English
norskBlar i forfatter "Vader, Anna"
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Can root-associated fungi mediate the impact of abiotic conditions on the growth of a High Arctic herb?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-04)Arctic plants are affected by many stressors. Root-associated fungi are thought to influence plant performance in stressful environmental conditions. However, the relationships are not well-known; do the number of fungal partners, their ecological functions and community composition mediate the impact of environmental conditions and/or influence host plant performance? To address these questions, ... -
Dead or Alive; or Does It Really Matter? Level of Congruency Between Trophic Modes in Total and Active Fungal Communities in High Arctic Soil
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-08)Describing dynamics of belowground organisms, such as fungi, can be challenging. Results of studies based on environmental DNA (eDNA) may be biased as the template does not discriminate between metabolically active cells and dead biomass. We analyzed ribosomal DNA (rDNA) and ribosomal RNA (rRNA) coextracted from 48 soil samples collected from a manipulated snow depth experiment in two distinct ... -
Linking extreme seasonality and gene expression in Arctic marine protists
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-05)At high latitudes, strong seasonal differences in light availability affect marine organisms and regulate the timing of ecosystem processes. Marine protists are key players in Arctic aquatic ecosystems, yet little is known about their ecological roles over yearly cycles. This is especially true for the dark polar night period, which up until recently was assumed to be devoid of biological activity. ... -
Microbial eukaryotes in an arctic under-ice spring bloom north of Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-28)Microbial eukaryotes can play prominent roles in the Arctic marine ecosystem, but their diversity and variability is not well known in the ice-covered ecosystems. We determined the community composition of microbial eukaryotes in an Arctic under-ice spring bloom north of Svalbard using metabarcoding of DNA and RNA from the hypervariable V4 region of 18S nrDNA. At the two stations studied, the ... -
Multiomics in the central Arctic Ocean for benchmarking biodiversity change
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-17)Multiomics approaches need to be applied in the central Arctic Ocean to benchmark biodiversity change and to identify novel species and their genes. As part of MOSAiC, EcoOmics will therefore be essential for conservation and sustainable bioprospecting in one of the least explored ecosystems on Earth. -
The recent transfer of a homing endonuclease gene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2005)The myxomycete Didymium iridis (isolate Panama 2) contains a mobile group I intron named Dir.S956-1 after position 956 in the nuclear small subunit (SSU) rRNA gene. The intron is efficiently spread through homing by the intron-encoded homing endonuclease I-DirI. Homing endonuclease genes (HEGs) usually spread with their associated introns as a unit, but infrequently also spread independent of ... -
Seasonality in land–ocean connectivity and local processes control sediment bacterial community structure and function in a High Arctic tidal flat
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-18)Climate change is altering patterns of precipitation, cryosphere thaw, and land–ocean influxes, affecting understudied Arctic estuarine tidal flats. These transitional zones between terrestrial and marine systems are hotspots for biogeochemical cycling, often driven by microbial processes. We investigated surface sediment bacterial community composition and function from May to September along a ... -
Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord—Different from subarctic fjords?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-23)The arctic Adventfjorden (78°N, 15°E, Svalbard) used to be seasonally ice-covered but has mostly been ice-free since 2007. We used this ice-free arctic fjord as a model area to investigate (1) how the vertical fl ux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sink- ing particle characteristics change seasonally and ... -
Variability and decadal trends in the Isfjorden (Svalbard) ocean climate and circulation – An indicator for climate change in the European Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020)Isfjorden, a broad Arctic fjord in western Spitsbergen, has shown significant changes in hydrography and inflow of Atlantic Water (AW) the last decades that only recently have been observed in the Arctic Ocean north of Svalbard. Variability and trends in this fjord’s climate and circulation are therefore analysed from observational and reanalysis data during 1987 to 2017. Isfjorden experienced a ... -
Vertical export of marine pelagic protists in an ice-free high-Arctic fjord (Adventfjorden, West Spitsbergen) throughout 2011-2012
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-06)The ecosystem role of Arctic microbial communities is still largely unknown. Based on a time-series study at the IsA station (West Spitsbergen), the seasonality and contribution of pelagic protists to the vertical flux was investigated at 7 time points during 2011-2012. The hydrography of this high-Arctic fjord was evaluated to identify impacts on the community composition during the different ... -
When a year is not enough: Further study of the seasonality of planktonic protist communities structure in an ice-free high arctic fjord (adventfjorden, west spitsbergen)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-20)As a contribution to understanding the ecological framework of protistan seasonal succession patterns, we present the weekly-to-monthly (January–October) light microscopy-based study of nano- and microplanktonic protist communities of Adventfjorden waters in 2013. In general, protist dynamics corresponded to the classic paradigm for the Arctic ice-free waters with extremely low abundance and diversity ...
