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The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of the interannual variability during the late summer season. At the same time will the cruise provide a late summer reference for the seasonal... more
The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of the interannual variability during the late summer season. At the same time will the cruise provide a late summer reference for the seasonal investigation that was separated to late summer and polar night 2019, and winter and spring 2021. The transect represents an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 10-39 hrs. Additional CTD stations (NLEG) were taken between the process stations to increase the hydrographic resolution on the transect. The work started at 76°N at the open Atlantic Water dominated station P1, was sea ice covered from station P4 at 79 45.00 °N and included deep water stations at the P7 station at 82°N in the Nansen Basin. The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected includes several disciplines to map the physical environment, th...
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Over recent years, rapid environmental changes in the Arctic and subarctic regions have caused significant alterations in the ecosystem structure and seasonality, including the primary productivity of the Barents Sea. This work aims at... more
Over recent years, rapid environmental changes in the Arctic and subarctic regions have caused significant alterations in the ecosystem structure and seasonality, including the primary productivity of the Barents Sea. This work aims at improving methodology for studying these features, by estimating chlorophyll-a (chl-a) concentrations in the transitional Barents Sea by remotely sensing its optical properties, in order to better understand the large-scale algal bloom dynamics in the region. The in-situ measurements of chl-a are collected from the year 2016 to 2018 over a wide area of the Barents Sea to cover the spatial and temporal variations in chl-a concentration. Optical images of the Barents Sea are captured by the Multi-Spectral Imager Instrument on Sentinel-2. Using these remotely sensed optical images and the in-situ measurements, we propose a match-up dataset creation method based on the distribution of the remotely sensed reflectance spectra. Different Machine Learning (ML) techniques are assessed to estimate concentration of chl-a using the match-up dataset. Most of these techniques have not been investigated before in the subarctic region such as the Barents Sea. The Ocean Color Net (OCN) regression model proposed in this study has outperformed other ML-based techniques including Support Vector Regression, Gaussian Process Regression, and the globally trained Case-2 Regional/Coast Colour (C2RCC) processing chain model C2RCC-Nets, as well as empirical methods based on spectral band ratios. A wide range of experiments has demonstrated the effectiveness of the proposed OCN for ocean color remote sensing in the subarctic region. The performance of the OCN is also presented spatially by computing chl-a maps in the Barents Sea.
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The Nansen Legacy cruise Q3 (Q3: 3rd quarter of the year) initiated the seasonal investigation of the northern Barents Sea and adjacent Arctic Basin. The cruise focused on comparing the state of the physical, chemical and biological... more
The Nansen Legacy cruise Q3 (Q3: 3rd quarter of the year) initiated the seasonal investigation of the northern Barents Sea and adjacent Arctic Basin. The cruise focused on comparing the state of the physical, chemical and biological conditions along the Nansen Legacy main transect in open waters and within the sea ice, addressing objectives of the work packages 'Physical drivers' (Research Foci 1), 'Human impact' (Research Foci 2) and 'The living Barents Sea' (Research Foci 3).
The scientific investigation of a rapidly changing northern environment leads to research questions of such intellectual, empirical and logistical complexity—and of such importance to the management of national resources and associated... more
The scientific investigation of a rapidly changing northern environment leads to research questions of such intellectual, empirical and logistical complexity—and of such importance to the management of national resources and associated international obligations—that they can only be addressed properly through national and prioritized cooperation, with the highest scientific standards.
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The Nansen Legacy Q3 cruise, 5-27 August 2019, initiated the seasonal investigations of the Nansen Legacy transect. The transect represent an environmental gradient going through the northern Barents Sea, and included 7 process stations... more
The Nansen Legacy Q3 cruise, 5-27 August 2019, initiated the seasonal investigations of the Nansen Legacy transect. The transect represent an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 6-53 hrs. CTD stations were taken to increase the hydrographic resolution on the transect. The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected ranged from physical observations, chemical, biological and geological data collection, and the aim was to link observations and measurements to improve our understanding of the systems involving both climate, human impacts and the ecosystems. Deployment of moorings and gliders extended the observational capacity in time and space, outside the cruise period.
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Poster no. B7 from Forum for Arctic Modeling & Observational Synthesis (Woods Hole Oceanographic Institution, 2-4 November 2016.
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Arctic sea ice is declining rapidly, simplifying access to oil and gas resources, enabling trans-Arctic shipping, and shifting the distribution of harvestable resources. This has brought the Arctic Ocean to the top of national and... more
Arctic sea ice is declining rapidly, simplifying access to oil and gas resources, enabling trans-Arctic shipping, and shifting the distribution of harvestable resources. This has brought the Arctic Ocean to the top of national and international political agendas. Alarmingly, sea-ice reductions are taking place more rapidly than predicted in any global climate model. This persistent mismatch between observed and predicted patterns makes planning and mitigation activities in the Arctic region even more complicated. Therefore, scientific knowledge of the present status of the Arctic Ocean and the process-based understanding of the mechanics of change are urgently needed to make useful predictions of future conditions throughout the Arctic region. The Arctic in Rapid Transition (ART) Initiative is an integrative, international, interdisciplinary, pan-Arctic network to study the spatial and temporal changes in sea ice cover and ocean circulation over all timescales to better understand a...
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As part of the Norwegian research project "CarbonBridge - Bridging marine productivity regimes: How Atlantic advective inflow affects productivity, carbon cycling and export in a melting Arctic Ocean" (NRC #226415, RIS #6637),... more
As part of the Norwegian research project "CarbonBridge - Bridging marine productivity regimes: How Atlantic advective inflow affects productivity, carbon cycling and export in a melting Arctic Ocean" (NRC #226415, RIS #6637), the concentration of inorganic nutrients and organic material (i.e. chlorophyll a, particulate organic matter), as well as primary and secondary production rates were determined from the upper 1000 m of the water column West and North of Spitsbergen. The flux of sinking organic material was also determined. In total three expeditions were conducted in 2014.
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Photophysiological and biochemical characteristics were investigated in natural communities of Arctic sea ice algae and phytoplankton to understand their respective responses towards variable irradiance and nutrient regimes. This study... more
Photophysiological and biochemical characteristics were investigated in natural communities of Arctic sea ice algae and phytoplankton to understand their respective responses towards variable irradiance and nutrient regimes. This study revealed large differences in photosynthetic efficiency and capacity between the 2 types of algal assemblages. Sea ice algal assemblages clearly displayed increased photoprotective energy dissipation under the highest daily average irradiance levels (>8 µmol photons m-2 s-1). In contrast, phytoplankton assemblages were generally light-limited within the same irradiance ranges. Furthermore, phytoplankton assemblages exhibited more efficient carbon assimilation rates in the low irradiance range compared to sea ice algae, possibly explaining the ability of phytoplankton to generate substantial under-ice blooms. They were also able to readily adjust and increase their carbon production to higher irradiances. The Arctic is warming more rapidly than any ...
Research Interests: Zoology, Environmental Science, Oceanography, Ecology, Algae, and 4 morePhytoplankton, Sea Ice, Arctic, and Irradiance
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In the late 1990s, both German and Norwegian scientists established time-series transects in the waters surrounding Svalbard. While Norwegian research focussed traditionally on the water column of the inner Kongsfjord to the shelf break,... more
In the late 1990s, both German and Norwegian scientists established time-series transects in the waters surrounding Svalbard. While Norwegian research focussed traditionally on the water column of the inner Kongsfjord to the shelf break, the Alfred Wegener Institute for Polar and Marine Research (AWI) concentrated on the nearby bottom communities between 1000 and 5500m water depth (HAUSGARTEN). In 2008, the Norwegian oil company StatoilHydro funded a new project called KongHau within the scope of the EU-Project HERMES. The main goal of KongHau is to connect the Kongsfjord and HAUSGARTEN bathymetric transects. In a complementary approach, researchers from the Norwegian ARCTOS network have thus begun to sample the pelagic environment at selected HAUSGARTEN stations while AWI-scientists explore the seafloor at selected Kongsfjord stations to characterise the bottom communities. Our novel approach integrates existing and new data from different compartments of the ecosystem. This enables us to adapt and apply existing models on marginal ice zone pelagic-benthic interactions in shallow waters to the HAUSGARTEN data set. It also allows us to assess Arctic pelagic and benthic ecosystem changes in relation to climate factors such as sea ice, hydrography, NAO and AO indices.
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The Arctic is undergoing rapid environmental and economic transformations. Recent climate warming, which is simplifying access to oil and gas resources, enabling trans-Arctic shipping, and shifting the distribution of harvestable... more
The Arctic is undergoing rapid environmental and economic transformations. Recent climate warming, which is simplifying access to oil and gas resources, enabling trans-Arctic shipping, and shifting the distribution of harvestable resources, has brought the ...
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... Affiliation: AA(IFM-GEOMAR, Kiel, Germany; ), AB(University of Quebec, Quebec, QC, Canada; ), AC(University of Trosmo, Tromso, Norway; ), AD(Clark University, Worcester, ME, USA; ), AE(Universtity of Alakska Fairbanks, Fairbanks, AK,... more
... Affiliation: AA(IFM-GEOMAR, Kiel, Germany; ), AB(University of Quebec, Quebec, QC, Canada; ), AC(University of Trosmo, Tromso, Norway; ), AD(Clark University, Worcester, ME, USA; ), AE(Universtity of Alakska Fairbanks, Fairbanks, AK, USA; ), AF(Fisheries and Oceans ...
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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.... more
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 flux (into surface layers <65 m) and 2) the downward flux of particulate organic carbon (POC) to ≤200 m. In the Arctic-influenced, drift ice-covered northern Barents Sea, we found a low upward nitrate flux into the surface layers (<0.1 mmol nitrate m–2 d–1) and a moderate downward POC flux (40–200 m: 150–250 mg POC m–2 d–1) during the late phase of a peak bloom. A 1-D residence time calculation indicated that the nitrate concentration in the surface layers constantly declined. In the Atlantic-influenced, ice-free, and weakly stratified southern Barents Sea a high upward nitrate flux...
Phytoplankton blooms in the Arctic Ocean's seasonal sea ice zone are expected to start earlier and occur further north with retreating and thinning sea ice cover. The current study is the first compilation of phytoplankton bloom... more
Phytoplankton blooms in the Arctic Ocean's seasonal sea ice zone are expected to start earlier and occur further north with retreating and thinning sea ice cover. The current study is the first compilation of phytoplankton bloom development and fate in the seasonally variable sea ice zone north of Svalbard from winter to late summer, using short-term sediment trap deployments. Clear seasonal patterns were discovered, with low winter and pre-bloom phytoplankton standing stocks and export fluxes, a short and intense productive season in May and June, and low Chl a standing stocks but moderate carbon export fluxes in the autumn post-bloom conditions. We observed intense phytoplankton blooms with Chl a standing stocks of >350 mg m−2 below consolidated sea ice cover, dominated by the prymnesiophyte Phaeocystis pouchetii. The largest vertical organic carbon export fluxes to 100 m, of up to 513 mg C m−2 day−1, were recorded at stations dominated by diatoms, while those dominated by ...
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The composition of sedimenting matter from the upper mixed layer was studied in relation to aggregation dynamics and food web structure in the stratified southern Gulf of Riga, Baltic Sea. Four stations were visited during three fortnight... more
The composition of sedimenting matter from the upper mixed layer was studied in relation to aggregation dynamics and food web structure in the stratified southern Gulf of Riga, Baltic Sea. Four stations were visited during three fortnight periods in spring (1995), midsummer (1994) and late summer (1993). In spring, diatoms constituted the major part of the sedimenting matter, and their
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... Vertical Xux from sea ice has mostly been studied in areas dominated by landfast ice (Michel et al. ... Grazing-impact by the ice-fauna is generally low, and ice algae may therefore be released as a pulse to the water column upon ice... more
... Vertical Xux from sea ice has mostly been studied in areas dominated by landfast ice (Michel et al. ... Grazing-impact by the ice-fauna is generally low, and ice algae may therefore be released as a pulse to the water column upon ice melt (Werner 2000; Michel et al. 2002). ...
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ABSTRACTThe Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 μm) from a depth... more
ABSTRACTThe Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 μm) from a depth of 25 m was determined using 454 sequencing of the 18S V4 region amplified from both DNA and RNA. The compositional changes throughout the year were assessed in relation toin situfjord environmental conditions. Size fractionation analyses of chlorophyllashowed that the photosynthetic biomass was dominated by small cells (<10 μm) most of the year but that larger cells dominated during the spring and summer. The winter and early-spring communities were more diverse than the spring and summer/autumn communities. Dinophyceae were predominant throughout the year. The ArcticMicromonasecotype was abundant mostly in the early-bloom and fall periods, whereas heterotrophs, such as marine stramenopiles (MASTs), Picozoa, and the parasitoid marine alveolates (...
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ABSTRACT Snow and ice control the light penetration into ice-covered Arctic waters, determining the onset of biological production after the winter. Changes in the snow and ice cover and their characteristics influence both the amount of... more
ABSTRACT Snow and ice control the light penetration into ice-covered Arctic waters, determining the onset of biological production after the winter. Changes in the snow and ice cover and their characteristics influence both the amount of light and the spectral distribution of light transmitted to the underlying water, with effects on timing, distribution, production rate and even species composition of the Arctic marine production. Light transmitted through the sea ice also provides a source of heat to the upper part of the water column, and may promote melting of the ice from the bottom. Spectral measurements of the transmitted solar flux were made at several locations in the Fram Strait-East Greenland Shelf region in April---May 2008, as part of the iAOOS-Norway project of interdisciplinary observations in the Arctic Ocean, and in September 2007 and 2008. These transmission measurements were made both immediately below ice floes, and as profiles to a depth of 80~m both beneath floes and beneath open water in leads. During the spring cruise, the corresponding biological productivity and biomass in the water column below the ice were measured. Together such data will increase our understanding of how a changing Arctic climate will influence the ecosystem and productivity. This presentation will present results from these transmission measurements, the first of their kind from this important region of sea ice export and biological and oceanographic activity, and their relationship to biological productivity, along with their implications for climate processes, including the formation and melting of sea ice.