| 1. |
- Aronsson, Mora, et al.
(author)
-
Developing a circumpolar programme for the monitoring of Arctic terrestrial biodiversity
- 2020
-
In: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49, s. 655-665
-
Journal article (peer-reviewed)abstract
- The Arctic is undergoing biological and environmental changes, and a coordinated effort to monitor is critical to detect these changes. The Circumpolar Biodiversity Monitoring Programme (CBMP) of the Arctic Council biodiversity working group, Conservation of Arctic Flora and Fauna (CAFF), has developed pan-Arctic biodiversity monitoring plans that aims to improve the ability to detect and report on long-term changes. Whilst introducing this special issue, this paper also presents the making of the terrestrial monitoring plan and discusses how the plan follows the steps required for an adaptive and ecosystem-based monitoring programme. In this article, we discuss how data on key findings can be used to inform circumpolar and global assessments, including the State of the Arctic Terrestrial Biodiversity Report, which will be the first terrestrial assessment made by the CBMP. Key findings, advice for future monitoring and lessons learned will be used in planning next steps of pan-Arctic coordinated monitoring.
|
|
| 2. |
- Bina, Pavel, et al.
(author)
-
Awareness, views and experiences of Citizen Science among Swedish researchers — two surveys
- 2021
-
In: JCOM - Journal of Science Communication. - : Sissa Medialab Srl. - 1824-2049. ; 20:06
-
Journal article (peer-reviewed)abstract
- In 2021 Sweden’s first national portal for citizen science will be launched to help researchers practice sustainable and responsible citizen science with different societal stakeholders. This paper present findings from two surveys on attitudes and experiences of citizen science among researchers at Swedish universities. Both surveys provided input to the development of the national portal, for which researchers are a key stakeholder group. The first survey (n=636) was exclusively focused on citizen science and involved researchers and other personnel at Swedish University of Agricultural Science (SLU). 63% of respondents at SLU had heard about citizen science (CS) prior to the survey; however a majority of these (61%) had not been involved in any CS initiative themselves. Dominant reasons for researchers choosing a CS approach in projects were to enable collection of large amounts of data (68%), improving the knowledge base (59%), improving data quality (25%), promote participants’ understanding in research (21%) and promote collaboration between the university and society (20%). The other survey (n=3 699) was on the broader topic of communication and open science, including questions on CS, and was distributed to researchers from all Swedish universities. 61% of respondents had not been engaged in any research projects where volunteers were involved in the process. A minority of the researchers had participated in projects were volunteers had collected data (18%), been involved in internal or external communication (16%), contributed project ideas (14%) and/or formulated research questions (11%). Nearly four out of ten respondents (37%) had heard about CS prior to the survey. The researchers were more positive towards having parts of the research process open to citizen observation, rather than open to citizen influence/participation. Our results show that CS is a far from well-known concept among Swedish researchers. And while those who have heard about CS are generally positive towards it, researchers overall are hesitant to invite citizens to take part in the research process.
|
|
| 3. |
- Convey, Peter, et al.
(author)
-
The importance of understanding annual and shorter term temperature patterns and variation in the surface levels of polar soils for terrestrial biota
- 2018
-
In: Polar Biology. - : Springer Publishing Company. - 0722-4060 .- 1432-2056. ; 41:8, s. 1587-1605
-
Journal article (peer-reviewed)abstract
- Ground temperatures in the top few centimetres of the soil profile are key in many biological processes yet remain very poorly documented, especially in the polar regions or over longer timescales. They can vary greatly seasonally and at various spatial scales across the often highly complex and heterogeneous polar landscapes. It is challenging and often impossible to extrapolate soil profile temperatures from meteorological air temperature records. Furthermore, despite the justifiably considerable profile given to contemporary large-scale climate change trends, with the exception of some sites on Greenland, few biological microclimate datasets exist that are of sufficient duration to allow robust linkage and comparison with these large-scale trends. However, it is also clear that the responses of the soil-associated biota of the polar regions to projected climate change cannot be adequately understood without improved knowledge of how landscape heterogeneity affects ground and sub-surface biological microclimates, and of descriptions of these microclimates and their patterns and trends at biologically relevant physical and temporal scales. To stimulate research and discussion in this field, we provide an overview of multi-annual temperature records from 20 High Arctic (Svalbard) and maritime Antarctic (Antarctic Peninsula and Scotia Arc) sites. We highlight important features in the datasets that are likely to have influence on biology in polar terrestrial ecosystems, including (a) summer ground and sub-surface temperatures vary much more than air temperatures; (b) winter ground temperatures are generally uncoupled from air temperatures; (c) the ground thawing period may be considerably shorter than that of positive air temperatures; (d) ground and air freeze–thaw patterns differ seasonally between Arctic and Antarctic; (e) rates of ground temperature change are generally low; (f) accumulated thermal sum in the ground usually greatly exceeds air cumulative degree days. The primary purpose of this article is to highlight the utility and biological relevance of such data, and to this end the full datasets are provided here to enable further analyses by the research community, and incorporation in future wider comparative studies.
|
|
| 4. |
- Coulson, Stephen
(author)
-
Changing microarthropod communities in front of a receding glacier in the High Arctic
- 2020
-
In: Insects. - : MDPI AG. - 2075-4450. ; 11
-
Journal article (peer-reviewed)abstract
- This study was carried out at Ny-angstrom lesund on Spitsbergen in Svalbard (High Arctic). Eight study sites were established along a transect from the fjord to the snout of the glacier. The sites differed from each other by the type of vegetation cover and soil characteristics. Soil samples were collected and placed in Tullgren funnels. Extracted arthropods were represented by two groups of mites (Mesostigmata and Oribatida) and springtails (Collembola). The pioneer species that occurred first after retreat of the glacier were representatives of the Collembola (Agrenia bidenticulata and Hypogastrura concolor). Later, other springtails appeared including Folsomia alpha, Folsomia quadrioculata, Hypogastrura concolor, Isotoma anglicana, Sminthurinus concolor and the first species of oribatid mites; Camisia foveolata and Tectocepheus velatus velatus. Arthropod communities recorded along the transect were characterized by large variations in both species composition and abundance of individuals. The greater the distance from the glacier snout, the greater the species richness (2 to 22 species). The mean number of species per sample was the lowest at site 8 (1 +/- 0.71) (the closest to the glacier) and greatest at site 1 (14 +/- 1.41) (furthest from the glacier). The Simpson's diversity index (D) was distinctly greater at sites 1 (4.61 +/- 0.06) and 3 (3.94 +/- 0.11) than at other sites, especially site 8 (1.07 +/- 0.06). Densities were least in the samples closest to the glacier (30 to 101 individuals; density 3000-10,100 individuals/m2). At the other locations, abundance was highly variable (905 to 7432 individuals; density 90,500-743,200 individuals/m2). The mean abundances were greatest at sites 2 and 3. The great variations in total abundances observed were often due to the presence or absence of one or more dominant species exhibiting extreme abundance variability between sites. The microarthropod community of the High Arctic is composed of heterogeneous circumpolar species, yet on a landscape scale is extremely dependent on local environmental conditions which may be subject to rapid change.
|
|
| 5. |
- Coulson, Stephen, et al.
(author)
-
Circumpolar terrestrial arthropod monitoring: A review of ongoing activities, opportunities and challenges, with a focus on spiders
- 2020
-
In: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49, s. 704-717
-
Research review (peer-reviewed)abstract
- The terrestrial chapter of the Circumpolar Biodiversity Monitoring Programme (CBMP) has the potential to bring international multi-taxon, long-term monitoring together, but detailed fundamental species information for Arctic arthropods lags far behind that for vertebrates and plants. In this paper, we demonstrate this major challenge to the CBMP by focussing on spiders (Order: Araneae) as an example group. We collate available circumpolar data on the distribution of spiders and highlight the current monitoring opportunities and identify the key knowledge gaps to address before monitoring can become efficient. We found spider data to be more complete than data for other taxa, but still variable in quality and availability between Arctic regions, highlighting the need for greater international co-operation for baseline studies and data sharing. There is also a dearth of long-term datasets for spiders and other arthropod groups from which to assess status and trends of biodiversity. Therefore, baseline studies should be conducted at all monitoring stations and we make recommendations for the development of the CBMP in relation to terrestrial arthropods more generally.
|
|
| 6. |
- Coulson, Stephen
(author)
-
Distribution and population characteristics of the soil mites Diapterobates notatus and Svalbardia paludicola (Acari: Oribatida: Ceratozetidae) in High Arctic Svalbard (Norway)
- 2017
-
In: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 40, s. 1545-1555
-
Journal article (peer-reviewed)abstract
- The Oribatida of High Arctic Svalbard are faunistically relatively well known, but the distribution, density, stage structure and other population parameters of most species are unknown. Here we focus on two ceratozetid species, Diapterobates notatus (Thorell, 1871) and Svalbardia paludicola Thor, 1930, and investigate the summer density, stage and sex structure, proportion of gravid females and the body size of these species in 33 locations and 11 vegetation classes of Svalbard. Diapterobates notatus occurred in all vegetation classes and at 29 locations, whereas S. paludicola occurred in only two vegetation classes and at three locations. The common occurrence of D. notatus in Svalbard may be due to: (1) cosmopolitan nature of this species which inhabits all vegetation classes but with a preference for open Dryas/Carex rupestris communities, (2) high biological potential (females were more abundant than males and carried 6-7 large eggs) resulting in a high proportion of juveniles, and (3) juvenile morphology which possesses long setae that may enhance passive dispersal by the wind. Adult body size was found to be greatest in the floristically diverse Arctic meadows. Svalbardia paludicola was particularly abundant in the Arctic meadow at Reinsdyrflya where juveniles were more plentiful than the adults. The nymphs of this species have shorter gastronotal setae than those of D. notatus which may limit their passive transport by the wind. Scutozetes clavatosensillus Ermilov, Martens & Tolstikov, 2013 was found in Mosselbukta (north Spitsbergen); this is the first observation of this species in Svalbard.
|
|
| 7. |
- Coulson, Stephen
(author)
-
Diversity and Distribution of Mites (Acari: Ixodida, Mesostigmata, Trombidiformes, Sarcoptiformes) in the Svalbard Archipelago
- 2020
-
In: Diversity. - : MDPI AG. - 1424-2818. ; 12
-
Journal article (peer-reviewed)abstract
- Svalbard is a singular region to study biodiversity. Located at a high latitude and geographically isolated, the archipelago possesses widely varying environmental conditions and unique flora and fauna communities. It is also here where particularly rapid environmental changes are occurring, having amongst the fastest increases in mean air temperature in the Arctic. One of the most common and species-rich invertebrate groups in Svalbard is the mites (Acari). We here describe the characteristics of the Svalbard acarofauna, and, as a baseline, an updated inventory of 178 species (one Ixodida, 36 Mesostigmata, 43 Trombidiformes, and 98 Sarcoptiformes) along with their occurrences. In contrast to the Trombidiformes and Sarcoptiformes, which are dominated in Svalbard by species with wide geographical distributions, the Mesostigmata include many Arctic species (39%); it would thus be an interesting future study to determine if mesostigmatid communities are more affected by global warming then other mite groups. A large number of new species (42 spp.) have been described from Svalbard, including 15 that have so far been found exclusively there. It is yet uncertain if any of these latter species are endemic: six are recent findings, the others are old records and, in most cases, impossible to verify. That the Arctic is still insufficiently sampled also limits conclusions concerning endemicity.
|
|
| 8. |
- Coulson, Stephen
(author)
-
Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard
- 2022
-
In: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 41
-
Research review (peer-reviewed)abstract
- For more than five decades, research has been conducted at Ny-Alesund, in Svalbard, Norway, to understand the structure and functioning of High Arctic ecosystems and the profound impacts on them of environmental change. Terrestrial, freshwater, glacial and marine ecosystems are accessible year-round from Ny-Alesund, providing unique opportunities for interdisciplinary observational and experimental studies along physical, chemical, hydrological and climatic gradients. Here, we synthesize terrestrial and freshwater research at Ny-Alesund and review current knowledge of biodiversity patterns, species population dynamics and interactions, ecosystem processes, biogeochemical cycles and anthropogenic impacts. There is now strong evidence of past and ongoing biotic changes caused by climate change, including negative effects on populations of many taxa and impacts of rain-on-snow events across multiple trophic levels. While species-level characteristics and responses are well understood for macro-organisms, major knowledge gaps exist for microbes, invertebrates and ecosystem-level processes. In order to fill current knowledge gaps, we recommend (1) maintaining monitoring efforts, while establishing a longterm ecosystem-based monitoring programme; (2) gaining a mechanistic understanding of environmental change impacts on processes and linkages in food webs; (3) identifying trophic interactions and cascades across ecosystems; and (4) integrating long-term data on microbial, invertebrate and freshwater communities, along with measurements of carbon and nutrient fluxes among soils, atmosphere, freshwaters and the marine environment. The synthesis here shows that the Ny-Alesund study system has the characteristics needed to fill these gaps in knowledge, thereby enhancing our understanding of High-Arctic ecosystems and their responses to environmental variability and change.
|
|
| 9. |
- Coulson, Stephen
(author)
-
Morphological ontogeny, distribution and descriptive population parameters of Hermannia reticulata (Acari: Oribatida: Hermanniidae), with comments on Crotonioidea
- 2017
-
In: International Journal of Acarology. - : Informa UK Limited. - 0164-7954 .- 1945-3892. ; 43, s. 52-72
-
Journal article (peer-reviewed)abstract
- The ontogeny is known for few species of the oribatid mite genus Hermannia (Hermanniidae). Here, we present the morphological ontogeny, distribution and some descriptive population parameters of Hermannia reticulata Thorell, 1871 collected from throughout Arctic Svalbard. All instars of Herm. reticulata are stocky, as other species of Hermannia Nicolet, 1855 for which ontogeny is known. They have gastronotal setae of similar form and ontogeny (12 pairs in the larva and 16 pairs in the nymphs and adult) and the same is true of prodorsal setae, except in Herm. reticulata the sensillus is clavate, whereas in the other species it is setiform. In Herm. reticulata, setae of the anal segment are delayed to the tritonymph as in most other studied species, whereas they first appear in the deutonymph in Herm. gibba. Studied species also differ by the number of epimeral setae in the nymphs and adult and the ontogeny of leg setae. Hermannia reticulata is a holarctic species and mainly occurs in the circumpolar region, but in Svalbard it is not common. Juveniles were as abundant as adults, but the density and stage structure varied among vegetation classes and samples, especially in rich moss tundra and bird cliff vegetation, where density was most variable. The morphological ontogeny of Herm. reticulata is compared with some other species of Crotonioidea.
|
|
| 10. |
- Coulson, Stephen
(author)
-
Morphological ontogeny, distribution of Hermannia scabra (Acari: Oribatida: Hermanniidae) in Svalbard and descriptive population parameters
- 2017
-
In: Acarologia. - : Les Amis d'Acarologia. - 0044-586X .- 2107-7207. ; 57, s. 877-892
-
Journal article (peer-reviewed)abstract
- The morphological ontogeny and distribution of Hermannia scabra (L. Koch, 1879) in Arctic Svalbard and descriptive population parameters were investigated. All instars of H. scabra are stocky, as in other species of Hermannia Nicolet, 1855, and have the same gastronotal setal ontogeny (12 pairs in the larve and 16 pairs in the nymphs and adults). In this species, the prodorsal setae are similar to other species of Hermannia, except for the bothridial seta which is clavate, as in H. reticulata Thorell, 1871. In other species of Hermannia the bothridial seta is setiform. Most prodorsal and gastronotal setae of H. scabra are phylliform whereas in other Hermannia species they are thickened. The number of epimeral setae in the nymphs and adults and the ontogeny of leg setae are characteristic for H. scabra. This species has a holarctic distribution and in Svalbard is not as common as H. reticulata, but it achieves higher density than the latter species, mainly due to the abundance of juveniles. Hermannia scabra prefers moist and wet localities, and in Svalbard the highest density is achieved in vegetation class 8 (wet vegetated flats, beaches, slopes and river fans with some exposed Dryas vegetation and graminoids Luzula sp.).
|
|
| 11. |
- Coulson, Stephen
(author)
-
No indication of arthropod-vectored viruses in mosquitoes (Diptera: Culicidae) collected on Greenland and Svalbard
- 2018
-
In: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 1581-1586
-
Journal article (peer-reviewed)abstract
- Viruses transmitted to vertebrates via arthropod vectors (so-called arboviruses) include many important pathogens such as dengue virus, Zika virus, and Sindbis virus. Mosquitoes represent the major vectors of many of these arboviruses and occur in all climatic zones, including the Arctic. The focal species, Aedes nigripes (Diptera: Culicidae), is the most widely distributed mosquito species in the Arctic. We screened over 11,000 specimens collected between 2012 and 2016 on Greenland (Kangerlussuaq) and Svalbard (Petuniabukta) for the presence of arboviruses which have previously been reported in latitudes up to 70A degrees N. Assays for arbovirus detection using RT-PCR with primers specific for the genera Alphavirus (family Togaviridae), Orthobunyavirus, Phlebovirus (Bunyaviridae), Flavivirus (Flaviviridae), and Orbivirus (Reoviridae) were negative for all specimens. Similar results were recently obtained in a screening focused on tick-borne pathogens on Svalbard. The findings suggest that the circulation of arboviruses at studied localities is currently negligible or nonexistent, possibly due to dispersal, climate, or biotic restrictions. However, global climate change could enhance vector abundance and activity, introduction of invasive host species, and increase in tourism which then could lead to emerging arbovirus outbreaks in the future, with considerable impact on local ecosystems.
|
|
| 12. |
- Coulson, Stephen, et al.
(author)
-
Status and trends of terrestrial arthropod abundance and diversity in the North Atlantic region of the Arctic
- 2020
-
In: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49, s. 718-731
-
Journal article (peer-reviewed)abstract
- The Circumpolar Biodiversity Monitoring Programme (CBMP) provides an opportunity to improve our knowledge of Arctic arthropod diversity, but initial baseline studies are required to summarise the status and trends of planned target groups of species known as Focal Ecosystem Components (FECs). We begin this process by collating available data for a relatively well-studied region in the Arctic, the North Atlantic region, summarising the diversity of key terrestrial arthropod FECs, and compiling trends for some representative species. We found the FEC classification system to be challenging to implement, but identified some key groups to target in the initial phases of the programme. Long-term data are scarce and exhibit high levels of spatial and temporal variability. Nevertheless, we found that a number of species and groups are in decline, mirroring patterns in other regions of the world. We emphasise that terrestrial arthropods require higher priority within future Arctic monitoring programmes.
|
|
| 13. |
- Coulson, Stephen
(author)
-
The Araneae of Svalbard: the relationships between specific environmental factors and spider assemblages in the High Arctic
- 2018
-
In: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 839-853
-
Journal article (peer-reviewed)abstract
- As top predators in the Arctic invertebrate fauna, spiders in Svalbard are key components of the terrestrial ecosystem. However, most descriptions consist of observations of species occurrence and few repeated sampling campaigns investigating these heterogeneous assemblages, or the relationship between microhabitats and seasonality, exist. Spider assemblages were evaluated along four altitudinal transects (c. 10-300 m above mean sea level) on the west coast of Spitsbergen, Svalbard, throughout the summer of 2012. The slopes were selected to include most of the vegetation types typical for this region of Svalbard. Eleven of the known 15 native spider species were collected (10 Linyphiidae and 1 Gnaphosidae). We used Generalised Linear Models (GLM) for each spider species to identify the factors best explaining spider species abundance and distribution. The distribution of the majority of spider species was best described by vegetation or topography and none was accurately predicted by temperature. Only two species (Erigone arctica palaearctica and Hilaira glacialis) were common at all four sites and these two constituted 54% (1650 and 639 individuals, respectively) of the total spider individuals trapped. That assemblages of linyphiid spiders can differ greatly over small local and temporal scales further demonstrates the complexity of the Arctic terrestrial invertebrate community.
|
|
| 14. |
- Coulson, Stephen
(author)
-
The terrestrial invertebrate fauna of EdgeOya, Svalbard: Arctic landscape community composition reflects biogeography patterns
- 2019
-
In: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 42, s. 837-850
-
Journal article (peer-reviewed)abstract
- Colonisation and immigration history is often neglected as a factor when investigating community or species distribution patterns. However, for dynamic systems that are still reacting to large-scale environmental change, such as the retreat of the ice since the last glacial maximum, colonisation history may explain a large amount of the variation between geographically distinct communities. The High Arctic archipelago of Svalbard presents an opportunity to test whether it is possible to observe the effects of large-scale biogeographical patterns on species distribution at landscape scales. Svalbard has one of the best described inventories of the invertebrate fauna in the Arctic. Nonetheless, the majority of the species records originate from the more accessible west coast and the invertebrate fauna of the whole eastern region, including EdgeOya, is virtually unknown. EdgeOya is located at the eastern fringe of the archipelago on the boundary between Palaearctic and Nearctic faunas. It was expected that post-colonisation dispersal within EdgeOya would conceal routes to the archipelago. Samples were obtained from six locations along the coast of EdgeOya between 2009 and 2010. 140 invertebrate species were identified belonging to 69 different genera of which 16 are new records for Svalbard. Most new species present an eastern Palaearctic distribution. Habitat variables (percentage cover of moss, lichen, vascular plant, or bare soil) fail to explain 35.5% of the differences among sites. However, cluster analysis reveals a clear east-west distribution pattern across the island suggesting that pan-Arctic dispersal routes can be identified even at relatively short geographical scales.
|
|
| 15. |
- Jones, Owen R., et al.
(author)
-
Senescence rates are determined by ranking on the fast-slow life-history continuum
- 2008
-
In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 11:7, s. 664-673
-
Journal article (peer-reviewed)abstract
- Comparative analyses of survival senescence by using life tables have identified generalizations including the observation that mammals senesce faster than similar-sized birds. These generalizations have been challenged because of limitations of life-table approaches and the growing appreciation that senescence is more than an increasing probability of death. Without using life tables, we examine senescence rates in annual individual fitness using 20 individual-based data sets of terrestrial vertebrates with contrasting life histories and body size. We find that senescence is widespread in the wild and equally likely to occur in survival and reproduction. Additionally, mammals senesce faster than birds because they have a faster life history for a given body size. By allowing us to disentangle the effects of two major fitness components our methods allow an assessment of the robustness of the prevalent life-table approach. Focusing on one aspect of life history - survival or recruitment - can provide reliable information on overall senescence.
|
|
| 16. |
- Kim, Jae-Young, et al.
(author)
-
Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
- 2020
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
-
Journal article (peer-reviewed)abstract
- 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
|
|
| 17. |
- Knape, Jonas, et al.
(author)
-
Temporal trends in opportunistic citizen science reports across multiple taxa
- 2022
-
In: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 51, s. 183-198
-
Journal article (peer-reviewed)abstract
- Opportunistic reporting of species observations to online platforms provide one of the most extensive sources of information about the distribution and status of organisms in the wild. The lack of a clear sampling design, and changes in reporting over time, leads to challenges when analysing these data for temporal change in organisms. To better understand temporal changes in reporting, we use records submitted to an online platform in Sweden (Artportalen), currently containing 80 million records. Focussing on five taxonomic groups, fungi, plants, beetles, butterflies and birds, we decompose change in reporting into long-term and seasonal trends, and effects of weekdays, holidays and weather variables. The large surge in number of records since the launch of the, initially taxa-specific, portals is accompanied by non-trivial long-term and seasonal changes that differ between the taxonomic groups and are likely due to changes in, and differences between, the user communities and observer behaviour.
|
|
| 18. |
- Krab, Eveline J, et al.
(author)
-
Experimentally increased snow depth affects high Arctic microarthropods inconsistently over two consecutive winters
- 2022
-
In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
-
Journal article (peer-reviewed)abstract
- Climate change induced alterations to winter conditions may affect decomposer organisms controlling the vast carbon stores in northern soils. Soil microarthropods are particularly abundant decomposers in Arctic ecosystems. We studied whether increased snow depth affected microarthropods, and if effects were consistent over two consecutive winters. We sampled Collembola and soil mites from a snow accumulation experiment at Svalbard in early summer and used soil microclimatic data to explore to which aspects of winter climate microarthropods are most sensitive. Community densities differed substantially between years and increased snow depth had inconsistent effects. Deeper snow hardly affected microarthropods in 2015, but decreased densities and altered relative abundances of microarthropods and Collembola species after a milder winter in 2016. Although increased snow depth increased soil temperatures by 3.2 °C throughout the snow cover periods, the best microclimatic predictors of microarthropod density changes were spring soil temperature and snowmelt day. Our study shows that extrapolation of observations of decomposer responses to altered winter climate conditions to future scenarios should be avoided when communities are only sampled on a single occasion, since effects of longer-term gradual changes in winter climate may be obscured by inter-annual weather variability and natural variability in population sizes.
|
|
| 19. |
- Ma, Li-Jun, et al.
(author)
-
Comparative genomics reveals mobile pathogenicity chromosomes in Fusarium.
- 2010
-
In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 464:7287, s. 367-73
-
Journal article (peer-reviewed)abstract
- Fusarium species are among the most important phytopathogenic and toxigenic fungi. To understand the molecular underpinnings of pathogenicity in the genus Fusarium, we compared the genomes of three phenotypically diverse species: Fusarium graminearum, Fusarium verticillioides and Fusarium oxysporum f. sp. lycopersici. Our analysis revealed lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity, indicative of horizontal acquisition. Experimentally, we demonstrate the transfer of two LS chromosomes between strains of F. oxysporum, converting a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in F. oxysporum. These findings put the evolution of fungal pathogenicity into a new perspective.
|
|
| 20. |
- Taylor, Jason J., et al.
(author)
-
Arctic terrestrial biodiversity status and trends: A synopsis of science supporting the CBMP State of Arctic Terrestrial Biodiversity Report
- 2020
-
In: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49:3, s. 833-847
-
Journal article (peer-reviewed)abstract
- This review provides a synopsis of the main findings of individual papers in the special issue Terrestrial Biodiversity in a Rapidly Changing Arctic. The special issue was developed to inform the State of the Arctic Terrestrial Biodiversity Report developed by the Circumpolar Biodiversity Monitoring Program (CBMP) of the Conservation of Arctic Flora and Fauna (CAFF), Arctic Council working group. Salient points about the status and trends of Arctic biodiversity and biodiversity monitoring are organized by taxonomic groups: (1) vegetation, (2) invertebrates, (3) mammals, and (4) birds. This is followed by a discussion about commonalities across the collection of papers, for example, that heterogeneity was a predominant pattern of change particularly when assessing global trends for Arctic terrestrial biodiversity. Finally, the need for a comprehensive, integrated, ecosystem-based monitoring program, coupled with targeted research projects deciphering causal patterns, is discussed.
|
|
