Controls on nitrification in a water-limited ecosystem: Experimental inhibition of ammonia-oxidising bacteria in the Patagonian steppe
We studied controls on nitrification in an undisturbed water-limited ecosystem by inhibiting autotrophic nitrifying bacteria in soils with varying levels of vegetative cover. The activity of nitrifying bacteria was disrupted using nitrapyrin, 2-chloro-6-(trichloromethyl)-pyridine, under field condit...
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| Autores principales: | , , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00380717_v35_n12_p1609_Lopez |
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| Sumario: | We studied controls on nitrification in an undisturbed water-limited ecosystem by inhibiting autotrophic nitrifying bacteria in soils with varying levels of vegetative cover. The activity of nitrifying bacteria was disrupted using nitrapyrin, 2-chloro-6-(trichloromethyl)-pyridine, under field conditions in three microenvironments (underneath shrubs, next to grasses and in bare soil). Ammonia-oxidising bacteria were detected by PCR analysis of DNA in soils. The inhibition of nitrification changed the concentrations of NO 3 - and NH4 + in the soil, while the microenvironment was most important in determining the response of bacteria to the inhibitor. Nitrapyrin application resulted in a significant (p < 0.05) reduction in soil NO3 - concentration (39%) and a significant increase (p < 0.001) in soil NH4 + concentration (41%). Untreated bare-soil microenvironments had the lowest concentrations of NH4 + (1.57 μg/g of dry soil) and NO3 - (0.49 μg/g of dry soil) when compared to the other microenvironments, and showed the highest impacts of nitrification inhibition. For example, NH4 + concentrations increased 288% and NO3 - concentrations decreased 60% in inhibited bare-soil microenvironments. In contrast, untreated microenvironments underneath shrubs had the highest levels of NH4 + (10.01 μg/g of dry soil) and NO3 - (0.69 μg/g of dry soil), but showed no significant effects of inhibition of nitrification on soil nitrogen concentrations. © 2003 Elsevier Ltd. All rights reserved. |
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