English
norskBlar i tittel Institutt for arktisk og marin biologi
Viser treff 1818-1837 av 1891
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Validating the Tritiated Water Method in Adult Harp Seal
(Master thesis; Mastergradsoppgave, 2022-05-16)As one of the top predators in the northeast Atlantic, and most numerous, the harp seal (Pagophilus groenlandicus), has a significant role in the higher trophic levels in the ecosystem. Their condition can be an indicator of changes in prey availability, competition with other species or even climate. It can also be a useful tool in predicting the pup production and breeding success. The ... -
Validation of pop-up satellite archival tags (PSATs) on Atlantic cod (Gadus morhua) in a Greenland fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-28)Traditional tagging techniques are simple and cost-effective, but inferences require recaptures and data on movement/migration are limited to a start and end position at unpredictable intervals. Pop-up satellite archival tags (PSATs) offer other opportunities, as they provide positions at pre-programmed times and collect on-route data, which can be used to describe position, behavior, and habitat ... -
Vandringsmønster til sjørøye og sjøørret i et nordnorsk fjordsystem
(Master thesis; Mastergradsoppgave, 2010-11-15)Det eksisterer lite kunnskap på marin sjøvandring til sjørøye og sjøørret, data som er viktige for å forvalte disse artene i framtiden. På bakgrunn av dette, ble tjue sjørøyer og tjue sjøørreter merket med akustiske merker fra Halsvassdraget i Finnmark. Fiskene ble fulgt ved hjelp av 50 automatiske lyttestasjoner, som var som var fordelt på tre transekt. Resultatene viste at artene fordelte seg ... -
Variability and quasi-decadal changes in the methane budget over the period 2000-2012
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-20)Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH<sub>4</sub> budget over 2000– 2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH<sub>4</sub> emissions. The GCP dataset integrates results from topdown studies (exploiting atmospheric observations within an atmospheric inverse-modelling ... -
Variability in Calanus spp. abundance on fine- to mesoscales in an Arctic fjord: implications for little auk feeding
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Variable individual- and population- level responses to ocean acidification
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-29)Population responses to marine climate change are determined by the strength of the selection pressure imposed by changing climate, the genetic variability within the population (i.e., among individuals), and phenotypic plasticity within individuals. Marine climate change research has focused primarily on population-level responses, yet it is at the level of the individual that natural selection ... -
Variable responses of carbon and nitrogen contents in vegetation and soil to herbivory and warming in high-Arctic tundra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-21)Chemical responses of tundra vegetation and tundra soil to environmental changes are likely to differ, with implications for ecosystem functioning, yet they are rarely compared. Here, we aimed at comparing sensitivity and magnitude of short-term carbon and nitrogen responses of three main tundra ecosystem compartments: vascular plants, mosses, and soil, to two environmental perturbations: herbivore ... -
Variation in abundance, diet, otolith zone patterns and black spot disease (Cryptocotyle lingua) of 0-group coastal cod (Gadus morhua L.) in northern Norway
(Master thesis; Mastergradsoppgave, 2006-12-11)Knowledge of the early life-history and habitat requirements of coastal cod is very sparse. Young of the year cod juveniles from three different locations in northern Norway were collected monthly from August to November 2005 using beach seine. Diet analyses based on stomach contents showed that 0-group cod mainly ate copepods, gammarids, polychaetes, mysids, shrimps and isopods. The three ... -
Variation in egg size, fecundity and size structure in female red king crab (Paralithodes camtschaticus, Tilesius 1815) from Varangerfjorden over time.
(Master thesis; Mastergradsoppgave, 2018-05-14)The introduced red king crab (Paralithodes camtschaticus) has successfully established in Norwegian waters since its release to the Barents Sea in the 1960’s. It has become an important commercial resource contributing to the local coastal society in the eastern region of Finnmark. The fishery consists of one quota regulated area east of 26° (North Cape) and an open fishery west of 26°E. During the ... -
Variation in epiphytic vegetation in spruce plantations and adjacent native birch forests in North Norway
(Master thesis; Mastergradsoppgave, 2007-05)Epiphytic vegetation can contribute to increased knowledge on how planting of spruce in areas where spruce does not occur naturally in the landscape can affect the environment. In the current study, 31 spruce plantations in Troms and Vesterålen in North Norway were investigated, with emphasis on species abundance of macrolichens on tree trunks and branches. The main assumption was that planting of ... -
Variation in functional trait composition of benthic invertebrates across depths and seasons in a subarctic lake
(Journal article; Tidsskriftartikkel, 2016-07-01)Benthic invertebrate communities play a fundamental role in lake ecosystems, and the understanding of how those benthic communities are structured, particularly in terms of the identity and spatiotemporal distribution of their functional traits, is key to our understanding of how lake ecosystems work. In Takvatn, a subarctic lake in northern Norway, we identified the taxonomic and functional identity ... -
Vegetation-environment analysis of areas with peat accumulation and hummock formation in the context of NiN (Natur i Norge). A study from Laggu, Gamvik municipality, Troms and Finnmark county.
(Master thesis; Mastergradsoppgave, 2021-05-18)A conspicuous type of heath and forest with peat accumulation and hummock formation in terrestrial systems has been investigated in Laggu, Gamvik municipality in northern Norway. The aim was to describe vegetational composition, soil depth and hummock distribution, and identify environmental factors that cause terrestrial peat accumulation. Vascular plants, bryophytes and lichens were registered ... -
Vekst, diett og stabile isotoper hos yngel av Atlantisk laks Salmo salar L. fanget i bekk- og hovedelv i Tanavassdraget
(Master thesis; Mastergradsoppgave, 2009-08)Tidligere studier fra Tanavassdraget har vist omfattende vandring av lakseparr (lakseyngel) bort fra gyte- og oppvekstområdene i hovedelva og opp i små sidebekker der det ikke foregår gyting av laks. Det er dokumentert bedre vekst i bekker enn i hovedelva, og undersøkelser av næringsforhold indikerer høyere mattilgang i bekk enn i hovedelv. Det er manglende kunnskap om hvordan lakseyngelens habitatvalg ... -
Velferdskriterier i reindriften
(Research report; Forskningsrapport, 2017-06-07)Formålet med prosjektet var å identifisere ulike faktorer som kunne påvirke velferd hos tamrein, og som kunne implementeres i produksjonssystemene, på beite, i gjerdet, på slakteriet, gjennom produktmerking og fremtidige kvalitetssikringssystemer. I den senere tid har det vært et økt fokus på dyrehelse og -velferd i reindrifta. Det har for eksempel vært et fokus på lave slaktevekter, spesielt i ... -
Vertical distributions of zooplankton using the Video Plankton Recorder in two high-latitude fjords. “A case study on diel migration in Billefjorden, Svalbard, and seasonal migration in Porsangerfjord, northern Norway”
(Master thesis; Mastergradsoppgave, 2015-08-17)Zooplankton is the link between primary producers and higher trophic levels, so it is of vital importance for the food chain. The strong seasonality in the Arctic affects the vertical distribution of zooplankton in the water column. Predators can also affect the vertical distributions of their prey in the water column due to avoidance adaptations. The importance of these differences between prey and ... -
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 ... -
Vertical fluxes of nitrate in the seasonal nitracline of the Atlantic sector of the Arctic Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-31)<p>This study compiles colocated oceanic observations of high-resolution vertical profiles of nitrate concentration and turbulent microstructure around the Svalbard shelf slope, covering both the permanently ice-free Fram Strait and the pack ice north of Svalbard. The authors present an overview over the seasonal evolution of the distribution of nitrate and its relation to upper ocean stratification. ... -
Vertical movements of Atlantic salmon postsmolts relative to measures of salinity and water temperature during the first phase of the marine migration
(Journal article; Tidsskriftartikkel; Peer reviewed, 2009)The migratory behaviour of hatchery-reared Atlantic salmon, Salmo salar L., post-smolts during the first phase of the marine migration was examined to assess their susceptibility to salmon lice, Lepeophtheirus salmonis (Krøyer), infestations. Swimming depths of eight post-smolts relative to the measured salinity and temperature were monitored for an average of 11.4 h following release outside the ... -
Vertical redistribution of principle water masses on the Northeast Greenland Shelf
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-10)The Northeast Greenland shelf (NEGS) is a recipient of Polar Water (PW) from the Arctic Ocean, Greenland Ice Sheet melt, and Atlantic Water (AW). Here, we compile hydrographical measurements to quantify long-term changes in fjords and coastal waters. We find a profound change in the vertical distribution of water masses, with AW shoaling >60 m and PW thinning >50 m since early 2000’s. The properties ... -
Vertikalt habitatbruk, næringsvalg og vekst hos en innsjølevende bestand av ørret (Salmo trutta L.) i Pasvikvassdraget
(Master thesis; Mastergradsoppgave, 2007-10-16)En av våre nordligste fiskespisende ørretbestander finnes i Pasvikvassdraget i Finnmark. Omfattende regulering av vassdraget har virket negativt på bestanden, og den blir nå opprettholdt gjennom årlige utsettinger. På 1990-tallet innvandret lagesild fra Enare-sjøen, og den ser ut til å ha hatt positiv effekt på ørreten. Denne undersøkelsen omhandler habitatbruk, næringsvalg og vekst hos innsjølevende ...
