 |
| Titel |
Spatial and temporal dynamics of stream chemistry in a forested watershed |
| VerfasserIn |
K. B. Piatek, S. F. Christopher, M. J. Mitchell |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 3 ; Nr. 13, no. 3 (2009-03-25), S.423-439 |
| Datensatznummer |
250011805
|
| Publikation (Nr.) |
 copernicus.org/hess-13-423-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| Spatial dynamics of solute chemistry and natural abundance isotopes of
nitrate (15N and 18O) were examined in seven locations and at the
watershed outlet in 2001 and 2002 in a forest watershed in the Adirondack
Mountains of New York State, USA. Temporal dynamics were examined during
five discharge periods: winter, snowmelt, spring, summer, and fall, based on
discharge levels at the watershed outlet. Solute concentrations were
variable across space and time with significant (p≤0.05) interaction
effects. Year*period was significant for pH, NH4+, NO3-,
total N, DOC, and total Al suggesting that inter-annual variability in
discharge levels was more important for these solutes than intra-annual
variability. Period*sampling point was significant for pH, Mg2+,
Ca2+, sum of base cations, Si, and total Al suggesting that the
differences in concentration of these solutes among sampling points were
moderated by discharge levels. In general, groundwater sources located in
upper watershed controlled stream chemistry at higher elevations with
highest pH, Ca2+, sum of base cations, Si, and SO42-
concentrations, with higher values in summer, and dilution effects during
snowmelt. Two low elevation wetlands had a substantial influence over stream
chemistry at those locations contributing lowest NO3- and highest
DOC. Snowmelt exhibited among the lowest pH, sum of base cations, and
SO42-, and highest NO3-, total N, and total Al; snowmelt
appeared to dilute groundwater, and flush stored soil-derived solutes.
Summer discharge, composed mainly of groundwater, exhibited the lowest flow,
among the highest Mg2+, Ca2+, and lowest DON, DOC, and total Al
concentrations. Isotopic analysis indicated that NO3- was
microbial with primary source in upper watershed soil, from where it was
flushed to stream under high discharge-conditions, or drained to groundwater
which became its secondary source when discharge was low. Watershed outlet
did not exhibit specific solute levels found at source-areas, but
represented solute dynamics in the rest of the watershed well. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|