Artificial surface films in the sea area near Sylt1

Brockmann, U. H.; Hühnerfuß, Heinrich; Kattner, Gerhard; Broecker, Hans‐Christoph; Hentzschel, G.

doi:10.4319/lo.1982.27.6.1050

Cited by 33 publications

(28 citation statements)

References 22 publications

(11 reference statements)

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“…Part of the hydrophobic material required to form a monomolecular film on the lake surface may be found in the microlayer DEL fraction, which ranged from 36 to 94 pg m-2 (Table 4). By comparison, 200 pg m-2 of a fatty acid having a mean surface area of 20 A2 is required to produce such a film (Brockmann et al 1982). Slick formation in lakes may therefore be a result of phytoplanktonneuston aggregations, where the capillary waves are damped by a combination of hydrophobic material excreted by the microorganisms and by allochthonous material.…”

Section: Resuh and Discussionmentioning

confidence: 99%

Origin and composition of surface slicks in lakes of differing trophic status1

Södergren

1987

Limnology & Oceanography

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The chemical and biological composition of freshwater microlayers was followed in surface slicks of eutrophic, oligotrophic, and dystrophic lakes and compared with conditions in the subsurface water. The slicks were sampled with a revolving cylinder coated with hydrophilic Teflon which collected a layer that ranged in thickness from 23 to 48 µm when collected at surface pressures of 3–8 mN m−1. The levels of organic and inorganic residues in the slicks were generally higher than those in the subsurface water. POC was enriched to a significantly greater extent in the dystrophic lake than in the three other lakes, but no relationship between trophic status and DOC enrichment was noted. Dissolved lipids were enriched by factors of 2.6–5.2 but represented only a minor fraction of the DOC content (~ 5%) of the microlayer. The DOC: DON ratio, color, UV absorbance, and fatty acid composition of the slicks suggested that most of the microlayer components were derived allochthonously. Combining the results of chemical and biological observations suggests that olizotrophic lakes may be partly covered by a thin layer of water with eutrophic properties.

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Section: Resuh and Discussionmentioning

confidence: 99%

Origin and composition of surface slicks in lakes of differing trophic status1

Södergren

1987

Limnology & Oceanography

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“…Our TKE measurements allowed us to increase the percentage of variance of k 660 that can be explained from 12% with U 10 as a single parameter to 40% with TKE. Additional factors affecting the determination of k 660 that were not measured directly but were observed visually included the presence of surfactants (Broecker et al, 1978;Brockmann et al, 1982;Frew et al, 2004), tidal current (Zappa et al, 2003) and precipitation (Ho et al, 2004). For example, on 1 August 2016, we deployed the Sniffle during light rainfall and obtained relatively high k 660 (average of 11.7 cm h -1 ; n = 2; Table S1).…”

Section: Factors Regulating Gas Transfer Velocitymentioning

confidence: 99%

Sniffle: a step forward to measure in situ CO2 fluxes with the floating chamber technique

Ribas-Ribas¹,

Kilcher

Wurl³

2018

Elementa: Science of the Anthropocene

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Understanding how the ocean absorbs anthropogenic CO 2 is critical for predicting climate change. We designed Sniffle, a new autonomous drifting buoy with a floating chamber, to measure gas transfer velocities and air-sea CO 2 fluxes with high spatiotemporal resolution. Currently, insufficient in situ data exist to verify gas transfer parameterizations at low wind speeds (<4 m s −1 ), which leads to underestimation of gas transfer velocities and, therefore, of air-sea CO 2 fluxes. The Sniffle is equipped with a sensor to consecutively measure aqueous and atmospheric pCO 2 and to monitor increases or decreases of CO 2 inside the chamber. During autonomous operation, a complete cycle lasts 40 minutes, with a new cycle initiated after flushing the chamber. The Sniffle can be deployed for up to 15 hours at wind speeds up to 10 m s −1. Floating chambers often overestimate fluxes because they create additional turbulence at the water surface. We correct fluxes by measuring turbulence with two acoustic Doppler velocimeters, one positioned directly under the floating chamber and the other positioned sideways, to compare artificial disturbance caused by the chamber and natural turbulence. The first results of deployment in the North Sea during the summer of 2016 demonstrate that the new drifting buoy is a useful tool that can improve our understanding of gas transfer velocity with in situ measurements. At low and moderate wind speeds and different conditions, the results obtained indicate that the observed tidal basin was acting as a source of atmospheric CO 2 . Wind speed and turbulence alone could not fully explain the variance in gas transfer velocity. We suggest that other factors like surfactants, rain or tidal current will have an impact on gas transfer parameterizations.

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“…These condensed slicks are known to significantly alter the physicochemical properties of the ocean surface water. Slicks reduce wind-wave coupling [Barget et al, 1970], decrease air-sea gas transport rates [Brockmann et al, 1982], change microwave emissivity [Alpers et al, 1982], and alter microwave radar ocean backscatter cross section [Hfi'hnerfuss et al, 1983a]. The effects of slicks in images of the ocean surface made by satellite-and aircraft-based methods employing microwave to optical wavelength radiation are of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Study of ocean slicks by nonlinear laser processes: 1. Second‐harmonic generation

Frysinger¹,

Asher²,

Korenowski³

et al. 1992

J. Geophys. Res.

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Reflected optical second‐harmonic generation (SHG) was applied for the first time to in situ study of the air‐sea interface. SHG signals were detected from the first several molecular layers of the ocean surface during the SAR X Band Ocean Nonlinearities (SAXON) Chesapeake Light Tower experiment in 1988, and during experiments on Nantucket Sound at the Woods Hole Oceanographic Institution in 1989. The SHG response of the ocean surface was observed to correlate with increased slick activity and surface tension measurements of surface water organic content. The SHG response was similar for naturally occurring slicks and for artificially created slicks of several known materials. The SHG signal intensity was also used to estimate the second‐order nonlinear optical susceptibility of the ocean surface. It was determined that the SHG nonlinear laser technique is a useful noninvasive probe for in situ studies of ocean surface chemistry.

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Artificial surface films in the sea area near Sylt1

Cited by 33 publications

References 22 publications

Origin and composition of surface slicks in lakes of differing trophic status1

Origin and composition of surface slicks in lakes of differing trophic status1

Sniffle: a step forward to measure in situ CO2 fluxes with the floating chamber technique

Study of ocean slicks by nonlinear laser processes: 1. Second‐harmonic generation

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