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41.
Atmosphere-borne acidic pollutants constitute an important, potentially critical, risk to aquatic ecosystems. Long-time series
datasets are a requirement in the assessment of the biological impacts of both increased and decreased loadings of acidic
pollutants and allow for the anticipation of future pollution loadings and their effects that can be acted upon with some
confidence. Little is known concerning levels of deposition of atmospheric pollutants and their effects on acid-sensitive
aquatic ecosystems in Ireland. Moreover, unequivocal evidence of acidification by atmospheric deposition is limited. The objective
of this study was to provide a preliminary assessment of pH response in three lake sites that are situated in acid-sensitive
areas of Ireland, and to determine whether pH response tends to be uniform or differs due to variations in atmospheric loading
and catchment properties. Levels of spheroidal carbonaceous particle (SCP) deposition have been used as a general indicator
of the timing and extent of atmospheric pollutant loading and ecosystem response has been assessed by estimating diatom-inferred
pH with a weighted-averaging calibration model (72 lakes) developed specifically for the Irish ecoregion. Levels of diatom-inferred
pH (DI-pH) appear to respond to increased and decreased levels of atmospheric pollution loads—as represented by SCPs—at two
of the three sites examined in the east and west of Ireland. In contrast, the site situated in the southwest of Ireland showed
a varying and less directional DI-pH response, possibly due to lower deposition pressures, large lake size, and more buffered
edaphic geology. 相似文献
42.