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Sites that are N-rich either naturally or following disturbance have a high potential to function as sources of most of the reactive N forms identified in Table 13.1 because mineralization and nitrification, the processes that produce most of these reactive forms, occur at high rates.

Nitrogen sinks are defined as habitats that have a high potential to remove reactive N from the environment, preventing its movement into adjacent ecosystems. Ecosystems such as wetlands that are wet and rich in organic materials, for example, have a great potential to function as sinks because of their ability to support denitri-fication. In many cases these sink areas absorb reactive N produced in source areas of the landscape. Riparian buffer zones next to streams, for example, can be managed to absorb nitrate moving out of crop fields in groundwater (Lowrance et al., 1984). This nitrate can be stored in plant tissue or in soil organic matter as organic N or can be denitrified to N gas and thereby released to the atmosphere—preferably as N2, a nonreactive form.

Humans have doubled the circulation of reactive N on earth, creating a nitrogen cascade in which added N flows through the environment, leading to degradation of air and water quality and coastal ecosystems in many areas (Vitousek et al., 1997; Galloway et al., 2003). Solutions to landscape, regional, and global N enrichment problems often rely heavily on managing microbial N transformations. For example, coastal areas of the Gulf of Mexico suffer from eutrophication

TABLE 13.4 Criteria for Determining if a Site Is a Source or a Sink of N in the Landscape (from Groffman, 2000)

Criteria

Is the site N rich?

Is the site highly disturbed?

Does the site have a high potential for denitrification?

Does the site have a high potential for NH3 volatilization?

Determinants

Fertilized Fine texture (clay) Legumes Wet tropics

Disturbance of plant uptake (e.g., harvest) Stimulation of mineralization (e.g., tillage) Disturbance of links between plant and microbial processes (e.g., tillage)

Wet soil

Well-aggregated

High available organic matter

and hypoxia that have been linked to excess N from the Mississippi river basin (Turner and Rabalais, 1994). Proposed solutions to this problem include better management of microbial N- transformations in crop fields as well as the creation of denitrifying wetland sinks for excess N moving out of agricultural areas (Mitsch et al., 2001).

Source-sink dynamics of N ultimately depend on the juxtaposition of different ecosystems in the landscape and the hydrologic and atmospheric transport vectors that link them—a complex topic that requires knowledge of hydrology and atmospheric chemistry in addition to soil ecology and microbiology. Because soil microbes play a crucial role in forming and consuming reactive N in the environment, however, their management can be an important and even crucial means for regulating N fluxes at local, regional, and global scales.

references and suggested reading

Bergsma, T. T., Robertson, G. P., and Ostrom, N. E. (2002). Influence of soil moisture and land use history on denitrification end products. J. Environ. Qual. 31, 711-717.

Cooper, G. S., and Smith, R. (1963). Sequence of products formed during denitrification. Soil Sci. Soc. Am. Pro. 27, 659-662.

De Boer, W., and Kowalchuk, G. A. (2001). Nitrification in acid soils: micro-organisms and mechanisms. Soil Biol. Biochem. 33, 853-866.

Firestone, M. K., and Davidson, E. A. (1989). Microbiological basis of NO and N2O production and consumption in soil. In "Trace Gas Exchange between Terrestrial Ecosystems and the Atmosphere" (M. D. Andreae and D. S. Schimel, eds.), pp. 7-22. Wiley, Berlin.

Francis, C. A., Roberts, K. J., Beman, J. M., Santoro, A. E., and Oakley, B. B. (2005). Ubiquity and diversity of ammonia-oxidizing archaea in water columns and sediments of the ocean. Proc. Natl. Acad. Sci. USA 102, 14683-14688.

Freitag, T. E., Chang, L., Clegg, C. D., and Prosser, J. I. (2005). Influence of inorganic nitrogen-management regime on the diversity of nitrite oxidizing bacteria in agricultural grassland soils. Appl. Environ. Microbiol. 71, 8323-8334.

Freney, J. R., Randall, P. J., Smith, J. W. B., Hodgkin, J., Harrington, K. J., and Morton, T. C. (2000). Slow release sources of acetylene to inhibit nitrification in soil. Nutrient Cycling Agroecosyst. 56, 241-251.

Galloway, J. N., Aber, J. D., Erisman, J. W., Seitzinger, S. P., Howarth, R. W., Cowling, E. B., and Cosby, B. J. (2003). The nitrogen cascade. BioScience 53, 341-356.

Groffman, P. M. (2000). Nitrogen in the environment. In "Handbook of Soil Science" (M. E. Sumner, ed.), pp. C190-200. CRC Press, Boca Raton, FL.

Groffman, P. M., and Tiedje, J. M. (1988). Denitrification hysteresis during wetting and drying cycles in soil. Soil Sci. Soc. Am. J. 52, 1626-1629.

Groffman, P. M., Tiedje, J. M., Robertson, G. P., and Christensen, S. (1988). Denitrification at different temporal and geographical scales: proximal and distal controls. In "Advances in Nitrogen Cycling in Agricultural Ecosystems" (J. R. Wilson, ed.), pp. 174-192. CAB International, Wallingford, UK.

Hart, S. C., Stark, J. M., Davidson, E. A., and Firestone, M. K. (1994). Nitrogen mineralization, immobilization, and nitrification. In "Methods of Soil Analysis," Part 2, "Microbiological and Biochemical Properties" (R. W. Weaver, J. S. Angle, P. J. Bottomley, D. F. Bezdicek, M. S. Smith, M. A. Tabatabai, and A. G. Wollum, eds.), pp. 985-1018. Soil Sci. Soc. Am., Madison, WI.

Head, I. M., Hiorns, W. D., Embley, T. M., McCarthy, A. J., and Saunders, J. R. (1993). The phylogeny of autotrophic ammonia-oxidizing bacteria as determined by analysis of 16S ribosomal RNA gene sequences. J. Gen. Microbiol. 139, 1147-1153.

Hyvönen, R., Agren, G. I., and Andren, O. (1996). Modeling long-term carbon and nitrogen dynamics in an arable soil receiving organic matter. Ecol. Appl. 6, 1345-1354.

Jetten, M. S. M. (2001). New pathways for ammonia conversion in soil and aquatic systems. Plant Soil 230, 9-19.

Juretschko, S., Timmermann, G., Schmid, M., Schleifer, K. H., Pommerening-Roser, A., Koops, H.-P., and Wagner, M. (1998). Combined molecular and conventional analyses of nitrifying bacterium diversity in activated sludge: Nitrosococcus mobilis and Nitrospira-like bacteria as dominant populations. Appl. Environ. Microbiol. 64, 3042-3051.

Könneke, M., Bernhard, A. E., de la Torre, J. R., Walker, C. B., Waterbury, J. B., and Stahl, D. A. (2005). Isolation of an autotrophic ammonia-oxidizing marine archaeon. Nature 437, 543-546.

Koops, H.-P., and Pommerening-Röser, A. (2001). Distribution and ecophysiology of the nitrifying bacteria emphasizing cultured species. FEMS Microbial. Ecol. 37, 1-9.

Koops, H.-P., Purkhold, U., Pommerening-Roser, A., Timmermann, G., and Wagner, M. (2003). The lithoautotrophic ammonia-oxidizing bacteria. In "The Prokaryotes: an Evolving Electronic Resource for the Microbiological Community" (M. Dworkin et al., eds.). Springer-Verlag, New York, http://link.springer-ny.com/link/service/books/10125/.

Kuypers, M. M. M., Lavik, G., Woebken, D., Schmid, M., Fuchs, B. M., Amann, R., Jorgensen, B. B., and Jetten, S. M. (2005). Massive nitrogen loss from the Benguela upwelling system through anaerobic ammonium oxidation. Proc. Natl. Acad. Sci. USA 102, 6478-6483.

Leininger, S., Urich, T., Schloter, M., Schwark, L., Qi, J., Nicol, G. W., Prosser, J. I., Schuster, S. C., and Schleper, C. (2006). Archaea predominate among ammonia-oxidizing prokaryotes in soils. Nature 442, 806-809.

Linn, D. M., and Doran, J. W. (1984). Effect of water-filled pore space on CO2 and N2O production in tilled and non-tilled soils. Soil Sci. Soc. Am. J. 48, 1267-1272.

Löhnis, F. (1913) "Vorlesungen uber Landwortschaftliche Bacterologia." Borntraeger, Berlin.

Lowrance, R. R., Todd, R. L., Fail, J., Hendrickson, O., Leonard, R., and Asmussen, L. (1984). Riparian forests as nutrient filters in agricultural water sheds. Bioscience 34, 374-377.

Mahendrappa, M. K., Smith, R. L., and Christiansen, A. T. (1966). Nitrifying organisms affected by climatic region in western U.S. Proc. Soil Sci. Soc. Am. 30, 60-62.

Mitsch, W. J., Day, J. W., Gilliam, J. W., Groffman, P. M., Hey, D. L., Randall, G. W., and Wang, N. (2001). Reducing nitrogen loading to the Gulf of Mexico from the Mississippi River basin: strategies to counter a persistent ecological problem. BioScience 51, 373-388.

Mulder, A., van de Graaf, A. A., Robertson, L. A., and Kuenen, J. G. (1995). Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor. FEMS Microbial. Ecol. 16, 177-184.

Norton, J. M. (2000). Nitrification. In "Handbook of Soil Science" (M. E. Sumner, ed.), pp. C160-181. CRC Press, Boca Raton, FL.

Prosser, J. I. (1989). Autotrophic nitrification in bacteria. In "Advances in Microbial Physiology" (A. H. Rose and D. W. Tempest, eds.), pp. 125-181. Academic Press, San Diego.

Prosser, J. I., and Embley, T. M. (2002). Cultivation-based and molecular approaches to characterisation of terrestrial and aquatic nitrifiers. Antonie van Leeuwenhoek 81, 165-179.

Purkhold, U., Pommerening-Roser, A., Juretschko, S., Schmid, M. C., Koops, H.-P., and Wagner, M. (2000). Phylogeny of all recognized species of ammonia oxidizers based on comparative 16S rRNA and amoA sequence analysis: implications for molecular diversity surveys. Appl. Environ. Microbiol. 66, 5368-5382.

Robertson, G. P., and Vitousek, P. M. (1981). Nitrification in primary and secondary succession. Ecology 62, 376-386.

Robertson, G. P. (1989). Nitrification and denitrification in humid tropical ecosystems. In "Mineral Nutrients in Tropical Forest and Savanna Ecosystems" (J. Proctor, ed.), pp. 55-70. Blackwell Sci., Cambridge, UK.

Robertson, G. P. (1997). Nitrogen use efficiency in row-crop agriculture: crop nitrogen use and soil nitrogen loss. In "Ecology in Agriculture" (L. Jackson, ed.), pp. 347-365. Academic Press, New York.

Robertson, G. P. (2000). Denitrification. In "Handbook of Soil Science" (M. E. Sumner, ed.), pp. C181-190. CRC Press, Boca Raton, FL.

Robertson, G. P., and Tiedje, J. M. (1987). Nitrous oxide sources in aerobic soils: nitrification, denitrification, and other biological processes. Soil Biol. Biochem. 19, 187-193.

Robertson, G. P., Wedin, D. A., Groffman, P. M., Blair, J. M., Holland, E., Harris, D., and Nadelhoffer, K. (1999). Soil carbon and nitrogen availability: nitrogen mineralization, nitrification, and soil respiration potentials. In "Standard Soil Methods for Long-Term Ecological Research" (G. P. Robertson, C. S. Bledsoe, D. C. Coleman, and P. Sollins, eds.), pp. 258-271. Oxford Univ. Press, New York.

Schimel, J. P., and Bennett, J. (2004). Nitrogen mineralization: challenges of a changing paradigm. Ecology 85, 591-602.

Schmidt, I., Hermelink, C., van de Pas-Schoonen, K., Strous, M., den Camp, H. J., Kuenen, J. G., and Jetten, M. S. M. (2002). Anaerobic ammonia oxidation in the presence of nitrogen oxides (NOx) by two different lithotrophs. Appl. Environ. Microbiol. 68, 5351-5357.

Sexstone, A. J., Revsbech, N. P., Parkin, T. B., and Tiedje, J. M. (1985). Direct measurement of oxygen profiles and denitrification rates in soil aggregates. Soil Sci. Soc. Am. J. 49, 645-651.

Silver, W. L., Herman, D. J., and Firestone, M. K. (2001). Dissimilatory nitrate reduction to ammonium in upland tropical forest soils. Ecology 82, 2410-2416.

Teske, A., Alm, E., Regan, J. M., Toze, S., Rittman, B. E., and Stahl, D. A. (1994). Evolutionary relationships among ammonia- and nitrite-oxidizing bacteria. J. Bacteriol. 176, 6623-6630.

Tiedje, J. M. (1988). Ecology of denitrification and dissimilatory nitrate reduction to ammonium. In "Biology of Anaerobic Microorganisms" (A. J. B. Zehnder, ed.), pp. 179-244. Wiley, New York.

Tisdale, S. L., Nelson, W. L., Beaton, J. D., and Havlin, J. L. (1993). "Soil Fertility and Fertilizers." 5th ed. Macmillan, New York.

Turner, R. E., and Rabalais, N. N. (1994). Coastal eutrophication near the Mississippi River delta. Nature 368, 619-621.

Vitousek, P. M., Aber, J. D., Howarth, R. W., Likens, G. E., Matson, P. A., Schindler, D. W., Schlesinger, W. H., and Tilman, D. G. (1997). Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 7, 737-750.

Winogradsky, S. (1892). Contributions a la morphologie des organismes de la nitrification. Arch. Sci. Biol. 1, 86-137.

Ye, R. W., Averill, B. A., and Tiedje, J. M. (1994). Denitrification of nitrite and nitric oxide. Appl. Environ. Microbiol. 60, 1053-1058.

Zumft, W. G. (1992): The denitrifying procaryotes. In "The Prokaryotes" (A. Balows, ed.). SpringerVerlag, New York.

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