Nitrogen deposition to and cycling in a deciduous forest.
The project described here seeks to answer questions regarding the role increased nitrogen (N) deposition is playing in enhanced carbon (C) sequestration in temperate mid-latitude forests, using detailed measurements from an AmeriFlux tower in southern Indiana (Morgan-Monroe State Forest, or MMSF). The measurements indicate an average atmosphere-surface N flux of approximately 6 mg-N m(-2) day(-1) during the 2000 growing season, with approximately 40% coming from dry deposition of ammonia (NH3), nitric acid (HNO3), and particle-bound N. Wet deposition and throughfall measurements indicate significant canopy uptake of N (particularly NH4+) at the site, leading to a net canopy exchange (NCE) of -6 kg-N ha(-1) for the growing season. These data are used in combination with data on the aboveground C:N ratio, litterfall flux, and soil net N mineralization rates to indicate the level of potential perturbation of C sequestration at this site.
Pryor
S C
SC
Department of Geography, Indiana University, Bloomington 47405, USA. spryor@indiana.edu
Barthelmie
R J
RJ
Carreiro
M
M
Davis
M L
ML
Hartley
A
A
Jensen
B
B
Oliphant
A
A
Randolph
J C
JC
Schoof
J T
JT
D000641:Ammonia / Q000378:metabolism; D001272:Atmosphere / Q000737:chemistry; D002244:Carbon / Q000378:metabolism; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D007196:Indiana; D017942:Nitric Acid / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D028222:Picea / Q000378:metabolism; D012987:Soil / Q000032:analysis; D013997:Time Factors; D014197:Trees / Q000378:metabolism*
D012987:Soil; D017942:Nitric Acid; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen