Denitrification rates

Grajek, W.H. and WaUcowiak-Tomczak, D., Factors influencing the denitrification rate of red beet juice by the bacteria Paracoccus denitrificans, J. Agric. Food Chem., 45, 1963, 1997. 

Sexstone AJ, Revsbech NP, Parkin TB, Tiedje JM. 1985. Direct measurement of oxygen profiles and denitrification rates in soil aggregates. Soil Sci Soc Am 1 49 645-51. 

Compared to denitrification rates, burial in the sediments is a minor loss of nitrogen from the oceans. Current estimates suggest that shelf sediments are the major site of denitrification (14TgNy ) with a minor contribution from the sediments in the open ocean (0.8TgN ). 

Estimates of denitrification rates range from 54 to 345 xmol/m2 per hour in streams with high rates of organic matter deposition, 12 to 56 xmol/m2 per hour in nutrient-poor oligotrophic lakes, and 42 to 171 xmol/m2 per hour in eutrophic lakes (62). Rudd et al. (64) reported an increase in the rate of denitrification from less than 0.1 to over 20 xmol/m2 per hour in an oligotrophic lake when nitric acid was added in a whole-lake experimental acidification. This result suggests that freshwater denitrification may be limited by N03" availability. In deep muds of slow-flowing streams, the process can effectively reduce N03" concentrations in... 

Figure 2. Effect of operating time on denitrification rate constants at 1000 psig...

Figure 3 shows a plot of the first-order denitrification rate constants vs. time on-stream at an operating pressure of 1500 psig. The catalysts with the highest initial denitrification activity at 1500 psig were catalyst... 

Stanford, G., Vanderpol, R. A., and Dzienia, S. (1975). Denitrification rates in relation to total and extractable soil carbon. Soil Sci. Soc. Am. Proc. 39, 284-289. 

Nielsen, K., Nielsen, L.P., and Rasmussen, P. (1995) Estuarine nitrogen retention independently estimated by the denitrification rate and mass balance methods a study of Norsminde Fjord, Denmark. Mar. Ecol. Prog. Ser. 119, 275-283. 

Nowicki, B.L. (1994) The effect of temperature, oxygen, salinity, and nutrient enrichment on estuarine denitrification rates measured with a modified nitrogen gas flux technique. Estuar. Coastal Shelf Sci. 38, 137-156. 

Sprensen, J. (1978) Denitrification rates in a marine sediment measured by the acetylene inhibition technique. Appl. Environ. Microbiol. 36 139-143. 

Ronner, U., and Sorensson, F. (1985). Denitrification rates in the low-oxygen waters ofthe stratified Baltic Proper. Appl. Environ. Microbiol. 50, 801—806. 

The approach is most useful in water samples because complete mixing of the tracer is possible. In sediments, rate measurements are constrained by the inhomogeneous nature of the sample and the dependence of rates on the structure of the environment. In this situation, fluxes between overlying water and sediment cores can be analyzed to obtain areal rates. In conjunction with tracer addition, estimates of nitrification rates can be obtained from the dilution ofN02 or N03 in the overlying water due to its production in the sediments (Capone et ai, 1992). The isotope pairing method for measurement of denitrification (Nielsen, 1992 Rysgaard et ai, 1993) is essentially an isotope dilution approach from which both nitrification and denitrification rates can be calculated. 

Bianchi, M., Bonn, P., and Fehatra (1994). Bacterial nitrification and denitrification rates in the Rhone River plume (northwestern Mediterranean Sea). Marine Ecology-Progress Series 103, 197-202. 

Magalhaes, C. M., Joye, S. B., Moreira, R. M., Weibe, W. J., and Bordalo, A. A. (2005). Effect of salinity and inorganic nitrogen concentrations on nitrification and denitrification rates in intertidal sediments and rocky biofifins of the Douro River estuary, Portugal. Water Research 9, 1783—1794. 

Various methods have been used to estimate water-column denitrification rates including stoichiometric relationships, measurements of the enzymatic activity of the electron transport system (ETS), and N03 incubation experiments. In combination with residence times or mass transport calculations these measurements yield areal denitrification rates. 

Again, one can then calculate the nitrate deficit from Eq. (6.4). This method has been used primarily to estimate denitrification rates in the Arabian Sea (HoweU et ah, 1997 Mantoura et ah, 1993 Naqvi, 1987). 

Measurement of the enzyme activity of the respiratory electron transport system (ETS activity) has also been used to estimate denitrification rates in the Arabian Sea (Naqvi and Shail a, 1993) and eastern tropical South Pacific (Codispoti and Packard, 1980) denitrification zones. To measure the ETS activity a crude enzyme extract is made by grinding filtered seawater samples in a buffered medium to liberate the enzymes, after which the ETS substrates NADT1+ and NADPT1+ along with tetrazo-hum salt are added as an artificial electron acceptor. Samples are then incubated for a... 

Sedimentary denitrification rates have been estimated from measured pore-water solute profiles using diagenetic models, determined direcdy via sediment incubation both on deck and in situ, and determined from N-incubation techniques. Sedimentary diagenetic process can be thought of as a simple reaction—diffusion-transport system (Berner, 1980 Boudreau, 1997). In a simple fine-grained sediment system, transport is via molecular diffusion and the diagenetic equation describing this system can be expressed as ... 

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