Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies

  • C. W. Osenberg (Contributor)
  • M. Sommerkorn (Contributor)
  • C. M. D'Antonio (Contributor)
  • C. L. Goodale (Contributor)
  • P. Schleppi (Contributor)
  • K. Holland (Contributor)
  • D. U. Hooper (Contributor)
  • B. A. Emmett (Contributor)
  • W. W. Wessel (Contributor)
  • H. D. Crook (Contributor)
  • H. E. Epstein (Contributor)
  • A. Tietema (Contributor)
  • S. E. Hobbie (Contributor)
  • W. S. Currie (Contributor)
  • B.A. Hungate (Northern Arizona University) (Contributor)
  • K. J. Nadelhoffer (Contributor)
  • S. Lamontagne (Contributor)
  • J. E. Compton (Contributor)
  • F. Stuart Chapin (Contributor)
  • C. J. Curtis (Contributor)
  • P. Gundersen (Contributor)
  • M. C. Mack (Contributor)
  • D. B. Dail (Contributor)
  • L. M. Christenson (Contributor)
  • J. Spoelstra (Contributor)
  • I. K. Schmidt (Contributor)
  • J. Schimel (Contributor)
  • S. S. Perakis (Contributor)
  • P. H. Templer (Contributor)
  • Donald R. Zak (Contributor)



Effects of anthropogenic nitrogen (N) deposition and the ability of terrestrial ecosystems to store carbon (C) depend in part on the amount of N retained in the system and its partitioning among plant and soil pools. We conducted a meta-analysis of studies at 48 sites across four continents that used enriched 15N isotope tracers in order to synthesize information about total ecosystem N retention (i.e., total ecosystem 15N recovery in plant and soil pools) across natural systems and N partitioning among ecosystem pools. The greatest recoveries of ecosystem 15N tracer occurred in shrublands (mean, 89.5%) and wetlands (84.8%) followed by forests (74.9%) and grasslands (51.8%). In the short term (<1 week after 15N tracer application), total ecosystem 15N recovery was negatively correlated with fine-root and soil 15N natural abundance, and organic soil C and N concentration but was positively correlated with mean annual temperature and mineral soil C:N. In the longer term (3–18 months after 15N tracer application), total ecosystem 15N retention was negatively correlated with foliar natural-abundance 15N but was positively correlated with mineral soil C and N concentration and C : N, showing that plant and soil natural-abundance 15N and soil C:N are good indicators of total ecosystem N retention. Foliar N concentration was not significantly related to ecosystem 15N tracer recovery, suggesting that plant N status is not a good predictor of total ecosystem N retention. Because the largest ecosystem sinks for 15N tracer were below ground in forests, shrublands, and grasslands, we conclude that growth enhancement and potential for increased C storage in aboveground biomass from atmospheric N deposition is likely to be modest in these ecosystems. Total ecosystem 15N recovery decreased with N fertilization, with an apparent threshold fertilization rate of 46 kg N·ha−1·yr−1 above which most ecosystems showed net losses of applied 15N tracer in response to N fertilizer addition.
Date made availableJan 1 2016
Publisherfigshare Academic Research System

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