Seasonal dynamics of atmospheric and river inputs of black carbon, and impacts on biogeochemical cycles in Halong Bay, Vietnam

Mari, Xavier; Van, Thuoc Chu; Guinot, Benjamin; Brune, Justine; Lefèbvre, Jean-Pierre; Raimbault, Patrick; Dittmar, Thorsten; Niggemann, Jutta

doi:10.1525/elementa.255

Cited by 9 publications

(17 citation statements)

References 75 publications

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“…To our knowledge, the effect of pH on the physical properties of natural ocean OM has been little investigated (Mari et al, 2017). However, a huge volume of literature exists concerning the effect of pH and other parameters in marine and sewage-sludge EPS, including divalent ions and salinity, on flocculation and adsorption of OM, particularly in membrane filtration (Baudez et al, 2011;Pilli et al, 2015;Villacorte et al, 2015;Zhang et al, 2016).…”

Section: Acidificationmentioning

confidence: 99%

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Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Jenkinson

Laurent

Ding

et al. 2018

Elementa: Science of the Anthropocene

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Jenkinson, IR, et al. 2018 Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes. Elem Sci Anth, 6: 26. DOI: https://doi.org/10.1525/elementa.283 IntroductionFor over a century, CO 2 levels in the atmosphere have been increasing at an accelerating rate. This increase is fuelled by anthropogenic CO 2 release, currently at over 9 billion tonnes annually (Le Quéré, 2015). As a greenhouse gas, CO 2 is leading to higher mean temperature on Earth (Friedlingstein et al., 2014) and in the world ocean, as well as increasing sea levels by thermal expansion and melting of ice caps (IPCC, 2014).The Ocean absorbs about 25% of the anthropically produced excess CO 2 (Le Quéré et al., 2015). As a result, the average surface ocean pH has decreased 0.1 units since the Industrial Revolution, i.e., a 30% increase in acidity (IPCC, 2014), and is predicted to fall another 0.3 to 0.4 units by 2100 if CO 2 emissions continue in a business-asusual scenario (Orr et al., 2005).In order to predict, manage and adapt to future changes in CO 2 dynamics, models of air-sea flux of CO 2 are being refined. This flux of CO 2 passes through the barrier of the sea surface microlayer (SML), here considered to be the top 50(±10) µm (Zhang et al., 1998). As the SML itself varies strongly in time and space in complex, nonlinear ways, modelling the effects of the SML on CO 2 flux as a function of pertinent future scenarios is also important.The importance of the SML in biologically modulating fluxes, particularly of CO 2 , is increasingly appreciated, and has recently been reviewed by Wurl et al. (2016Wurl et al. ( , 2017 and by Engel et al. (2017b). Therefore, the aim of this paper is to review known and suspected mechanical aspects of how biologically produced organic matter (OM) modulates air-sea fluxes of CO 2 . We particularly address thalassorheological observations of biologically increased 3D viscosity and elasticity, 2D compression-dilation rheology, 2D shear rheology and foam dynamics. Gas exchange reduction (GER) at the air-sea interface is positively related to the concentration of organic matter (OM) in the top centimetre of the ocean, as well as to phytoplankton abundance and primary production. The mechanisms relating OM to GER remain unclear, but may involve mechanical (rheological) damping of turbulence in the water immediately below the surface microlayer, damping of ripples and blocking of molecular diffusion by layers of OM, as well as electrical effects. To help guide future research in GER, particularly of CO 2 , we review published rheological properties of ocean water and cultures of phytoplankton and bacteria in both 3D and 2D deformation geometries, in water from both the surface layer and underlying water. Production of foam modulates air-sea exchange of many properties and substances, perhaps including climate-changing gases such as CO 2 . We thus also review biological modulation of production and decay of whitecaps and other sea foam. In the ocea...

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Section: Acidificationmentioning

confidence: 99%

“…Some BC enters the coastal ocean in the dissolved (<0.8 µm) form in river runoff, However, most of it enters the global ocean through deposition of airborne, particulate BC (Mari et al, 2017). Airborne BC is part of the family of atmospheric aerosols.…”

Section: A Decreasing Trend In Production and Deposition Of Black Carbonmentioning

confidence: 99%

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Jenkinson

Laurent

Ding

et al. 2018

Elementa: Science of the Anthropocene

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“…For example, the Bay is located a few tens of kilometers from the largest industrial zone and trading harbor in Vietnam (i.e., Haiphong) and is bordered in the North by open coal mining. In addition to these local sources, northern Vietnam is impacted by atmospheric BC originating from China during the dry season (B Guinot, personal communication; Mari et al, 2017). Altogether, these intense human activities result in high deposition of BC onto the surface waters of Halong Bay.…”

Section: Study Sitementioning

confidence: 99%

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

Ram

Mari

Brune

et al. 2018

Elementa: Science of the Anthropocene

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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 CO 2 production in this critical layer between ocean and atmosphere.

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“…In the water column, DBC represents from 1 to 7% of the pool of dissolved organic carbon (DOC) (Mannino and Harvey, 2004;Ziolkowski and Druffel, 2010). The contribution of PBC to the pool of suspended particulate organic carbon (POC) in surface waters decreases from >50% in highly BC-impacted coastal zones (Mari et al, 2017a) to <3% in oceanic surface waters (Fang et al, 2016). Finally, in the surface microlayer (SML), which represents the interfacial boundary layer (typically 40-100 µm thick) between the atmosphere and the ocean (Wurl et al, 2017, and references herein), and which constitutes the main entrance gate for BC into the ocean, BC concentration can be very high and contribute from 11 to 97% of the pool of POC (Mari et al, 2017a).…”

Section: Introductionmentioning

confidence: 99%

“…In the atmosphere, BC is associated with other aerosols, the input of BC to the marine environment may lead to an enrichment in BCassociated elements, such as organic carbon (Willey et al, 2000;Raymond, 2005), nutrients (Mahowald et al, 2008;Kanakidou et al, 2012;Wang et al, 2015), trace metals (Paytan et al, 2009;Ito, 2013), and even pesticides (Kunz et al, 2005), potentially altering the structure and activity of phytoplankton (Paytan et al, 2009;Guo et al, 2012) and bacterial (Cattaneo et al, 2010;Mari et al, 2014;Pradeep Ram et al, 2018) communities. In addition, it has been shown that the BC introduced into marine surface waters sorbs dissolved organic matter (DOM), nutrients and small particles, and stimulate aggregation processes (Mari et al, 2014(Mari et al, , 2017a. The introduction of BC to the surface of the ocean may alter the initial steps of the biological carbon pump, i.e., DOM cycling and marine snow aggregate formation (Mari et al, 2014(Mari et al, , 2017a.…”

Section: Introductionmentioning

confidence: 99%

Biogeochemical Impacts of a Black Carbon Wet Deposition Event in Halong Bay, Vietnam

et al. 2019

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Black carbon (BC) is emitted to the atmosphere during biomass, biofuel, and fossil fuel combustion, and leaves the atmosphere via dry or wet deposition on land and on the ocean. On a global scale, wet deposition accounts for about 80% of the total atmospheric BC inputs to the ocean. The input of BC particles to the ocean can enrich surface waters with carbon and associated elements, and owing to high porosity and surface-active properties, BC can alter biogeochemical cycles by sorbing dissolved compounds and promoting aggregation. The rain-mediated input of BC to the ocean and its consequences on nutrient concentrations and particle dynamics were studied in Halong Bay, Vietnam, during a 24-h cycle impacted by short and heavy rainfall events. This study suggests that once introduced in the surface ocean via wet deposition, BC sorbs dissolved organic matter (DOM) and stimulates aggregation processes. The observed wet deposition events were characterized by sudden and pulsed inputs of BC particles that created a thin layer of sinking surface-active aggregates, acting as a net-like scavenger for DOM, nutrients (especially phosphate), and small particles. In addition, the wet deposition events coincided with an enrichment of nutrients in the surface microlayer, with an excess input of nitrogen relative to phosphorus leading to an increase of the molar N:P ratio from 24:1 to 37:1. In the underlying water, the molar N:P ratio also increased (i.e., from 39:1 to 64:1), and this can be attributed to the preferential scavenging of dissolved P-compounds on sinking BC-aggregates.

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Seasonal dynamics of atmospheric and river inputs of black carbon, and impacts on biogeochemical cycles in Halong Bay, Vietnam

Cited by 9 publications

References 75 publications

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

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

Biogeochemical Impacts of a Black Carbon Wet Deposition Event in Halong Bay, Vietnam

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