Artikler, rapporter og annet (arktisk og marin biologi): Recent submissions
Now showing items 41-60 of 1522
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From Winter to Late Summer in the Northwestern Barents Sea Shelf: Impacts of Seasonal Progression of Sea Ice and Upper Ocean on Nutrient and Phytoplankton Dynamics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-11)Strong seasonality is a key feature of high-latitude systems like the Barents Sea. While the interannual variability and long-term changes of the Barents Sea are well-documented, the seasonal progression of the physical and biological systems is less known, mainly due to poor accessibility of the seasonally ice-covered area in winter and spring. Here, we use an extensive set of physical and biological ... -
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-13)Sea ice algae have a broad salinity tolerance but can experience stress during rapid decreases in salinity that occur with seasonal ice melt and during ice sample melt. This study investigated the impact of salinity on the photophysiological responses of bottom-ice algal communities from two Svalbard fjords (Tempelfjorden and Van Mijenfjorden). To further investigate the impact of salinity alone, ... -
Assessing net primary production in the northwestern Barents Sea using in situ, remote sensing and modelling approaches
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-24)The northwestern Barents Sea (NW-BS) is a highly productive region within the transitional zones of an Atlantic to Arctic-dominated marine ecosystem. The steep latitudinal gradients in sea ice concentration, Atlantic and Arctic Water, offer an opportunity to test hypotheses on physical drivers of spatial and temporal variability of net primary production (NPP). However, quantifying NPP in such a ... -
Development and calibration of a high dynamic range and autonomous ocean-light instrument to measure sub-surface profiles in ice-covered waters
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-23)The optical chain and logger (OptiCAL) is an autonomous ice-tethered observatory equipped with multiple light sensors for mapping the variation of light with depth. We describe the instrument and present an ensemble calibration for downwelling irradiance E<sub>PAR</sub> in [µmolm<sup>−2</sup>s<sup>−1</sup>]. Results from a long-term deployment in the Arctic Ocean demonstrate that the OptiCAL can ... -
Biogeography of microbial communities in high-latitude ecosystems: Contrasting drivers for methanogens, methanotrophs and global prokaryotes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-27)Methane-cycling is becoming more important in high-latitude ecosystems as global warming makes permafrost organic carbon increasingly available. We explored 387 samples from three high-latitudes regions (Siberia, Alaska and Patagonia) focusing on mineral/organic soils (wetlands, peatlands forest), lake/pond sediment and water. Physicochemical, climatic and geographic variables were integrated ... -
Cuscuta campestris fine-tunes gene expression during haustoriogenesis as an adaptation to different hosts
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-14)The Cuscuta genus comprises obligate parasitic plants that have an unusually wide host range. Whether Cuscuta uses different infection strategies for different hosts or whether the infection strategy is mechanistically and enzymatically conserved remains unknown. To address this, we investigated molecular events during the interaction between field dodder (Cuscuta campestris) and two host species ... -
Model-informed classification of broadband acoustic backscatter from zooplankton in an in situ mesocosm
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-07)Classification of zooplankton to species with broadband echosounder data could increase the taxonomic resolution of acoustic surveys and reduce the dependence on net and trawl samples for ‘ground truthing’. Supervised classification with broadband echosounder data is limited by the acquisition of validated data required to train machine learning algorithms (‘classifiers’). We tested the hypothesis ... -
Impacts of a warming climate on concentrations of organochlorines in a fasting high arctic marine bird: Direct vs. indirect effects?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-30)The present study examined how climate changes may impact the concentrations of lipophilic organochlorines (OCs) in the blood of fasting High Arctic common eiders (Somateria mollissima) during incubation. Polychlorinated biphenyls (PCBs), 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p′-DDE), hexachlorobenzene (HCB) and four chlordane compounds (oxychlordane, trans-chlordane and trans- and ... -
The positive effect of plant diversity on soil carbon depends on climate
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-19)Little is currently known about how climate modulates the relationship between plant diversity and soil organic carbon and the mechanisms involved. Yet, this knowledge is of crucial importance in times of climate change and biodiversity loss. Here, we show that plant diversity is positively correlated with soil carbon content and soil carbon-to-nitrogen ratio across 84 grasslands on six continents ... -
Still Arctic? — The changing Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-13)The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and ... -
Diffusive and advective cross-frontal fluxes of inorganic nutrients and dissolved inorganic carbon in the Barents Sea in autumn
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-21)The Atlantic Water, entering the Arctic through the Barents Sea and Fram Strait, is the main source of nutrients in the Arctic Ocean. The Barents Sea is divided by the Polar Front into an Atlantic-dominated domain in the south, and an Arctic-dominated domain in the north. The Polar Front is a thermohaline structure, which is topographically-steered at sub-surface, and influenced by the seasonal ... -
Hydrography, inorganic nutrients and chlorophyll a linked to sea ice cover in the Atlantic Water inflow region north of Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-04)Changes in the inflow of Atlantic Water (AW) and its properties to the Arctic Ocean bring more warm water, contribute to sea ice decline, promote borealisation of marine ecosystems, and affect biological and particularly primary productivity in the Eurasian Arctic Ocean. One of the two branches of AW inflow follows the shelf break north of Svalbard, where it dominates oceanographic conditions, ... -
Abrupt permafrost thaw triggers activity of copiotrophs and microbiome predators
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-05)Permafrost soils store a substantial part of the global soil carbon and nitrogen. However, global warming causes abrupt erosion and gradual thaw, which make these stocks vulnerable to microbial decomposition into greenhouse gases. Here, we investigated the microbial response to abrupt in situ permafrost thaw. We sequenced the total RNA of a 1 m deep soil core consisting of up to 26 500-year-old permafrost ... -
Atlantification influences zooplankton communities seasonally in the northern Barents Sea and Arctic Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)The Barents Sea is undergoing rapid ocean warming with less sea ice and increased Atlantic inflow, shifting the pelagic ecosystem towards a more boreal one, a process referred to as Atlantification. While such changes have already been documented in the southern and central Barents Sea, less is known about the degree of Atlantification in the northern Barents Sea and Arctic Ocean. In this seasonal ... -
Horizon scanning of potential threats to high-Arctic biodiversity, human health and the economy from marine invasive alien species: A Svalbard case study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-09)The high Arctic is considered a pristine environment compared with many other regions in the northern hemisphere. It is becoming increasingly vulnerable to invasion by invasive alien species (IAS), however, as climate change leads to rapid loss of sea ice, changes in ocean temperature and salinity, and enhanced human activities. These changes are likely to increase the incidence of arrival and ... -
New insights into the Barents Sea Calanus glacialis population dynamics and distribution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-18)Arctic copepods are major grazers and vital food for planktivores in polar ecosystems but challenging to observe due to remoteness and seasonal sea ice coverage. Models offer higher spatio-temporal resolution, and individual-based models (IBMs) are useful since they incorporate individual variability which characterizes most copepod populations. Here, we present an IBM of the Arctic copepod Calanus ... -
Skogens helsetilstand i Norge. Resultater fra skogskadeovervåkingen i 2022
(Research report; Forskningsrapport, 2023-11-17)Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter ... -
Modulation of intestinal growth and differentiation by photoperiod and dietary treatment during smoltification in Atlantic salmon (Salmo salar, L.)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-15)Atlantic salmon undergo smoltification, a process that prepares the fish to enter and thrive in seawater (SW). Several physiological changes occur during smolting, especially in osmoregulatory tissues, the gill, the kidney, and the intestine. Here we characterized the effects on intestinal morphogenesis of two different, commonly used smoltification regimes during the end of the freshwater phase, ... -
Lack of strong seasonality in macrobenthic communities from the northern Barents Sea shelf and Nansen Basin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-12)The Barents Sea has been coined ‘the Arctic hotspot’ of climate change due to the rapidity with which environmental changes are taking place. This transitional domain from Atlantic to Arctic waters is home to highly productive benthic communities. This system strongly fluctuates on a seasonal basis in its sympagic-pelagicbenthic coupling interactions, with potential effects on benthic standing ... -
Rich local knowledge despite high transience in an Arctic community experiencing rapid environmental change
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-04)Environmental monitoring and long-term research produce detailed understanding, but its collective effort does not add up to ‘the environment’ and therefore may be difficult to relate to. Local knowledge, by contrast, is multifaceted and relational and therefore can help ground and complement scientific knowledge to reach a more complete and holistic understanding of the environment and changes ...