Influence of atmospheric deposition on biogeochemical cycles in an oligotrophic ocean system
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Published:2021-10-22
Issue:20
Volume:18
Page:5699-5717
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ISSN:1726-4189
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Container-title:Biogeosciences
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language:en
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Short-container-title:Biogeosciences
Author:
Van Wambeke France, Taillandier Vincent, Desboeufs Karine, Pulido-Villena ElviraORCID, Dinasquet JulieORCID, Engel AnjaORCID, Marañón EmilioORCID, Ridame CélineORCID, Guieu Cécile
Abstract
Abstract. The surface mixed layer (ML) in the Mediterranean Sea is a well-stratified
domain characterized by low macronutrients and low chlorophyll content for almost 6 months of the year. In this study we characterize the
biogeochemical cycling of nitrogen (N) in the ML by analyzing simultaneous in situ measurements of atmospheric deposition, nutrients in seawater, hydrological conditions, primary production, heterotrophic prokaryotic production, N2 fixation and leucine aminopeptidase activity. Dry deposition was continuously measured across the central and western open Mediterranean Sea, and two wet deposition events were sampled, one in the Ionian Sea and one in the Algerian Basin. Along the transect, N budgets were computed to compare the sources and sinks of N in the mixed layer. In situ leucine aminopeptidase
activity made up 14 % to 66 % of the heterotrophic prokaryotic N demand, and the N2 fixation rate represented 1 % to 4.5 % of the phytoplankton N demand. Dry atmospheric deposition of inorganic nitrogen, estimated from dry deposition of nitrate and ammonium in aerosols, was higher than the N2 fixation rates in the ML (on average 4.8-fold). The dry atmospheric input of inorganic N represented a highly variable proportion of biological N demand in the ML among the stations, 10 %–82 % for heterotrophic
prokaryotes and 1 %–30 % for phytoplankton. As some sites were visited on several days, the evolution of biogeochemical properties in the ML and within the nutrient-depleted layers could be followed. At the Algerian Basin site, the biogeochemical consequences of a wet dust deposition event were monitored through high-frequency sampling. Notably, just after the rain, nitrate was higher in the ML than in the nutrient-depleted layer below. Estimates of nutrient transfer from the ML into the nutrient-depleted layer could explain up to a third of the nitrate loss from the ML. Phytoplankton did not benefit directly from the atmospheric inputs into the ML, probably due to high competition with heterotrophic prokaryotes, also limited by N and phosphorus (P) availability at the time of this study.
Primary producers decreased their production after the rain but recovered
their initial state of activity after a 2 d lag in the vicinity of the
deep chlorophyll maximum layer.
Funder
Institut Français de Recherche pour l'Exploitation de la Mer Ministerio de Ciencia e Innovación
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Ecology, Evolution, Behavior and Systematics
Reference88 articles.
1. Aminot, A. and Kérouel, R.: Dosage automatique des nutriments dans les
eaux marines, in: Méthodes d'analyses en milieu marin, edited by:
IFREMER, MEDD, Éditions Quae, Plouzané, France, 188 pp., IBSN 978-2-7592-0023-8, 2007. 2. Bardouki, H., Liakakou, H., Economou, C., Sciare, J., Smolik, J., Zdimal,
V., Eleftheriadis, K., Lazaridis, M., Dye, C., and Mihalopoulos, N.:
Chemical composition of size resolved atmospheric aerosols in the eastern
Mediterranean during summer and winter, Atmos. Environ., 37, 195–208, 2003. 3. Bonnet, S., Grosso, O., and Moutin, T.: Planktonic dinitrogen fixation along a longitudinal gradient across the Mediterranean Sea during the stratified period (BOUM cruise), Biogeosciences, 8, 2257–2267, https://doi.org/10.5194/bg-8-2257-2011, 2011. 4. Bonnet, S., Caffin, M., Berthelot, H., and Moutin, T.: Hot spot of N2
fixation in the western tropical South Pacific pleads for a spatial
decoupling between N2 fixation and denitrification, PNAS letter, 144, E2800–E2801, https://doi.org/10.1073/pnas.1619514114, 2017. 5. Caffin, M., Berthelot, H., Cornet-Barthaux, V., Barani, A., and Bonnet, S.: Transfer of diazotroph-derived nitrogen to the planktonic food web across gradients of N2 fixation activity and diversity in the western tropical South Pacific Ocean, Biogeosciences, 15, 3795–3810, https://doi.org/10.5194/bg-15-3795-2018, 2018.
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