Microbial biosurfactant production: The effect of the Bacillus strain JF-2 biosurfactant on anaerobic hydrocarbon degradation, and the presence of indigenous biosurfactant-producing bacteria in soils.

A series of experiments was designed utilizing the biosurfactant produced by Bacillus JF2. Specifically, these experiments were designed to determine if the presence of various levels of pre-purified JF2 biosurfactant would affect the degradation of a range of hydrocarbons under a variety of anaerobic conditions. A second goal of these experiments was to discern if in situ production of the JF2 biosurfactant would increase the degradation of these hydrocarbons to a greater degree than if the biosurfactant was added in its pre-purified form. These experiments have indicated how future work should proceed. This work also suggests that it may be more practical to stimulate indigenous biosurfactant producing bacteria within a soil than to add either pre-purified compound or to attempt in situ production.This manuscript includes a review of information regarding biosurfactants. A detailed description of the Bacillus species JF2 biosurfactant, including the genetics and physiology of biosurfactant production, is provided. Additionally, a comprehensive review of the literature regarding the use of biosurfactants in hydrocarbon degradation studies is included.The second portion of this dissertation investigates the presence of biosurfactant producing bacteria in uncontaminated and hydrocarbon contaminated soils. Prior research indicated that the number of bacterial biosurfactant producers in soil may be influenced by the presence of hydrocarbon contamination as well as levels of organic matter and fungi. The purpose of this study was to determine the relationship between soil organic matter levels, hydrocarbon contamination, numbers of fungi, and numbers of indigenous biosurfactant producers. Six soils were used: two hydrocarbon impacted soils, each paired with uncontaminated soil, and two pristine soils with different levels of organic matter. Gross numbers of fungi were higher in soils with higher levels of organic matter. Soils containing higher numbers of fungi contained a greater percentage of biosurfactant-producing aerobic heterotrophs, but only in the absence of a hydrocarbon. The percentage of biosurfactant producers was greater when hydrocarbon contamination was present. Additionally, the presence of the Bacillus subtilis srfA gene, which encodes a highly conserved region of the surfactant synthetase complex, was monitored directly in soils for the first time by PCR amplification and Southern hybridization

Using complementary microanalytical techniques to analyse diamond anvil cell experiments

Diamond anvil cell (DAC) experiments are being used with increasing frequency to examine deep planetary processes. A variety of analytical techniques are available to characterise the products of high-pressure, high-temperature DAC experiments. Recent developments in both sample preparation and analytical techniques allow in-situ measurements made during experiments (typically synchrotron-source X-ray techniques) to be supplemented and supported by ex-situ measurements made of the extracted experimental sample after the experiment. The combination of complementary microanalytical techniques facilitates the verification of analytical results and allows additional information to be obtained from these technically-challenging experiments. Techniques with differing spatial resolutions can also be effectively used together. This contribution describes some techniques used to analyse the products of DAC experiments, and discusses example case studies from the Earth and planetary sciences where the combination of several complementary techniques has resulted in important additional insight into the interpretation of DAC experimental results

Colorado Native Plant Society Newsletter, Vol. 8 No. 1, January-February 1983

https://epublications.regis.edu/aquilegia/1170/thumbnail.jp

Ferropicrites as evidence for lithological heterogeneity in the mantle source of continental fl ood basalts

The sublithospheric mantle must be chemically heterogeneous as a consequence of billions of years\ud worth of continuous subduction. Evidence for heterogeneity is strong in ocean island settings, where\ud variability in isotopic, major and trace element composition is frequently attributed to variability in\ud the mantle source. In continental fl ood basalt (CFB) provinces, signals of mantle-derived hetero-\ud geneity are obscured by fractionated and contaminated nature of CFB magmas. However, outcrops of\ud primitive magmas that more closely represent primary mantle melts are found in some CFB provinces.\ud This study focuses on picrites and ferropicrites from the Paraná-Etendeka CFB province, and also ex-\ud amines ferropicrites from the Karoo CFB province, which are found as dykes and thin fl ows. Ferropi-\ud crites are Fe-rich, Al-poor magmas equally primitive and Mg-rich as the peridotite-derived picrites,\ud but cannot have formed from peridotite melting.\ud The sample sets are investigated by supplementing published whole-rock and mineral analyses\ud with new mineral chemistry and melt inclusion data. Incompatible trace element compositions of their\ud olivine-hosted melt inclusions are very homogeneous, suggesting that their primary fractional mantle\ud melts underwent extensive mixing prior to the onset of crystallisation. Compared with primitive melt\ud inclusions from other settings, inclusions in these and other CFB provinces are well-mixed. The\ud crystallisation temperatures of olivine phenocrysts in these samples were determined by Al-in-olivine\ud thermometry, with maximum crystallisation temperatures of ∼ 1500 °C identifi ed in some Etendeka\ud picrites. These require a very high mantle potential temperature (TP ); the ferropicrites crystallised at\ud somewhat lower temperatures. XANES analyses confi rmed that the spinel Fe\ud 3+\ud /FeT were within the\ud thermometer’s calibrated range.\ud Ferropicrite has been suggested to originate from high pressure, low fraction melting of mantle\ud pyroxenite. The Etendeka ferropicrite geochemistry is examined with the aid of a new thermodynamic\ud model in order to interrogate its mantle source lithology and melting conditions. Modelling indicates\ud that both the major and trace element composition of ferropicrite is indeed more compatible with\ud garnet clinopyroxenite melting than peridotite melting, and that elevated TP plume conditions are\ud required in its formation. By comparison, picrite major element chemistry is consistent with a high\ud TP depleted peridotite melt. If a depleted peridotite and hybrid pyroxenite source mineralogy are\ud used for picrite and Etendeka ferropicrite, respectively, then they both represent ∼ 10–20% mantle\ud melting

NETLAKE guidelines for automated monitoring system development. Factsheet 007: Communication options.

The purpose of this fact sheet is to provide some advice on the available methods to communicate with and retrieve data from your automated monitoring system

NETLAKE guidelines for automated monitoring system development. Factsheet 001: options for buoy design.

In this factsheet, we describe some of the options that can be used to house an automatic monitoring station (AMS) on a lake

NETLAKE guidelines for automated monitoring system development. How to deploy a low cost option (Factsheet 003).

In this factsheet, we give an overview of one “low cost” platform system

Colorado Native Plant Society Newsletter, Vol. 9 No. 4, July-September 1985

The Colorado Native Plant Society Newsletter will be published on a bimonthly basis. The contents will consist primarily of a calendar of events, notes of interest, editorials, listings of new members and conservation news. Until there is a Society journal, the Newsletter will include short articles also. The deadline for the Newsletter is one month prior to its release.https://epublications.regis.edu/aquilegia/1026/thumbnail.jp

Comment on: “Investigating Earth’s Formation History Through Copper & Sulfur Metal–Silicate Partitioning During Core-Mantle Differentiation” by Mahan et al. (2018)

The physical and chemical conditions of terrestrial core formation play a key role in the distribution of elements between the Earth’s silicate mantle and metallic core. To explore this, Mahan et al. (2018a) present experimentally-derived partitioning data, showing how Cu distributes itself between metal and silicate at lower-mantle PT conditions with implications for planetary accretion and core formation. Eight experiments were performed in a diamond anvil cell (DAC) and each sample was welded to a copper grid for analysis. An offset in partitioning behaviour was subsequently noted between the high-P experiments and the lower-P dataset. However, when analysing the DAC experiments by electron probe microanalysis, the authors did not account for the secondary fluorescence of Cu that arises from the sample holder. Using Monte Carlo simulations of X-ray and electron transport, we show that the fluorescence of the Cu grid, originating from high energy continuum X-rays emitted from the sample, makes a significant contribution to the reported measurement of Cu in both the silicate and metallic phases. This is in good agreement with previous measurements made on Cu-free analogues. On average, around 70% of the published Cu concentrations are attributable to X-rays that originate externally to the sample. The reported offset in KDmet-sil at high pressures may reflect the different experimental and analytical protocol used, rather than a true pressure effect. Although adequate post-hoc corrections can be made, uncertainties around the exact sample and detector geometries make it difficult to refine simulations and derive accurate correction factors for each experiment