Weathering tropical

Wong, T. P., Byappanahalli, M., Yoneyama, B., and Ray, C. (2008). An evaluation of the mobility of pathogen indicators, Escherichia coli and bacteriophage MS-2, in a highly weathered tropical soil under unsaturated conditions. ]. Water ELealth 6,131-140. 

Where crystalline rock or highly weathered tropical soils are present (i.e. where weathering inputs are low or exhausted), dissolved freshwater chemistry is most influenced by natural atmospheric inputs, for example sea spray and dust, as well as by anthropogenic gases, for example S02. 

Gijsman, A. J., Oberson, A., Tiessen, H., and Frie.sen, D. K. (1996). Limited applicability of the CENTURY model to highly weathered tropical soils. Agronomy J. 88, 894-903. 

Microbial phosphorus is quantified after fumigation of soil with chloroform or hexa-nol to kill soil microorganisms (Brookes et al., 1982). The various modifications of the method, especially in terms of extractants and use of calibration factors, are described elsewhere in this volume (see Oberson and Joner, Chapter 7). For highly weathered tropical soils, the fumigation-extraction method with anion exchange resin membranes (Kouno et al., 1995) or Bray (NH F-HCl) extraction (Oberson et al., 1997) may be most suitable. 

Daroub, S.H., Cerakis, A., Ritchie, J.T., Friesen, D.K. and Ryan, J. (2003) Development of a soil-plant phosphorus simulation model for calcareous and weathered tropical soils. Agricultural Systems 76, 1 157-1 181. 

CHEMICAL WEATHERING (Tropical climate, slow uplift)... 

Special insulation and coating of stator windings and overhangs are sometimes essential to ensure protection against tropical weather, fungus growth, moisture, oil abrasives, and acid and alkali fumes. Powerhouse treatment is one insulating process that ctin meet all these requirements (see Section 9..T). 

Late rites, which are oxide/silicate ores such as gamierite, (Ni,Mg)6Si40io(OH)8, and nickeliferous limonite, (Fe,Ni)0 (0H).nH20, which have been concentrated by weathering in tropical rainbelt areas such as New Caledonia, Cuba and Queensland. 

Weathering in a tropical climate causes polyethylene containers to crack, polypropylene (PP) ropes to rupture, and ABS telephones to foil. Polystyrene (PS) and cellulose acetate films used as packing materials also fail due to weathering. 

Snack Bar garnishes the pitcher with a slice of grapefruit, like a Mediterranean sun. You might drink until it goes down in the evening the house cocktail isn t wearing a watch, and it s as sensual as tropical weather. 

Oxisols Highly weathered and leached, residual Fe and A1 oxides Tropical areas with a stable landscape... 

Fig. 9-8 Histogram of dissolved solids of samples from the Orinoco and Amazon River basins and corresponding denudation rates for morpho-tectonic regions in the humid tropics of South America (Stal-lard, 1985). The approximate denudation scale is calculated as the product of dissolved solids concentrations, mean armual runoff (1 m/yr), and a correction factor to account for large ratios of suspended load in rivers that drain mountain belts and for the greater than average annual precipitation in the lowlands close to the equator. The correction factor was treated as a linear function of dissolved solids and ranged from 2 for the most dilute rivers (dissolved solids less than lOmg/L) to 4 for the most concentrated rivers (dissolved solids more than 1000 mg/L). Bedrock density is assumed to be 2.65 g/cm. (Reproduced with permission from R. F. Stallard (1988). Weathering and erosion in the humid tropics. In A. Lerman and M. Meybeck, Physical and Chemical Weathering in Geochemical Cycles," pp. 225-246, Kluwer Academic Publishers, Dordrecht, The Netherlands.)...

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