Atmospheric deposition to a low-elevation spruce-fir forest, Maine, USA
Mclaughlin, JW; Fernandez, IJ; Richards, KJ
| HERO ID | 123812 |
|---|---|
| In Press | No |
| Year | 1996 |
| Title | Atmospheric deposition to a low-elevation spruce-fir forest, Maine, USA |
| Authors | Mclaughlin, JW; Fernandez, IJ; Richards, KJ |
| Journal | Journal of Environmental Quality |
| Volume | 25 |
| Issue | 2 |
| Page Numbers | 248-259 |
| Abstract | A spruce-fir forest in central-Maine, USA, has been the site of dry and wet atmospheric deposition measurements since 1988. Precipitation flux of hydrogen ions (H+) and sulfate (SO42-) decreased by 24 and 42%, respectively, during the study period, but no temporal trends occurred for precipitation H+ or SO(4)2- concentrations. Decreased precipitation fluxes were likely due to a 33% decrease in precipitation amounts during the latter years of the study. Both H+ and SO42- concentrations and fluxes in throughfall decreased, corresponding to decreases in dry deposition of those constituents. No nitrate (NO3-) concentration or flux trends occurred in precipitation, throughfall, or dry deposition. Hydrogen, NO3-, and NH4+ had a negative net canopy exchange (NCE) attributable to N deficiency at this site and acid neutralization in the canopy. Sulfate and magnesium (Mg2+) were conservative and had no NCE. Calcium (Ca2+) and potassium (K+) had a positive NCE due to canopy leaching. A comparison of bulk and wet-only precipitation collectors showed that SO42-, Ca2+, and K+ concentrations were greater in solutions from a bulk collector compared with a wet-only collector. The differences were partially attributable to dry deposition. Throughfall H+, Ca2+, and dissolved organic carbon (DOC) concentrations were higher in weekly wet-only collections composited monthly, compared with weekly bulk collections composited either weekly or monthly. Nitrate concentration, however, was lowest in the wet-only thronghfall collections. Differences likely resulted from spatial variability. Ongoing research is attempting to further define trends apparent to date, and to determine the mechanisms controlling these characteristics. |
| Doi | 10.2134/jeq1996.00472425002500020007x |
| Wosid | WOS:A1996UB98300006 |
| Url | https://www.agronomy.org/publications/jeq/abstracts/25/2/JEQ0250020248 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Is Qa | No |