Resumen

CASTRO-MANCILLA, Yudith Viridiana et al. Variation of soil microbial populations affected by the addition of hydrocarbons. Terra Latinoam [online]. 2013, vol.31, n.3, pp.221-230. ISSN 2395-8030.

Microbial populations are altered by the presence of hydrocarbons, particularly those who are capable of using as a carbon source. This work aimed to evaluate the effect of hydrocarbons on soil microbial populations. The experiment was conducted under greenhouse conditions with five treatments: T1 = control; T2 = soil + oil; T3 = soil + oil + nitrogen and phosphorus (NP); T4 = soil + diesel and T5 = soil + diesel + nitrogen and phosphorus (NP). Agricultural soil was used expressly contaminated with 10% by weight in automotive lubricating oil for T2 and T3 or with diesel for T4 and T5. The variation in soil microbial populations was determined by the technique of most probable number (MPN). We measured soil respiration and the total content of petroleum hydrocarbons. The results indicated that soil microorganisms and hydrocarbon degraders were stimulated by the presence of oil and diesel. The population ranged from 1 × 105 CFU g-1 control soil to 1 × 108 CFU g-1 in the soil with diesel + nitrogen and phosphorus, the latter was the highest value. The addition of both hydrocarbons increased soil biological activity evaluated as the index and soil respiration measured as CO2 production, which ranged from 1% in the control soil to 9% in the soil + diesel and nutrients (NP). It is concluded that diesel and automotive lubrication oil influenced the dynamics of soil microbial populations and microbial community that uses them as a carbon source, as indicated by CO2 production, by product of hydrocarbon degradation. The balance of carbon, nitrogen and phosphorus (C:N:P) in soils, favors the use of hydrocarbons by soil microbial populations; microbial populations are limited to the substrate, that is to say, the amount of available hydrocarbons in the soil.

Palabras llave : bioremediation; microorganisms.