Calcite lilypads and ledges at Lorusio Hot Springs, Kenya Rift Valley: travertine precipitation at the air-water interface

1999 ◽  
Vol 36 (4) ◽  
pp. 649-666 ◽  
Author(s):  
Robin W Renaut ◽  
Brian Jones ◽  
Caroline Le Turdu
Keyword(s):  
Water Surface ◽  
Microbial Mats ◽  
Hot Springs ◽  
Water Interface ◽  
Kenya Rift ◽  
Similar Morphology ◽  
Northern Kenya ◽  
Air Water Interface ◽  
Capillary Evaporation ◽  
Outflow Channel

Travertine forming at Lorusio Hot Springs in the northern Kenya Rift is constructed mainly by lilypads and ledges. The lilypads are flat, accretionary structures rooted to the substrate that are composed mostly of platy calcite crystals. They grow outward from a nucleus, subparallel to the water surface, at or just below the air-water interface. Precipitation results from rapid degassing of CO2. Ledges, which have a similar morphology and internal structure, are attached to the margin of a spring pool or outflow channel. As they grow laterally, lilypads and ledges may coalesce with their neighbours to produce thin (1-3 cm) beds of travertine, examples of which are exposed in subfossil deposits at the site. Once established, lilypads and ledges modify the outflow and can act as substrates for precipitation of other minerals and colonization by microbes on their cooler subaerial surfaces. Pore fluids are drawn upward through the lilypads by capillary evaporation. Amorphous silica then precipitates as surficial crusts upon microbial mats or forms spicular microstromatolites, some of which also contain calcite laminae. Efflorescent Na-CO3 salts commonly encrust the drier central platforms of the exposed lilypad. The unusual abundance of lilypads and ledges at Lorusio reflects (i) the low-relief setting and the hydrostatic head, which limit terrace development, and (ii) the high temperature (>75°C) of the waters, which inhibits colonization by microbial mats at crystal growth sites. Similar structures form in cave pools, evaporating brines, and freezing water at sites where precipitation is induced by several processes active at the air-water interface.

Unified Molecular View of the Air/Water Interface Based on Experimental and Theoretical χ(2)Spectra of an Isotopically Diluted Water Surface

2011 ◽  
Vol 133 (42) ◽  
pp. 16875-16880 ◽  
Author(s):  
Satoshi Nihonyanagi ◽  
Tatsuya Ishiyama ◽  
Touk-kwan Lee ◽  
Shoichi Yamaguchi ◽  
Mischa Bonn ◽  
...  
Keyword(s):  
Water Surface ◽  
Water Interface ◽  
Air Water Interface

scholarly journals Deprotonation of formic acid in collisions with a liquid water surface studied by molecular dynamics and metadynamics simulations

2016 ◽  
Vol 18 (43) ◽  
pp. 29756-29770 ◽  
Author(s):  
Garold Murdachaew ◽  
Gilbert M. Nathanson ◽  
R. Benny Gerber ◽  
Lauri Halonen
Keyword(s):  
Molecular Dynamics ◽  
Formic Acid ◽  
Liquid Water ◽  
Water Surface ◽  
Bulk Liquid ◽  
Water Interface ◽  
Air Water Interface

Formic acid has a lower barrier to deprotonation at the air–water interface than in bulk liquid water.

Comparison of Profiles and Fluxes of Heat and Momentum Above and Below an Air-Water Interface

1982 ◽  
Vol 104 (1) ◽  
pp. 34-39 ◽  
Author(s):  
B. M. Howe ◽  
A. J. Chambers ◽  
S. P. Klotz ◽  
T. K. Cheung ◽  
R. L. Street
Keyword(s):  
Heat Transfer ◽  
Surface Layer ◽  
Water Surface ◽  
Temperature Fields ◽  
Water Interface ◽  
Law Of The Wall ◽  
Air Water Interface ◽  
Total Energy Flux ◽  
Momentum And Heat Transfer ◽  
Water Surface Layer

The velocity and temperature fields on both sides of an air-water interface were examined experimentally in order to understand better the physical processes of momentum and heat transfer through the surface layers about the interface. An examination of temperature and velocity profiles plotted in “law-of-the-wall” coordinates leads to the conclusion that, both in the air and in the water, the mechanism of momentum transfer is affected by surface roughness changes, but the mechanism of heat transfer is not. In the water surface layer the velocity fluctuations due to the wave-related motions are of the same order as the purely turbulent motions. The turbulent components closely resemble those found in boundary layers over solid walls. The measured total energy flux from the interface agrees well with the measured single-phase, vertical heat transport through the water surface layer.

scholarly journals Enhanced active motion of Janus colloids at the water surface

Soft Matter ◽  
2015 ◽  
Vol 11 (37) ◽  
pp. 7376-7384 ◽  
Author(s):  
Xiaolu Wang ◽  
Martin In ◽  
Christophe Blanc ◽  
Maurizio Nobili ◽  
Antonio Stocco
Keyword(s):  
Rotational Motion ◽  
Water Surface ◽  
Confinement Effect ◽  
Water Interface ◽  
Active Motion ◽  
Air Water Interface

Self-propelled Janus colloids show enhanced active motion when trapped at the water surface. Trajectories are more directional and velocities are higher than those in the bulk. The confinement effect given by the air–water interface strongly reduces the rotational motion of the colloid while not hindering self-propulsion.

scholarly journals Light-driven locomotion of a centimeter-sized object at the air–water interface: effect of fluid resistance

RSC Advances ◽  
2019 ◽  
Vol 9 (15) ◽  
pp. 8333-8339 ◽  
Author(s):  
Hisato Kawashima ◽  
Akihisa Shioi ◽  
Richard J. Archer ◽  
Stephen J. Ebbens ◽  
Yoshinobu Nakamura ◽  
...  
Keyword(s):  
Water Surface ◽  
Near Infrared ◽  
Infrared Laser ◽  
Interface Effect ◽  
Water Interface ◽  
Fluid Resistance ◽  
Air Water Interface

Centimeter-sized flat-headed push pin with photothermal properties can be moved on a water surface by a simple near-infrared laser.

scholarly journals Formation of Multilayered Photosynthetic Biofilms in an Alkaline Thermal Spring in Yellowstone National Park, Wyoming

2009 ◽  
Vol 75 (8) ◽  
pp. 2464-2475 ◽  
Author(s):  
Sarah M. Boomer ◽  
Katherine L. Noll ◽  
Gill G. Geesey ◽  
Bryan E. Dutton
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Microbial Mats ◽  
Thermal Spring ◽  
High Abundance ◽  
Water Interface ◽  
Air Water Interface ◽  
Thermal Features ◽  
Glass Rods ◽  
Sequence Types

ABSTRACT In this study, glass rods suspended at the air-water interface in the runoff channel of Fairy Geyser, Yellowstone National Park, WY, were used as a substratum to promote the development of biofilms that resembled multilayered mat communities in the splash zone at the geyser's source. This approach enabled the establishment of the temporal relationship between the appearance of Cyanobacteria, which ultimately formed the outer green layer, and the development of a red underlayer containing Roseiflexus-like Chloroflexi. This is the first study to define time-dependent successional events involved in the development of differently colored layers within microbial mats associated with many thermal features in Yellowstone National Park. Initial (1-month) biofilms were localized below the air-water interface (60 to 70°C), and the majority of retrieved bacterial sequence types were similar to Synechococcus and Thermus isolates. Biofilms then shifted, becoming established at and above the air-water interface after 3 months. During winter sampling (6 to 8 months), distinct reddish orange microcolonies were observed, consistent with the appearance of Roseiflexus-like sequences and bacteriochlorophyll a pigment signatures. Additionally, populations of Cyanobacteria diversified to include both unicellular and filamentous cell and sequence types. Distinct green and red layers were observed at 13 months. Planctomycetes-like sequences were also retrieved in high abundance from final biofilm layers and winter samples. Finally, biomass associated with geyser vent water contained Roseiflexus-like sequence types, in addition to other high-abundance sequence types retrieved from biofilm samples, supporting the idea that geothermal water serves as an inoculum for these habitats.

scholarly journals Hydrophobicity of Water at the Surface as Studied by laser-Induced Fluorescence Microscopy

1998 ◽  
Vol 17 (4) ◽  
pp. 175-184 ◽  
Author(s):  
Yao-qun Li ◽  
Shinya Sasaki ◽  
Takanori Inoue ◽  
Teiichiro Ogawa
Keyword(s):  
Fluorescence Microscopy ◽  
Fluorescence Spectrum ◽  
Water Surface ◽  
Laser Induced Fluorescence ◽  
Interface Region ◽  
Water Interface ◽  
Microscopic Approach ◽  
Hydrocarbon Solvents ◽  
Air Water Interface

A sensitive comparative fluorescence microscopic approach was developed and used to study the water at the air-water interface region. An insoluble chromophore mesoc-α,β,γ,δ-tetraphenylporphine (TPP) was spread on the water. Its fluorescence spectrum indicated that the spectrum of TPP on the water surface was similar to those measured in nonpolar hydrocarbon solvents. Thus, the water at the surface was concluded to be hydrophobic and less polar than the water in the bulk.

Co-operative motion of multiple benzoquinone disks at the air–water interface

2015 ◽  
Vol 17 (44) ◽  
pp. 29891-29898 ◽  
Author(s):  
Jennifer E. Satterwhite-Warden ◽  
Dilip K. Kondepudi ◽  
James A. Dixon ◽  
James F. Rusling
Keyword(s):  
Interfacial Tension ◽  
Water Surface ◽  
Water Interface ◽  
Air Water Interface

Co-operative locomotion of multiple benzoquinone particles was observed at the air–water interface and driven by heterogeneous interfacial tension fields formed on the water surface.

Sign in / Sign up

Export Citation Format

Share Document