Title: Soil Biology & Biochemistry

Title: Soil Biology & Biochemistry

ISO Abbreviated Title: Soil Biol. Biochem.

JCR Abbreviated Title: Soil Biol Biochem

ISSN: 0038-0717

Issues/Year: 12

Journal Country England

Language: Multi-Language

Publisher: Pergamon-Elsevier Science Ltd

Publisher Address: The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England

Subject Categories:

Agriculture, Soil Science: Impact Factor 1.747, 1/29 (2000)

Mullen, M.D., Wolf, D.C., Beveridge, T.J. and Bailey, G.W. (1992), Sorption of heavy-metals by the soil fungi Aspergillus-Niger and Mucor-rouxii. Soil Biology & Biochemistry, 24 (2), 129-135.

Full Text: S\Soi Bio Bio24, 129.pdf

Abstract: Sorption of the nitrate salts of cadmium(II), copper(II), lanthanum(III) and silver(I) by two fungi, Aspergillus niger and Mucor rouxii, was evaluated using Freundlich adsorption isotherms and energy dispersive X-ray electron microscopy. The linearized Freundlich isotherm described the metal sorption data well for metal concentrations of 5 µm^-1 mm metal. Differences in metal binding were observed among metals, as well as between fungal species- Calculated Freundlich K values indicated that metal binding decreased in the order La³⁺ greater-than-or-equal-to Ag⁺ > Cu²⁺ > Cd²⁺. However, sorption of Ag⁺ was greater than that of La³⁺ from solutions of 0.1 and 1 mm metal and likely due to precipitation at the cell wall surface. At the 1 mm initial concentration, there were no significant differences between the two fungi in metal sorption, except for Ag⁺ binding. At the 5 µm concentration, there was no difference between the fungi in their sorption capacities for the four metals. Electron microscopy-energy dispersive X-ray analysis indicated that silver precipitated onto cells as colloidal silver. The results indicate that Freundlich isotherms may be useful for describing short-term metal sorption by fungal biomass and for comparison with other soil constituents in standardized systems.

Keywords: Bacillus-Subtilis, Stability-Constants, Cell-Walls, Biomass, Removal, Cadmium, Adsorption, Retention, Polymers, Binding

Ledin, M., Krantzrulcker, C. and Allard, B. (1996), Zn, Cd and Hg accumulation by microorganisms, organic and inorganic soil components in multicompartment systems. Soil Biology & Biochemistry, 28 (6), 791-799.

Full Text: S\Soi Bio Bio28, 791.pdf

Abstract: A multi-compartment system, PIGS (Partitioning in Geobiochemical Systems), with five compartments was constructed to study metal distribution between soil constituents. Soil microorganisms (Pseudomonas putida, Trichoderma harzianum) were compared with common soil minerals (kaolin and aluminium oxide) and solid organic matter (peat) with respect to their ability to accumulate Zn, Cd and Hg. Experiments were conducted under conditions that are representative of natural soils concerning pH, metal concentration, ionic strength and microbial activity. Different relative amounts of the solid phases were used to approach natural conditions. Results from the PIGS indicated considerable differences in metal distribution between the various solids and also indicated that for the different solid phases metal distribution was related to variations in pH and ionic strength of the solutions in different ways. The presence of fulvic acid generally decreased metal accumulation by peat and microorganisms around neutral pH. Accumulation by organic compounds (peat), as well as by microorganisms, was substantial under experimental conditions used, i.e. up to more than 40 and 20% of the added metals was accumulated by these components, respectively. In some cases the considerable accumulation of trace metals by the fungus and the bacterium under acidic conditions is of particular interest, since this process may counteract the metal-mobilizing effects of soil acidification. It is evident from our study that microorganisms should not be overlooked when studying metal interactions with soil constituents.

Krantz-Rülcker, C., Allard, B. and Schnürer, J. (1996), Adsorption of IIB-metals by three common soil fungi: Comparison and assessment of importance for metal distribution in natural soil systems. Soil Biology & Biochemistry, 28 (7), 967-975.

Full Text: S\Soi Bio Bio28, 967.pdf

Abstract: Interactions of IIb-elements, Zn, Cd and Hg, with three common soil fungi, Trichoderma harzianum, Penicillium spinulosum and Mortierella isabellina, have been studied. The accumulation of the metals by the fungi was studied as a function of pH at constant ionic strength and at concentration levels of the metals representative of natural systems. Two stages of fungal activity were considered in the experiments. The fungi generally exhibited high affinity for metal ions indicated by distribution coefficients (log K_d, in 1 kg^-1) of about 3.5±1, 2.5±1 and 4±1 for Zn, Cd and Hg, respectively. The pH-dependence of the accumulation as well as the isotherms at constant pH were similar between the fungi, and the maximum capacities were at least 50 mmoles kg^-1 mycelium (dw). Metal accumulation by starved mycelia was almost independent of pH, while non-starved mycelia in two cases accumulated more metals at low pH. Calculations of the distribution of metals in a model soil system of inorganic and organic constituents as well as fungal biomass indicated that the amounts of metal associated to the fungi are negligible at neutral pH. However, due to the ability of these fungi to accumulate metals independently of pH, the fraction of metals associated to fungal biomass at low pH may be significant, and, in some cases, predominant. This illustrates that the effects of fungi on metal distribution in soil should not be neglected, e.g. during a progressing acidification.

Speir, T.W., Kettles, H.A., Parshotam, A., Searle, P.L. and Vlaar, L.N.C. (1999), Simple kinetic approach to determine the toxicity of As(V) to soil biological properties. Soil Biology & Biochemistry, 31 (5), 705-713.

Full Text: S\Soi Bio Bio31, 705.pdf

Full Text: Three New Zealand soils of contrasting texture, organic matter content and CEC were amended with Na₂HAsO₄.7H₂O solutions, spanning the concentration range, 0–50 mol As[V] g^-1 soil. Samples were assayed for phosphatase, sulphatase and urease enzyme activities and for basal respiration, microbial biomass C (by substrate-induced respiration, SIR), dimethyl sulphoxide (DMSO)-reducing activity and denitrification, 3 and 60 d after amendment. Only phosphatase, sulphatase and DMSO-reducing activities were consistently inhibited by As[V], the remaining properties were generally unaffected or were stimulated. When inhibition occurred, it could in most instances be explained by one or both of two simple Michaelis Menten kinetic models. The first of these (model 1) described fully competitive kinetics and the second (model 2) described partially competitive kinetics. A single inhibition constant, similar to ED₅₀ (ecological dose) as conceptualised in previous studies, could be calculated. In comparison with heavy metals, As[V] was not a potent inhibitor of soil biochemical properties, with ED₅₀ values ranging from 2.18–556 mol As g^-1 soil (0.163–41.7 g kg^-1). Generally, phosphatase was the most sensitive property, probably due to the structural similarity of phosphate and arsenate. Basal respiration and denitrification were the most activated properties, the former increasing linearly with increasing As[V] concentration. Soil textural characteristics influenced the sensitivity of properties between the different soils, the coarsely textured sandy soil was both the most biochemically sensitive to and the least sorptive of As[V]. For one soil only there was a consistent effect of time since amendment, with diminished inhibition or enhanced activation at 60 d compared with 3 d.

Kampichler, C., Bruckner, A. and Kandeler, E. (2001), Use of enclosed model ecosystems in soil ecology: A bias towards laboratory research. Soil Biology & Biochemistry, 33 (3), 269-275.

Full Text: S\Soi Bio Bio33, 269.pdf

Enclosed model ecosystems, or microcosms, have become a major research tool in soil ecology. Due to the speed, statistical power and mechanistic insights attainable with laboratory-based microcosm experiments, these have added considerably to our ecological knowledge. However, soil ecologists agree that, due to problems of scale and artificiality, microcosm research should be carried out in the context of appropriately scaled field model ecosystems (e.g. mesocosms). This paper aims at clarifying the terminology of enclosed model ecosystems as well as determining and discussing the frequency with which laboratory and field model ecosystems are used in current soil-ecological research. Among 92 model ecosystem studies published from 1993 to 1998 in soil biological journals, only 19 were performed in the field. Laboratory microcosms are, on average, significantly smaller and experiment duration is significantly shorter than in field model ecosystem studies. They are easier to maintain and allow for a larger number of experiments in a unit of time. We argue that the bias towards laboratory research is mainly caused by the growing demand for publications with high-impact ratings in an increasingly competitive scientific world and by the fact that an increasing emphasis is being placed on subjects where research can be carried out very quickly.

Keywords: Microcosm, Mesocosm, Enclosure, Scale, Reality, Publication Impact Factors