In situ measurements of hydrogen sulfide, oxygen, and temperature in diffuse fluids of the ultramafic-hosted Logatchev hydrothermal vent field (Mid-Atlantic Ridge)

The Logatchev hydrothermal vent field (14°45'N, Mid-Atlantic Ridge) is located in a ridge segment characterized by mantle-derived ultramafic outcrops. Compared to basalt-hosted vents, Logatchev high temperature fluids are relatively low in sulfide indicating that the diffuse, low temperature fluids of this vent field may not contain sufficient sulfide concentrations to support a chemosymbiotic invertebrate community. However, the high abundances of bathymodiolin mussels with bacterial symbionts related to free-living sulfur oxidizing bacteria suggested that bioavailable sulfide is present at Logatchev. To clarify if diffuse fluids above mussel beds of Bathymodiolus puteoserpentis provide the reductants and oxidants needed by their symbionts for aerobic sulfide oxidation, in situ microsensor measurements of dissolved hydrogen sulfide and oxygen were combined with simultaneous temperature measurements. High temporal fluctuations of all three parameters were measured above the mussel beds. H2S and O2 co-existed with mean concentrations between 9-31 µM (H2S) and 216-228 µM (O2). Temperature maxima (<= 7.4°C) were generally concurrent with H2S maxima (<= 156 µM) and O2 minima (>= 142 µM). Long-term measurements for 250 days using temperature as a proxy for oxygen and sulfide concentrations indicated that the mussels were neither oxygen- nor sulfide-limited. Our in situ measurements at Logatchev indicate that sulfide may also be bioavailable in diffuse fluids from other ultramafic-hosted vents along slow- and ultraslow-spreading ridges.

An an[n]otated bibliography of rural development, urbanization, and levels of living in Peru /

"December 1979."

Economic consequences of urbanization in Mexico /

Mode of access: Internet.

Ecosystem impacts of urbanization assessment methodology /

Mode of access: Internet.

The city: urbanism and urbanization in major world regions.

"Readings" at the end of each chapter.

SHEAL II, NASA's Shuttle High-Energy Astrophysics Laboratory : broad band X-ray telescope/diffuse X-ray spectrometer /

Title from cover.

The urbanization of the Negro church in Detroit; second semester report to the Earhart Foundation for Community Leadership per Dr. R. D. McKenzie.

"This report is the result of field work done among twelve Spiritualist churches ... 1934-1935."--p. [1]

Research on the effects of urbanization on small stream flow quality /

Mode of access: Internet.

Biological control of spotted and diffuse knapweeds.

"Issued December 1994"--P. [2].

Urbanization and changing land uses : a bibliography of selected references, 1950-58 /

Includes index.

Development of guides for urbanization in rural areas affected by building of industrial plants; an interim report.

At head of cover title: Housing research.

The Coordinated City’s Mutation Machine: Capitalism, Sympathy, and Urbanization in Seattle’s South Lake Union Neighborhood

Thesis (Ph.D.)--University of Washington, 2016-06

Comparing the concentration of calcium hydroxide in the diffuse double layer by modeling and experiment

The leaching of elements from the surface of charged fly ash particles is known to be an unsteady process. The mass transfer resistance provided by the diffuse double layer has been quantified as one of the reasons for this delayed leaching. In this work, a model based on mass transfer principles for predicting the concentration of calcium hydroxide in the diffuse double layer is presented. The significant difference between predicted calcium hydroxide concentration and the experimentally measured is explained.