ISSN:
1573-5117
Keywords:
denitrification
;
nitrification
;
nitrate ammonification
;
nitrite
;
lake sediment
;
bioturbation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Sediment cores containing different densities of Chironomus plumosus, ranging from 0 to 12 000 ind. m−2, were incubated in the laboratory, with 100 and 39% O2 saturation in the overlying water. Rates of O2 uptake, and fluxes of the various inorganic N species were measured after addition of 15NO inf3 su− to the overlying water. The animals enhanced O2 and NO inf3 su− uptake, due to irrigation. Denitrification of NO inf3 su− coming from the overlying water (Dw) and dissimilatory NO inf3 su− reduction to NH inf4 sup+ (DNRA) represented 20–30 and 4–10% of the NO inf3 su− uptake, respectively. Only 20–40% of the measured NH inf4 sup+ effluxes corresponded to DNRA, the rest was probably due to animal excretion. Nitrite production, mostly from dissimilatory NO inf3 sup− reduction, was detected at both 39 and 100% oxygen saturation. Higher rates of NO inf2 su− production at the lower oxygen concentrations, were probably due to a thinner oxic layer, compared to fully oxygenated waters. The presence of Chironomus plumosus increased nitrification rates, relative to non-inhabited microcosms. However, nitrification rates were low compared to Dw, probably due to low numbers of nitrifiers in the sediment. At 39% oxygen saturation, rates of nitrification and denitrification of NO inf3 su− generated within the sediment were not measurable.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00014989
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