Competition between acetic- acid utilizing methane bacteria in relation to indispensable trace elements.

1996 ◽  
Vol 25 (3) ◽  
pp. 155-158
Author(s):  
MASANOBU Takashima ◽  
R. E. Speece
2018 ◽  
Vol 15 (8) ◽  
pp. 2271-2288 ◽  
Author(s):  
Rachel U. Shelley ◽  
William M. Landing ◽  
Simon J. Ussher ◽  
Helene Planquette ◽  
Geraldine Sarthou

Abstract. The fractional solubility of aerosol-derived trace elements deposited to the ocean surface is a key parameter of many marine biogeochemical models. Despite this, it is currently poorly constrained, in part due to the complex interplay between the various processes that govern the solubilisation of aerosol trace elements. In this study, we used a sequential two-stage leach to investigate the regional variability in fractional solubility of a suite of aerosol trace elements (Al, Ti, Fe, Mn, Co, Ni, Cu, Zn, Cd, and Pb) from samples collected during three GEOTRACES cruises to the North Atlantic Ocean (GA01, GA03-2010, and GA03-2011). We present aerosol trace element solubility data from two sequential leaches that provide a solubility window, covering a conservative lower limit to an upper limit, the maximum potentially soluble fraction, and discuss why this upper limit of solubility could be used as a proxy for the bioavailable fraction in some regions. Regardless of the leaching solution used in this study (mild versus strong leach), the most heavily loaded samples generally had the lowest solubility. However, there were exceptions. Manganese fractional solubility was relatively uniform across the full range of atmospheric loading (32 ± 13 and 49 ± 13 % for ultra high-purity water and 25 % acetic acid leaches, respectively). This is consistent with other marine aerosol studies. Zinc and Cd fractional solubility also appeared to be independent of atmospheric loading. Although the average fractional solubilities of Zn and Cd (37 ± 28 and 55 ± 30 % for Zn and 39 ± 23 and 58 ± 26 % for Cd, for ultra high-purity water and 25 % acetic acid leaches, respectively) were similar to Mn, the range was greater, with several samples being 100 % soluble after the second leach. Finally, as the objective of this study was to investigate the regional variability in TE solubility, the samples were grouped according to air mass back trajectories (AMBTs). However, we conclude that AMBTs are not sufficiently discriminating to identify the aerosol sources or the potential effects of atmospheric processing on the physicochemical composition and solubility of the aerosols.


Soil Research ◽  
2015 ◽  
Vol 53 (4) ◽  
pp. 401 ◽  
Author(s):  
Thuy C. Nguyen ◽  
Paripurnanda Loganathan ◽  
Tien V. Nguyen ◽  
Thi T. N. Pham ◽  
Jaya Kandasamy ◽  
...  

Trace elements (TEs) in road-deposited sediments (RDS) can be transported by stormwater to neighbouring water bodies to cause aquatic pollution. A study was conducted in Kogarah Bay, Sydney, Australia, to assess the possible sources and potential mobility of TEs in RDS and the contribution to the TE load to the adjacent waterbed sediments in canals and the bay. Of the 11 TEs analysed, pseudo-total concentrations of zinc (Zn), copper (Cu), vanadium (V), chromium (Cr), and antimony (Sb) were greatly enriched in RDS over baseline soils (top 10 cm depth) collected in bushlands. All TE concentrations in waterbed sediments (top 10 cm depth) were similar to those in baseline soils but lower than in RDS. Correlation and principal component analyses revealed that Zn, Cu, Cr and Sb were related to each other in RDS, and probably originated from tyres and brake linings. Vanadium occurred in another component, likely to have originated mainly from road asphalt. Pseudo-total and mobile-fraction (0.1 m acetic acid, pH 2.85 extraction) TE concentrations in RDS were: iron > manganese, Zn > Cu, lead > Cr, nickel, V, Sb, cadmium. The potential ecological TE risk was low to medium in RDS but low in baseline soils and waterbed sediments.


1980 ◽  
Vol 71 (2) ◽  
pp. 103-121 ◽  
Author(s):  
M. L. Berrow ◽  
R. L. Mitchell

ABSTRACTTotal contents of 29 trace and major elements and extractable contents of 20 elements were determined in the horizons of 4 profiles, 2 freely drained and 2 very poorly drained, of Scottish soils on drifts of basic igneous or granitic origin. The probable behaviour of other elements is suggested in the light of the results obtained. It is shown that in the course of pedological weathering, many elements are mobilised and become extractable by relatively weak reagents such as ammonium acetate (when readily exchangeable), dilute acetic acid (when less readily exchangeable or acid-soluble) or EDTA (when chelated or exchangeable). The forms in which different elements occur in the different horizons are assessed. In the surface horizons rich in organic matter many elements, such as Co, Ni, Fe, V, Cu, Cd, Sn and Pb, appear to occur mainly in chelated form; fewer, particularly Mn, are only in exchangeable form with plant uptake being largely responsible. Lower in the profiles the most common forms are acetic acid-soluble or, in gleyed horizons, exchangeable. In these horizons the degree of mobilisation is greater than in the corresponding freely drained horizons, the effect being most apparent for elements in readily weathered minerals.


OALib ◽  
2016 ◽  
Vol 03 (05) ◽  
pp. 1-7
Author(s):  
Yeboue Koffi F. Kouakou ◽  
Houphouet F. Yapi ◽  
Gnogbo Alexis Bahi ◽  
Goueh Gnahoue ◽  
Allico J. Djaman

Author(s):  
N.C. Lyon ◽  
W. C. Mueller

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.


Author(s):  
O.T. Woo ◽  
G.J.C. Carpenter

To study the influence of trace elements on the corrosion and hydrogen ingress in Zr-2.5 Nb pressure tube material, buttons of this alloy containing up to 0.83 at% Fe were made by arc-melting. The buttons were then annealed at 973 K for three days, furnace cooled, followed by ≈80% cold-rolling. The microstructure of cold-worked Zr-2.5 at% Nb-0.83 at% Fe (Fig. 1) contained both β-Zr and intermetallic precipitates in the α-Zr grains. The particles were 0.1 to 0.7 μm in size, with shapes ranging from spherical to ellipsoidal and often contained faults. β-Zr appeared either roughly spherical or as irregular elongated patches, often extending to several micrometres.The composition of the intermetallic particles seen in Fig. 1 was determined using Van Cappellen’s extrapolation technique for energy dispersive X-ray analysis of thin metal foils. The method was employed to avoid corrections for absorption and fluorescence via the Cliff-Lorimer equation: CA/CB = kAB · IA/IB, where CA and CB are the concentrations by weight of the elements A and B, and IA and IB are the X-ray intensities; kAB is a proportionality factor.


Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.


1979 ◽  
Vol 7 (6) ◽  
pp. 1330-1331
Author(s):  
E. D. WILLS

Sign in / Sign up

Export Citation Format

Share Document