SEARCH

SEARCH BY CITATION

references

  • Aber JD, Nadelhoffer KJ, Steudler P, Melillo JM. 1989. Nitrogen saturation in northern forest ecosystems. Bio Science 39: 378386.
  • Abuzinadah RA, Finlay RD, Read DJ. 1986. The role of proteins in the nitrogen nutrition of ectomycorrhizal plants. II. Utilization of protein by mycorrhizal plants of Pinus contorta. New Phytologist 103: 495506.
  • Amarger N, Mariotti A, Mariotti F. 1977. Essai d'estimation du taux d'azote fixé symbiotiquement chez le Lupin par le tracage ísotopíque naturel (5l3N). Comptes Rendus Academic Science du Paris, Serie D 284: 21792182.
  • Amberger A, Schmidt H-L. 1987. Natürliche isotopengehalte von nitrate als indikatoren fur dessen herkunft. Geochimicu et Cosmochimca Acta 51: 26992705.
  • Andrews M. 1986. The partitioning of nitrate assimilation between root and shoot of higher plants. Plant, Cell and Environment 9: 511519.
  • Aravena R, Evans ML, Cherry JA. 1993. Stable isotopes of oxygen and nitrogen in source identification of nitrate from septic systems. Ground Water 31: 180186.
  • Arrhenius O. 1931. Markanalysen i arkeologins tjänst. Geologiska Foreningens Forhandlingar 53: 4759.
  • Bajwa R, Abuarghub SM, Read DJ. 1985. The biology of mycorrhiza in the Ericaceae. X. The utilization of protein and the production of proteolytic enzymes by the mycorrhizal endophyte and by mycorrhizal plants. New Phytologist 101: 469486.
  • Bardin R, Domenach A-M, Chalamet A. 1977. Rapports isotopiques naturels de l'azote. II. Variations d'abondance du 13N dans les echantillons de sols et plants; applications. Revue Td'Ecologie et de Biology du Sol 14: 395402.
  • Barrit -A, Lemley M. 1989. Automated N-15/C-13 analysis of biological materials. International Laboratory Techniques 19: 8291.
  • BergersenFJ., (ed.) 1980. Methods for evaluating biological nitrogen fixation. Chichester , UK : John Wiley.
  • Bergersen FJ, Peoples MB, Turner GL. 1988. Isotopic discriminations during the accumulation of nitrogen by soybeans. Australian Journal of Plant Physiology 15: 407420.
  • Bergersen FJ, Turner GL. 1983. An evaluation of 16N methods for estimating nitrogen-fixation in a Subterranean clover-perennial ryegrass sward. Australian Journal of Agricultural Research 34: 391401.
  • Bergersen FJ, Turner GL, Amarger N, Mariotti F, Mariotti A. 1986. Strain of Rhizobium lupinus determines the natural abundance of 15N in root nodules of Lupinus spp. Soil Biology and Biochemistry 18: 97101.
  • Bigeleisen J. 1965. Chemistry of isotopes. Science 147: 463471.
  • Binkley D, Hart SC. 1989. Components of nitrogen availability assessments in forest soils. Advances in Soil Science 10: 57112.
  • Binkley D, Soiling P, McGill WB. 1985. Natural abundance of rritrogen-15 as a tool for tracing alder-fixed nitrogen. Soil Science Society of America Journal 49: 444447.
  • Birch HF. 1958. The effect of soil drying on humus decomposition and nitrogen availability. Plant and Soil 10: 931.
  • Bjarnason S. 1988. Calculation of gross nitrogen immobilization and mineralization in soil. Journal of Soil Science 39: 393406.
  • Bjorkman E. 1960. Monotropa hypopitys L an epiparasite on tree roots. Physiologia Planlarum 13: 308327.
  • Bremer E, van Kessel C. 1990. Appraisal of the nitrogen-15 natural-abundance method for quantifying dinitrogen fixation. Soil Science Society of America Journal 54: 404411.
  • Broadbent FE, Rauschkolb RS, Lewis KA, Chang GY. 1980. Spatial variability of nitrogen-15 and total nitrogen in some virgin and cultivated soils. Soil Science Society of America Journal 44: 524527.
  • Bryan BA, Shearer GB, Skecters JL, Kohl DH. 1983. Variable expression of the nitrogen isotope effect associated with denitrification of nitrite. Journal of Biological Chemistry 258: 86138617.
  • Canadell J, Jackson JB, Ehleringer JR. Mooney HA, Sala OE, Schulze E-D. 1996. Maximum rooting depth of vegetation types at the global stale. Oecologia 108: 583595.
  • Chapin FS III, Moilanen L, Kielland K. 1993. Preferential use of organic nitrogen for growth by a non-mycorrhizal arctic sedge. Saturn 361: 150153.
  • Cheng HH, Bremner JM, Edwards AP. 1964. Variations in nitrogen-15 abundance in soils. Science 146: 15741575.
  • Craig H, Miller SL, Wasserberg. 1964. Isotopic and cosmic chemistry. Amsterdam : North-Holland.
  • Cullings KW, Szaro TM, Bruns TD. 1996. Evolution of extreme specialization within a lineage of ectomycorrhizal epiparasites. Nature 379: 6366.
  • Dauncey KDM. 1952. Phosphate content of soils on archaeological sices. Advances in Science 9: 3336.
  • Davidson EA, Hart SC, Firestone MK. 1992. Internal cycling of nitrate in soils of a mature coniferous forest. Ecology 73: 11481156.
  • Davidson EA, Hart SC, Shanks CA, Firestone MK. 1991. Measuring gross nitrogen mineralization, immobilization, and nitrification by 15N isotope dilution in intact soil cores. Journal of Sail Science 42: 335349.
  • Davidson EA, Stark JM, Firestone MK. 1990. Microbial production and consumption of nitrate in an annual grassland. Ecology 71: 19681975.
  • Delwiche CC, Steyn PL. 1970. Nitrogen isotope fractionation in soils and microbial reactions. Environmental Science and Technology 4: 929935.
  • Delwiche CC, Zinke PJ, Johnson CM, Virginia RA. 1979. Nitrogen isotope distribution as a presumptive indication of nitrogen fixation. Botanical Gazette 140: 6569.
  • DeNiro MJ, Hastorf CA. 1985. Alteration of 15N/14N and 13C/12C ratios of plant matter during the initial stages of diagenesis: studies utilizing archaeological specimens from Peru. Geochemical Cosmochimica Acta 49: 97115.
  • Durka W, Schulze E-D, Gebauer G, Voerkelius S. 1994. Effects of forest decline on uptake and leaching of deposited nitrate determined from 15N and 18O measurements. Nature 372: 765767.
  • Edwards AP. 1973. Isotope tracer techniques for identification of sources of nitrate pollution. Journal of Environmental Quality 2: 382387.
  • Ehleringer JR, Mooney HA, Rundel PW, Evans RD, Palma B, Delatorre J. 1992. Lack of nitrogen cycling in the Atacama Desert. Nature 359: 316318.
  • Emmett BA, Kjonaas OJ, Gundersen P, Koopmans C, Tietema A, Sleep D. 1997. Natural abundance of 15N in forests across a nitrogen deposition gradient. Forest Ecology and Management, in press.
  • Ericsson A, Nordén L-G, Näsholm T, Walheim M. 1993. Mineral nutrient tmbalancesand arginine concentrations in needles of Picea abies (L.) Karst. from two areas with different levels of airborne deposition. Trees 8: 6774.
  • Evans RD, Bloom AJ, Sukrapanna SS, Ehleringer JR. 1996. Nitrogen isotope composition of tomato (Lycopersicon esculentum Mill. cv. T-5) grown under ammonium or nitrate nutrition. Plant. Cell and Environment 19: 13171323.
  • Farquhar GD, O'Leary MH, Berry JA. 1982. On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves. Australian Journal of Plant Physiology 9: 121137.
  • Feigin A, Shearer G, Kohl DH, Commoner B. 1974. The amount and nitrogen-15 content of nitrate in soil profiles from two central Illinois fields in a corn-soybean rotation. Soil Science Society of America Proceedings 38: 465471.
  • Felker P, Clark PR. 1982. Position of mesquite (Prompts spp.) nodulation and nitrogen fixation (acetylene reduction) in 3-m long phraetophytically simulated soil columns. Plant and Soil 64: 297305.
  • Focht DD. 1973. Isotope fractionation of 15N and 14N in microbiological nitrogen transformations: a theoretical model. Journal of Environmental Quality 3: 247252.
  • Frank AB. 1885. Über die auf Wurzelsymbiose beruhende Ernährung gewisser Bäume durch unterirdischer Pilze. Berichte Deutsche Botanische Gesellschaft 3: 128145.
  • Freyer HD. 1978. Seasonal trends of NH4+ and NH3 nitrogen isotope composition in rain collected at Jülich. Germany. Tellus 30: 8392.
  • Gaebler OH, Choitz HC, Vitti TG, Vukmirovich R. 1963. Significance of N-15 excess in nitrogenous compounds of biological origin. Canadian Journal of Biochemistry and Physiology 41: 10891097.
  • Gaebler OH, Vitti TG, Vukmirovich R. 1966. Isotope effects on metabolism of 14N and 15N from unlabeled dietary proteins. Canadian Journal of Biochemistry 44: 12491257.
  • Garten CT Jr. 1992. Nitrogen isotope composition of ammonium and nitrate in bulk precipitation and forest throughfall. International Journal of Environmental Analytical Chemistry 47: 3345.
  • Garten CT Jr. 1993. Variation in foliar N abundance and the availability of soil nitrogen on Walker Branch Watershed. Ecology 74: 20982113.
  • Garten CT Jr, van Miegrot H. 1994. Relationships between soil nitrogen dynamics and natural 1SN abundance in plant foliage from the Great Smoky Mountain National Park. Canadian Journal of Forest Research 24: 16361645.
  • Gebauer G, Dietrich P. 1993. Nitrogen isotope ratios in different compartments of a mixed stand of spruce, larch and beech trees and of understorey vegetation including fungi. Isotopenpraxis 29: 3544.
  • Gebauer G, Schulze E-D. 1991. Carbon and nitrogen isotope ratios in different compartments of a healthy and a declining Picea abies forest in the Fichtelgebirge, NE Bavaria. Oecologia 87: 198207.
  • Gigon A, Rorison IH. 1972. The response of some ecologically distinct species to nitrate- and to ammonium-nitrogen Journal of Ecology 60: 92102.
  • Goodroad LL, Keeney DR. 1984. Nitrous oxide emissions from forest, marsh, and prairie ecosystems. Journal of Environmental Quality 13: 448452.
  • Hart SC, Nason GE, Myrold DD, Perry DA. 1994. Dynamics of gross nitrogen transformations in an old-growth forest: the carbon connection. Ecology 75: 880891.
  • Hauck RD. 1973. Nitrogen tracers in nitrogen cycle studies-past use and future needs. Journal of Environmental Quality 2: 317327.
  • Hauck RD, Bartholomew WV, Bremner JM, Broadbent FE, Cheng HH, Edwards AP, Keeney DR, Legg JO, Olsen SR, Porter LK. 1972. Use of variations in natural nitrogen isotope abundance for environmental studies: a questionable approach. Science 177: 453454.
  • Haystead A. 1983. Analysis of nitrogen isotope ratios by mass spectrometry. In: SmithKA, ed. Soil Analysis: Instrumental Techniques and Related Procedures. New York : Marcel Dekker, 377406.
  • Heaton THE. 1986. Isotopic studies of nitrogen pollution in the hydrosphere and atmosphere: a review. Chemical Geology 59: 87102.
  • Heaton THE. 1987. 15N/14N ratios of nitrate and ammonium in rain at Pretoria, South Africa. Atmospheric Environment 21: 843852.
  • Heaton THE, Vogel JC, von la Chevallerie G, Collett G. 1986. Climatic influence on the isotopic composition of bone nitrogen. Nature 322: 822824.
  • Heisey RM, Dejwiche CC, Virginia RA, Wrona AF, Bryan BA. 1980. A new nitrogen fixing non-legume Chamaebatia foliolosa (Rosaceae). American Journal of Botany 63: 429431.
  • Herman DJ, Rundel PW. 1989, Nitrogen isotope fractionation in burned and unburned chaparall soils. Soil Science Society of America Journal 53: 12291236.
  • Hermes J, Weiss P, Cleland WW. 1985. The use of nitrogen-15 and deuterium isotope effects to determine the chemical mechanism of phenylalanine-lyase. Biochemistry 24: 29592967.
  • Hesselman H. 1917. Studier över salpeterbildningen i naturliga jordmåner och dess betydelse i växtekalogiskt avseende. Skogsvårdsforeningens Tidskrift 22: 301550.
  • Hoch MP, Fogel ML, Kirchman DL. 1994. Isotope fractionation during ammonium uptake by marine microbial assemblages. Geomicrobiology Journal 12: 113127.
  • Hoefs J. 1997. Stable isotope geochemistry, 4th edn. Berlin : Springer Verlag.
  • Hoering TC. 1955. Variations of nitrogen-15 abundance in naturally occurring substances. Science 122: 12331234.
  • Hoering TC, Ford HT. 1960. The isotope effect in the fixation of nitrogen by Azotobacter. Journal of American Chemical Society 82: 376378.
  • Högberg P. 1986. Nitrogen fixation and nutrient relations in savanna woodland trees (Tanzania). Journal of Applied Ecology 23: 675688.
  • Högberg P. 1990a. 15N natural abundance as a possible marker of the ectomycorrhizal habit of trees in mixed African woodlands. New Phytologist 115: 483486.
  • Högberg P. 1990b. Forests losing large quantities of nitrogen have elevated 15N/14N ratios. Oecologia 84: 229231.
  • Högberg P. 1991. Development of 15N enrichment in a nitrogen-fertilized forest soil-plant system. Soil Biology & Biochemistry 23: 335338.
  • Högberg P, Alexander IJ. 1995. Role of root symbioses in African woodland and forest: evidence from 15N abundance and foliar analysis. Journal of Ecology 83: 217224.
  • Högberg P, Högbom L, Schinkel H, Högberg M, Johannisson C, Wallmark H. 1996. 15N abundance of surface soils, roots and mycorrhizas in profiles of European forest soils. Oecologia 108: 207214.
  • Högberg P, Johannisson C. 1993. 15N abundance of forests is correlated with losses of nitrogen. Plant and Soil 157: 147150.
  • Högberg P, Johannisson C, Högberg M. Högbom L, Nasholm T, Hallgren J-E. 1995. Measurements of abundances of 1JN and 13C as tools in retrospective studies of N balances and water stress in forests; a discussion of preliminary results. Plant and Soil 168169: 125 – 133.
  • Högberg P, Nasholm T, Högbom L. Stahl L. 1994. Use of 16N labelling and “N natural abundance to quantify the role of mycorrhizas in N uptake by plants: importance of seed N and of changes in the 15N labelling of the available N. New Phytologist 127: 515519.
  • Högberg P, Tamm C-O, Högberg M. 1992. Variations in 15N abundance in u forest fertilization trial; critical Loads of N, N saturation, contamination and effects of revitalization fertilization. Plant and Soil 142: 211219.
  • Hübner H. 1986. Isotope effects of nitrogen in the soil and biosphere. In: FritzP, FontesJC, eds. Handbook of Environmental Isotope Geochemistry, vol. 2B. Amsterdam : Elsevier, 361425.
  • Ingelög T, Nohrstedt H-Ö. 1993. Ammonia formation and soil pH increase by decomposing fruit bodies of macrofungi. Oecologia 93: 449491.
  • Ingestad T. 1982. Relative addition rates and external concentration: driving variables used in plant nutrition research. Plant, Cell and Environment 5: 443453.
  • Jansson S-L. 1958. Tracer studies on nitrogen transformations in soil with special attention to mineralization-immobilization relationships. Annals of the Royal Agricultural College of Sweden 24: 101361.
  • Jenkinson DS. 1990. An introduction to the global nitrogen cycle. Soil Use and Management 6: 5661.
  • Johannisson C. 1996. 15 abundance as an indicator of N-saturation of coniferous forest. Ph.D. thesis. SLU, Umeå, Sweden .
  • Johannisson C, Högberg P. 1994. 15N abundances of soils and plants along an experimentally induced forest nitrogen supply gradient. Oecologia 97: 322325.
  • Jones HG, Quarmby C, Harrison AF. 1991. A root bioassay test for nitrogen deficiency in forest trees. Forest Ecology and Management 42: 267282.
  • Junk G, Svec HV. 1958. The absolute abundance of the nitrogen isotopes in the atmosphere and compressed gas from various sources. Geochimica et Cosmochimica Acta 14: 234243.
  • Karamanos RE, Rennie DA. 1978. N isotope fractionation during exchange reactions with soil clay. Canadian Journal of Soil Science 58: 6370.
  • Karamanos RE, Rennie DA. 1980a. Changes in natural 15N abundance associated with pedogenic processes m soil. I. Changes associated with saline seeps. Canadian Journal of Soil Science 60: 337344.
  • Karamanos RE, Rennie DA. 1980b. Changes in natural 15N abundance associated with pedogenic processes in soils. II. Changes on different slope positions. Canadian Journal of Soil Science 60: 365372.
  • Karamanos RE, Voroney RP, Rennie DA. 1981. Variation in natural 15N abundance of central Saskatchewan soils. Soil Science Society of America Journal 45: 826828.
  • Kawanashi T, Hayashi V, Kihou N, Yoneyama T, Ozaki Y. 1993. Dispersion effect on the apparent nitrogen isotope fractionation factor associated with denitrification in soil: evaluation by a mathematical model. Soil Biology and Biochemistry 25: 349354.
  • Kerley SJ, Jarvis SC. 1996. Preliminary studies of the impact of excreted X on cycling and uptake of N in pasture systems using natural abundance stable isotope discrimination. Plant and Soil 178: 287294.
  • Kielland K. 1995. Landscape patterns of free amino acids in arctic tundra soils. Biogeochemistry 31: 8598.
  • Kirshenbaum I, Smith JS, Crowell T, Graff J, Mokee R. 1947. Separation of the nitrogen isotopes by the exchange reaction between ammonia and solutions of ammonium nitrate. Journal of Chemical Physics 15: 440446.
  • Kohl DH, Bryan BA, Shearer GB, Virginia RA. 1981. Concerning the heterogeneity- of the natural abundance of 15N in soil. Soil Science Society of America Journal 45: 450451.
  • Kohl DH, Shearer GB. 1980. Isotopic fractionation associated with symbiotic N2 fixation and uptake of NO3 by plants. Plant Physiology 66: 5156.
  • Kohl DH, Shearer GB. 1995. Using variations in natural 15N abundance to investigate N cycle processes. In: WadaEt YoneyamaT. MinagawaM, AndoT, FryBD, eds. Stable Isotopes in the Biosphere. Kyoto , Japan : Kyoto University Press, 103130.
  • Kohl DH, Shearer GB, Commoner B. 1971. Fertilizer nitrogen: contribution to nitrate in surface water in a corn belt watershed. Science 174: 13311334.
  • Kohl DH, Shearer GB, Commoner B. 1972. Reply to Hauck. et al. Science 177: 454456.
  • Kohl DH, Shearer GB, Commoner B. 1973. Variation of 15N in corn and soil following application of fertilizer nitrogen. Soil Science Society of America Proceedings 37: 888892.
  • Koopmans CJ. 1996. The impact of reduced nitrogen deposition on nitrogen cycling in Dutch forest ecosystems. Ph.D. thesis, University of Amsterdam, Amsterdam , The Netherlands .
  • Larsson C-M. 1994. Responses of the nitrate uptake system to external nitrate availability: a whole plant perspective. In: RoyJ, GamierA, eds. A Whole Plant Perspective on Carbon-Nitrogen Interactions. The Hague : SPB Academic Publishing, 3145.
  • Leake JR, Read DJ. 1990. Chitin as a nitrogen source for mycorrhizal fungi. Mycological Research 94: 993995.
  • Ledgard SF. 1989. Nutrition, moisture and rhizobial strain influence isotopic fractionation during N2 fixation in pasture legumes. Soil Biology and Biochemistry 21: 6568.
  • Ledgard SF, Freney JR, Simpson JR. 1984. Variations in natural enrichment of 15N in the profiles of some Australian pasture soils. Australian Journal of Sail Research 22: 155164.
  • Ledgard SF, Simpson JR, Freney JR, Bergersen FJ 1985a. Effect of reference plant on estimation of nitrogen fixation by subterranean clover using 15N methods. Australian Journal of Agricultural Research 36: 663676.
  • Ledgard SF, Woo KC, Bergersen FJ. 1985b. Isotopic fractionation during reduction of nitrate and nitrite by extracts of spinach leaves. Australian Journal of Plant Physiology 12: 631640.
  • Lee JA, Stewart GR. 1978. Ecological aspects of nitrogen assimilation. Advances in Botanical Research 6: 143.
  • Lee RB, Drew MC. 1989. Rapid, reversible inhibition of nitrate influx in barley by ammonium. Journal of Experimental Botany 40: 741752.
  • Letofle R. 1980. Nitrogen-15 in the natural environment. In: FritzP, FontesJC, eds. Handbook of Environmental Isotope Geochemistry. vol 14. Amsterdam : Elsevier, 407433.
  • Lindau CW, Spalding RF. 1984. Major procedural discrepancies in soil extracted nitrate levels and nitrogen isotopic values. Ground Water 22: 273278.
  • Lloyd D. 1993. Aerobic denitrification in soils and sediments: from Fallacies to facts. Trends in Ecology and Evolution 8: 352356.
  • Macko SA, Fogel-Estep ML, Engel Mil. Hare PE. 1986. Kinetic fractionation of stable nitrogen isotopes during amino acid transamination. Geochemica et Cosmochimica Acta 50: 21432146.
  • Macko SA, Ostrom NE. 1994. Pollution studies using stable isotopes. In: LajthaK. MichenerRH. eds. Stable Isotopes Ecology and Environmental Science. Boston , MA , USA : Black-well. 4562.
  • Mariotti A. 1983. Atmospheric nitrogen is a reliable standard for natural δ15N abundance measurements. Suture 303: 685687.
  • Mariotti A, Germon GC, Hubert P, Kaiser P, Letolle R, Tardieux A, Tardieux P. 1981. Experimental determination of nitrogen kinetic isotope fractionation: some principles; illustrations for the denitrification and nitrification processes. Plant and Soil 62: 413430.
  • Mariotti A, Landreau A, Simon B. 1988. 15N isotope biogeochemistry and natural denitrification process in groundwater: application to the chalk aquifer of northern France. Geochimica et Cosmochimica Acta 52: 18691878.
  • Mariotti A, Mariotti F, Amarger N, Pizelle G, Ngambi JM, Champigny ML, Moyse A. 1980a. Fractionements isotopique de l'azote lors des processes d'absorption des nitrates et de fixation de I'azote atmosphérique par les plants. Physiologic Vegetate 18: 163181.
  • Mariotti A, Mariotti F, Champigny M-L, Amarger N, Moyse A. 1982. Nitrogen isotope fractionation associated with nitrate reductase activity and uptake of NO3 by pearl millet. Plant Physiology 69: 880884.
  • Mariotti A, Pierre D, Vedy JC, Bruckert S, Guillemot J. 1980b. The abundance of natural nitrogen-15 in the organic matter of soils along an altitudinal gradient. Catena 7: 293300.
  • Marschner H, Haussling M, George E. 1991. Ammonium and nitrate uptake rates and rhizosphere pH in non-mycorrhizal roots of Norway spruce (Picea abies (L.) Karst.). Trees 5: 1421.
  • Martin F, Botton B. 1993. Nitrogen metabolism of ectomycorrhizal fungi and ectomycorrhiza. Advances in Plant Pathology 9: 83102.
  • McKey D. 1994, Legumes and nitrogen: the evolutionary ecology of a nitrogen-demanding lifestyle. In: SprentII, McKeyD, eds. Advances in Legume Systematics 5 The Nitrogen Factor, Kew Royal Botanic: Gardens, 211228.
  • Meints VW, Boone LV, Kurtz LT. 1975a. Natural 15N abundance in soil, leaves and grain as influenced by long-term additions of fertilizer N at several rates. Journal of Environmental Quality 4: 486490.
  • Meints VW, Shearer GB, Kohl DH, Kurtz LT. 1975b. A comparison of unenriched versus 15N enriched fertilizer as a tracer for N fertilizer uptake. Soil Science 119: 421425.
  • Meiander L, Saunders WH Jr. 1980. Reaction rates of isotopic molecules. New York : John Wiley.
  • Michelsen A, Schmidt IK, Jonasson S, Quarmby C, Sleep D. 1996. Leaf 15N abundance of subarctic plants provides field evidence that ericoid, ectomycorrhizal and non- and arbuscular mycorrhizal species access different sources of nitrogen. Oecologia 105: 5363.
  • Minagawa M, Wada E. 1984. Stepwise enrichment of 15N along food chains: further evidence and the relation between δ15N and animal age. Geochimica et Cosmochimica Acta 48: 11351140.
  • Mizutani H, Hasegawa H, Wada E. 1986. High nitrogen isotope ratio for soils of seahird rookeries. Biogeochemistry 2: 221247.
  • Mizutani H, Kabaya Y, Moors PJ, Speir TW, Lyon GL. 1991a. Nitrogen isotope ratios identify deserted seabird colonies. The Auk 108: 960964.
  • Mizutani H, Kabaya Y, Wada E. 1991b. Linear correlation between latitude and soil 15N enrichment at seabird rookeries. Naturwissenschaften 78: 3436.
  • Mizutani H, Wada E. 1988. Nitrogen and carbon isotope ratios in seabird rookeries and their ecological implications. Ecology 69: 340349.
  • Moore H. 1974. Isotopic measurements of atmospheric nitrogen compounds. Tellus 26: 169174.
  • Nadelhoffer KJ, Fry B. 1988. Controls on natural nitrogen-15 and carbon-13 abundances in forest soil organic matter. Soil Science Society of America Journal 52: 16331640.
  • Nadelhoffer KJ, Fry B. 1994. Nitrogen isotope studies in forest ecosystems. In: LajthaK. MichtnerR. eds. Stable Isotopes in Ecology and Environmental Science. Boston , MA , USA : Blackwell Scientific Publications. 2344.
  • Nadelhoffer KJ, Shaver G, Fry B, Giblin A, Johnson L, McKane R. 1996. 15N natural abundance and N use by tundra plants. Oecologia 107: 386394.
  • Nambiar EKS. 1987. Do nutrients retranslocate from fine roots Canadian Journal of Forest Research 17: 913918.
  • Nasholm T. 1994. Removal of nitrogen during needle senescence in Scots pine (Pinus sylrestris L.). Oecologia 99: 290296.
  • Nasholm T, Ericsson A. 1990. Seasonal changes in amino acids, protein and total nitrogen in needles of fertilized Scots pine trees. Tree Physiology 6: 267281.
  • Näsholm T., Nordin A, Edfast A-B, Hdgberg P. 1997. Identification of coniferous forest with symptoms of incipient nitrogen saturation through analyses of N-fractions and N-isotope ratios of trees. Journal of Environmental Quality 26: 302309.
  • Newman El, Reddell P. 1987. The distribution of mycorrhizas among families of vascular plants. New Phytologist 106: 745751.
  • Nier AO. 1947. A mass spectrometer for isotope and gas analysis. Refines in Science instrumentation 18: 398411.
  • Nohrstedt H-C, Sikstrom U, Ring E, Nasholm T, Hogberg P, Persson T. 1996. Nitrate in soil water in three Norway spruce stands in southwest Sweden as related to N-deposition and soil. stand and foliage properties. Canadian Journal of Forest Research 26: 836848.
  • Nommik H, Pluth DJ, Larsson K, Mahendrappa MK. 1994. Isotopie fractionation accompanying fertilizer nitrogen transformations in soil and trees of a Scots pine ecosystem. Plant and Soil 158: 169182.
  • Ohlson M, Högbom L. 1993. Species-specific dynamics in nitrate reductase activity in coexisting swamp forest plants. Journal of Ecology 81: 739744.
  • Parkin TB. 1987. Soil microsites as a source of denitrification variability. Soil Science Society of America Journal 51: 11941199.
  • Parwell A, Ryhage AR, Wickman FE. 1957. Natural variations in the relative abundance of nitrogen isotopes. Geochimica et Cosmochimica Acta 11: 165170.
  • Pate JS, Stewart GR, Unkovich M. 1993. 15N natural abundance of plant and soil components of a Banksia woodland system in relation to nitrate utilization, life form, mycorrhizal status and N, fixing abilities of component species. Plant, Cell and Environment 16: 365373.
  • Paul EA, Clark FE. 1989. Soil microbiology and biochemistry. San Diego , CA . USA : Academic Press.
  • Pearson J, Slewart GR. 1993. The deposition of atmospheric ammonia and its effects on plants. New Phytologist 125: 283305.
  • PeoplesMB, FaizahAW, RerkasemB, HerridgeDF., (eds) 1989. Methods for evaluating nitrogen fixation by nodulated legumes in the field. Canberra : Australian Centre for International Agricultural Research.
  • Peterson BJ, Fry B. 1987. Stable isotopes in ecosystem studies. Annual Review of Ecology and Systematic 18: 293320.
  • Peterson BJ, Howarth RW, Garriti RH. 1985. Multiple stable isotopes used to trace the flow of organic matter in estuarine food webs. Science 227: 13611363.
  • Phillips WS. 1963. Depth of roots in soil. Ecology 44: 424.
  • Piccolo MC, Neill C, Melillo JM, Cerri CC, Steudler PA. 1996. 15N natural abundance in forest and pasture soils of the Brazilian Amazon Basin. Plant and Soil 182: 249258.
  • Poulson SR, Chamberlain CP, Friedland AJ. 1995. Nitrogen isotope variation of tree rings as a potential indicator of environmental change. Chemical Geology (Isotope Geoscience Section) 125: 307315.
  • Raison RJ. 1979. Modification of the soil environment by vegetation fires, with particular reference to nitrogen transformations: a review. Plant and Soil 51: 73108.
  • Raven JA. 1987. The application of mass spectrometry to biochemical and physiological studies. In: DaviesDD. ed. The Bit/chemistry of Plants, Vol 13. Methodology. San Diego , CA , USA : Academic Press. 127180.
  • Reiaero A, Shearer GB, Bryan BA, Skeeters JL, Kohl DH. 1983. Site of natural 15N enrichment of soybean nodules. Plant Physiology 72: 265268.
  • Riga A, van Praag HJ, Brigode N. 1971. Rapports isotopique naturel de 1'azote dans quelques sols forestiers et agricoies dt Belgique soumis a divers traitments culturaux. Geoderms 6: 213222.
  • Riha SJ, Campbell GS, Wolfe J. 1986. A model of competition for ammonium among heterotrophs. nitrifiers, and roots. Soil Science Society of America Journal 50: 14631466.
  • Robertson GP, Tiedje JM. 1984. Denitrification and nitrous oxide production in successional and old-growth Michigan forests. Sad Science Society of American Journal 48: 383389.
  • Robinson D, Smith KA. 1991. Analysis of nitrogen isotope ratios by mass spectrometry. In: SmithKA ed. Soil Analysis. Modern instrumental Techniques, 2nd edn. New York : Marcel Dekker, 465503.
  • Scheromm P, Plassard C. 1988. Nitrogen nutrition of nonmycorrhizal pine (Pinus pinaster) grown on nitrate or ammonium. Plant Physiology and Biochemistry 26: 261269.
  • Schoenheimer R, Rittenberg D. 1929. Studies in protein metabolism. I. General considerations in the application of isotopes to the study of protein metabolism. The normal abundance of nitrogen isotopes in amino acids. Journal of Biological Chemistry 127: 285290.
  • Schowen RL, Schowen KB. 1995. Present and future prospects in the application of stable isotopes to structure–function studies of biological macromolecules: direct, non-competitive determinations of stable isotope effects. In: WadaE, YoneyamaT. MinagawaM, AndoT. FryBD, eds. Stable isotopes in the Biosphere. Kyoto , Japan : Kyoto University Press, 5977.
  • Schulze E-D, Chapin FSIH, Gebauer G. 1994. Nitrogen nutrition and isotope differences among life forms at the northern tree line of Alaska. Oecologia 100: 406412.
  • Schulze E-D, Gebauer G, Schulze W, Pate JS. 1991a. The utilization of nitrogen from insect capture by different growth forms of Drosera from Southwest Australia. Oecologia 87: 240246.
  • Schulze E-D, Gebauer G, Ziegler H, Lange OL. 1991b. Estimates of nitrogen fixation by trees on an aridity gradient fan Namibia. Oecologia 88: 451455.
  • Schulze E-D, Lange OL, Ziegler H, Gebauer G. 1991c. Carbon and nitrogen isotope ratios of mistletoes growing on nitrogen and non-nitrogen fixing hosts and on CAM plants in the Namib desert confirm psirtial heterotrophy. Oecologia 88: 457462.
  • Selles F, Karamanos RE. 1986. Variations in natural nitrogen-15 abundance as an aid in manure-nitrogen studies. Journal of Environmental Quality 15: 2430.
  • Shearer GB, Duffy J, Kohl DH, Commoner B. 1974. A steady state model of isotopic fractionation accompanying nitrogen transformations in soils. Soil Science Society of America Proceedings 38: 315322.
  • Shearer GB, Kohl DH. 1986. N, fixation in field settings: estimations based on natural 15N abundance. Australian Journal of Plant Physiology 13: 699757.
  • Shearer GB, Kohl DH. 1988. Nitrogen isotopic fractionation and 18O exchange in relation to the mechanism of denitrification of nitrite by Pseudomonads stutzeri. Journal of Biological Chemistry 263: 1323113245.
  • Shearer GB, Kohl DH. 1993. Natural abundance of 15N: fractional contribution of two sources to a common sink and use of isotope discrimination. In: KnowlesR, BlackburnTH. eds. Nitrogen Isotope Techniques. San Diego : Academic Press, 89125.
  • Shearer GB, Kohl DH, Chien SH. 1978. The nitrogtn-l5 abundance in a wide variety of soils. Soil Science Society of America Journal 42: 899902.
  • Shearer GB, Kohl DH, Virginia RA, Bryan BA, Skeeters JL, Nilsen ET, Sharifi MR, Rundel PW. 1983. Estimates of N2- fixation from the natural abundance of 15N in Sonoran desert ecosystems. Oecologia 56: 365373.
  • Shearer GB, Legg JO. 1975. Variations in the natural abundance of 15N of wheat plants in relation to fertilizer nitrogen applications. Sail Science Society of America Proceedings 39: 896901.
  • Skujins J. 1981. Nitrogen cycling in arid ecosystems. Ecological Bulletins 33: 477491.
  • Smith BN, Epstein S. 1971. Two categories of 13C: 12C ratios for higher plants. Plant Physiology 47: 380384.
  • Smith SE, Read DJ. 1997. Mycorrhizal symbiosis, 2nd edn. London : Academic Press.
  • Sprent JI, Geoghegan IE, Whitty PW, James EK. 1996. Natural abundance of 15N and 15C in nodulated legumes and other plants in the cerrado and neighbouring regions of Brazil. Oecologia 105: 440446.
  • Steele KW, Bonish BM, Daniel RM, O'Hara GW. 1983. Effect of rhizobial strains and host plant on nitrogen isotopic fractionation in legumes. Plant Physiology 72: 10011004.
  • Steele KW, Daniel RM. 1978. Fractionation of nitrogen isotopes by animals, a further complication to the use of variations in natural abundance of 15N for tracer studies. Journal of Agricultural Science (Cambridge) 90: 79.
  • Stewart GR, Schmidt S, Handley LL, Turnbull MH, Erskine PD, Joly CA. 1995. 15N natural abundance of vascular rainforest epiphytes: implications for nitrogen source and acquisition. Plant, Cell and Environment 18: 8590.
  • Sutherland RA, van Kessel C, Pennock DJ. 1991. Spatial variability of nitrogen-15 natural abundance. Soil Science Society of America Journal 55: 13391347.
  • Taylor AFS, Hogbom L, Hogberg M, Lyon TJE, Nasholm T, Hogberg P. 1997. Natural 15N abundance in fruit bodies of ectomycorrhizal fungi from boreal forests. New Phytologist, 136: 000000.
  • Tiedje JM, Sexstone AJ, Myrold DD, Robinson JA. 1982. Denitrification: ecological niches, competition and survival. Antonie van Leeuwenhoek 48: 569583.
  • Tiessen H, Karamanos RE, Stewart JWB, Selles F. 1984. Natural nirrogen-15 abundance as an indicator of soil organic matter transformations in native and cultivated soils. Soil Science Society of America Journal 48: 312315.
  • Timmer VR, Armstrong G. 1987. Diagnosing nutritional status of containerized tree seedlings: comparative plant analysis. Soil Science Society America Journal 51: 10821086.
  • Tong JY, Yankwich PE. 1957. Calculation of experimental isotope effects for pseuda first-order irreversible reactions. Journal of Physical Chemistry 61: 540543.
  • Treseder KK, Davidson DW, Ehleringer JR. 1995. Absorption of ant-provided carbon dioxide and nitrogen by a tropical epiphyte. Nature 375: 137139.
  • Turner GL, Bergersen FJ, Tantala H. 1983. Natural enrichment of δ15N during decomposition of plant material in soil. Sail Biology and Biochemistry 15: 495497.
  • Turner GL, Gault RR, Morthorpe L, Chase DL, Bergersen FJ. 1987. Differences in the natural abundance of 15N in the extractable mineral nitrogen of cropped and fallowed surface soils. Australian Journal of Agricultural Research 38: 1525.
  • van Damm D, van Breemen N. 1994. NICCCE: fl mode) for cycling of nitrogen and carbon isotopes in coniferous forest ecosystems. Ecological Modelling 79: 255275.
  • van Dijk HFG, Roelofs JGM. 1988. Effects of excessive ammonium deposition on the nutritional status and condition of pine needles. Physiologia Plantarum 73: 494501.
  • van Kessel C, Farrell RE, Pennock DJ. 1994a. Carbon-13 and nitrogen-15 natural abundance in crop residues and soil organic matter. Soil Science Society of America Journal 58: 382389.
  • van Kessel C, Farrell RE, Roskoski JP, Keane KM. 1994b. Recycling of the naturally occuring 15N in an established stand of Leucaena leucocephala. Soil Biology and Biochemistry 26: 757762.
  • Virginia RA, Delwiche CC. 1982. Natural N-I5 abundance of presumed N2fixing and non- N2fixing plants from selected ecosystems. Oecologia 54: 317325.
  • Vitousek PM, Shearer GB, Kohl DH. 1989. Foliar 15N natural abundance in Hawaiian rainforest: patterns and possible mechanisms. Oecologia 78: 383388.
  • Wada E, Imaizumi R, Takai Y. 1984. Natural abundance of 15N in soil organic matter with special reference to paddy soils in Japan: biogeochemical implications on the nitrogen cycle. Geochemical Journal 18: 109123.
  • Wada E, Shibata R, Torii T. 1981. 15N abundance in Antarctica: origin of soil nitrogen and ecological implications. Saiure 292: 327329.
  • Wellburn AR. 1990. Why are atmospheric oxides of nitrogen usually phytotoxic and not alternative fertilizers. New Phytologist 115: 395429.
  • Wellman RP, Cook FD, Krouse HR. 1968. Nitrogen-15: microbial alteration of abundance. Science 161: 269270.
  • Wetselaar R, Farquhar GD. 1980. Nitrogen losses from tops of plants. Advances in Agronomy 33: 263302.
  • Winkier E, Gebauer G. 1993. Investigations on the nitrogen metabolism of forest trees by mathematical modelling of natural isotope ratios. Isotopenpraxis 29: 199214.
  • Witty JF. 1983. Estimating N2fixation in the field using 15N-relabelled fertilizer: some problems and solutions. Soil Biology and Biochemistry 15: 631639.
  • Yoneyama T. 1988. Natural abundance of 15N in root nodules of pea and broad bean. Journal of Plant Physiology 132: 5962.
  • Yoneyama T. 1995. Nitrogen metabolism and fractionation of nitrogen isotopes in plants. In: WadaE, YoneyamaT, MinagawaM. AndoT. FryBD, eds. Stable Isotopes in the Biosphere. Kyuto , Japan : Kyoto University Press, 92102.
  • Yoneyama T, Kaneko A. 1989. Variations in the natural abundance of 15N in nitrogenous fractions of komatsunu plants supplied with nitrate. Plain and Celt Physiology 30: 957962.
  • Yoneyama T, Murakami T, Boonkerd N, Wadisirisuk P, Siripin S, Kouno K. 1990, Natural 15N abundance in shrub and tree legumes, Casuarina and non-N2-fixing plants in Thailand. Plant and Soil 128: 287292.
  • Yoneyama T, Muraoka T, Murakami T, Boonkeerd N. 1993. Natural abundance of 15N in tropical plants with emphasis on tree legumes. Plant and Soil 153: 295304.
  • Yoneyama T, Omata T, Nakata S, Yasaki J. 1991. Fractionation of nitrogen isotopes during the uptake and assimilation of ammonia by plants. Plant and CM Physiology 32: 12111217.
  • Yoneyama T, Sasakawa H. 1991. Enrichment of 15N natural abundance in Frankia-infected nodules. Soil Science and Plant Nutrition 37: 741743.
  • Yoshida N. 1988. 15N depleted N2O as a product of nitrification Nature 335: 528529.
  • Yoshida N, Morimolo H, Harane M, Koike I, Malsuo S, Wada E, Saino T, Hattori A. 1989. Nitrification rates and 15N abundances of N2O and NO3 in the western North Pacific. Nature 342: 895897.
  • Zak DR, Groffman PM, Christensen S, Pregitzer Tiedje JM. 1990. The vernal dam: plant–microbe competition for nitrogen in northern hardwood forests. Ecology 71: 51656.