors through shifts in species distributions and changes to biodiversity. These changes may occur rapidly due to the short generation times and high dispersal capabilities of both phyto- and zooplankton. Spatial patterns and contemporary trends in plankton diversity throughout the circumpolar region were assessed using data from more than 300 lakes in the U.S.A. (Alaska), Canada, Greenland, Iceland, the Faroe Islands, Norway, Sweden, Finland, and Russia. The main objectives of this study were: (1) to assess spatial patterns of plankton diversity focusing on pelagic communities; (2) to assess dominant component of beta diversity (turnover or nestedness); (3) to identify which environmental factors best explain diversity; and (4) to provide recommendations for future monitoring and assessment of freshwater plankton communities across the Arctic region. Phytoplankton and crustacean zooplankton diversity varied substantially across the Arctic and was positively related to summer air temperature. However, for zooplankton, the positive correlation between summer temperature and species numbers decreased with increasing latitude. Taxonomic richness was lower in the high Arctic compared to the sub- and low Arctic for zooplankton but this pattern was less clear for phytoplankton. Fennoscandia and inland regions of Russia represented hotspots for, respectively, phytoplankton and zooplankton diversity, whereas isolated regions had lower taxonomic richness. Ecoregions with high alpha diversity generally also had high beta diversity, and turnover was the most important component of beta diversity in all ecoregions. For both phytoplankton and zooplankton, climatic variables were the most important environmental factors influencing diversity patterns, consistent with previous studies that examined shorter temperature gradients. However, barriers to dispersal may have also played a role in limiting diversity on islands. A better understanding of how diversity patterns are determined by colonisation history, environmental variables, and biotic interactions requires more monitoring data with locations dispersed evenly across the circumpolar Arctic. Furthermore, the importance of turnover in regional diversity patterns indicates that more extensive sampling is required to fully characterise the species pool of Arctic lakes.Peer reviewe

    Appraisals, emotions and emotion regulation: An integrative approach

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    The present work aims to investigate the relation between appraisals, emotions, and emotion regulation strategies by creating a structural equation model which integrates these three aspects of the emotion process. To reach this aim, Italian students (N = 610) confronted with their high school diploma examination completed a questionnaire 3 weeks before the beginning of the exam. Results showed that they experienced primarily three types of emotions—anxiety/fear, frustration/powerlessness, positive emotions—which were related to specific appraisal profiles. Importantly, these appraisal profiles and emotions were associated with the use of different strategies for regulating emotions: anxiety/fear was associated with focusing on the exam, drug use, and an inability to distance oneself from the exam; frustration/powerlessness, with use of suppression, distancing, and drugs; positive emotion, with reappraisal and problem focused strategies. The effectiveness of these different strategies will be discussed

    Effects of rising temperature on pelagic biogeochemistry in mesocosm systems: a comparative analysis of the AQUASHIFT Kiel experiments

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    A comparative analysis of data, obtained during four indoor-mesocosm experiments with natural spring plankton communities from the Baltic Sea, was conducted to investigate whether biogeochemical cycling is affected by an increase in water temperature of up to 6 °C above present-day conditions. In all experiments, warming stimulated in particular heterotrophic bacterial processes and had an accelerating effect on the temporal development of phytoplankton blooms. This was also mirrored in the build-up and partitioning of organic matter between particulate and dissolved phases. Thus, warming increased both the magnitude and rate of dissolved organic carbon (DOC) build-up, whereas the accumulation of particulate organic carbon (POC) and phosphorus (POP) decreased with rising temperature. In concert, the observed temperature-mediated changes in biogeochemical components suggest strong shifts in the functioning of marine pelagic food webs and the ocean’s biological carbon pump, hence providing potential feedback mechanisms to Earth’s climate system

    OvervÄking av langtransporterte forurensninger 2009. sammendragsrapport

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    Rapporten presenterer sammendrag av resultatene for 2009 fra tre overvĂ„kingsprogrammer: “OvervĂ„king av langtrans­portert forurenset luft og nedbĂžr”, ”OvervĂ„kingsprogram for skogskader” (OPS) og “Program for terrestrisk naturovervĂ„king” (TOV). The report presents results for 2009 from three national monitoring programmes on long-range transboundary air pollution

    Towards a descriptive catalogue of the Greek manuscripts of the Royal Library, Copenhagen

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    Schartau Bjarne, Smith Ole L. Towards a descriptive catalogue of the Greek manuscripts of the Royal Library, Copenhagen. In: Scriptorium, Tome 28 n°2, 1974. pp. 332-338

    Prevalence of perinatal depression and anxiety in both parents

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    Importance New and expectant parents experience perinatal mood disorders, with consequences to parenting ability, bonding with the neonate, interpersonal relationships, and health and well-being of parents. Research shows that maternal and paternal perinatal mood disorders are associated, but no recent systematic review has addressed the prevalence of perinatal mood disorders in both mothers and fathers (parental dyad). Objective To examine the prevalence of perinatal mood disorders in parental dyads and identify factors associated with perinatal mood disorders in parental dyads. Data Sources Ovid (MEDLINE, Embase, and PsycINFO) and Web of Science were searched from January 1, 1990, to June 8, 2021, for observational studies reporting on the prevalence of perinatal depression or anxiety in a parental dyad. Study Selection Studies reporting the prevalence of anxiety or depression in both members of a parental dyad were included, with diagnosis according to established criteria (Diagnostic and Statistical Manual of Mental Disorders [Fifth Edition], International Classification of Diseases, 11th Revision) or use of validated screening tools. Data Extraction and Synthesis Prevalence data were extracted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were analyzed in subgroups: antenatal depression, early postnatal depression (0-12 weeks), late postnatal depression (3-12 months), and perinatal anxiety. Pooled prevalence was calculated using a random-effects meta-analysis model. Quality assessment was performed using Joanna Briggs Institute Appraisal Checklist for Studies Reporting Prevalence Data. Data were analyzed in June 2021. Main Outcomes and Measures Prevalence of perinatal anxiety and perinatal depression in parental dyads. Results Twenty-three studies were included, with data from 29 286 couples. The pooled prevalence of antenatal depression in both parents was 1.72% (95% CI, 0.96%-2.48%; P < .001). The prevalence of early postnatal depression (up to 12 weeks post partum) was 2.37% (95% CI, 1.66%-3.08%; P < .001) and the prevalence of late postnatal depression (3-12 months post partum) was 3.18% (95% CI, 2.3-4.05; P < .001). Only 3 studies reported on perinatal anxiety in both parents, precluding a quantitative analysis. Conclusions and Relevance In up to 3.18% of couples, both parents may concurrently experience perinatal depression. Perinatal health care must consider the mental health needs of parents, both as individuals and as a parental dyad. Further research is needed to examine outcomes in families where both parents experience perinatal mood disorders

    Modeling the Speciation and Biogeochemistry of Iron at the Bermuda Atlantic Time-series Study Site

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    By means of numerical modeling we analyze the cycling of iron between itsvarious physical (dissolved, colloidal, particulate) and chemical(redox state and organic complexation) forms in the upper mixed layer.With our proposed model it is possible to obtain a first quantitativeassessment of how this cycling influences iron uptake byphytoplankton and its loss via particle export. Themodel is forced with observed dust deposition rates, mixed layer depths, andsolar radiation at the site of the Bermuda Atlantic Timeseries Study(BATS). It contains an objectively optimized ecosystem model whichyields results close to the observational data from BATS that has beenused for the data-assimilation procedure.It is shown that the mixed layer cycle strongly influences the cyclingof iron between its various forms. This is mainly due to the lightdependency of photoreductive processes, and to the seasonality ofprimary production. The daily photochemical cycle is driven mainly bythe production of superoxide and its amplitude depends on theconcentration and speciation of dissolved copper.Model results are almost insensitive to the dominant form of dissolvediron within dust deposition, and also to the form of iron that istaken up directly during algal growth.In our model solutions, the role of the colloidal pumping mechanismdepends strongly on assumptions on the colloid aggregation andphotoreduction rate
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