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Alewell, Christine ; Mitchell, Myron J. ; Likens, Gene E. ; Krouse, H. Roy:
Sources of stream sulfate at the Hubbard Brook Experimental forest : long-term analysis using stable isotopes.
In: Biogeochemistry.
Bd. 44
(1999)
Heft 3
.
- S. 281-299.
ISSN 1573-515X
DOI: https://doi.org/10.1023/A:1006058913822
Abstract
Sulfur deposition in the northeastern U.S. has been decreasing since the 1970s and there has been a concomitant decrease in the SO42- lost from drainage waters from forest catchments of this region. It has been established previously that the SO42- lost from drainage waters exceeds SO42- inputs in bulk precipitation, but the cause for this imbalance has not been resolved. The use of stable S isotopes and the availability of archived bulk precipitation and stream water samples at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire provided a unique opportunity to evaluate potential sources and sinks of S by analyzing the long-term patterns (1966-1994) of the d34S values of SO42- . In bulk precipitation adjacent to the Ecosystem Laboratory and near Watershed 6 the d34S values were greater (mean: 4.5 and 4.2l, respectively) and showed more variation (variance: 0.49 and 0.30) than stream samples from Watersheds 5 (W5) and 6 (W6) (mean: 3.2 and 3.7; variance: 0.09 and 0.08, respectively). These results are consistent with other studies in forest catchments that have combined results for mass balances with stable S isotopes. These results indicate that for those sites, including the HBEF, where atmospheric inputs are -1 yr-1 , most of the deposited SO42- cycles through the biomass before it is released to stream water. Results from W5, which had a whole-tree harvest in 1983-1984 showed that adsorption/desorption processes play an important role in regulating net SO42- retention for this watershed-ecosystem. Although the isotopic results suggest the importance of S mineralization, conclusive evidence that there is net mineralization has not yet been shown. However, S mass balances and the isotopic result are consistent with the mineralization of organic S being a major contributor to the SO42- in stream waters at the HBEF.
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER7238 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Lehrstuhl Bodenökologie Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 09 Okt 2015 05:56 |
| Letzte Änderung: | 13 Apr 2018 08:40 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/20292 |