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  • 1
    Online Resource
    Online Resource
    Data_Sheet_1.pdf
    Frontiers Media SA ; 2021
    In:  Frontiers in Marine Science Vol. 8 ( 2021-10-15)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 8 ( 2021-10-15)
    Abstract: The marine dinoflagellate genus Prorocentrum Ehrenberg comprises many species occupying primarily benthic or epiphytic habitats, particularly in tropical and sub-tropical waters. Despite concerted efforts to establish phylogenetic associations, there remain unresolved issues in defining morphospecies and membership in species complexes. The study described herein addressed the inter- and infraspecific relationships of members of the Prorocentrum lima and Prorocentrum hoffmannianum species complexes (PLSC and PHSC, respectively) by applying multivariate approaches in morphotaxonomy, molecular phylogenetics and chemodiversity to establish affinities among multiple clonal isolates. Morphotaxonomic analysis showed consistency with classical morphospecies descriptors, and high variability in cell size and dimensions, but did not challenge current species complex concepts. Phylogenetic analysis of ITS/5.8S rDNA sequences from isolates from the Gulf of California, Caribbean Sea, and Gulf of Mexico coasts compared with archived global GenBank sequences served to define five consistent clades with separation of the PLSC and PHSC. Secondary structure modeling of ITS2 rRNA variation based on compensatory base changes (CBC) was effective in resolving details of the respective species complexes and even indicated putative incipient or cryptic speciation due to potential hybridization barriers. This study represents the largest ( n = 67 isolates) chemodiversity analysis of polyketide-derived toxins associated with diarrheic shellfish poisoning (DSP) from a benthic dinoflagellate genus. Relative composition of some analogs (OA, OA-D8, DTX1, DTX1a, and DTX1a-D8), including two new undescribed isomers, distinguished P. lima from P. hoffmannianum sensu lato , but without clear associations with substrate type or geographical origin. Although all P. lima and most (one exception) P. hoffmannianum were toxigenic, the total cell toxin content could not be linked at the species level. This research demonstrates that clonal chemodiversity in toxin composition cannot yet be effectively applied to define ecological niches or species interactions within local assemblages. Phylogenetic analysis of the ITS/5.8 rDNA, particularly when combined with secondary structure modeling, rather than only a comparison of LSU rDNA sequences, is a more powerful approach to identify cryptic speciation and to resolve species complexes within benthic dinoflagellate groups.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    URL: Article
    DOI: 10.3389/fmars.2021.716669
    DOI: 10.3389/fmars.2021.716669.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 2
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    Online Resource
    High-resolution physical–biogeochemical structure of a filament and an eddy of upwelled water off northwest Africa
    Copernicus GmbH ; 2020
    In:  Ocean Science Vol. 16, No. 1 ( 2020-02-28), p. 253-270
    Details
    In: Ocean Science, Copernicus GmbH, Vol. 16, No. 1 ( 2020-02-28), p. 253-270
    Abstract: Abstract. Nutrient-rich water upwells offshore of northwest Africa and is subsequently advected westwards. There it forms eddies and filaments with a rich spatial structure of physical and biological/biogeochemical properties. Here we present a high-resolution (2.5 km) section through upwelling filaments and an eddy obtained in May 2018 with a TRIAXUS towed vehicle equipped with various oceanographic sensors. Physical processes at the mesoscale and submesoscale such as symmetric instability, trapping of fluid in eddies, and subduction of low potential vorticity (which we use as a water mass tracer) water can explain the observed distribution of biological production and export. We found a nitrate excess (higher concentrations of nitrate than expected from oxygen values if only influenced by production and remineralization processes) core of an anticyclonic mode water eddy. We also found a high nitrate concentration region of ≈5 km width in the mixed layer where symmetric instability appears to have injected nutrients from below into the euphotic zone. Similarly, further south high chlorophyll-a concentrations suggest that nutrients had been injected there a few days earlier. Considering that such interactions of physics and biology are ubiquitous in the upwelling regions of the world, we assume that they strongly influence the productivity of such systems and their role in CO2 uptake. The intricate interplay of different parameters at the kilometer scale needs to be taken into account when interpreting single-profile and/or bottle data in dynamically active regions of the ocean.
    Type of Medium: Online Resource
    ISSN: 1812-0792
    URL: Article
    URL: Article
    DOI: 10.5194/os-16-253-2020
    DOI: 10.5194/os-16-253-2020-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2183769-7
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  • 3
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    Global oceanic diazotroph database version 2 and elevated estimate of global oceanic N 2 fixation
    Copernicus GmbH ; 2023
    In:  Earth System Science Data Vol. 15, No. 8 ( 2023-08-15), p. 3673-3709
    Details
    In: Earth System Science Data, Copernicus GmbH, Vol. 15, No. 8 ( 2023-08-15), p. 3673-3709
    Abstract: Abstract. Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, the first version of the global oceanic diazotroph database (version 1) was published. Here, we present an updated version of the database (version 2), significantly increasing the number of in situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, diazotrophic cell abundance, and nifH gene copy abundance have increased by 184 %, 86 %, and 809 %, respectively. Version 2 includes two new data sheets for the nifH gene copy abundance of non-cyanobacterial diazotrophs and cell-specific N2 fixation rates. The measurements of N2 fixation rates approximately follow a log-normal distribution in both version 1 and version 2. However, version 2 considerably extends both the left and right tails of the distribution. Consequently, when estimating global oceanic N2 fixation rates using the geometric means of different ocean basins, version 1 and version 2 yield similar rates (43–57 versus 45–63 Tg N yr−1; ranges based on one geometric standard error). In contrast, when using arithmetic means, version 2 suggests a significantly higher rate of 223±30 Tg N yr−1 (mean ± standard error; same hereafter) compared to version 1 (74±7 Tg N yr−1). Specifically, substantial rate increases are estimated for the South Pacific Ocean (88±23 versus 20±2 Tg N yr−1), primarily driven by measurements in the southwestern subtropics, and for the North Atlantic Ocean (40±9 versus 10±2 Tg N yr−1). Moreover, version 2 estimates the N2 fixation rate in the Indian Ocean to be 35±14 Tg N yr−1, which could not be estimated using version 1 due to limited data availability. Furthermore, a comparison of N2 fixation rates obtained through different measurement methods at the same months, locations, and depths reveals that the conventional 15N2 bubble method yields lower rates in 69 % cases compared to the new 15N2 dissolution method. This updated version of the database can facilitate future studies in marine ecology and biogeochemistry. The database is stored at the Figshare repository (https://doi.org/10.6084/m9.figshare.21677687; Shao et al., 2022).
    Type of Medium: Online Resource
    ISSN: 1866-3516
    URL: Article
    URL: Article
    DOI: 10.5194/essd-15-3673-2023
    DOI: 10.5194/essd-15-3673-2023-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2023
    detail.hit.zdb_id: 2475469-9
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  • 4
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    Diversity and biogeography of planktonic diatoms in Svalbard fjords: The role of dispersal and Arctic endemism in phytoplankton community structuring
    University of California Press ; 2022
    In:  Elementa: Science of the Anthropocene Vol. 10, No. 1 ( 2022-08-09)
    Details
    In: Elementa: Science of the Anthropocene, University of California Press, Vol. 10, No. 1 ( 2022-08-09)
    Abstract: Understanding the processes that shape the community structure of Arctic phytoplankton is crucial for predicting responses of Arctic ecosystems to the ongoing ocean warming. In particular, little is known about the importance of phytoplankton dispersal by the North Atlantic Current and the prevalence and maintenance of Arctic endemism. We investigated the diversity and biogeography of diatoms from five Svalbard fjords and the Hausgarten observatory (Fram Strait) by combining diatom cultivation and 18S rRNA gene metabarcoding. In total, 50 diatom strains were isolated from the area during the HE492 cruise in August 2017. The strains were identified taxonomically using molecular and morphological approaches, and their biogeographic distribution was mapped using the local metabarcoding dataset and a global compilation of published metabarcoding datasets. Biogeographic analysis was also conducted for the locally most abundant diatom metabarcoding amplicon sequence variants. The biogeographic analyses demonstrated that Arctic diatoms exhibit three general biogeographic distribution types: Arctic, Arctic-temperate, and cosmopolitan. At Hausgarten and in outer Isfjorden on the west coast of Svalbard, the communities were dominated by genotypes with Arctic-temperate and cosmopolitan distribution. Diatom communities in nearby Van Mijenfjorden, inner Isfjorden and Kongsfjorden were dominated by genotypes with Arctic-temperate distribution, and cosmopolitan species were less abundant. The genotypes endemic to the Arctic had lower abundance on the west coast of Svalbard. The two northernmost fjords (Woodfjorden and Wijdefjorden) had a higher abundance of genotypes endemic to the Arctic. Our results demonstrate that the diatom communities in the Svalbard area consist of genotypes endemic to the Arctic, and genotypes with broader biogeographic distribution, all of which are further structured by local environmental gradients. Finer biogeographic patterns observed within Arctic-temperate and cosmopolitan genotypes suggest that certain genotypes can be used as indicators of increasing influence of Atlantic waters on the phytoplankton community structure in the Svalbard area.
    Type of Medium: Online Resource
    ISSN: 2325-1026
    URL: Article
    DOI: 10.1525/elementa.2021.00117
    Language: English
    Publisher: University of California Press
    Publication Date: 2022
    detail.hit.zdb_id: 2745461-7
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  • 5
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    Online Resource
    Concepts towards Functional Eukaryotic Microbial Biogeography in the Ocean
    MDPI AG ; 2022
    In:  Journal of Marine Science and Engineering Vol. 10, No. 11 ( 2022-11-11), p. 1730-
    Details
    In: Journal of Marine Science and Engineering, MDPI AG, Vol. 10, No. 11 ( 2022-11-11), p. 1730-
    Abstract: High-throughput sequencing technologies have revolutionized microbial diversity studies, shedding light on the oceans’ plankton evolution, distribution, and biological activity. Whereas marine prokaryotes have been more extensively studied and specific methods developed, the research on microbial eukaryotes (protists) is falling behind, with major groups still largely unknown regarding their ecology and function. Because of numerous anthropogenic pressures, it is increasingly important to highlight the functional roles of protists in marine ecosystems. This review outlines the practices, challenges, and opportunities of high-throughput sequencing approaches (i.e., metabarcoding, metagenomics, and metatranscriptomics) to disentangle evolutionary, ecological, and functional aspects of protists in the ocean. These multidimensional approaches allow us to move from the classic picture of microbial biogeography towards functional microbial biogeography, explicitly highlighting the role of protists therein. We provide resources for functional classification and reflect on the current and future potential. We outline aspects of detecting and describing ecosystem changes at the species, population, and community levels, advancing methodological approaches for studying taxonomic diversity towards functional and evolutionary biodiversity concepts, seeking a more complete understanding and monitoring of ocean ecosystems.
    Type of Medium: Online Resource
    ISSN: 2077-1312
    URL: Article
    DOI: 10.3390/jmse10111730
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2738390-8
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  • 6
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    Microbial diversity through an oceanographic lens: refining the concept of ocean provinces through trophic‐level analysis and productivity‐specific length scales
    Wiley ; 2022
    In:  Environmental Microbiology Vol. 24, No. 1 ( 2022-01), p. 404-419
    Details
    In: Environmental Microbiology, Wiley, Vol. 24, No. 1 ( 2022-01), p. 404-419
    Abstract: In the marine realm, microorganisms are responsible for the bulk of primary production, thereby sustaining marine life across all trophic levels. Longhurst provinces have distinct microbial fingerprints; however, little is known about how microbial diversity and primary productivity change at finer spatial scales. Here, we sampled the Atlantic Ocean from south to north (~50°S–50°N), every ~0.5° latitude. We conducted measurements of primary productivity, chlorophyll‐ a and relative abundance of 16S and 18S rRNA genes, alongside analyses of the physicochemical and hydrographic environment. We analysed the diversity of autotrophs, mixotrophs and heterotrophs, and noted distinct patterns among these guilds across provinces with high and low chlorophyll‐ a conditions. Eukaryotic autotrophs and prokaryotic heterotrophs showed a shared inter‐province diversity pattern, distinct from the diversity pattern shared by mixotrophs, cyanobacteria and eukaryotic heterotrophs. Additionally, we calculated samplewise productivity‐specific length scales, the potential horizontal displacement of microbial communities by surface currents to an intrinsic biological rate (here, specific primary productivity). This scale provides key context for our trophically disaggregated diversity analysis that we could relate to underlying oceanographic features. We integrate this element to provide more nuanced insights into the mosaic‐like nature of microbial provincialism, linking diversity patterns to oceanographic transport through primary production.
    Type of Medium: Online Resource
    ISSN: 1462-2912 , 1462-2920
    URL: Issue
    URL: Article
    DOI: 10.1111/emi.v24.1
    DOI: 10.1111/1462-2920.15832
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2020213-1
    SSG: 12
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  • 7
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    Perspectives on Documenting Methods to Create Ocean Best Practices
    Frontiers Media SA ; 2021
    In:  Frontiers in Marine Science Vol. 7 ( 2021-1-21)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 7 ( 2021-1-21)
    Abstract: This perspective outlines how authors of ocean methods, guides, and standards can harmonize their work across the scientific community. We reflect on how documentation practices can be linked to modern information technologies to improve discoverability, interlinkages, and thus the evolution of distributed methods into common best practices within the ocean community. To show how our perspectives can be turned into action, we link them to guidance on using the IOC-UNESCO Ocean Best Practice System to support increased collaboration and reproducibility during and beyond the UN Decade of Ocean Sciences for Sustainable Development.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    DOI: 10.3389/fmars.2020.556234
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 8
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    Diazotrophy in the Indian Ocean: Current understanding and future perspectives
    Wiley ; 2023
    In:  Limnology and Oceanography Letters Vol. 8, No. 5 ( 2023-10), p. 707-722
    Details
    In: Limnology and Oceanography Letters, Wiley, Vol. 8, No. 5 ( 2023-10), p. 707-722
    Abstract: Dinitrogen (N 2 ) fixation provides the major source of reactive nitrogen in the open ocean, sustaining biological productivity. The Indian Ocean (IO) covers 22% of the ocean surface, while it only represents 1% of the global diazotroph database. Hence, constraining the sources of nitrogen in the IO is crucial. Here, we compile three decades of N 2 fixation and diazotroph DNA data in the IO. Our analysis reveals basin‐scale yearly rates between ~ 7 and 13 Tg N yr −1 . These rates are in the range of previous modeling‐based estimates but may represent a lower bound estimate due to the lack of data in this basin. Diazotroph variability among sub‐basins may suggest endemicity but needs to be taken with caution due to biased sampling toward certain seasons and uneven spatial coverage. We provide recommendations for a more accurate representation of the IO in the global nitrogen budget and our knowledge of diazotroph biogeography.
    Type of Medium: Online Resource
    ISSN: 2378-2242 , 2378-2242
    URL: Issue
    URL: Article
    DOI: 10.1002/lol2.v8.5
    DOI: 10.1002/lol2.10343
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2876718-4
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  • 9
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    Online Resource
    Publisher Correction: Carbon dioxide sink in the Arctic Ocean from cross-shelf transport of dense Barents Sea water
    Springer Science and Business Media LLC ; 2023
    In:  Nature Geoscience Vol. 16, No. 2 ( 2023-02), p. 189-189
    Details
    In: Nature Geoscience, Springer Science and Business Media LLC, Vol. 16, No. 2 ( 2023-02), p. 189-189
    Type of Medium: Online Resource
    ISSN: 1752-0894 , 1752-0908
    URL: Article
    DOI: 10.1038/s41561-022-01109-8
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2396648-8
    detail.hit.zdb_id: 2405323-5
    SSG: 16,13
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  • 10
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    Carbon dioxide sink in the Arctic Ocean from cross-shelf transport of dense Barents Sea water
    Springer Science and Business Media LLC ; 2023
    In:  Nature Geoscience Vol. 16, No. 1 ( 2023-01), p. 82-88
    Details
    In: Nature Geoscience, Springer Science and Business Media LLC, Vol. 16, No. 1 ( 2023-01), p. 82-88
    Abstract: Large amounts of atmospheric carbon can be exported and retained in the deep sea on millennial time scales, buffering global warming. However, while the Barents Sea is one of the most biologically productive areas of the Arctic Ocean, carbon retention times were thought to be short. Here we present observations, complemented by numerical model simulations, that revealed a deep and widespread lateral injection of approximately 2.33 kt C d −1 from the Barents Sea shelf to some 1,200 m of the Nansen Basin, driven by Barents Sea Bottom Water transport. With increasing distance from the outflow region, the plume expanded and penetrated into even deeper waters and the sediment. The seasonally fluctuating but continuous injection increases the carbon sequestration of the Barents Sea by 1/3 and feeds the deep sea community of the Nansen Basin. Our findings combined with those from other outflow regions of carbon-rich polar dense waters highlight the importance of lateral injection as a global carbon sink. Resolving uncertainties around negative feedbacks of global warming due to sea ice decline will necessitate observation of changes in bottom water formation and biological productivity at a resolution high enough to quantify future deep carbon injection.
    Type of Medium: Online Resource
    ISSN: 1752-0894 , 1752-0908
    URL: Article
    DOI: 10.1038/s41561-022-01069-z
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2396648-8
    detail.hit.zdb_id: 2405323-5
    SSG: 16,13
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