, Volume 132, Issue 1–2, pp 213–231 | Cite as

Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range

  • Eve-Lyn S. Hinckley
  • Brian A. Ebel
  • Rebecca T. Barnes
  • Sheila F. Murphy
  • Suzanne P. Anderson


Several decades of research in alpine ecosystems have demonstrated links among the critical zone, hydrologic response, and the fate of elevated atmospheric nitrogen (N) deposition. Less research has occurred in mid-elevation forests, which may be important for retaining atmospheric N deposition. To explore the fate of N in the montane zone, we conducted plot-scale experimental rainfall events across a north–south transect within a catchment of the Boulder Creek Critical Zone Observatory. Rainfall events mimicked relatively common storms (20–50% annual exceedance probability) and were labeled with 15N-nitrate (\( {\text{NO}}_{3}^{ - } \)) and lithium bromide tracers. For 4 weeks, we measured soil–water and leachate concentrations of Br, \( {}^{15}{\text{NO}}_{3}^{ - } , \) and \( {\text{NO}}_{3}^{ - } \) daily, followed by recoveries of 15N species in bulk soils and microbial biomass. Tracers moved immediately into the subsurface of north-facing slope plots, exhibiting breakthrough at 10 and 30 cm over 22 days. Conversely, little transport of Br or \( {}^{15}{\text{NO}}_{3}^{ - } \) occurred in south-facing slope plots; tracers remained in soil or were lost via pathways not measured. Hillslope position was a significant determinant of soil 15N-\( {\text{NO}}_{3}^{ - } \) recoveries, while soil depth and time were significant determinants of 15N recovery in microbial biomass. Overall, 15N recovery in microbial biomass and leachate was greater in upper north-facing slope plots than lower north-facing (toeslope) and both south-facing slope plots in August; by October, 15N recovery in microbial N biomass within south-facing slope plots had increased substantially. Our results point to the importance of soil properties in controlling the fate of N in mid-elevation forests during the summer season.


15N tracer Lithium bromide Hillslope aspect Hydrologic response Convective storm Critical Zone Observatory 



E.S.H. and R.T.B. were funded by National Science Foundation Earth Sciences Postdoctoral Fellowships (NSF EAR 0847987 and 0814457) during the study. Faculty, staff, and students associated with the Boulder Creek CZO (NSF EAR 0724960 and 1331828) provided additional support. We thank Chris Seibold, Holly Miller, and staff at the Niwot Ridge LTER’s Kiowa Laboratory for rapid, careful analysis of all samples. We also thank Rory Cowie, Alexandra Czastkiewicz, Daniel Eldridge, Hana Fancher, Abigail Langston, BobbiJo Littrell, Christina Pruett, and Nathan Rock for assistance with the field tracer studies. The authors thank Edward Stets and three anonymous reviewers for their very helpful comments on the manuscript. Data included in this paper are available for download via the Boulder Creek Critical Zone Observatory website ( Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government.


  1. Aber JD, Magill A, McNulty SG, Boone RD, Nadelhoffer KJ, Downs M, Hallett R (1995) Forest biogeochemistry and primary production altered by nitrogen saturation. Water Air Soil Pollut 85:1665–1670CrossRefGoogle Scholar
  2. Anderson RS, Riihimaki CA, Safran EB, MacGregor KR (2006) Facing reality: Late Cenozoic evolution of smooth peaks, glacially ornamented valleys, and deep river gorges of Colorado’s Front Range. In: Willett SD, Hovius N, Branden MT, Fisher D (eds) Tectonics, climate, and landscape evolution. Geological Society of America special paper 398, p 397–418. doi: 10.1130/2006.2398(25)
  3. Anderson SP, von Blanckenburg F, White AF (2007) Physical and chemical controls on the critical zone. Elements 3:315–319CrossRefGoogle Scholar
  4. Anderson SP, Anderson RS, Tucker GE (2012) Landscape scale linkages in critical zone evolution. C r Geosci 344:586–596. doi: 10.1016/j.crte.2012.10.008 CrossRefGoogle Scholar
  5. Baron JS, Rueth HM, Wolfe AM, Nydick KR, Allstott EJ, Minear JT, Moraska B (2000) Ecosystem responses to nitrogen deposition in the Colorado Front Range. Ecosystems 3:352–368. doi: 10.1007/s100210000032 CrossRefGoogle Scholar
  6. Barry RG (1973) A climatological transect on the east slope of the Front Range, Colorado. Arct Alp Res 5:89–110CrossRefGoogle Scholar
  7. Bashkin VN, Park SU, Choi MS, Lee CB (2002) Nitrogen budgets for the Republic of Korea and the Yellow Sea region. Biogeochemistry 57(58):387–403CrossRefGoogle Scholar
  8. Befus KM, Sheehan AF, Leopold M, Anderson SP, Anderson RS (2011) Seismic constraints on critical zone architecture, Boulder Creek Watershed, Front Range, Colorado. Vadose Zone J 10(3):915–927CrossRefGoogle Scholar
  9. Benedict KB, Day D, Schwandner FM, Kreidenweis SM, Schichtel B, Malm WC, Collett JL Jr (2013) Observations of atmospheric reactive nitrogen species in Rocky Mountain National Park and across northern Colorado. Atmos Environ 64:66–76CrossRefGoogle Scholar
  10. Berendse F, Van Breemen N, Rydin H, Buttler A, Heijmans M, Hoosbeek MR, Lee JA, Mitchell E, Saarinen T, Vasander H, Wallén B (2001) Raised atmospheric CO2 levels and increased N deposition cause shifts in plant species composition and production in Sphagnum bogs. Glob Change Biol 7(5):591–598. doi: 10.1046/j.1365-2486.2001.00433.x CrossRefGoogle Scholar
  11. Birkeland PW, Shroba RR, Burns SA, Price AB, Tonkin PJ (2003) Integrating soils and geomorphology in mountains—an example from the Front Range of Colorado. Geomorphology 55:329–344CrossRefGoogle Scholar
  12. Brantley SL, Goldhaber MB, Ragnarsdottir KV (2007) Crossing disciplines and scales to understand the critical zone. Elements 3:307–314CrossRefGoogle Scholar
  13. Brooks PD, Williams MW, Schmidt SK (1995) Snowpack controls on soil nitrogen dynamics in the Colorado alpine. In: IAHS publications—series of proceedings and reports. International Association of Hydrological Sciences no. 228. IAHS, Wallingford, p. 283–292 (1981)Google Scholar
  14. Brooks PD, Williams MW, Schmidt SK (1998) Inorganic nitrogen and microbial biomass dynamics before and during spring snowmelt. Biogeochemistry 43(1):1–15CrossRefGoogle Scholar
  15. Cabrera ML, Beare MH (1993) Alkaline persulfate oxidation for determining total nitrogen in microbial biomass extracts. Soil Sci Soc Am J 57:1007–1012CrossRefGoogle Scholar
  16. Casciotti KL, Sigman DM, Hastings MG, Böhlke JK, Hilkert A (2002) Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Anal Chem 74(19):4905–4912. doi: 10.1021/ac020113w CrossRefGoogle Scholar
  17. Cherrey KD, Flury M, Harsh JB (2003) Nitrate and colloid transport through coarse Hanford sediments under steady state, variably saturated flow. Water Resour Res. doi: 10.1029/2002WR001944 Google Scholar
  18. Cole JC, Braddock WA (2009) Geologic map of the Estes Park 30′ × 60′ quadrangle, north-central Colorado. US Geological Survey. Scientific Investigations Map 3039Google Scholar
  19. Dane JH, Hopmans JW (2002a) Hanging water column. In: Dane JH, Topp GC (eds) Methods of soil analysis, Part 4: physical methods. Soil Science Society of America book series no. 5. Soil Science Society of America, Madison, p 680–683Google Scholar
  20. Dane JH, Hopmans JW (2002b) Pressure plate extractor. In: Dane JH, Topp GC (eds) Methods of soil analysis, Part 4: physical methods. Soil Science Society of America book series no. 5. Soil Science Society of America, Madison, p 688–690Google Scholar
  21. Dethier DP, Lazarus ED (2006) Geomorphic inferences from regolith thickness, chemical denudation and CRN erosion rates near the glacial limit, Boulder Creek Catchment and vicinity, Colorado. Geomorphology 75:384–399. doi: 10.1016/j.geomorph.2005.07.029 CrossRefGoogle Scholar
  22. Diek S, Temme AJAM, Teuling AJ (2014) The effect of spatial soil variation on the hydrology of a semi-arid Rocky Mountains Catchment. Geoderma 235–236:113–126. doi: 10.1016/j.geoderma.2014.06.028 CrossRefGoogle Scholar
  23. Eilers KG, Debenport S, Anderson SP, Fierer N (2012) Digging deeper to find unique microbial communities: the strong effect of depth on the structure of bacterial and archaeal communities in soil. Soil Biol Biochem 50:58–65CrossRefGoogle Scholar
  24. Fang Y, Gundersen P, Mo J, Weixing Z (2009) Nitrogen leaching in response to increased nitrogen inputs in subtropical monsoon forests in southern China. For Ecol Manag 257(1):332–342. doi: 10.1016/j.foreco.2008.09.004 CrossRefGoogle Scholar
  25. Fierer N, Schimel JP (2002) Effects of drying–rewetting frequency on soil carbon and nitrogen transformations. Soil Biol Biochem 34(6):777–787CrossRefGoogle Scholar
  26. Fierer N, Schimel JP (2003) A proposed mechanism for the pulse in carbon dioxide production commonly observed following the rapid rewetting of a dry soil. Soil Sci Soc Am J 67:798–805CrossRefGoogle Scholar
  27. Fierer N, Schimel JP, Holden PA (2003) Variations in microbial community composition through two soil depth profiles. Soil Biol Biochem 35:167–176CrossRefGoogle Scholar
  28. Foster MA, Anderson RS, Wyshnytzky CE, Ouimet WB, Dethier DP (2015) Hillslope-lowering rates and mobile-regolith residence times from in situ and meteoric 10Be analysis: Boulder Creek Critical Zone Observatory, Colorado. GSA Bull 125(5–6):862–878. doi: 10.1130/B31115.1 CrossRefGoogle Scholar
  29. Gee GW, Campbell MD, Campbell GS, Campbell JH (1992) Rapid measurement of low soil water potentials using a water activity meter. Soil Sci Soc Am J 56:1068–1070CrossRefGoogle Scholar
  30. Goulding KWT, Bailey NJ, Bradbury NJ, Hargreaves P, Howe M, Murphy DV, Poulton PR, Willison TW (2008) Nitrogen deposition and its contribution to nitrogen cycling and associated soil processes. N Phytol 139(1):49–58. doi: 10.1046/j.1469-8137.1998.00182.x CrossRefGoogle Scholar
  31. Gruber N, Galloway JN (2008) An earth-system perspective of the global nitrogen cycle. Nature 451:293–296. doi: 10.1038/nature06592 CrossRefGoogle Scholar
  32. Gundersen P, Emmett BA, Kjønaas OJ, Koopmans CJ, Tietema A (1998) Impact of nitrogen deposition on nitrogen cycling in forests: a synthesis of NITREX data. For Ecol Manag 101(1–3):37–55. doi: 10.1016/S0378-1127(97)00124-2 CrossRefGoogle Scholar
  33. Higgins RW, Yao Y, Wang XL (1997) Influence of the North American monsoon system on the US summer precipitation regime. J Clim 10:2600–2622CrossRefGoogle Scholar
  34. Hinckley ES, Ebel BA, Barnes RT, Williams MW, Anderson SP (2012) Aspect control of water movement on hillslopes near the rain–snow transition of the Colorado Front Range. Hydrol Process 28(1):74–85. doi: 10.1002/hyp.9549 CrossRefGoogle Scholar
  35. Hinckley ELS, Barnes RT, Anderson SP, Williams MW, Bernasconi SM (2014) Nitrogen retention and transport differ by hillslope aspect at the rain–snow transition of the Colorado Front Range. J Geophys Res Biogeosci 119(7):1281–1296. doi: 10.1002/2013JG002588 CrossRefGoogle Scholar
  36. Hirobe M, Tokuchi N, Iwatsubo G (1998) Spatial variability of soil nitrogen transformation patterns along a forest slope in a Cryptomeria japonica D. Don plantation. Eur J Soil Biol 34(3):123–131. doi: 10.1016/S1164-5563(00)88649-5 CrossRefGoogle Scholar
  37. Hopp L, Harman C, Desilets SLE, Graham CB, McDonnell JJ, Troch PA (2009) Hillslope hydrology under glass: confronting fundamental questions of soil-water-biota co-evolution at Biosphere 2. Hydrol Earth Syst Sci 13(11):2105–2118CrossRefGoogle Scholar
  38. Jin L, Ravella R, Ketchum B, Bierman PR, Heaney P, White T, Brantley SL (2010) Mineral weathering and elemental transport during hillslope evolution at the Susquehanna/Shale Hills Critical Zone Observatory. Geochim Cosmochim Acta 74(13):3669–3691CrossRefGoogle Scholar
  39. LeBauer DS, Treseder KK (2008) Nitrogen limitation of net primary productivity in terrestrial ecosystems is globally distributed. Ecology 89:371–379. doi: 10.1890/06-2057.1 CrossRefGoogle Scholar
  40. Månsson KF, Falkengren-Grerup U (2003) The effect of nitrogen deposition on nitrification, carbon and nitrogen mineralization and litter C:N ratios in oak (Quercus robur L.) forests. For Ecol Manag 179(1–3):455–467. doi: 10.1016/S0378-1127(02)00535-2 CrossRefGoogle Scholar
  41. Marr JW (1961) Ecosystems of the east slope of the Front Range in Colorado. Series in biology, paper 21. Accessed 3 Jan 2015
  42. Matson PA, Lohse KA, Hall SJ (2002) The globalization of nitrogen deposition: consequences for terrestrial ecosystems. Ambio 31(2):113–119. doi: 10.1579/0044-7447-31.2.113 CrossRefGoogle Scholar
  43. McCrackin ML, Harms TK, Grimm NB, Hall SJ, Kaye JP (2008) Responses of soil microorganisms to resource availability in urban, desert soils. Biogeochemistry 87(2):143–155CrossRefGoogle Scholar
  44. Nadelhoffer KJ, Downs MR, Fry B (1999) Sinks for 15N-enriched additions to an oak forest and a red pine plantation. Ecol Appl 9(1):72–86CrossRefGoogle Scholar
  45. National Atmospheric Deposition Program (NADP) (2013) Accessed 6 Sept 2013
  46. National Resources Conservation Service (NRCS) (2009) Custom soil resource report for Arapaho-Roosevelt National Forest Area, Colorado, parts of Boulder, Clear Creek, Gilpin, Grand, Park, and Larimer Counties. USDA, Washington, DCGoogle Scholar
  47. Neff JC, Holland EA, Dentener FJ, McDowell WH, Russell KM (2002) The origin, composition and rates of organic nitrogen deposition: a missing piece of the nitrogen cycle? Biogeochemistry 57(1):99–136CrossRefGoogle Scholar
  48. Nimmo JR, Winfield KA (2002) Miscellaneous methods [water retention and storage]. In: Dane JH, Topp GC (eds) Methods of soil analysis, Part 4: physical methods. Soil Science Society of America book series no. 5. Soil Science Society of America, Madison, p 710–714Google Scholar
  49. Parsekian AD, Singha K, Ainsley BJ, Holbrook WS, Slater L (2015) Multiscale geophysical imaging one the critical zone. Rev Geophys 53:1–26. doi: 10.1002/2014RG000465 CrossRefGoogle Scholar
  50. Peet RK (1981) Forest vegetation of the Colorado Front Range. Vegetatio 45:3–75CrossRefGoogle Scholar
  51. Perica S, Martin D, Pavlovic S, Roy I, St. Laurent M, Trypaluk C, Unruh D, Yekta M, Bonnin G (2013) NOAA Atlas 14, precipitation-frequency atlas of the United States, vol 8 (version 2.0). National Oceanic and Atmospheric Administration, Silver SpringGoogle Scholar
  52. Reynolds WD, Elrick DE (2002) Constant head soil core (tank) method. In: Dane JH, Topp GC (eds) Methods of soil analysis, Part 4—physical methods. Soil Science Society of America book series no. 5. Soil Science Society of America, Madison, p 804–808Google Scholar
  53. Robertson GP, Hutson MA, Evans FC, Tiedje JM (1988) Spatial variability in a successional plant community: patterns of nitrogen availability. Ecology 69(5):1517–1524CrossRefGoogle Scholar
  54. Robertson GP, Paul EA, Harwood RR (2000) Greenhouse gases in intensive agriculture: contributions of individual gases to the radiative forcing of the atmosphere. Science 289(5486):1922–1925. doi: 10.1126/science.289.5486.1922 CrossRefGoogle Scholar
  55. Sigman DM, Casciotti KL, Andreani M, Barford C, Galanter M, Böhlke JK (2001) A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Anal Chem 73(17):4145–4153. doi: 10.1021/ac010088e CrossRefGoogle Scholar
  56. Silver WL, Thompson AW, Reich A, Ewel JJ, Firestone MK (2005) Nitrogen cycling in tropical plantation forests: potential controls on nitrogen retention. Ecol Appl 15:1604–1614CrossRefGoogle Scholar
  57. Stark JM, Hart SC (1996) Diffusion technique for preparing salt solutions, Kjeldahl digests, and persulfate digests for N-15 analysis. Soil Sci Soc Am J 60:1846–1855CrossRefGoogle Scholar
  58. Templer PH, Mack MC, Chapin FS III, Christenson LM, Compton LE, Crook HD, Currie WS et al (2012) Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies. Ecology 93(8):1816–1829CrossRefGoogle Scholar
  59. Tsunogai U, Komatsu DD, Daita S, Kazemi GA, Nakagawa F, Noguchi I, Zhang J (2010) Tracing the fate of atmospheric nitrate deposited onto a forest ecosystem in Eastern Asia using Δ17O. Atmos Chem Phys 10:1809–1820. doi: 10.5194/acp-10-1809-2010 CrossRefGoogle Scholar
  60. van Genuchten MT (1980) A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal, 44(5): 892-898Google Scholar
  61. van Genuchten MT, Leij FJ, Yates SR (1991) The RETC code for quantifying the hydraulic functions of unsaturated soils. Report EPA/600/2091/065. Robert S. Kerr Environmental Research Laboratory, Office of Research and Development, US Environmental Protection Agency, AdaGoogle Scholar
  62. Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, Schindler DW, Schlesinger WH, Tilman DG (1997) Human alteration of the global nitrogen cycle: sources and consequences. Ecol Appl 7:737–750. doi: 10.1890/1051-0761(1997)007[0737:HAOTGN]2.0.CO;2 Google Scholar
  63. Weintraub SR, Taylor PG, Porder S, Cleveland CC, Asner GP, Townsend AR (2015) Topographic controls on soil nitrogen availability in a lowland tropical forest. Ecology 96(6):1561–1574CrossRefGoogle Scholar
  64. Western Regional Climate Center (WRCC) (2011) Accessed 6 Dec 2011
  65. Williams MW, Baron JS, Caine N, Sommerfeld R, Sanford R (1996) Nitrogen saturation in the Rocky Mountains. Environ Sci Technol 30(2):640–646CrossRefGoogle Scholar
  66. Williams MW, Barnes RT, Parman JN, Freppaz M, Hood E (2011) Stream water chemistry along an elevational gradient from the Continental Divide to the foothills of the Rocky Mountains. Vadose Zone J 10:900–914. doi: 10.2136/vzj2010.0131 CrossRefGoogle Scholar
  67. Zavaleta ES, Shaw MR, Chiarello NR, Mooney HA, Field CB (2003) Additive effects of simulated climate changes, elevated CO2, and nitrogen deposition on grassland diversity. Proc Natl Acad Sci USA 100(13):7650–7654. doi: 10.1073/pnas.0932734100 CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2017

Authors and Affiliations

  • Eve-Lyn S. Hinckley
    • 1
    • 2
  • Brian A. Ebel
    • 3
  • Rebecca T. Barnes
    • 4
  • Sheila F. Murphy
    • 5
  • Suzanne P. Anderson
    • 2
    • 6
  1. 1.Environmental Studies ProgramUniversity of ColoradoBoulderUSA
  2. 2.Institute of Arctic and Alpine ResearchBoulderUSA
  3. 3.National Research ProgramUnited States Geological SurveyLakewoodUSA
  4. 4.Colorado CollegeColorado SpringsUSA
  5. 5.United States Geological SurveyBoulderUSA
  6. 6.Department of Geography, 260 UCBUniversity of ColoradoBoulderUSA

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