Etude expérimentale de la dénitrification in situ en eaux courantes : application à la rivière Charente

Torre, M.; Rebillard, J.P.; Ayphassorho, H.; Labroue, L.; Helmer, Christine

doi:10.1051/limn/1992023

Cited by 12 publications

(4 citation statements)

References 10 publications

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“…Increases in the input of nitrogen (N) from fertilisers and other sources in recent decades have been reflected in rises in the concentration of combined N in many rivers and other aquatic systems (Royal Commission of Environmental Protection, 1983;Torre et al, 1992). However, mass balance calculations for total N in some Ontario rivers (Hill, 1979(Hill, , 1981(Hill, , 1983) have shown that there was a net loss of N. Among the important processes involved in this loss is denitrification, which is the dissimilatory reduction of nitrate, via nitrite, to the gaseous products, N 2 O and/or N 2 .…”

Section: Introductionmentioning

confidence: 99%

Denitrification in river sediments: relationship between process rate and properties of water and sediment

1998

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1. A survey was made of denitrification and nitrous oxide (N2O) production in river sediments at fifty sites in north‐east England during one season in order to investigate the relationship between rates and environmental factors likely to influence these processes. The sites were chosen to represent a wide range of physical and chemical conditions. Denitrification rate and N2O production were measured within 5 h of sampling using the slurry acetylene blockage technique. 2. Denitrification rate ranged from less than 0.005–260 nmol N g–1 DW h–1, tending to increase in a downstream direction. N2O production ranged from negative values (net consumption) to 13 nmol N2O‐N g–1 DW h–1 and accounted for 0–115% of the N gases produced. 3. Denitrification rate and N2O concentration in the sediment were correlated positively with nitrate concentration in the water column, water content of the sediment and percentage of fine (< 100 μm) particles in the sediment. 4. The variation in denitrification rate was satisfactorily explained (64% total variance) by a model employing measurements of water nitrate and water content of sediments. No simple or multiple relationship was found for N2O production.

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Section: Introductionmentioning

confidence: 99%

Denitrification in river sediments: relationship between process rate and properties of water and sediment

1998

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“…Although rivers are usually the first aquatic system to receive the excess of nitrate, fewer studies have been undertaken on them than on soils or estuaries. Only one (2,27) or a few sites down the river (4) have been sampled, and it is therefore difficult to generalize from the results. According to the river continuum concept of Vannote et al (28), the physical and chemical variables of water and sediments should present a gradient from the headwaters to the estuary, which should elicit a series of responses within the denitrifying bacterial population.…”

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confidence: 99%

Kinetic Parameters of Denitrification in a River Continuum

García‐Ruiz

Pattinson

Whitton

1998

Appl Environ Microbiol

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Kinetic parameters for nitrate reduction in intact sediment cores were investigated by using the acetylene blockage method at five sites along the Swale-Ouse river system in northeastern England, including a highly polluted tributary, R. Wiske. The denitrification rate in sediment containing added nitrate exhibited a Michaelis-Menten-type curve. The concentration of nitrate for half-maximal activity (Kmap ) by denitrifying bacteria increased on passing downstream from 13.1 to 90.4 μM in the main river, but it was highest (640 μM) in the Wiske. The apparent maximal rate (Vmaxap ) ranged between 35.8 and 324 μmol of N m−2 h−1 in the Swale-Ouse (increasing upstream to downstream), but it was highest in the Wiske (1,194 μmol N m−2 h−1). A study of nitrous oxide (N2O) production at the same time showed that rates ranged from below the detection limit (0.05 μmol of N2O-N m−2 h−1) at the headwater site to 27 μmol of N2O-N m−2 h−1 at the downstream site. In the Wiske the rate was up to 570 μmol of N2O-N m−2 h−1, accounting for up to 80% of total N gas production.

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“…For that purpose, several authors have proposed to measure nitrate uptake using benthic chambers in the field (e.g. Chestéri-koff et al 1992, Torre et al 1992, Duff et al 1996. We decided not to choose this method because it prevents atmospheric reaeration due to the complete isolation of the volume of water from the atmosphere.…”

Section: Discussionmentioning

confidence: 99%

Comparative use of field and laboratory mesocosms for in-stream nitrate uptake measurement

Turlan¹,

Bírgand²,

Marmonier

2007

Ann. Limnol. - Int. J. Lim.

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Recent publications suggest that in large watersheds a large proportion (20 to 70%) of the net nitrogen input to the aquatic environment may be removed during water's downstream path towards the outlet. In small watersheds there are few to no evaluations of the importance of in-stream processes in the overall nitrogen budget due in part to the lack of simple and robust methods for measuring in-stream nitrate uptake. We propose a comparative study for laboratory and field measurements on open mesocosms, 30 cm in diameter. Nitrate uptake was evaluated from the kinetics of disappearance of nitrate in water overlying undisturbed sediment cores, both in the laboratory and in-situ. Using both laboratory and in-situ mesocosms was an effort to determine whether the methods were comparable and applicable on a routine basis. Nitrate disappearance kinetics in the laboratory yielded expected results, which are that nitrate uptake rates are linearly correlated to nitrate concentration in the water column. In such conditions, our results show that the potential for nitrate uptake in streams can be calculated from the mass transfer coefficient. Our comparative study shows that incubations conducted in the laboratory intrinsically limit hyporheic exchanges, associated with small water level fluctuations, which may in fact prevail in the field as the in-situ incubations have shown. In-situ experiments yielded unexpected results, such as the succession of disappearance and gain of nitrate in the mesocosms through time. This was attributed to hyporheic exchanges, both natural and artificially induced by the design of the mesocosms. Both methods should be considered for future nitrate uptake studies as they yield complementary results, provided that some simple changes are made in the design of in-situ mesocosms.

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Etude expérimentale de la dénitrification in situ en eaux courantes : application à la rivière Charente

Cited by 12 publications

References 10 publications

Denitrification in river sediments: relationship between process rate and properties of water and sediment

Denitrification in river sediments: relationship between process rate and properties of water and sediment

Kinetic Parameters of Denitrification in a River Continuum

Comparative use of field and laboratory mesocosms for in-stream nitrate uptake measurement

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