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Effects of nitrate availability and the presence of Glyceria maxima the composition and activity of the dissimilatory nitrate-reducing bacterial community

Nijburg, J.W. and Coolen, M. and Gerards, S. and Klein Gunnewiek, P.J.A. and Laanbroek, H.J. (1997) Effects of nitrate availability and the presence of Glyceria maxima the composition and activity of the dissimilatory nitrate-reducing bacterial community. Applied and Environmental Microbiology, 63, 931-937. ISSN 0099-2240.

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Official URL: http://aem.asm.org/content/63/3/931.abstract

Abstract

The effects of nitrate availability and the presence of Glyceria maxima on the composition and activity of the dissimilatory nitrate-reducing bacterial community were studied in the laboratory. Four different concentrations of NO3-, 0, 533, 1434, and 2,905 mu g of NO3--N g of dry sediment(-1), were added to pots containing freshwater sediment, and the pots were then incubated for a period of 69 days. Upon harvest, NH4+ was not detectable in sediment that received 0 or 533 mu g of NO3-- N g of dry sediment(-1). Nitrate concentrations in these pots ranged from 0 to 8 mu g of NO3--N g of dry sediment(-1) at harvest. In pots that received 1,434 or 2,905 mu g of NO3--N g of dry sediment(-1), final concentrations varied between 10 and 48 mu g of NH4+-N g of dry sediment(-1) and between 200 and 1,600 mu g of NO3--N g of dry sediment(-1), respectively. Higher input levels of NO3- resulted in increased numbers of potential nitrate-reducing bacteria and higher potential nitrate-reducing activity in the rhizosphere. In sediment samples from the rhizosphere, the contribution of denitrification to the potential nitrate-reducing capacity varied from 8% under NO3--limiting conditions to 58% when NO3- was in ample supply. In bulk sediment with excess NO3-, this percentage was 44%. The nitrate-reducing community consisted almost entirely of NO2--accumulating or NH4+-producing gram- positive species when NO3- was not added to the sediment. The addition of NO3- resulted in an increase of denitrifying Pseudomonas and Moraxella strains. The factor controlling the composition of the nitrate-reducing community when NO3- is limited is the presence of G. maxima. In sediment with excess NO3-, nitrate availability determines the composition of the nitrate-reducing community. [KEYWORDS: Denitrifying bacteria; denitrification; soil; sediments; populations; rhizosphere; reduction; acetylene; plants; roots]

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:10519
Deposited On:25 Nov 2011 01:00
Last Modified:31 Mar 2014 10:17

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