| 1. |
- Belle, Simon
(författare)
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Reconstruction of Past Dynamics of Methane-Oxidizing Bacteria in Lake Sediments Using a Quantitative PCR Method: Connecting Past Environmental Changes and Microbial Community
- 2019
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Ingår i: Geomicrobiology Journal. - : Informa UK Limited. - 0149-0451 .- 1521-0529. ; 36, s. 570-579
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a quantitative PCR (qPCR) method was applied to amplify ancient DNA (aDNA) of different methane-oxidizing bacteria (MOB) types in lake sediments and to reconstruct microbial community dynamics over the last 1200 years. We also used reconstructions of in-lake nutrients concentrations, air temperature fluctuations, and sedimentary organic matter dynamics to study impacts of past environmental and climatic changes on MOB community composition. DNA preservation in lake sediments is sufficient, and qPCR amplification was successfully applied to the analysis of MOB aDNA. Temporal changes in MOB community showed different patterns between lakes, and drivers of past MOB dynamics slightly differed between lakes and among MOB groups. Overall, MOB developments were generally correlated to proxies of organic matter quality/quantity and climate data. Moreover, our results could emphasize the importance of nutrients availability in structuring MOB community, and the higher ability of MOB type 2 to access nutrients under nitrogen/nutrients limited conditions. Therefore, our study provides an operational and time-effective method to reconstruct past CH4 oxidation in lakes and could help to identify the driving factors of past temporal dynamics of MOB community.
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| 2. |
- Belle, Simon, et al.
(författare)
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Unravelling chironomid biodiversity response to climate change in subarctic lakes across temporal and spatial scales
- 2022
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 849, s. 2621-2633
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Tidskriftsartikel (refereegranskat)abstract
- We combined paleolimnological reconstructions and space-for-time substitutions to unravel chironomid biodiversity responses to climate change in subarctic mountains across temporal and spatial scales. Using sediment records, we found that long-term temporal changes in chironomid taxonomic diversity were mainly induced by the temperature tolerance/optimum of species, while little changes in functional diversity were found due to the replacement of similar functional-type taxa within the community. Overall, paleolimnological reconstructions suggested the selection of larger chironomid species by long-term climate cooling and little changes in trophic guilds. Space-for-time substitutions showed, however that low-elevation lakes with forested have more sediment-feeding taxa and larger larvae than high-elevation lakes, thus, suggesting the selection of large chironomid morphotypes with a sediment-feeding mode under warmer climate. Space-for-time substitutions and paleolimnological reconstructions, therefore, gave contrasting results for the link between climate and functional diversity of chironomid communities, likely because space-for-time substitutions failed to match the extent of both spatial and temporal climatic gradients. We suggest that future studies must address biodiversity issues across both temporal and spatial scales as an improved understanding of biodiversity responses to climate change may help us to understand how biodiversity will be affected by ongoing and future change.
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| 3. |
- Chapron, Guillaume
(författare)
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Overestimates of maternity and population growth rates in multi-annual breeders
- 2013
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Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 59, s. 237-243
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Tidskriftsartikel (refereegranskat)abstract
- There has been limited attention to estimating maternity rate because it appears to be relatively simple. However, when used for multi-annual breeder species, such as the largest carnivores, the most common estimators introduce an upward bias by excluding unproductive females. Using a simulated dataset based on published data, we compare the accuracy of maternity estimates derived from standard methods against estimates derived from an alternative method. We show that standard methods overestimate maternity rates in the presence of unsuccessful pregnancies. Importantly, population growth rates derived from a matrix model parameterized with the biased estimates may indicate increasing populations although the populations are stable or even declining. We recommend the abandonment of the biased standard methods and to instead use the unbiased alternative method for population projections and assessments of population viability.
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| 4. |
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| 5. |
- Van Couvering, Elizabeth, 1969-
(författare)
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Faces and charts : platform strategies for visualising the audience, the case of Facebook
- 2022
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Ingår i: Information, Communication and Society. - : Taylor & Francis. - 1369-118X .- 1468-4462. ; 25:11, s. 1524-1541
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Tidskriftsartikel (refereegranskat)abstract
- Although the audience as an industrial media product has been scrutinised by scholars for decades, the visual presentation of the audience has been nearly absent from scholarly analysis. This article examines the interfaces that Facebook uses to present its audience to three different user groups (ordinary Facebook members, publishers, and finally advertisers) using a social semiotic analytical framework to analyse visuals, interactive elements and desired user paths. The interface displayed to ordinary users, the Facebook Friends page, uses a visual language with roots in the college yearbook, showing rows of faces with minimal available interactivity. This interface preserves the humanity of the audience, suggesting egalitarian social structures and timeless space outside Facebook's ordinary flow. The interfaces displayed to institutional users, Page Insights and Audience Insights, for publishers and advertisers respectively, are quite different, characterised by a multiplicity of charts and high interactivity, with a clear path for the user that ends in 'boosting' your page or 'buying' your audience. The Audience Insights pages for advertisers feature advanced interactive tools which use the conventions of experimental science. These two interfaces do significant rhetorical work, dehumanising and abstracting audiences into data quantities which can be packaged as products, and encouraging publishers to focus on the production of data measuring engagement. Both the promotion of the value of data and the elision of audience work and surveillance, graphically represented in the different interfaces, help platform businesses like Facebook strategically, by increasing the value of their data and by suppressing audience concerns about surveillance.
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