Details of AMOR-Bflux porewater and sediment data

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Dataset identification

Title of datasetAMOR-Bflux porewater and sediment data
Narrative summary of datasetEstuarine regions are generally considered a major source of atmospheric CO2 as a result of the high organic carbon (OC) mineralization rates in their water column and sediments. Yet, the intensity of anaerobic respiration processes in the sediments tempered by the reoxidation of reduced metabolites near the sediment-water interface controls the flux of benthic alkalinity. This alkalinity may partially buffer metabolic CO2 generated by benthic OC respiration in sediments. Thus sediments with high anaerobic respiration rates could contribute less to local acidification than previously thought. In this study, a benthic chamber was deployed in the Rhône River prodelta and the adjacent continental shelf (Gulf of Lions, NW Mediterranean) in late summer to assess the fluxes of total alkalinity (TA) and dissolved inorganic carbon (DIC) from the sediment. Concurrently, in situ O2 and pH microprofiles, voltammetric profiles and pore water composition were measured in surface sediments to identify the main biogeochemical processes controlling the net production of alkalinity in these sediments. Benthic TA and DIC fluxes to the water column, ranging between 14 and 74 mmol m-2 d-1 and 18 and 78 mmol m-2 d-1, respectively, were up to 8 times higher than DOU rates (10.4 ± 0.9 mmol m-2 d-1) close to the river mouth, but their intensity decreased offshore, as a result of the decline in OC inputs. In the zone close to the river mouth, pore water redox species indicated that TA and DIC were mainly produced by microbial sulfate and iron reduction. Despite the complete removal of sulfate from pore waters, dissolved sulfide concentrations were low and significant concentration of FeS were found indicating the precipitation and burial of iron sulfide minerals with an estimated burial flux of 12.5 mmol m-2 d-1 near the river mouth. By preventing reduced iron and sulfide reoxidation, the precipitation and burial of iron sulfide increases the alkalinity release from the sediments during the spring and summer months. Under these conditions, the sediment provides a net source of alkalinity to the bottom waters which mitigates the effect of the benthic DIC flux on the carbonate chemistry of coastal waters and weakens the partial pressure of CO2 increase in the bottom waters that would occur if DIC was produced only. 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.
Cruise
  • 486_15008700
  • Start date2015-09-04
    End date2015-09-14

    Responsible organisations

    CountryFrance
    Organisation nameIfremer, Scientific Information Systems for the sea
    Role of organisationDataset Holding Organisation
    CountryFrance
    Organisation nameSEA scieNtific Open data Edition
    Role of organisationPublisher
    How to citeRassmann Jens, Eitel Eryn M., Lansard Bruno, Cathalot Cecile, Brandily Christophe, Taillefert Martial, Rabouille Christophe (2019). AMOR-Bflux porewater and sediment data. SEANOE. https://doi.org/10.17882/70376 In addition to properly cite this dataset, it would be appreciated that the following work(s) be cited too, when using this dataset in a publication : Rassmann Jens, Eitel Eryn M., Lansard Bruno, Cathalot Cecile, Brandily Christophe, Taillefert Martial, Rabouille Christophe (2020). Benthic alkalinity and dissolved inorganic carbon fluxes in the Rhône River prodelta generated by decoupled aerobic and anaerobic processes. Biogeosciences, 17(1), 13-33. Publisher's official version : https://archimer.ifremer.fr/doc/00600/71163/

    Dataset availability

    Original dataset download linkhttps://cloud.emodnet-ingestion.eu/index.php/s/shc6Qax704Ggxuy
    Dataset formatDocuments
    PDF
    Public accessNo limitations
    License for useCC-BY 4.0
    TypeDataset
    DOIhttps://doi.org/10.17882/70376

    Locations

    Map
    Latitude north boundary43.33
    Longitude east boundary5.02
    Latitude south boundary43.2
    Longitude west boundary4.57
    Sea areaMediterranean Sea, Western Basin

    Data types, collection and processing

    Observation typeinapplicable
    ParameterConcentration of carbohydrates, phenols, alkanols (alcohols), ethers, aldehydes and ketones in sediment
    Instrument typebenthic incubation chambers
    Platform typeresearch vessel
    Platform nameTethys II
    Data quality processing informationProcessed data

    Process information

    Submitting organisationCEA, Climate and Environmental Sciences Laboratory
    Submission identifier (UUID)a53ad03f-3730-7303-3033-000000070376
    Date of dataset creation2019-11-19
    Date of dataset revision2019-11-21
    Date of metadata creation2020-1-27
    Date of metadata latest revision2023-03-30
    Date of publishing2023-04-16
    Processing data centreIfremer, Scientific Information Systems for the sea
    Summary record-ID1309