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norskBlar i forfatter "Wiedmann, Ingrid"
Viser treff 1-13 av 13
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Aggregate feeding by the copepods Calanus and Pseudocalanus controls carbon flux attenuation in the Arctic shelf sea during the productive period
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-24)Up to 95% of the oceanic primary production is recycled within the upper few hundred meters of the water column. Marine snow and zooplankton fecal pellets in the upper water column are often recycled at rates exceeding those measured for microbial degradation, suggesting that zooplankton might be important for flux attenuation of particulate organic carbon in the upper ocean. However, direct evidence ... -
Arctic Observations Identify Phytoplankton Community Composition as Driver of Carbon Flux Attenuation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-24)The attenuation coefficient <i>b</i> is one of the most common ways to describe how strong the carbon flux is attenuated throughout the water column. Therefore, <i>b</i> is an essential input variable in many carbon flux and climate models. Marsay et al. (2015, <a href=https://doi.org/10.1073/pnas.1415311112>https://doi.org/10.1073/pnas.1415311112</a>) proposed that the median surface water temperature ... -
Biogenic silica production and diatom dynamics in the Svalbard region during spring
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-06)Diatoms are generally the dominant contributors to the Arctic Ocean spring bloom, which is a key event in regional food webs in terms of capacity for secondary production and organic matter export. Dissolved silicic acid is an obligate nutrient for diatoms and has been declining in the European Arctic since the early 1990s. The lack of regional silicon cycling information precludes understanding the ... -
Hva forskerne egentlig gjør
(Chronicle; Kronikk, 2018-10-19)<p><i>Introduction</i>: Forskningsdagene ved UiT Norges arktiske universitet, åpen dag ved Framsenteret, ulike arrangement rundt UiTs 50 års jubileum og en UiT spesialforestilling på Hålogaland teater: Forskningen i Tromsø har vist seg seg fram denne høsten. Uansett hvor du går i Tromsø, så formidler forskere til deg at forskning er spennende og at det er kjempegøy å være forsker. Som forsker står ... -
Macrofauna and meiofauna food-web structure from Arctic fjords to deep Arctic Ocean during spring: A stable isotope approach
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-13)The knowledge on benthic trophic relations is particularly important for understanding the functioning of still pristine and less studied Arctic Ocean ecosystems. This study examines the benthic food-web structure in the European sector of the Arctic Ocean and assesses if and how it differs along depth gradients in the marginal seaice zone during spring. Samples of the sediment organic matter were ... -
Pelagic ecosystem dynamics between late autumn and the post spring bloom in a sub-Arctic fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-13)Marine ecosystems, and particularly fjords, are experiencing an increasing level of human activity on a yearround basis, including the poorly studied winter period. To improve the knowledge base for environmentally sustainable management in all seasons, this study provides hydrographic and biological baseline data for the sub-Arctic fjord Kaldfjorden, Northern Norway (69.7 N, 18.7 E), between ... -
Potential drivers of sinking particle´s size spectra and vertical POC flux: Turbulence, phytoplankton and zooplankton
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Potential drivers of the downward carbon and particle flux in Arctic marine ecosystems under contrasting hydrographical and ecological situations
(Doctoral thesis; Doktorgradsavhandling, 2015-11-13)Detailed predictions of the downward particulate organic carbon (POC) flux in a future Arctic are challenging due to the poor understanding of potential drivers. Short-term sediment traps, partly modified with gel-containing jars, were deployed in the Barents Sea (BS) and in Adventfjorden, Svalbard, to determine the downward POC flux and the particle flux (≥ 0.05 mm equivalent spherical diameter ... -
Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-17)Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (C<sub>T</sub>), alkalinity (A<sub>T</sub>), ... -
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 ... -
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-02)Increased sea ice melt alters vertical surface-mixing processes in Arctic seas. More melt water strengthens the stratification, but an absent ice cover also exposes the uppermost part of the water column to wind-induced mixing processes. We conducted a field study in the Barents Sea, an Arctic shelf sea, to examine the effects of stratification and vertical mixing processes on 1) the upward nitrate ... -
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 ... -
What feeds the benthos in the Arctic basins? Assembling a carbon budget for the deep Arctic ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-16)Half of the Arctic Ocean is deep sea (>1000 m), and this area is currently transitioning from being permanently ice-covered to being seasonally ice-free. Despite these drastic changes, it remains unclear how organisms are distributed in the deep Arctic basins, and particularly what feeds them. Here, we summarize data on auto- and heterotrophic organisms in the benthic, pelagic, and sympagic realm ...
