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  • 1
    Online Resource
    Online Resource
    Sea-ice derived meltwater stratification slows the biological carbon pump: results from continuous observations
    Springer Science and Business Media LLC ; 2021
    In:  Nature Communications Vol. 12, No. 1 ( 2021-12-15)
    Details
    In: Nature Communications, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2021-12-15)
    Abstract: The ocean moderates the world’s climate through absorption of heat and carbon, but how much carbon the ocean will continue to absorb remains unknown. The North Atlantic Ocean west (Baffin Bay/Labrador Sea) and east (Fram Strait/Greenland Sea) of Greenland features the most intense absorption of anthropogenic carbon globally; the biological carbon pump (BCP) contributes substantially. As Arctic sea-ice melts, the BCP changes, impacting global climate and other critical ocean attributes (e.g. biodiversity). Full understanding requires year-round observations across a range of ice conditions. Here we present such observations: autonomously collected Eulerian continuous 24-month time-series in Fram Strait. We show that, compared to ice-unaffected conditions, sea-ice derived meltwater stratification slows the BCP by 4 months, a shift from an export to a retention system, with measurable impacts on benthic communities. This has implications for ecosystem dynamics in the future warmer Arctic where the seasonal ice zone is expected to expand.
    Type of Medium: Online Resource
    ISSN: 2041-1723
    URL: Article
    DOI: 10.1038/s41467-021-26943-z
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2553671-0
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  • 2
    Online Resource
    Online Resource
    Table_6.xlsx
    Frontiers Media SA ; 2022
    In:  Frontiers in Marine Science Vol. 9 ( 2022-12-21)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 9 ( 2022-12-21)
    Abstract: The central Arctic Ocean is rapidly changing due to amplified warming and sea ice retreat. Nonetheless, it remains challenging to document and decipher impacts on key ecosystem processes such as primary production and pelagic-benthic coupling, due to limited observations in this remote area. Here we investigated environmental changes at the Laptev Sea continental slope (60-3400 m water depth) from the surface to the seafloor, by replicating sample transects two decades apart. Mean break-up of sea ice occurred earlier and mean freeze-up occurred later in 2012 compared to 1993, extending the ice-free period by more than 30 days. On average, observations and model results showed an annual increase in primary production of 30% and more in the study area in 2012. In contrast, calculated and modelled fluxes of particulate organic carbon (POC) to the seafloor were only slightly higher in 2012 and did not extend as far into the deep Laptev Sea as the increase in primary production, possibly due to a more developed retention system. Nevertheless, benthic surveys revealed a substantial increase in phytodetritus availability at the seafloor along the entire transect from the shelf edge to the deep sea. This calls for carbon input by lateral advection from the shelves, additional input from sea ice, and/or a late summer bloom. We also investigated the composition and activity of bacterial communities at the seafloor and potential linkages to the observed environmental changes. While bacterial abundance, biomass and overall community structure showed no systematic differences between the two contrasting years at all depths, extracellular enzymatic activities had increased as a result of higher food availability. This was partly reflected in higher benthic oxygen uptake, indicating a moderate impact on benthic remineralization rates at the time of sampling. Our results show considerable effects of ocean warming and sea ice loss on the ecosystem from the surface ocean to the seafloor in the Laptev Sea, which are likely to continue in the coming decades.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    DOI: 10.3389/fmars.2022.1004959
    DOI: 10.3389/fmars.2022.1004959.s001
    DOI: 10.3389/fmars.2022.1004959.s002
    DOI: 10.3389/fmars.2022.1004959.s003
    DOI: 10.3389/fmars.2022.1004959.s004
    DOI: 10.3389/fmars.2022.1004959.s005
    DOI: 10.3389/fmars.2022.1004959.s006
    DOI: 10.3389/fmars.2022.1004959.s007
    DOI: 10.3389/fmars.2022.1004959.s008
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2757748-X
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  • 3
    Online Resource
    Online Resource
    Variations of microbial communities and substrate regimes in the eastern Fram Strait between summer and fall
    Wiley ; 2022
    In:  Environmental Microbiology Vol. 24, No. 9 ( 2022-09), p. 4124-4136
    Details
    In: Environmental Microbiology, Wiley, Vol. 24, No. 9 ( 2022-09), p. 4124-4136
    Abstract: Seasonal variations in day length and temperature, in combination with dynamic factors such as advection from the North Atlantic, influence primary production and the microbial loop in the Fram Strait. Here, we investigated the seasonal variability of biopolymers, microbial abundance and microbial composition within the upper 100 m during summer and fall. Flow cytometry revealed a shift in the autotrophic community from picoeukaryotes dominating in summer to a 34‐fold increase of Synechococcus by fall. Furthermore, a significant decline in biopolymers concentrations covaried with increasing microbial diversity based on 16S rRNA gene sequencing along with a community shift towards fewer polymer‐degrading genera in fall. The seasonal succession in the biopolymer pool and microbes indicates distinct metabolic regimes, with a higher relative abundance of polysaccharide‐degrading genera in summer and a higher relative abundance of common taxa in fall. The parallel analysis of DOM and microbial diversity provides an important baseline for microbe–substrate relationships over the seasonal cycle in the Arctic Ocean.
    Type of Medium: Online Resource
    ISSN: 1462-2912 , 1462-2920
    URL: Issue
    URL: Article
    DOI: 10.1111/emi.v24.9
    DOI: 10.1111/1462-2920.16036
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2020213-1
    SSG: 12
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  • 4
    Online Resource
    Online Resource
    DataSheet_1.docx
    Frontiers Media SA ; 2023
    In:  Frontiers in Marine Science Vol. 10 ( 2023-7-11)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 10 ( 2023-7-11)
    Abstract: Marine sinking particles sequester atmospheric carbon dioxide to the deep ocean via the biological carbon pump. Understanding how environmental shifts drive changes in the microbial composition of particles, and how these affect the export of organic matter from the surface to the deep ocean, is critical, especially in the rapidly changing Arctic Ocean. Here, we applied next generation sequencing of the 18S and 16S rRNA genes to sediment trap samples from around 200 m water depth in the eastern Fram Strait, covering a time frame of more than one decade (2000-2012). The aim was to characterize their microbial composition during annual highest particulate organic carbon flux events. The bimodal annual spring and summer export fluxes were representative of the strong seasonality in the region. Furthermore, the study period was characterized by considerable interannual variation, marked especially by a warm water anomaly between 2005 and 2007. During this period changes in the hydrography and sea ice cover also led to measurable changes in the microbial composition of particles. The warm water period was marked by a decrease in diatoms affiliated with Chaetoceros , an increase of small phytoplankton and an increase in sequence abundance of the bacterial taxa Oceanospirillales , Alteromonadales and Rhodobacterales on the particles. The resulting changes in microbial composition and the associated microbial network structure suggest the emergence of a more developed retention system in the surface ocean. Our results provide the first long-term assessment of the microbial composition of sinking particles in the Arctic Ocean, and stress the importance of sea ice and hydrography for particle composition and subsequent flux of organic matter to deeper waters.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    URL: Article
    DOI: 10.3389/fmars.2023.1173384
    DOI: 10.3389/fmars.2023.1173384.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2023
    detail.hit.zdb_id: 2757748-X
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  • 5
    Online Resource
    Online Resource
    Sea ice presence is linked to higher carbon export and vertical microbial connectivity in the Eurasian Arctic Ocean
    Springer Science and Business Media LLC ; 2021
    In:  Communications Biology Vol. 4, No. 1 ( 2021-11-03)
    Details
    In: Communications Biology, Springer Science and Business Media LLC, Vol. 4, No. 1 ( 2021-11-03)
    Abstract: Arctic Ocean sea ice cover is shrinking due to warming. Long-term sediment trap data shows higher export efficiency of particulate organic carbon in regions with seasonal sea ice compared to regions without sea ice. To investigate this sea-ice enhanced export, we compared how different early summer phytoplankton communities in seasonally ice-free and ice-covered regions of the Fram Strait affect carbon export and vertical dispersal of microbes. In situ collected aggregates revealed two-fold higher carbon export of diatom-rich aggregates in ice-covered regions, compared to Phaeocystis aggregates in the ice-free region. Using microbial source tracking, we found that ice-covered regions were also associated with more surface-born microbial clades exported to the deep sea. Taken together, our results showed that ice-covered regions are responsible for high export efficiency and provide strong vertical microbial connectivity. Therefore, continuous sea-ice loss may decrease the vertical export efficiency, and thus the pelagic-benthic coupling, with potential repercussions for Arctic deep-sea ecosystems.
    Type of Medium: Online Resource
    ISSN: 2399-3642
    URL: Article
    DOI: 10.1038/s42003-021-02776-w
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2919698-X
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