Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events

C. Ridame, M. Le Moal, Cecile Guieu, E. Ternon, I. C. Biegala, S. L'Helguen, M. Pujo-Pay

    Research output: Contribution to journalArticle

    Abstract

    A better understanding of the factors controlling N 2 fixation is a pre-requisite for improving our knowledge on the contribution of N 2 fixation process in the nitrogen cycling. Trace-metal clean nutrient/dust addition bioassays (+P, +PFe, +dust) were performed at three stations located in the western, central and eastern Mediterranean Sea, in summer 2008 as part of the BOUM cruise. The main goals were (1) to investigate the nutrient factor(s) limiting N 2 fixation (uptake of 15N 2) and (2) to evaluate the potential impact of a Saharan dust event on this biological process during the stratification period. Initially, surface waters at the three stations were DIP-depleted (<10 nM) while the DFe concentrations were relatively high (from 1.2 to 2.3 nM) most likely due to atmospheric iron accumulation in the surface mixed layer. At all stations, Saharan dust input relieved the ambient nutrient limitation of the diazotrophic activity as demonstrated by the strong stimulation of N 2 fixation (from 130 % to 430 %). The highest dust stimulation of N 2 fixation was recorded at the station located in the eastern basin. The response of diazotrophic activity to nutrient additions was variable between the sampled stations suggesting a spatial variability of the factor controlling N 2 fixation over the whole basin. At all stations, N 2 fixation was not limited by Fe nor co-limited by P and Fe. At the western station, N 2 fixation was DIP limited while at the eastern one, N 2 fixation was first DIP limited, then was limited by one or several chemical element(s) released by dust. Our results demonstrated that a Saharan dust input was able to relieve these successive on going limitations. Very interestingly, at the station located in the central basin, N 2 fixation was not limited by the availability of P yet it was strongly stimulated by dust addition (x3.1). A chemical element or a combination of several, released by the added dust may have been responsible for the observed stimulations of N 2 fixation. These results indicated that Saharan dust pulses to the surface Mediterranean waters, in addition to P and Fe, could be a source of chemical(s) element(s) that are necessary for metabolic processes and therefore influence rates of N 2 fixation.

    Original languageEnglish (US)
    Pages (from-to)2773-2783
    Number of pages11
    JournalBiogeosciences
    Volume8
    Issue number9
    DOIs
    StatePublished - Oct 6 2011

    Fingerprint

    Mediterranean Sea
    dust
    fixation
    nutrient
    nutrients
    chemical element
    chemical elements
    basins
    basin
    Mediterranean Water
    station
    nutrient limitation
    trace elements
    surface water
    biological processes
    limiting factor
    bioassays
    trace metal
    mixed layer
    bioassay

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics
    • Earth-Surface Processes

    Cite this

    Ridame, C., Le Moal, M., Guieu, C., Ternon, E., Biegala, I. C., L'Helguen, S., & Pujo-Pay, M. (2011). Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events. Biogeosciences, 8(9), 2773-2783. https://doi.org/10.5194/bg-8-2773-2011

    Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events. / Ridame, C.; Le Moal, M.; Guieu, Cecile; Ternon, E.; Biegala, I. C.; L'Helguen, S.; Pujo-Pay, M.

    In: Biogeosciences, Vol. 8, No. 9, 06.10.2011, p. 2773-2783.

    Research output: Contribution to journalArticle

    Ridame, C, Le Moal, M, Guieu, C, Ternon, E, Biegala, IC, L'Helguen, S & Pujo-Pay, M 2011, 'Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events', Biogeosciences, vol. 8, no. 9, pp. 2773-2783. https://doi.org/10.5194/bg-8-2773-2011
    Ridame, C. ; Le Moal, M. ; Guieu, Cecile ; Ternon, E. ; Biegala, I. C. ; L'Helguen, S. ; Pujo-Pay, M. / Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events. In: Biogeosciences. 2011 ; Vol. 8, No. 9. pp. 2773-2783.
    @article{6928967bbda34283a5556739bbf1b209,
    title = "Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events",
    abstract = "A better understanding of the factors controlling N 2 fixation is a pre-requisite for improving our knowledge on the contribution of N 2 fixation process in the nitrogen cycling. Trace-metal clean nutrient/dust addition bioassays (+P, +PFe, +dust) were performed at three stations located in the western, central and eastern Mediterranean Sea, in summer 2008 as part of the BOUM cruise. The main goals were (1) to investigate the nutrient factor(s) limiting N 2 fixation (uptake of 15N 2) and (2) to evaluate the potential impact of a Saharan dust event on this biological process during the stratification period. Initially, surface waters at the three stations were DIP-depleted (<10 nM) while the DFe concentrations were relatively high (from 1.2 to 2.3 nM) most likely due to atmospheric iron accumulation in the surface mixed layer. At all stations, Saharan dust input relieved the ambient nutrient limitation of the diazotrophic activity as demonstrated by the strong stimulation of N 2 fixation (from 130 {\%} to 430 {\%}). The highest dust stimulation of N 2 fixation was recorded at the station located in the eastern basin. The response of diazotrophic activity to nutrient additions was variable between the sampled stations suggesting a spatial variability of the factor controlling N 2 fixation over the whole basin. At all stations, N 2 fixation was not limited by Fe nor co-limited by P and Fe. At the western station, N 2 fixation was DIP limited while at the eastern one, N 2 fixation was first DIP limited, then was limited by one or several chemical element(s) released by dust. Our results demonstrated that a Saharan dust input was able to relieve these successive on going limitations. Very interestingly, at the station located in the central basin, N 2 fixation was not limited by the availability of P yet it was strongly stimulated by dust addition (x3.1). A chemical element or a combination of several, released by the added dust may have been responsible for the observed stimulations of N 2 fixation. These results indicated that Saharan dust pulses to the surface Mediterranean waters, in addition to P and Fe, could be a source of chemical(s) element(s) that are necessary for metabolic processes and therefore influence rates of N 2 fixation.",
    author = "C. Ridame and {Le Moal}, M. and Cecile Guieu and E. Ternon and Biegala, {I. C.} and S. L'Helguen and M. Pujo-Pay",
    year = "2011",
    month = "10",
    day = "6",
    doi = "10.5194/bg-8-2773-2011",
    language = "English (US)",
    volume = "8",
    pages = "2773--2783",
    journal = "Biogeosciences",
    issn = "1726-4170",
    publisher = "European Geosciences Union",
    number = "9",

    }

    TY - JOUR

    T1 - Nutrient control of N 2 fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events

    AU - Ridame, C.

    AU - Le Moal, M.

    AU - Guieu, Cecile

    AU - Ternon, E.

    AU - Biegala, I. C.

    AU - L'Helguen, S.

    AU - Pujo-Pay, M.

    PY - 2011/10/6

    Y1 - 2011/10/6

    N2 - A better understanding of the factors controlling N 2 fixation is a pre-requisite for improving our knowledge on the contribution of N 2 fixation process in the nitrogen cycling. Trace-metal clean nutrient/dust addition bioassays (+P, +PFe, +dust) were performed at three stations located in the western, central and eastern Mediterranean Sea, in summer 2008 as part of the BOUM cruise. The main goals were (1) to investigate the nutrient factor(s) limiting N 2 fixation (uptake of 15N 2) and (2) to evaluate the potential impact of a Saharan dust event on this biological process during the stratification period. Initially, surface waters at the three stations were DIP-depleted (<10 nM) while the DFe concentrations were relatively high (from 1.2 to 2.3 nM) most likely due to atmospheric iron accumulation in the surface mixed layer. At all stations, Saharan dust input relieved the ambient nutrient limitation of the diazotrophic activity as demonstrated by the strong stimulation of N 2 fixation (from 130 % to 430 %). The highest dust stimulation of N 2 fixation was recorded at the station located in the eastern basin. The response of diazotrophic activity to nutrient additions was variable between the sampled stations suggesting a spatial variability of the factor controlling N 2 fixation over the whole basin. At all stations, N 2 fixation was not limited by Fe nor co-limited by P and Fe. At the western station, N 2 fixation was DIP limited while at the eastern one, N 2 fixation was first DIP limited, then was limited by one or several chemical element(s) released by dust. Our results demonstrated that a Saharan dust input was able to relieve these successive on going limitations. Very interestingly, at the station located in the central basin, N 2 fixation was not limited by the availability of P yet it was strongly stimulated by dust addition (x3.1). A chemical element or a combination of several, released by the added dust may have been responsible for the observed stimulations of N 2 fixation. These results indicated that Saharan dust pulses to the surface Mediterranean waters, in addition to P and Fe, could be a source of chemical(s) element(s) that are necessary for metabolic processes and therefore influence rates of N 2 fixation.

    AB - A better understanding of the factors controlling N 2 fixation is a pre-requisite for improving our knowledge on the contribution of N 2 fixation process in the nitrogen cycling. Trace-metal clean nutrient/dust addition bioassays (+P, +PFe, +dust) were performed at three stations located in the western, central and eastern Mediterranean Sea, in summer 2008 as part of the BOUM cruise. The main goals were (1) to investigate the nutrient factor(s) limiting N 2 fixation (uptake of 15N 2) and (2) to evaluate the potential impact of a Saharan dust event on this biological process during the stratification period. Initially, surface waters at the three stations were DIP-depleted (<10 nM) while the DFe concentrations were relatively high (from 1.2 to 2.3 nM) most likely due to atmospheric iron accumulation in the surface mixed layer. At all stations, Saharan dust input relieved the ambient nutrient limitation of the diazotrophic activity as demonstrated by the strong stimulation of N 2 fixation (from 130 % to 430 %). The highest dust stimulation of N 2 fixation was recorded at the station located in the eastern basin. The response of diazotrophic activity to nutrient additions was variable between the sampled stations suggesting a spatial variability of the factor controlling N 2 fixation over the whole basin. At all stations, N 2 fixation was not limited by Fe nor co-limited by P and Fe. At the western station, N 2 fixation was DIP limited while at the eastern one, N 2 fixation was first DIP limited, then was limited by one or several chemical element(s) released by dust. Our results demonstrated that a Saharan dust input was able to relieve these successive on going limitations. Very interestingly, at the station located in the central basin, N 2 fixation was not limited by the availability of P yet it was strongly stimulated by dust addition (x3.1). A chemical element or a combination of several, released by the added dust may have been responsible for the observed stimulations of N 2 fixation. These results indicated that Saharan dust pulses to the surface Mediterranean waters, in addition to P and Fe, could be a source of chemical(s) element(s) that are necessary for metabolic processes and therefore influence rates of N 2 fixation.

    UR - http://www.scopus.com/inward/record.url?scp=80053433037&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=80053433037&partnerID=8YFLogxK

    U2 - 10.5194/bg-8-2773-2011

    DO - 10.5194/bg-8-2773-2011

    M3 - Article

    VL - 8

    SP - 2773

    EP - 2783

    JO - Biogeosciences

    JF - Biogeosciences

    SN - 1726-4170

    IS - 9

    ER -