%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Jatiault, R.
%A Dhont, D.
%A Besson, F.
%A Tedetti, Marc
%A de Fommervault, O. P.
%A Loncke, L.
%A Bourrin, F.
%A Goutx, M.
%A de Madron, X. D.
%T Water column poly-aromatic hydrocarbon anomalies measured with submersible gliders in the Angolan natural oil seepage province
%D 2021
%L fdi:010082720
%G ENG
%J Deep-Sea Research Part I : Oceanographic Research Papers
%@ 0967-0637
%K Glider ; Fluorescence ; Polycyclic aromatic hydrocarbons ; Seeps ; Oxygen minimum zone
%K ANGOLA ; ATLANTIQUE ; CONGO BASSIN
%M ISI:000686607200004
%P 103588 [16 ]
%R 10.1016/j.dsr.2021.103588
%U https://www.documentation.ird.fr/hor/fdi:010082720
%> https://www.documentation.ird.fr/intranet/publi/2021-10/010082720.pdf
%V 175
%W Horizon (IRD)
%X Fluorescence sensors mounted on unmanned underwater gliders open new ways of investigation to detect dissolved hydrocarbons in seawater. A glider was deployed for 20 days to monitor biogeochemical and physical signals associated with natural hydrocarbon seepages within the first 700 m in the Angolan waters. The glider was equipped with fluorometers (MiniFluo-UV) to measure the concentrations of polycyclic aromatic hydrocarbons (PAH) of interest, i.e. naphthalene, phenanthrene, fluorene and pyrene. A continuous PAH-like signal detected within the 70 m layer below the sea surface is associated with high chlorophyll concentration in the deep chlorophyll maximum. Vertical PAH-like anomalies forming either strong spikes or diffuse columns down to 700 m are observed at the exact location of oil seep sites identified on Synthetic Aperture Radar satellite images. An similar to 200 m thick layer of enhanced PAH-like concentration, topped by a thermo/pycnocline identified at 280-300 m water depth, is measured in concomitance with the decrease in oxygen concentration. The concomitance of these signals suggests that lower oxygen concentrations induce a preservation of hydrocarbons within the eastern Atlantic oxygen minimum zone. Even if the absence of in-situ measurements limits the understanding of physical and biogeochemical processes affecting PAH concentrations, the measurements conducted at the edges of the OMZ suggests a relationship with microbial activity and organic matter dynamics in this layer. The results presented here show that gliders equipped with PAH sensors represent a promising means for monitoring hydrocarbons in the oceans, especially when they are coupled with other systems (i.e. Synthetic Aperture Radar).
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