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  • 1
    Online Resource
    Online Resource
    Seasonal modification of the Arctic Ocean intermediate water layer off the eastern Laptev Sea continental shelf break (2009)
    Associated volumes
    Details Availability
    In: Journal of geophysical research. C, Oceans, Hoboken, NJ : Wiley, 1978, 114(2009), 6, 2169-9291
    In: volume:114
    In: year:2009
    In: number:6
    In: extent:19
    Description / Table of Contents: Through the analysis of observational mooring data collected at the northeastern Laptev Sea continental slope in 2004-2007, we document a hydrographic seasonal signal in the intermediate Atlantic Water (AW) layer, with generally higher temperature and salinity from December-January to May-July and lower values from May-July to December-January. At the mooring position, this seasonal signal dominates, contributing up to 75% of the total variance. Our data suggest that the entire AW layer down to at least 840 m is affected by seasonal cycling, although the strength of the seasonal signal in temperature and salinity reduces from 260 m (±0.25ʿC and ±0.025 psu) to 840 m (±0.05ʿC and ±0.005 psu). The seasonal velocity signal is substantially weaker, strongly masked by high-frequency variability, and lags the thermohaline cycle by 45-75 days. We hypothesize that our mooring record shows a time history of the along-margin propagation of the AW seasonal signal carried downstream by the AW boundary current. Our analysis suggests that the seasonal signal in the Fram Strait Branch of AW (FSBW) at 260 m is predominantly translated from Fram Strait, while the seasonality in the Barents Sea branch of AW (BSBW) domain (at 840 m) is attributed instead to the seasonal signal input from the Barents Sea. However, the characteristic signature of the BSBW seasonal dynamics observed through the entire AW layer leads us to speculate that BSBW also plays a role in seasonally modifying the properties of the FSBW.
    Type of Medium: Online Resource
    Pages: 19 , graph. Darst
    ISSN: 2169-9291
    URL: http://onlinelibrary.wiley.com/enhanced/doi/10.1029/2008JC005229/
    DOI: 10.1029/2008JC005229
    Language: English
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  • 2
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    Natural variability or anthropogenically-induced variation? Insights from 15 years of multidisciplinary observations at the arctic marine LTER site HAUSGARTEN (2016)
    Elsevier
    In:  Ecological Indicators, 65 . pp. 89-102.
    Details
    Publication Date: 2019-02-01
    Description: Time-series studies of arctic marine ecosystems are rare. This is not surprising since polar regions are largely only accessible by means of expensive modern infrastructure and instrumentation. In 1999, the Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research (AWI) established the LTER (Long-Term Ecological Research) observatory HAUSGARTEN crossing the Fram Strait at about 79° N. Multidisciplinary investigations covering all parts of the open-ocean ecosystem are carried out at a total of 21 permanent sampling sites in water depths ranging between 250 and 5500 m. From the outset, repeated sampling in the water column and at the deep seafloor during regular expeditions in summer months was complemented by continuous year-round sampling and sensing using autonomous instruments in anchored devices (i.e., moorings and free-falling systems). The central HAUSGARTEN station at 2500 m water depth in the eastern Fram Strait serves as an experimental area for unique biological in situ experiments at the seafloor, simulating various scenarios in changing environmental settings. Long-term ecological research at the HAUSGARTEN observatory revealed a number of interesting temporal trends in numerous biological variables from the pelagic system to the deep seafloor. Contrary to common intuition, the entire ecosystem responded exceptionally fast to environmental changes in the upper water column. Major variations were associated with a Warm-Water-Anomaly evident in surface waters in eastern parts of the Fram Strait between 2005 and 2008. However, even after 15 years of intense time-series work at HAUSGARTEN, we cannot yet predict with complete certainty whether these trends indicate lasting alterations due to anthropologically-induced global environmental changes of the system, or whether they reflect natural variability on multiyear time-scales, for example, in relation to decadal oscillatory atmospheric processes.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.ecolind.2015.10.001
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Summertime plankton ecology in Fram Strait - a compilation of long- and short-term observations (2015)
    Norwegian Polar Institute
    In:  Polar Research, 34 (23349).
    Details
    Publication Date: 2019-07-10
    Description: Between Greenland and Spitsbergen, Fram Strait is a region where cold ice-covered Polar Water exits the Arctic Ocean with the East Greenland Current (EGC) and warm Atlantic Water enters the Arctic Ocean with the West Spitsbergen Current (WSC). In this compilation, we present two different data sets from plankton ecological observations in Fram Strait: (1) long-term measurements of satellite-derived (1998–2012) and in situ chlorophyll a (chl a) measurements (mainly summer cruises, 1991–2012) plus protist compositions (a station in WSC, eight summer cruises, 1998–2011); and (2) short-term measurements of a multidisciplinary approach that includes traditional plankton investigations, remote sensing, zooplankton, microbiological and molecular studies, and biogeochemical analyses carried out during two expeditions in June/July in the years 2010 and 2011. Both summer satellite-derived and in situ chl a concentrations showed slight trends towards higher values in the WSC since 1998 and 1991, respectively. In contrast, no trends were visible in the EGC. The protist composition in the WSC showed differences for the summer months: a dominance of diatoms was replaced by a dominance of Phaeocystis pouchetii and other small pico- and nanoplankton species. The observed differences in eastern Fram Strait were partially due to a warm anomaly in the WSC. Although changes associated with warmer water temperatures were observed, further long-term investigations are needed to distinguish between natural variability and climate change in Fram Strait. Results of two summer studies in 2010 and 2011 revealed the variability in plankton ecology in Fram Strait.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3402/polar.v34.23349
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Long-term zooplankton swimmer sampling with sediment traps in northeastern Fram Strait in times of global change (2016)
    In:  [Poster] In: ICES/PICES 6. Zooplankton Production Symposium "New Challenges in a Changing Ocean", 09.-13.05.2016, Bergen, Norway .
    Details
    Publication Date: 2020-11-02
    Description: The by-collection of zooplankton swimmers in time-series sediment traps offers a unique insight into year-round and inter-annual trends in zooplankton population dynamics. These samples are especially valuable in remote and difficult to access areas such as the Arctic, where samples from the ice-covered winter season are rare. In the present study we investigate the year-round swimmer composition of sediment trap samples collected at water depths of 200-300 m over a period of 12 years (2000-2012) at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN located in the northeastern Fram Strait (79? N, 4? E). Here we describe seasonal and inter-annual appearances within the dominant zooplankton groups including amphipods, chaetognaths, copepods, ostracods and pteropods. Amphipods and copepods made up the largest amount of the swimmer fraction. Although the seasonal occurrence of these groups was relatively consistent between years there were notable inter-annual variations in abundance that suggested the influence of different environmental conditions. In addition to these general patterns, specific changes were also detected. Notably, concerning pelagic amphipods, the occurrence of a southern invader Themisto compressa could be observed from 2004 onwards. Concurrent to this observation a reversal in dominance of the arctic pteropod species Limacina helicina towards the subarctic-boreal L. retroversa was noticed. In addition to a long-term trend in warming in eastern Fram Strait since 1997, a warm anomaly event was also observed during late 2004 to 2007. Whether these trends indicate lasting alterations due to global environmental change, or simply reflect natural variability on multiyear time-scales is presently unclear.
    Type: Conference or Workshop Item , NonPeerReviewed
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    OceanRep: Poster
  • 5
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    Seasonal modification of the Arctic Ocean intermediate water layer off the eastern Laptev Sea continental shelf break (2009)
    AGU (American Geophysical Union)
    In:  Journal of Geophysical Research: Oceans, 114 (C6). C06010.
    Details
    Publication Date: 2019-09-23
    Description: Through the analysis of observational mooring data collected at the northeastern Laptev Sea continental slope in 2004–2007, we document a hydrographic seasonal signal in the intermediate Atlantic Water (AW) layer, with generally higher temperature and salinity from December–January to May–July and lower values from May–July to December–January. At the mooring position, this seasonal signal dominates, contributing up to 75% of the total variance. Our data suggest that the entire AW layer down to at least 840 m is affected by seasonal cycling, although the strength of the seasonal signal in temperature and salinity reduces from 260 m (±0.25°C and ±0.025 psu) to 840 m (±0.05°C and ±0.005 psu). The seasonal velocity signal is substantially weaker, strongly masked by high-frequency variability, and lags the thermohaline cycle by 45–75 days. We hypothesize that our mooring record shows a time history of the along-margin propagation of the AW seasonal signal carried downstream by the AW boundary current. Our analysis suggests that the seasonal signal in the Fram Strait Branch of AW (FSBW) at 260 m is predominantly translated from Fram Strait, while the seasonality in the Barents Sea branch of AW (BSBW) domain (at 840 m) is attributed instead to the seasonal signal input from the Barents Sea. However, the characteristic signature of the BSBW seasonal dynamics observed through the entire AW layer leads us to speculate that BSBW also plays a role in seasonally modifying the properties of the FSBW.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Format: text
    DOI: 10.1029/2008JC005229
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Carbon, silicon, carbonate, seston, and biogenic and lithogenic export fluxes from sediment traps deployed in the Eurasian Arctic Ocean (2020)
    PANGAEA
    Details
    Publication Date: 2023-03-16
    Keywords: AWI_BioOce; Biogenic, flux; Biological Oceanography @ AWI; Calcium carbonate, flux; Carbon, organic, particulate, flux; DATE/TIME; DEPTH, water; Duration, number of days; Elevation of event; Event label; FRAM; FRontiers in Arctic marine Monitoring; Gakkel_A1-1; Gakkel_N1-1; Latitude of event; Lithogenic, flux; Longitude of event; MOOR; Mooring; PS78/255-1; PS78/262-3; Seston, flux; Silicon, dissolved + particulate, flux
    Type: Dataset
    Format: text/tab-separated-values, 518 data points
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    DATA PANGAEA
  • 7
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    Chlorophyll a measured on water bottle samples during POLARSTERN cruise ARK-XXVII/3 (2015)
    PANGAEA
    Details
    Publication Date: 2023-03-16
    Keywords: Arctic Ocean; ARK-XXVII/3; AWI_BioOce; Biological Oceanography @ AWI; Chlorophyll a; CTD/Rosette; CTD-RO; Date/Time of event; DEPTH, water; Elevation of event; Event label; Expendable CTD; incl. ice station; Laptev Sea; Latitude of event; Longitude of event; Polarstern; PS80/201-1; PS80/209-1; PS80/213-1; PS80/215-1; PS80/218-1; PS80/220-1; PS80/230-1; PS80/234-1; PS80/235-1; PS80/238-1; PS80/244-1; PS80/250-1; PS80/256-1; PS80/263-1; PS80/269-1; PS80/271-1; PS80/275-1; PS80/284-1; PS80/287-1; PS80/289-1; PS80/294-1; PS80/295-1; PS80/297-1; PS80/298-1; PS80/311-1; PS80/314-1; PS80/316-1; PS80/317-1; PS80/319-1; PS80/329-1; PS80/333-2; PS80/336-1; PS80/341-1; PS80/357-1; PS80/370-1; PS80/372-1; PS80/377-1; PS80/380-1; PS80/383-1; PS80/396-1; PS80/XCTD30-1; PS80 IceArc; XCTD
    Type: Dataset
    Format: text/tab-separated-values, 235 data points
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    DATA PANGAEA
  • 8
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    Flux of organisms at AWI HAUSGARTEN from mooring Fevi16 (2016)
    PANGAEA
    Details
    Publication Date: 2023-03-25
    Keywords: Appendicularia, fecal pellet carbon, flux; Appendicularia, fecal pellet volume; ARK-XXII/1c; Coccolithophoridae cell, flux; Copepoda, fecal pellet carbon, flux; Copepoda, fecal pellet volume; DATE/TIME; DEPTH, water; Diatoms, empty, valve, flux; Diatoms, full, valve, flux; Diatoms, total, valve, flux; Duration, number of days; Fecal pellet carbon, flux; FEVI16; Flagellates, flux; Mooring (long time); MOORY; North Greenland Sea; Polarstern; PS70; PS70/218-1, HGIV; Sample code/label
    Type: Dataset
    Format: text/tab-separated-values, 570 data points
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    DATA PANGAEA
  • 9
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    Flux of organisms at AWI HAUSGARTEN from mooring Lander-2007 (2016)
    PANGAEA
    Details
    Publication Date: 2023-03-25
    Keywords: Appendicularia, fecal pellet carbon, flux; Appendicularia, fecal pellet volume; ARK-XXII/1c; Coccolithophoridae cell, flux; Copepoda, fecal pellet carbon, flux; Copepoda, fecal pellet volume; DATE/TIME; DEPTH, water; Diatoms, empty, valve, flux; Diatoms, full, valve, flux; Diatoms, total, valve, flux; Duration, number of days; Fecal pellet carbon, flux; Lander-2007; Mooring (long time); MOORY; North Greenland Sea; Polarstern; PS70; PS70/223-1; Sample code/label
    Type: Dataset
    Format: text/tab-separated-values, 116 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 10
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    Flux of biomarkers and organisms at AWI HAUSGARTEN from two moorings (2016)
    PANGAEA
    In:  Supplement to: Lalande, Catherine; Nöthig, Eva-Maria; Bauerfeind, Eduard; Hardge, Kristin; Beszczynska-Möller, Agnieszka; Fahl, Kirsten (2016): Lateral supply and downward export of particulate matter from upper waters to the seafloor in the deep eastern Fram Strait. Deep Sea Research Part I: Oceanographic Research Papers, 114, 78-89, https://doi.org/10.1016/j.dsr.2016.04.014
    Details
    Publication Date: 2023-01-13
    Description: Time-series sediment traps were deployed at 4 depths in the eastern Fram Strait from July 2007 to June 2008 to investigate variations in the magnitude and composition of the sinking particulate matter from upper waters to the seafloor. Sediment traps were deployed at 196 m in the Atlantic Water layer, at 1296 and 2364 m in the intermediate and deep waters, and at 2430 m on a benthic lander in the near-bottom layer. Fluxes of total particulate matter, particulate organic carbon, particulate organic nitrogen, biogenic matter, lithogenic matter, biogenic particulate silica, calcium carbonate, dominant phytoplankton cells, and zooplankton fecal pellets increased with depth, indicating the importance of lateral advection on fluxes in the deep Fram Strait. The lateral supply of particulate matter was further supported by the constant fluxes of biomarkers such as brassicasterol, alkenones, campesterol, beta-sitosterol, and IP25 at all depths sampled. However, enhanced fluxes of diatoms and appendicularian fecal pellets from the upper waters to the seafloor in the presence of ice during spring indicated the rapid export (15-35 days) of locally-produced large particles that likely contributed most of the food supply to the benthic communities. These results show that lateral supply and downward fluxes are both important processes influencing the transport of particulate matter to the seafloor in the deep eastern Fram Strait, and that particulate matter size dictates the prevailing sinking process.
    Type: Dataset
    Format: application/zip, 4 datasets
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    DATA PANGAEA
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