Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam)

Elementa: Science of the Anthropocene, Feb 2018

Increasing human activity has raised concerns about the impact of deposition of anthropogenic combustion aerosols (i.e., black carbon; BC) on marine processes. The sea surface microlayer (SML) is a key gate for the introduction of atmospheric BC into the ocean; however, relatively little is known of the effects of BC on bacteria-virus interactions, which can strongly influence microbially mediated processes. To study the impact of BC on bacteria-virus interactions, field investigations involving collection from the SML and underlying water were carried out in Halong Bay (Vietnam). Most inorganic nutrient concentrations, as well as dissolved organic carbon, were modestly but significantly higher (p = 0.02–0.05) in the SML than in underlying water. The concentrations of particulate organic carbon (though not chlorophyll a) and of total particulate carbon, which was composed largely of particulate BC (mean = 1.7 ± 6.4 mmol L–1), were highly enriched in the SML, and showed high variability among stations. On average, microbial abundances (both bacteria and viruses) and bacterial production were 2- and 5fold higher, respectively, in the SML than in underlying water. Significantly lower bacterial production (p < 0.01) was observed in the particulate fraction (>3 μm) compared to the bulk sample, but our data overall suggest that bacterial production in the SML was stimulated by particulate BC. Higher bacterial production in the SML than in underlying water supported high viral lytic infection rates (from 5.3 to 30.1%) which predominated over percent lysogeny (from undetected to 1.4%). The sorption of dissolved organic carbon by black carbon, accompanied by the high lytic infection rate in the black carbon-enriched SML, may modify microbially mediated processes and shift the net ecosystem metabolism (ratio of production and respiration) to net heterotrophy and CO2 production in this critical layer between ocean and atmosphere.

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Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam)

Special Collection: Special Feature: The sea surface microlayer Research Article Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam) Authors: A. S. Pradeep Ram , Laboratoire Microorganismes, Génome et Environnement, UMR CNRS 6023, Université Clermont Auvergne, 63178 Aubière Cedex, FR X close X. Mari, Aix Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), 13288, Marseille; and Sorbonne Universités, UPMC, Université Paris 06, CNRS, Laboratoire d’Océanographie de Villefranche (LOV), 181 Chemin du Lazaret, 06230 Villefranche-sur-Mer, FR X close J. Brune, UMR MARBEC, IRD, CNRS, IFREMER, Université Montpellier, FR X close J. P. Torréton, UMR MARBEC, IRD, CNRS, IFREMER, Université Montpellier, FR X close V. T. Chu, Institute of Marine Environment and Resources (IMER), Vietnam Academy of Science and Technology (VAST), Haiphong, VN X close P. Raimbault, Aix Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), 13288, Marseille, FR X close J. Niggemann, Research Group for Marine Geochemistry (ICBM-MPI Bridging Group), University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, 26129 Oldenburg, DE X close T. Sime-Ngando Laboratoire Microorganismes, Génome et Environnement, UMR CNRS 6023, Université Clermont Auvergne, 63178 Aubière Cedex, FR X close Abstract Increasing human activity has raised concerns about the impact of deposition of anthropogenic combustion aerosols (i.e., black carbon; BC) on marine processes. The sea surface microlayer (SML) is a key gate for the introduction of atmospheric BC into the ocean; however, relatively little is known of the effects of BC on bacteria-virus interactions, which can strongly influence microbially mediated processes. To study the impact of BC on bacteria-virus interactions, field investigations involving collection from the SML and underlying water were carried out in Halong Bay (Vietnam). Most inorganic nutrient concentrations, as well as dissolved organic carbon, were modestly but significantly higher (p = 0.02–0.05) in the SML than in underlying water. The concentrations of particulate organic carbon (though not chlorophyll a) and of total particulate carbon, which was composed largely of particulate BC (mean = 1.7 ± 6.4 mmol L–1), were highly enriched in the SML, and showed high variability among stations. On average, microbial abundances (both bacteria and viruses) and bacterial production were 2- and 5fold higher, respectively, in the SML than in underlying water. Significantly lower bacterial production (p < 0.01) was observed in the particulate fraction (>3 μm) compared to the bulk sample, but our data overall suggest that bacterial production in the SML was stimulated by particulate BC. Higher bacterial production in the SML than in underlying water supported high viral lytic infection rates (from 5.3 to 30.1%) which predominated over percent lysogeny (from undetected to 1.4%). The sorption of dissolved organic carbon by black carbon, accompanied by the high lytic infection rate in the black carbon-enriched SML, may modify microbially mediated processes and shift the net ecosystem metabolism (ratio of production and respiration) to net heterotrophy and CO2 production in this critical layer between ocean and atmosphere. Knowledge Domain: Ocean Science Keywords: black carbon,  virus-bacteria interaction,  viral lysis,  lysogeny,  sea surface microlayer,  tropical coastal ocean  How to Cite: Pradeep Ram AS, Mari X, Brune J, Torréton JP, Chu VT, Raimbault P, et al.. Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam). Elem Sci Anth. 2018;6(1):13. DOI: http://doi.org/10.1525/elementa.276 124 Views 32 Downloads Altmetric  Published on 09 Feb 2018 Peer Reviewed  CC BY 4.0 Managing Editor-in-Chief: Jody W. Deming; University of Washington, US Associate Editor: Tamar Barkay; Rutgers The State University of New Jersey, US 1. Introduction The coastal ocean – where land, ocean and atmosphere interact – constitutes one of the most geochemically and biologically active areas of the biosphere (Gattuso et al., 1998), and one that is also subjected to increasing anthropogenic pressure. In today’s context, one such pressure, which will likely escalate in the near future as a consequence of continuously intense industrial activity, is the input of black carbon (BC) particles via atmospheric deposition or riverine runoff from land drainage (Guazzotti et al., 2001; Forbes et al., 2006). The term “black carbon” is used for aerosols that result from soot emission generated by incomplete combu (...truncated)


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A. S. Pradeep Ram, X. Mari, J. Brune, J. P. Torréton, V. T. Chu, P. Raimbault, J. Niggemann, T. Sime-Ngando. Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam), Elementa: Science of the Anthropocene, 2018, pp. 13, Volume 6, Issue 1, DOI: 10.1525/elementa.276