The Atlantic Ocean surface microlayer from 50°N to 50°S is ubiquitously enriched in surfactants at wind speeds up to 13 m s<sup>−1</sup>

Sabbaghzadeh, Bita; Upstill‐Goddard, Robert C.; Beale, Rachael; Pereira, Ryan; Nightingale, Philip D.

doi:10.1002/2017gl072988

Cited by 64 publications

(100 citation statements)

References 45 publications

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“…The highest friction velocity in water at which the water surface remained smooth and without wind waves in this facility was 1.4 cm/s corresponding to a smooth water surface up to a wind speed of u 10 ≈ 13 m/s. This is supported by the findings of Sabbaghzadeh et al (2017), who measured surfactant enrichment 20 in the sea surface microlayer up to u 10 ≈ 13 m/s as well.…”

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confidence: 83%

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Variability of air-sea gas transfer velocities in the Baltic Sea

Nagel

Krall

Jähne

2018

Preprint

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Heat transfer velocities measured during three different campaigns in the Baltic Sea using the Active Controlled Flux Technique (ACFT) with wind speeds ranging from 5.3 to 14.8 m s −1 are presented. Careful scaling of the heat transfer velocities to gas transfer velocities using Schmidt number exponents measured in a laboratory study allows to compare the measured transfer velocities to existing gas transfer velocity parameterizations, which use wind speed as the controlling parameter. The measured data and other field data clearly show that some gas transfer velocities are much lower than the empirical wind speed 5 parametrizations. This indicates that the dependencies of the transfer velocity on the fetch, i. e., the history of the wind and the age of the wind wave field, and the effects of surface active material need to be taken into account.In the last decades, the dual-tracer technique, especially with the tracer pair 3 He/SF 6 , has become state of the art of measuring the gas transfer velocity in situ. A recent review by Ho et al. (2011) proposed k 600 [cm h −1 ] = 0.262 ± 0.022u 2 10 [u 10 in m s −1 ]as the best fit to all available 3 He/SF 6 dual tracer data points.However, mass balance techniques such as the dual tracer method have a large time constant of up to weeks and large spatial 20 scales of a few tens of kilometers, smoothing away varying micrometeorological and surface conditions (e. g. the degree of surface contamination by surface active material).Ocean Sci. Discuss., https://doi.

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confidence: 83%

“…Surfactants are enriched in the sea surface microlayer in the worlds oceans (Wurl et al, 2011) over a wide range of wind 25 speeds as high as u 10 = 13 m s −1 (Sabbaghzadeh et al, 2017). ln the Baltic sea, high surface activities were measured (Schmidt and Schneider, 2011), with a seasonal dependency in a near-shore position.…”

Section: Surfactantsmentioning

confidence: 99%

Variability of air-sea gas transfer velocities in the Baltic Sea

Nagel

Krall

Jähne

2018

Preprint

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“…In this respect, Sabbaghzadeh et al (2017), in two transects in the Atlantic from 50°N to 50°S, found little or no relationship between U 10 and the enrichment factor of "surfactant" concentration in the SML relative to that in 7-m deep subsurface water. Measurements were made at U 10 values ranging from 0.5 to 13 m s -1 , and this implies that such wind speeds cause little or no "mixing down" of the surface-associated OM.…”

Section: Om In the Sml And Gas Exchange Reduction (Ger)mentioning

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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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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“…The main task of our work was to study the luminescent properties of the molecules that form a surface microfilm. However, the sea surface microlayer is a gelatinous film created by polysaccharides, lipids, proteins and chromophoric dissolved organic matter (Sabbaghzadeh et al, 2017;Cunliffe et al, 2013) and consists of dissolved, colloidal and particulate matter. Thus, so as not to dispose of the absorbing and fluorescent matter involved into a gel structure, we do not filtrate the samples.…”

Section: Laboratory Spectroscopic Measurements Of Cdom and Fdom Opticmentioning

confidence: 99%

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

et al. 2017

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Abstract. The fluorescence and absorption measurements of the samples collected from a surface microlayer (SML) and a subsurface layer (SS), at a depth of 1 m, were studied during three research cruises in the Baltic Sea along with hydrophysical studies and meteorological observations. Several absorption (E 2 : E 3 , S, S R ) and fluorescence (fluorescence intensities at Coble classified peaks: A, C, M, T the ratio (M + T ) / (A + C) , HIX (humification index)) indices of colored and fluorescent dissolved organic matter (CDOM and FDOM) helped to describe the changes in molecular size and weight as well as in composition of organic matter. The investigation allowed the assessment of a decrease in the contribution of two terrestrial components (A and C) with increasing salinity (∼ 1.64 and ∼ 1.89 % in the SML and ∼ 0.78 and ∼ 0.71 % in the SS, respectively) and an increase in components produced in situ (M and T ) with salinity (∼ 0.52 and ∼ 2.83 % in the SML and ∼ 0.98 and ∼ 1.87 % in the SS, respectively). Hence, a component T reveals the biggest relative changes along the transect from the Vistula River outlet to Gdansk Deep, in both the SML and SS, although an increase was higher in the SML than in the SS (∼ 18.5 and ∼ 12.3 %, respectively). The ratio E 2 : E 3 points to greater changes in the molecular weight of CDOM affected by a higher rate of photobleaching in the SML. The HIX index reflects a more advanced stage of humification and condensation processes in the SS. Finally, the results reveal a higher rate of degradation processes occurring in the SML than in the SS. Thus, the specific physical properties of surface active organic molecules (surfactants) may modify, in a specific way, the solar light spectrum entering the sea and a penetration depth of the solar radiation. Research on the influence of surfactants on the physical processes linked to the sea surface becomes an important task, especially in coastal waters and in the vicinity of the river mouths.

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The Atlantic Ocean surface microlayer from 50°N to 50°S is ubiquitously enriched in surfactants at wind speeds up to 13 m s⁻¹

Cited by 64 publications

References 45 publications

Variability of air-sea gas transfer velocities in the Baltic Sea

Variability of air-sea gas transfer velocities in the Baltic Sea

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

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

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The Atlantic Ocean surface microlayer from 50°N to 50°S is ubiquitously enriched in surfactants at wind speeds up to 13 m s−1

Cited by 64 publications

References 45 publications

Variability of air-sea gas transfer velocities in the Baltic Sea

Variability of air-sea gas transfer velocities in the Baltic Sea

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

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

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The Atlantic Ocean surface microlayer from 50°N to 50°S is ubiquitously enriched in surfactants at wind speeds up to 13 m s⁻¹