Enrichment of organochlorine contaminants in the sea surface microlayer: An organic carbon-driven process

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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Succession of the sea-surface microlayer in the coastal Baltic Sea under natural and experimentally induced low-wind conditions

Biogeosciences ◽

10.5194/bg-7-2975-2010 ◽

2010 ◽

Vol 7 (9) ◽

pp. 2975-2988 ◽

Cited By ~ 35

Author(s):

C. Stolle ◽

K. Nagel ◽

M. Labrenz ◽

K. Jürgens

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Baltic Sea ◽

Community Composition ◽

Temporal Variability ◽

Sea Surface ◽

Surface Microlayer ◽

Clear Understanding ◽

Carbon And Nitrogen ◽

Sea Surface Microlayer

Abstract. The sea-surface microlayer (SML) is located within the boundary between the atmosphere and hydrosphere. The high spatial and temporal variability of the SML's properties, however, have hindered a clear understanding of interactions between biotic and abiotic parameters at or across the air-water interface. Among the factors changing the physical and chemical environment of the SML, wind speed is an important one. In order to examine the temporal effects of minimized wind influence, SML samples were obtained from the coastal zone of the southern Baltic Sea and from mesocosm experiments in a marina to study naturally and artificially calmed sea surfaces. Organic matter concentrations as well as abundance, 3H-thymidine incorporation, and the community composition of bacteria in the SML (bacterioneuston) compared to the underlying bulk water (ULW) were analyzed. In all SML samples, dissolved organic carbon and nitrogen were only slightly enriched and showed low temporal variability, whereas particulate organic carbon and nitrogen were generally greatly enriched and highly variable. This was especially pronounced in a dense surface film (slick) that developed during calm weather conditions as well as in the artificially calmed mesocosms. Overall, bacterioneuston abundance and productivity correlated with changing concentrations of particulate organic matter. Moreover, changes in the community composition in the field study were stronger in the particle-attached than in the non-attached bacterioneuston. This implies that decreasing wind enhances the importance of particle-attached assemblages and finally induces a succession of the bacterial community in the SML. Eventually, under very calm meteorological conditions, there is an uncoupling of the bacterioneuston from the ULW.

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The influence of environmental drivers on the enrichment of organic carbon in the sea surface microlayer and in submicron aerosol particles – measurements from the Atlantic Ocean

Elem Sci Anth ◽

10.1525/elementa.225 ◽

2017 ◽

Vol 5 ◽

Cited By ~ 14

Author(s):

Manuela van Pinxteren ◽

Stefan Barthel ◽

Khanneh Wadinga Fomba ◽

Konrad Müller ◽

Wolf von Tümpling ◽

...

Keyword(s):

Biological Activity ◽

Organic Carbon ◽

Chlorophyll A ◽

Aerosol Particles ◽

Enrichment Factors ◽

Sea Surface ◽

Environmental Drivers ◽

Surface Microlayer ◽

Marine Aerosol ◽

Sea Surface Microlayer

The export of organic matter from ocean to atmosphere represents a substantial carbon flux in the Earth system, yet the impact of environmental drivers on this transfer is not fully understood. This work presents dissolved and particulate organic carbon (DOC, POC) concentrations, their enrichment factors in the sea surface microlayer (SML), and equivalent measurements in marine aerosol particles across the Atlantic Ocean. DOC concentrations averaged 161 ± 139 µmol L–1 (n = 78) in bulk seawater and 225 ± 175 µmol L–1 (n = 79) in the SML; POC concentrations averaged 13 ± 11 µmol L–1 (n = 80) and 17 ± 10 µmol L–1 (n = 80), respectively. High DOC and POC enrichment factors were observed when samples had low concentrations, and lower enrichments when concentrations were high. The impacts of wind speed and chlorophyll-a levels on concentrations and enrichment of DOC and POC in seawater were insignificant. In ambient submicron marine aerosol particles the concentration of water-soluble organic carbon was approximately 0.2 µg m–3. Water-insoluble organic carbon concentrations varied between 0.01 and 0.9 µg m–3, with highest concentrations observed when chlorophyll-a concentrations were high. Concerted measurements of bulk seawater, the SML and aerosol particles enabled calculation of enrichment factors of organic carbon in submicron marine ambient aerosols, which ranged from 103 to 104 during periods of low chlorophyll-a concentrations and up to 105 when chlorophyll-a levels were high. The results suggest that elevated local biological activity enhances the enrichment of marine-sourced organic carbon on aerosol particles. However, implementation of the results in source functions based on wind speed and chlorophyll-a concentrations underestimated the organic fraction at low biological activity by about 30%. There may be additional atmospheric and oceanic parameters to consider for accurately predicting organic fractions on aerosol particles.

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Calcium bridging drives polysaccharide co-adsorption to a proxy sea surface microlayer

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01407b ◽

2021 ◽

Author(s):

Kimberly Anne Carter-Fenk ◽

Abigal Dommer ◽

Michelle E. Fiamingo ◽

Jeongin Kim ◽

Rommie Amaro ◽

...

Keyword(s):

Organic Carbon ◽

Mass Fraction ◽

Co Adsorption ◽

Ocean Surface ◽

Sea Surface ◽

Sea Spray ◽

Surface Microlayer ◽

Sea Surface Microlayer ◽

Sea Spray Aerosol ◽

Significant Mass

Saccharides comprise a significant mass fraction of organic carbon in sea spray aerosol (SSA), but the mechanisms through which saccharides are transferred from seawater to the ocean surface and eventually...

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Succession of the sea-surface microlayer in the Baltic Sea under natural and experimentally induced low-wind conditions

Biogeosciences Discussions ◽

10.5194/bgd-7-3153-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 3153-3187 ◽

Cited By ~ 1

Author(s):

C. Stolle ◽

K. Nagel ◽

M. Labrenz ◽

K. Jürgens

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Baltic Sea ◽

Community Composition ◽

Temporal Variability ◽

Sea Surface ◽

Surface Microlayer ◽

Clear Understanding ◽

Carbon And Nitrogen ◽

Sea Surface Microlayer

Abstract. The sea-surface microlayer (SML) is located within the boundary between the atmosphere and hydrosphere. The high spatial and temporal variability of the SML's properties, however, have hindered a clear understanding of interactions between biotic and abiotic parameters at or across the air-water interface. Among the factors changing the physical and chemical environment of the SML, wind speed is an important one. In order to examine the temporal effects of minimized wind influence, SML samples were obtained from the southern Baltic Sea and from mesocosm experiments in a marina to study naturally and artificially calmed sea surfaces. Organic matter concentrations as well as abundance, 3H-thymidine incorporation, and the community composition of bacteria in the SML (bacterioneuston) compared to the underlying bulk water (ULW) were analyzed. In all SML samples, dissolved organic carbon and nitrogen were only slightly enriched and showed low temporal variability, whereas particulate organic carbon and nitrogen were generally greatly enriched and highly variable. This was especially pronounced in a dense surface film (slick) that developed during calm weather conditions as well as in the artificially calmed mesocosms. Overall, bacterioneuston abundance and productivity correlated with changing concentrations of particulate organic matter. Moreover, changes in the community composition in the field study were stronger in the particle-attached than in the non-attached bacterioneuston. This implies that decreasing wind enhances the importance of particle-attached assemblages and finally induces a succession of the bacterial community in the SML. Eventually, under very calm meteorological conditions, there is an uncoupling of the bacterioneuston from the ULW.

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