Details of Nutrient data collected during the iMAR 2021/Eurofleets+ research cruise in Mid Atlantic Ridge (Azores EEZ)


Dataset identification

Title of datasetNutrient data collected during the iMAR 2021/Eurofleets+ research cruise in Mid Atlantic Ridge (Azores EEZ)
Narrative summary of datasetThis dataset was produced during the iMAR cruise “The Integrated assessment of the distribution of Vulnerable Marine Ecosystem along the Mid-Atlantic Ridge (MAR) in the Azores region”, that took place aboard the Research Vessel Pelagia of the Royal Netherlands Institute for Sea Research between May 18th  and June 2nd 2021. The iMAR cruise aimed to evaluate the role of the MAR in shaping latitudinal and trans-Atlantic patterns in deep-sea biogeography, connectivity and assemblages of deep-sea megafauna. This expedition was funded by the SEA OCEANS program of Eurofleets+ and the H2020 European project iAtlantic, and was led by the University of the Azores (Portugal) in collaboration with the Hydrographic Institute and University of Porto (Portugal), the University of Aarhus (Denmark), the National Oceanography Center (United Kingdom), GEOMAR (Germany), the University Museum of Bergen (Norway), the PP Shirshov Institute of Oceanology (Russia), and the University of Vale do Itajaí (Brazil). Nutrient analysis was performed according to Grasshoff et al, adopted for a 5 channel continues flow analyzer (Skalar San Plus, Skalar Analytical B. V., Breda, The Netherlands). Nitrite and nitrate+nitrite was measured using an ammonia buffer and sulfanilamide/alpha-Naphthylethylene diamine dihydrochloride colour reagent in phosphoric acid, with reduction of nitrate to nitrite by cadmium column of at least 80% measured reduction capacity (90-100% achieved), followed by quantification with spectrophotometric determination of the nitrite-azo dye at 540 nm. Nitrate was determined as the difference between nitrate+nitrite and nitrite measurements. Ammonia was measured using a citrate/tartrate buffer and phenol color reagent, catalyzed by hypochlorite and nitroprusside , followed by quantification with spectrophotometric determination of the phenol-ammonia complex at 630 nm. Phosphate samples reacted with antimo nytartrate and ammonium molybdate solution in sulfuric acidified solution, the resulting complex wasreduced by ascorbic acid to a deep blue dye, followed by quantification with spectrophotometric determination of the reduced antimony-phospho-molybdate complex at 880 nm. Silicate samples was acidified with sulfuric acid and reacted with ammonium molybdate solution, reduced by ascorbic acid to a blue dye with oxalic acid to remove phosphate interference , followed by quantification with spectrophotometric determination of the reduced molybdo-silicate complex at 810 nm. Methods used are accredited with expected detection limit of 0,04 µM for nitrite, 0,1 µM for nitrate, 0,3 µM for ammonia, 0,06 µM for Phosphate and 0,2 µM for silicate, with expected RSD between 4 and 7%for the individual nutrients. Certified reference materials (VKI type QC RW1 for ammonia, phosphate and nitrate) and internal reference materials for Nitrite and silicate was spiked at two levels to natural low nutrient seawater sample for quality assurance, recovering 91-109% of the spike for nitrite, nitrate, phosphate and silicate at with RSD% of 1 to 5%, and recovery of 84-91% for ammonia, with RSDs up to 15%. No corrections was performed on data the recoveries. Except for ammonia, all results was within the acceptance limits for accredited analysis. Analysis was performed over two runs, one with triplicates and then a fourth spare sample was included to investigate the ammonia instability, but it could not be determined if this was due to storage/transport or instrument The “.CSV” files of fully processed data contain data collected mainly in the North portion of the MAR in the Exclusive Economic Zone around the Azores. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.
Project/programmeEUROFLEETS+: An Alliance of European marine research infrastructure to meet the evolving needs of the research and industrial communities
  • 590_iMAR
  • Start date2021-05-19
    End date2021-06-02

    Responsible organisations

    Organisation nameIfremer, Scientific Information Systems for the sea
    Role of organisationDataset Holding Organisation
    Organisation nameSEA scieNtific Open data Edition
    Role of organisationPublisher
    How to citeMohn Christian, Larsen Martin Mørk, Evans Susan, Neves De Sousa Laura, Rodrigues Luis, Dominguez-Carrió Carlos, Taranto Gerald H., Carreiro-Silva Marina, Morato Telmo (2022). Nutrient data collected during the iMAR 2021/Eurofleets+ research cruise in Mid Atlantic Ridge (Azores EEZ). SEANOE.

    Dataset availability


    Latitude north boundary42.484475
    Longitude east boundary-28.559438
    Latitude south boundary38.236108
    Longitude west boundary-30.935026
    Sea areaNorth Atlantic Ocean
    Atlantic Ocean
    Northeast Atlantic Ocean (40W)

    Data types, collection and processing

    Observation typeinapplicable
    ParameterNitrate+nitrite concentration parameters in the water column
    Phosphate concentration parameters in the water column
    Silicate concentration parameters in the water column
    Platform typeship
    Platform namePelagia
    Data quality processing informationRaw data

    Process information

    Submitting organisationOKEANOS
    Submission identifier (UUID)a53ad03f-3836-8363-3631-000000086115
    Date of dataset creation2022-04-22
    Date of dataset revision2022-05-13
    Date of metadata creation2022-5-15
    Date of metadata latest revision2022-05-31
    Date of publishing2022-06-16
    Date of processed dataset publication2022-06-22
    Processing data centreNational Institute of Oceanography and Applied Geophysics - OGS, Division of Oceanography
    Summary record-ID1052