Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

Air-water interface: dynamics of nutrients and picoplankton in the surface microlayer of a humic lake

1997 ◽  
Vol 26 (2) ◽  
pp. 319-322 ◽  
Author(s):  
Anna Hillbricht-Ilkowska ◽  
Iwona Jasser ◽  
Iwona Kostrzewska-Szlakowska
Keyword(s):  
Surface Microlayer ◽  
Water Interface ◽  
Humic Lake ◽  
Interface Dynamics ◽  
Air Water Interface

Chlorinated Hydrocarbons in the Surface Microlayer and Subsurface Water of the Niagara River, 1985-86

1988 ◽  
Vol 23 (2) ◽  
pp. 292-300 ◽  
Author(s):  
R. James Maguire ◽  
Richard J. Tkacz
Keyword(s):  
Chlorinated Hydrocarbons ◽  
Lake Ontario ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Water Interface ◽  
Niagara River ◽  
Niagara Falls ◽  
Increased Risk ◽  
Air Water Interface ◽  
High Concentrations

Abstract The surface microlayer of the Niagara River at Niagara-on-the-Lake was sampled 34 times in 1985-86, and was shown to contain PCBs, chlorobenzenes and chlorinated hydrocarbons at concentrations generally up to 40 times greater than concentrations 1n subsurface water. Organisms which spend part or all of their lives at the air-water interface are thus likely to be at increased risk relative to subsurface water exposure. A small “spill” of PCBs 1n the river on July 29, 1986 was only detected in the surface micro-layer, and not in subsurface water. On this date, concentrations of PCBs in the surface microlayer were up to 6,400 times larger than concentrations in the subsurface water, and 1t appeared that the “spill” was downstream of Niagara Falls and the Whirlpool. Despite such high concentrations of chlorinated hydrocarbons in the surface microlayer, at no time during this study did the microlayer contribute significantly, relative to subsurface water, to the loading (i.e., amounts) of these chemicals from the Niagara River to Lake Ontario.

Ecophysiological and Phylogenetic Studies ofNevskia ramosa in Pure Culture

1998 ◽  
Vol 64 (5) ◽  
pp. 1890-1894 ◽  
Author(s):  
Heike St�rmeyer ◽  
J�rg Overmann ◽  
Hans-Dietrich Babenzien ◽  
Heribert Cypionka
Keyword(s):  
Nitrogenase Activity ◽  
Hydrophobic Surface ◽  
Surface Films ◽  
Organic Substrates ◽  
Water Interface ◽  
Phylogenetic Studies ◽  
Air Water Interface ◽  
Pure Cultures ◽  
Close Relatives ◽  
First Time

ABSTRACT During the last 100 years, the neuston bacterium Nevskia ramosa has been described several times. This bacterium forms conspicuous rosette-like microcolonies at the air-water interface. In this study, pure cultures of Nevskia ramosawere obtained for the first time, from a bog lake (strain Soe1, DSMZ 11499T) and a freshwater ditch (strain OL1, DSMZ 11500). The isolates showed special adaptations to life in the epineuston. They formed hydrophobic surface films with a dull appearance. N. ramosa is sensitive to UV radiation but revealed a very effective photorepair mechanism. Exposure to light at a wavelength of 350 nm after UV treatment raised the number of surviving cells by several orders of magnitude. The isolates grew with a broad range of organic substrates. Surface films were formed only in the absence of combined nitrogen; however, nitrogenase activity was not detected. It appears that during growth at the air-water interface the cells benefit from trapping ammonia from the air. The G+C content of the DNA was 67.8 and 69.0 mol% for strains Soe1 and OL1, respectively. The slight difference was confirmed by enterobacterial repetitive intergenic consensus PCR. The 16S rRNA sequences revealed 99.2% similarity. Thus, both isolates belong to the same species. The phylogenetic analysis indicated that Nevskia is a member of the gamma-subclass Proteobacteria that has no known close relatives.

scholarly journals Impact of anions on the surface organisation of lipid monolayers at the air–water interface

2017 ◽  
Vol 14 (7) ◽  
pp. 407 ◽  
Author(s):  
Siyang Li ◽  
Lin Du ◽  
Wenxing Wang
Keyword(s):  
Surface Properties ◽  
Surface Pressure ◽  
Sea Surface ◽  
Sea Spray ◽  
Surface Microlayer ◽  
Water Interface ◽  
Marine Aerosols ◽  
Sea Surface Microlayer ◽  
Air Water Interface ◽  
Surface Active

Environmental contextLipids released from lysis of phytoplankton cells are enriched in the sea surface microlayer. Such surface-active organics can be transferred through bursting bubbles to sea-spray aerosols where they can influence atmospheric chemistry. The results presented here suggest that phospholipids combine more readily with SO42− than with Br−, leading to enrichment of organic-coated sulfate salts in marine aerosols. AbstractInorganic salts and organic matter are known to be present at higher levels in the sea surface microlayer and marine aerosols; however, the impact of common anions on their surface properties is not well understood. Here, a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer was enriched with the sodium and ammonium salts of different anions (Br−, Cl−, NO3−, SO42−, CH3COO−, and HCO3−), and the effects on the surface properties of the monolayer were investigated. The monolayer phase behaviour and the structure of the lipid phases were studied by surface pressure–area (π–A) isotherms and infrared reflection-absorption spectroscopy (IRRAS). The presence of salts in the subphase was found to increase the surface pressure of the DPPC monolayer at a fixed area per molecule. The effect of the anions follows the order of the Hofmeister series. The higher concentration of salt solution caused the π–A isotherm to shift to larger area. The IRRAS spectra demonstrate that the ordering of the DPPC molecules in the liquid condensed phase remains essentially unaffected, even at higher electrolyte concentrations. DPPC molecules combined with SO42− could be transferred from the ocean to sea spray aerosol. The present study finds that the anions have significant influence on the surface organisation and, consequently, the interfacial properties, of the surface-active species at the air–water interface, a finding that has further implications for atmospheric aerosol nucleation.

Possible ecological implications of the high cell surface hydrophobicity of the fish pathogen Aeromonas salmonicida

1992 ◽  
Vol 38 (10) ◽  
pp. 1048-1052 ◽  
Author(s):  
Øivind Enger ◽  
Berit K. Thorsen
Keyword(s):  
Cell Surface ◽  
Water Column ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Aeromonas Salmonicida ◽  
Fish Farm ◽  
Surface Microlayer ◽  
Water Interface ◽  
Air Water Interface ◽  
Key Words Immunofluorescence

The abundance of the fish pathogenic bacterium Aeromonas salmonicida in different parts of the marine environment was determined in a fish farm stocked with Atlantic salmon (Salmo salar) suffering from furunculosis. By application of highly specific monoclonal antibodies and immunofluorescence techniques, the bacterium was found in high abundances (4.3 × 103 cells/mL) at the air-water interface. Aeromonas salmonicida was also registered in high numbers in the sediments beneath the farm, and in moderate to low numbers in the water column. When samples were collected in the environment outside the fish farm, the number of A. salmonicida was below the detection limit in surface samples, but the bacterium could be detected in the water column in samples collected downstream to the farm. The high number of A. salmonicida found in the lipid-rich air-water interface is discussed, taking into consideration the high hydrophobicity of the cell surface of the bacterium and the physical and ecological conditions in this specific habitat. Key words: immunofluorescence, total bacterial counts, surface microlayer, furunculosis.

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