Measurement of wet deposition of inorganic and organic nitrogen in a forest environment

TitleMeasurement of wet deposition of inorganic and organic nitrogen in a forest environment
Publication TypeJournal Article
Year of Publication2005
AuthorsHill K.A, Shepson PB, Galbavy ES, Anastasio C
JournalJournal of Geophysical Research
Date Published2005

Dissolved inorganic (NO-3 and NH+4) and organic nitrogen (DON) were measured in precipitation at the University of Michigan Biological Station (UMBS) near Pellston, Michigan, in an open field and under the forest canopy from June to August 2004. Experiments to test the stability of the rain samples were conducted to evaluate different collection methods. Comparison of the two data sets allows the interactions between precipitation and the forest canopy to be examined. In addition, the measurements of wet-deposited total nitrogen were compared to calculated estimates of total dry-deposited nitrogen. Stability tests of the samples indicated that the samples must be frozen during collection. The average distribution of wet-deposited nitrogen for the summer was 32.9 (±0.5)% nitrate, 52.5 (±0.3)% ammonium, and 14.6 (±0.9)% DON in an open field and 42.5 (±0.9)% nitrate, 38.9 (±1.0)% ammonium, and 18.8 (±1.4)% DON under the forest canopy. Canopy-precipitation interactions were observed to cause a 68 (±4)% increase in nitrate, a 4 (±2)% decrease in ammonium, and an 81 (±16)% increase in DON in the collectors under the forest canopy. A comparison of wet and dry nitrogen deposition indicated that dry deposition may contribute more nitrogen than wet deposition to this site. However, our measurements indicate that much of the dry-deposited nitrogen is lost, some of which is likely revolatilized.