Nitrification sediments

Continuous Multicomponent Distillation Column 501 Gas Separation by Membrane Permeation 475 Transport of Heavy Metals in Water and Sediment 565 Residence Time Distribution Studies 381 Nitrification in a Fluidised Bed Reactor 547 Conversion of Nitrobenzene to Aniline 329 Non-Ideal Stirred-Tank Reactor 374 Oscillating Tank Reactor Behaviour 290 Oxidation Reaction in an Aerated Tank 250 Classic Streeter-Phelps Oxygen Sag Curves 569 Auto-Refrigerated Reactor 295 Batch Reactor of Luyben 253 Reversible Reaction with Temperature Effects 305 Reversible Reaction with Variable Heat Capacities 299 Reaction with Integrated Extraction of Inhibitory Product 280... 

The biogeochemical cycling of nitrogen is very much controlled by redox reactions. This perspective is presented in Figure 24.3 for the redox reactions that take place in the water column and sediments. The major pathways of reduction are nitrogen fixation, assimilatory nitrogen reduction, and denitrification. The major oxidation processes are nitrification and anaerobic ammonium oxidation (anammox). Each of these is described next in further detail. 

Reddy KR, Patrick WH, Jr., Lindau CW. 1989. Nitrification-denitrification at the plant root-sediment interface in wetlands. Limnology and Oceanography 34 1004-1013. 

Seventeen genera of facultative anaerobic bacteria (e.g., Pseudomonas and Bacillus) can perform denitrification under anaerobic or low-oxygen conditions, where they use NO3- as an electron acceptor during anaerobic respiration (Jaffe, 2000). In fact, in many estuaries, denitrification is limited by the availability of NC>3 (Koike and Sprensen, 1988 Cornwell et al., 1999). Sources of NC>3 and NC>2 for denitrification are from diffusive inputs from the overlying water column and nitrification in the sediments (Jenkins and Kemp, 1984). The activity of other bacterial processes under anoxic conditions has been shown to affect the activity of denitrifying bacteria. For example, SO42- reduction occurs in anoxic sediments whereby SC>42 is reduced to sulfide (Morse et al., 1992)—more... 

Figure 10.15 Major pathways of the N cycle in sediments (a), as a function of redox conditions in bottom waters and sediments (b). Both diffusive and advective processes strongly control the distribution of O and N compounds which ultimately affect the coupling between nitrification and denitrification. (Modified from Jprgensen and Boudreau, 2001.)...

An, S.M., and Joye, S.B. (2001) Enhancement of coupled nitrification-denitrification by benthic photosynthesis in shallow estuarine sediments. Limnol. Oceanogr. 46, 62-74. 

Carini, S., Orcutt, B.N., and Joye, S.B. (2003) Interactions between methane oxidation and nitrification in coastal sediments. Geomicrobiol. J. 20, 355-374. 

Henriksen, K., Hansen, J.I., and Blackburn, T.H. (1981) Rates of nitrification, distribution of nitrifying bacteria, and nitrate fluxes in different types of sediment from Danish waters. Mar. Biol. 61, 299-304. 

Henriksen, K., and Kemp, W.M. (1988) Nitrification in estuarine and coastal marine sediments. In Nitrogen Cycling in Coastal Marine Environments. SCOPE (Blackburn, T.H., and Sprensen, J., eds.), pp. 207-249, John Wiley, New York. 

Hulth, S., Aller, R.C., and Gilbert, F. (1999) Coupled anoxic nitrification/manganese reduction in marine sediments. Geochim. Cosmochim. Acta 63, 49-66. 

Jensen, K., Sloth, N.P., Rysgaard-Petersen, N., Rysgaard, S., and Revsbech, N.P. (1994) Estimation of nitrification and denitrification from microprofiles of oxygen and nitrate in model sediments. Appl. Environ. Microbiol. 60, 2094—2100. 

Joye, S.B., and Hollibaugh, J.T (1995) Sulfide inhibition of nitrification influences nitrogen regeneration in sediments. Science 270, 623-625. 

Risgaard-Petersen, N. (2003) Coupled nitrification-denitrification in autotrophic and heterotrophic estuarine sediments on the influence of benthic algae. Limnol. Oceanogr. 48, 93-105. 

Rysgaard, S., Christensen, P.B., and Nielsen, L.P. (1995) Seasonal variation in nitrification and denitrification in estuarine sediment colonized by benthic microalgae and bioturbating infauna. Mar. Ecol. Prog. Ser. 126, 111-121. 

Rysgaard, S., Thastum, P., Dalsgaard, T., Christensen, P.B., and Sloth, N.P. (1999) Effects of salinity on NH4+ adsorption capacity, nitrification, and denitrification in Danish estuarine sediments. Estuaries 22, 21-30. 

Usui, T., Koike, I., and Ogura, N. (2001) N2O production, nitrification and denitrification in an estuarine sediment. Estuar. Coastal Shelf Sci. 52, 769-781. 

In some cases, the effects of complex environmental mixtures could be accounted for in terms of concentration-additive effects of a few chemicals. In sediments of the German river Spittelwasser, which were contaminated by chemical industries in its vicinity, around 10 chemicals of a cocktail of several hundred compounds were found to explain the toxicity of the complex mixture to different aquatic organisms (Brack et al. 1999). The complex mixture of chemicals contained in motorway runoff proved toxic to a crustacean species (Gammarus pulex). Boxall and Maltby (1997) identified 3 polycyclic aromatic hydrocarbons (PAHs) as the cause of this toxicity. Subsequent laboratory experiments with reconstituted mixtures revealed that the toxicity of motorway runoff could indeed be traced to the combined concentration-additive effects of the 3 PAHs. Svenson et al. (2000) identified 4 fatty acids and 2 monoterpenes to be responsible for the inhibitory effects on the nitrification activity of the bacteria Nitrobacter in wastewater from a plant for drying wood-derived fuel. The toxicity of the synthetic mixture composed of 6 dominant toxicants agreed well with the toxicity of the original sample. 

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