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| Titel |
Recovery from acidification of lochs in Galloway, south-west Scotland, UK: 1979-1998 |
| VerfasserIn |
R. C. Ferrier, R. C. Helliwell, B. J. Cosby, A. Jenkins, R. F. Wright |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 5, no. 3 ; Nr. 5, no. 3, S.421-432 |
| Datensatznummer |
250002564
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| Publikation (Nr.) |
 copernicus.org/hess-5-421-2001.pdf |
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| Zusammenfassung |
| The Galloway region of south-west Scotland
has historically been subject to long-term deposition of acidic precipitation
which has resulted in acidification of soils and surface
waters and subsequent damage to aquatic ecology. Since the end of the 1970s,
however, acidic deposition has decreased substantially.
The general pattern is for a rapid decline in non-marine sulphate in rainwater
over the period 1978-1988 followed by stable
concentrations to the mid-1990s. Concentrations of nitrate and ammonium in
deposition have remained constant between 1980 and 1998.
Seven water quality surveys of 48 lochs in the Galloway region have been
conducted between 1979 and 1998. During the first 10 years, from
1979, there was a major decline in regional sulphate concentrations in the
lochs, which was expected to have produced a decline in base cations
and an increase in the acid neutralising capacity. But sea-salt levels (as
indicated by chloride concentrations) were approximately 25%
higher in 1988 than in 1979 and thus short-term acidification due to sea-salts
offset much of the long-term recovery trend expected in the lochs.
During the next 10 years, however, the chloride concentrations returned to 1979
levels and the lochs showed large increases in acid neutralising
capacity despite little change in sulphate concentrations. From the observed
decline in sulphate deposition and concentrations of sulphate
in the lochs, it appears that approximately 75% of the possible improvement in
acid neutralising capacity has already occurred over the
20-year period (1979-1998). The role of acid deposition as a driving factor for
change in water chemistry in the Galloway lochs is confounded
by concurrent changes in other driving variables, most notably, factors related
to episodic and year-to-year variations in climate. In
addition to inputs of sea-salts, climate probably also influences other chemical
signals such as peaks in regional nitrate concentrations and the
sharp increase in dissolved organic carbon during the 1990s.
Keywords: acidification, recovery, Galloway, sulphur, nitrogen |
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