Institutt for arktisk og marin biologi: Nye registreringer
Viser treff 921-940 av 2084
-
Site-specific responses of fungal and bacterial abundances to experimental warming in litter and soil across arctic and alpine tundra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)Vegetation change of the Arctic tundra due to global warming is a well-known process, but the implication for the belowground microbial communities, key in nutrient cycling and decomposition, is poorly understood. We characterized the fungal and bacterial abundances in litter and soil layers across 16 warming experimental sites at 12 circumpolar locations. We investigated the relationship between ... -
The hidden influence of large particles on ocean colour
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-17)Optical constituents in the ocean are often categorized as water, phytoplankton, sediments and dissolved matter. However, the optical properties of seawater are influenced, to some degree, by scattering and absorption by all particles in the water column. Here we assess the relevant size ranges for determining the optical properties of the ocean. We present a theoretical basis supporting the hypothesis ... -
Redefining the oceanic distribution of Atlantic salmon
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-10)Determining the mechanisms driving range-wide reductions in Atlantic salmon marine survival is hindered by an insufcient understanding of their oceanic ecology and distribution. We attached 204 pop-up satellite archival tags to post-spawned salmon when they migrated to the ocean from seven European areas and maiden North American salmon captured at sea at West Greenland. Individuals migrated ... -
Early spring subglacial discharge plumes fuel under-ice primary production at a Svalbard tidewater glacier
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-27)Subglacial upwelling of nutrient-rich bottom water is known to sustain elevated summer primary production in tidewater-glacier-influenced fjord systems. However, the importance of subglacial upwelling during the early spring season has not been considered yet. We hypothesized that subglacial discharge under sea ice is present in early spring and that its flux is sufficient to increase phytoplankton ... -
Dense mesopelagic sound scattering layer and vertical segregation of pelagic organisms at the Arctic-Atlantic gateway during the midnight sun
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-18)Changes in vertical and spatial distributions of zooplankton and small pelagic fish impact the biological carbon pump and the distribution of larger piscivorous fish and marine mammal species. However, their distribution and abundance remain poorly documented at high latitudes because of the difficulties inherent to sampling relatively fast-moving organisms in ice-covered waters. This study documents ... -
Summer and winter MgCO3 levels in the skeletons of Arctic bryozoans
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-02)<p>In the Arctic, seasonal patterns in seawater biochemical conditions are shaped by physical, chemical, and biological processes related to the alternation of seasons, i.e. winter polar night and summer midnight sun. In summertime, CO<sub>2</sub> concentration is driven by photosynthetic activity of autotrophs which raises seawater pH and carbonate saturation state (Ω). In addition, restriction of ... -
Caligus elongatus and other sea lice of the genus Caligus as parasites of farmed salmonids: A review
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-24)This review was prompted by reports of unusually large numbers of sea lice tentatively identified as <i>Caligus elongatus</i> infesting farmed salmon in northern Norway. Following a brief introduction to the sea lice problem in salmonid aquaculture, the review is divided into a further eight sections. The first is a review of existing information on the life cycle and behaviour of <i>Caligus</i> ... -
Let it glow! Adapting a method to detect microplastics in snow and evaluate the potential for long-range transport
(Master thesis; Mastergradsoppgave, 2020-05-31)Harmonization of methods in microplastics research is lacking; this is affecting the comparability of results and hindering reproducibility. Investigating microplastics in snow is a relatively new field of research, and it can be used to answer questions about long-range atmospheric transport of microplastics. In this thesis, snow sampling methods were combined with the dye, Nile Red, to develop a ... -
Spring sea ice algal development in the sub-Arctic Ramfjorden, northern Norway
(Master thesis; Mastergradsoppgave, 2020-05-29)The seasonal development of sea ice algae and bacteria was investigated in Ramfjorden, Norway, from February to April 2019 and compared to data from two Arctic fjords, Van Mijenfjorden and Billefjorden, sampled in April 2019. The sea ice in Ramfjorden was heavily freshwater influenced with bulk salinities ranging from 0.0 to 2.8, similar to those found in freshwater influenced Baltic Sea ice. The ... -
Fecundity and egg size in anadromous brown trout Salmo trutta
(Master thesis; Mastergradsoppgave, 2020-05-31)Historically, anadromous salmonids provided a necessary provisioning service for Norwegian coastal settlements that has transitioned into the socio-cultural service that they provide today. Over the past decades, human impact has caused anadromous salmonid populations to decline. A recent assessment found many Norwegian sea trout populations to be in poor condition. Reference point management has ... -
Linking methane fluxes and oxidation rates to methane oxidizing bacteria in an Arctic terrestrial methane seep, Svalbard
(Master thesis; Mastergradsoppgave, 2020-05-29)Global warming has especially detrimental effects on Arctic regions. One major issue is permafrost thaw and sub-permafrost methane escape via surface seeps. While the mitigation potential of methane-consuming bacteria on marine pingo-like methane seeps is well described, terrestrial methane seeps are still understudied. Recently, open system pingos have gained attention as terrestrial methane seeps. ... -
Hibernation in European Hamsters (Cricetus crisetus): An assessment of brain permeability during torpor-arousal cycling
(Master thesis; Mastergradsoppgave, 2020-05-22)Hibernation is a physiological and behavioural adaptation that permits survival during seasonal periods of energy shortage via a combination of pre-hibernal energy storage and hibernal metabolic depression, i.e. torpor. The central mechanisms in the brain that control torpor expression and arousal from it has been under investigation since the dawn of hibernation research but remains unknown. Recent ... -
Arctic coastal benthos long-term responses to perturbations under climate warming: Climate change impact on Arctic benthos
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)<p>Climate warming influences structure and function of Arctic benthic ecosystems. Assessing the response of these systems to perturbations requires long-term studies addressing key ecological processes related to recolonization and succession of species. Based on unique time-series (1980–2017), this study addresses successional patterns of hard-bottom benthos in two fjords in NW Svalbard after a ... -
Biogeography of epibenthic assemblages in the central Beaufort Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-27)Benthic communities change drastically in both biomass and community structure with increasing water depth on a global scale, attributed to a combination of food supply, environmental drivers, as well as physiological and competitive capacities. In the Arctic, benthic biogeographic patterns are additionally thought to be a result of the region’s glaciation history. Here, we investigate gross epibenthic ... -
New species of aquatic chytrids from Oman
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-12)Oman is a desert country in the south of the Middle East. Springs and other water sources that harbor aquatic organisms can be separated by hundreds of kilometers. In Oct 2019, we isolated four freshwater aquatic fungi (Chytridiomycota) from benthic detritus baited with pine pollen on a general nutrient medium near Salalah, Oman. Database queries of nuc 28S rRNA (28S) and internal transcribed spacer ... -
Feeding ecology and interactions of invasive vendace and DR whitefish in the Pasvik watercourse
(Master thesis; Mastergradsoppgave, 2021-02-15)Introductions and invasions of species outside their natural range can have devastating effects on the native species and be a major driver of biodiversity change. When the zooplanktivorous vendace invaded the Pasvik watercourse in the 1990s, it quickly took over the ecological role of the native DR whitefish. In the upper part of the watercourse, DR whitefish was displaced from the pelagic habitat ... -
Gastrointestinal nematodes in Icelandic reindeer (Rangifer tarandus tarandus)
(Master thesis; Mastergradsoppgave, 2021-01-18)Reindeer (<i>Rangifer tarandus</i>) are host to gastrointestinal-tract nematodes (GINs) throughout the world. Some populations of reindeer exist in almost complete isolation from others, and this can have a key influence on the species and infection rates of GINs. An example of an isolated reindeer population occurs in Iceland. In this study, I have investigated the prevalence of GINs in Icelandic ... -
Adaptive niche-based sampling to improve ability to find rare and elusive species: Simulations and field tests
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-27)<ol> <li>Sampling efficiency is crucial to overcome the data crisis in biodiversity and to understand what drives the distribution of rare species.</li <li>Adaptive niche‐based sampling (ANBS) is an iterative sampling strategy that relies on the predictions of species distribution models (SDMs). By predicting highly suitable areas to guide prospection, ANBS could improve the efficiency of sampling ... -
Nest association between two predators as a behavioral response to the low density of rodents
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-04)Many birds nest in association with aggressive birds of other species to benefit from their protection against predators. We hypothesized that the protective effect also could extend to foraging resources, whereby the resultant resource-enriched habitats near a nest of aggressive raptors could be an alternative cause of associations between nesting bird species with non-overlapping foraging niches. ... -
Phytoplankton community succession and dynamics using optical approaches
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-04)The phytoplankton in coastal regions are responding to constant environmental changes, thus the use of proxies derived from in situ frequent time-series observations and validated from traditional microscopic or pigment methods can be a solution for detecting rapid responses of community dynamics and succession. In this study, we combined in situ high-frequency (every 30 min from May to September ...