Oecologia

, Volume 94, Issue 3, pp 314–317 | Cite as

A break in the nitrogen cycle in aridlands? Evidence from δp15N of soils

  • R. D. Evans
  • J. R. Ehleringer
Original Papers

Abstract

We examined the content and isotopic composition of nitrogen within soils of a juniper woodland and found that a cryptobiotic crust composed of cyanobacteria, lichens, and mosses was the predominant source of nitrogen for this ecosystem. Disturbance of the crust has resulted in considerable spatial variability in soil nitrogen content and isotopic composition; intercanopy soils were significantly depleted in nitrogen and had greater abundance of 15N compared to intra-canopy soils. Variations in the 15N/14N ratio for inter- and intra-canopy locations followed similar Rayleigh distillation curves, indicating that the greater 15N/14N ratios for inter-canopy soils were due to relatively greater net nitrogen loss. Coverage of cryptobiotic crusts has been reduced by anthropogenic activities during the past century, and our results suggest that destruction of the cryptobiotic crust may ultimately result in ecosystem degradation through elimination of the predominant source of nitrogen input.

Key words

δ15Cryptobiotic crusts Deserts Nitrogen cycling Rayleigh distillation 

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References

  1. Belnap J (1993) Recovery rates of cryptobiotic crusts: inoculant use and assessment methods. Great Basin Nat 53:89–95Google Scholar
  2. Belnap J, Gardner JS (1993) Soil microstructure in soils of the Colorado Plateau: the role of the cyanobacterium Microcoleus vaginatus. Great Basin Nat 53:40–47Google Scholar
  3. Beymer RJ, Klopatek JM (1992) Effects of grazing on cryptogamic crusts in pinyon-juniper woodlands in Grand Canyon National Park. Am Midl Nat 127:139–148Google Scholar
  4. Boring LR, Swank WT, Waide JB, Henderson GS (1988) Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesis. Biogeochemistry 6:119–159Google Scholar
  5. Bowden WB (1986) Gaseous nitrogen emissions from undisturbed terrestrial ecosystems: an assessment of their impacts on local and global nitrogen budgets. Biogeochemistry 2:249–279Google Scholar
  6. Campbell SE, Seeler JS, Glolubic S (1989) Desert crust formation and soil stabilization. Arid Soil Res Reh 3:217–228Google Scholar
  7. Fiedler R, Proksch G (1975) The determination of nitrogen-15 by emission and mass spectrometry in biochemical analysis: a review. Anal Chim Acta 78:1–62Google Scholar
  8. Fustec E, Mariotti A, Grillo X, Sajus J (1991) Nitrate removal by denitrification in alluvial ground water: role of a former channel. J Hydrol 123:337–354Google Scholar
  9. Harper KT, Marble JR (1988) A role for nonvascular plants in management of arid and semiarid regions. In: Tueller PT (ed) Vegetation science applications for rangeland analysis and management. Kluwer Academic, Boston, pp 135–169Google Scholar
  10. Heaton THE (1986) Isotopic studies of nitrogen pollution in the hydrosphere and atmosphere: a review. Chem Geol 59:87–102Google Scholar
  11. Junge CE (1958) The distribution of ammonia and nitrate in rain water over the United States. Trans Am Geophys Union 39:241–248Google Scholar
  12. Kleiner EF, Harper KT (1972) Environment and community organization in grasslands of Canyonlands National Park. Ecology 53:299–309Google Scholar
  13. Mariotti A (1984) Atmospheric nitrogen is a reliable standard for natural 15N abundance measurements. Nature 311:251–252Google Scholar
  14. Mariotti A, Germon JC, Hubert P, Kaiser P, Letolle R, Tardieux A, Tardieus P (1981) Experimental determination of nitrogen kinetic isotope fractionation: some principles; illustration for the denitrification and nitrification processes. Plant Soil 62:413–430Google Scholar
  15. Minagawa M, Winter DA, Kaplan IR (1984) Comparison of Kjeldahl and combustion methods for measurement of nitrogen isotope ratios in organic matter. Anal Chem 56:1859–1861Google Scholar
  16. Nadelhoffer KJ, Fry B (1988) Controls on natural nitrogen-15 and carbon-13 abundances in forest soil organic matter. Soil Sci Soc Am J 52:1633–1640Google Scholar
  17. Peterjohn WT, Schlesinger WH (1990) Nitrogen loss from deserts in the southwestern United States. Biogeochemistry 10:67–79Google Scholar
  18. Schlesinger WH, Reynolds JF, Cunningham GL, Huenneke LF, Jarrell WM, Virginia RA, Whitford WG (1990) Biological feedbacks in global desertification. Science 247:1043–1048Google Scholar
  19. Shearer G, Kohl DH (1986) N2-fixation in field settings: estimation based on natural 15N abundance. Aust J Plant Physiol 13:699–756Google Scholar
  20. Virginia RA, Jarrell WM (1985) Soil properties in a mesquite-dominated Sonoran Desert ecosystem. Soil Sci Soc Am J 47:138–144Google Scholar
  21. West NE (1990) Structure and function of microphytic soil crusts in wildland ecosystems of arid to semi-arid regions. Adv Ecol Res 20:179–223Google Scholar
  22. West NE, Skujins J (1977) The nitrogen cycle in North American cold-winter semi-desert ecosystems. Oecol Plant 12:45–53Google Scholar
  23. Young JR, Ellis EC, Hidy GM (1988) Deposition of air-borne acidifiers in the western environment. J Environ Qual 17:1–26Google Scholar

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • R. D. Evans
    • 1
  • J. R. Ehleringer
    • 1
  1. 1.Stable Isotope Facility for Environmental Research, Department of BiologyUniversity of UtahSalt Lake CityUSA

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