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| Vertical variation of dissimilatory nitrate reductase activity and nitrate reducer in the sediments of Lake Donghu |
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Abstract Sediment cores in 3 different sites in Lake Donghu were sampled. And the vertical variation of dissimilatory nitrate reductase (dNaR) activity, nitrate reducer populations, as well as the contents of TOC, TN and NO3--N in sediments were determined. The results showed that the activity of dNaR varied with different sites. The highest activity of dNaR occurred at site III where the pollution load was the highest, and the lowest activity occurred at site I with lowest pollution load. However, the vertical variation patterns of dNaR activity in 3 sites were similar: the top layer of 0cm~15cm showed higher activity, then the activity decreased acutely with the increase of depth below the layer of 15cm. As to Nitrate reducer populations, the quantity kept decreasing with the depth in all 3 sites. Furthermore, the results of statistic analysis revealed that the activity of dNaR was positive correlated to the contents of NO3--N and nitrate reducer (P<0.01) populations (P<0.05), but not correlated to the contents of TOC and TN.
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Received: 11 June 2009
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