 |
| Titel |
Coherent response of lakes in Ontario, Canada to reductions in sulphur deposition: the effects of climate on sulphate concentrations |
| VerfasserIn |
P. J. Dillon, K. M. Somers, J. Findeis, M. C. Eimers |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 7, no. 4 ; Nr. 7, no. 4, S.583-595 |
| Datensatznummer |
250004714
|
| Publikation (Nr.) |
 copernicus.org/hess-7-583-2003.pdf |
|
|
|
|
|
| Zusammenfassung |
| Sulphate deposition in south-central Ontario declined between 1976 and 2000
by more than 50%, whereas lake sulphate (SO42–) concentrations
decreased by, on average, only half as much. To investigate the factors that controlled
this slower than expected response, the temporal patterns in lake
SO42– concentrations were compared with patterns in both deposition
and climate, since climate has a major influence on the hydrological cycle in this part
of the continent. To do this, the temporal coherence in SO42–
concentrations between 9 lake basins was estimated using the intraclass correlation from
a repeated-measures analysis of variance and two subsets of lakes were found (six in one
group, four in the other), each with lakes having synchronous patterns. One subset
(4 lakes) included the 3 with the longest water replenishment times (>3.4 yr) which
are expected to respond to decreases in SO42– deposition more
slowly. However, the average pattern reflecting the temporal changes of each of the
two subsets was very similar. The response of both subsets of lakes to the decreasing
SO42– deposition over two decades was independent of the degree
of acidification or sensitivity to acidification of the lakes. In a determination of
which factors best predicted each of those two subsets’ SO42–
time series, good predictive models were produced by regional/global-scale climate
indices, specifically the Southern Oscillation Index (SOI) describing the El Niño
Southern Oscillation (ENSO) and the North Atlantic Oscillation Index (NAOI), as well
as by SO42– deposition indices. When the predictor variables
were combined, models which described the long-term changes in lake
SO42– concentration best included the SOI, the NAOI and
SO42– deposition. Thus, large-scale climate factors play a
major role in determining the response of aquatic systems to changes in
SO42– deposition, perhaps through their influence on lake
and/or catchment processes that effectively delay recovery.
Keywords: Atmospheric deposition, lake recovery, temporal trends, climate, temporal
coherence |
| |
|
| Teil von |
|
|
|
|
|
|
|
|