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Blood serum and other tissues of white suckers (Catostomus commersoni) and other species of fish have been examined in a preliminary effort to understand losses of fish from acid lakes. Maturing females of highly acid George Lake failed to show the normal degree of increase in serum calcium over males captured in the same location. Elevated serum calcium was always observed in females, relative to males, from nonacid locations when maturation stages were similar. A number of body tissues were examined to determine whether the distributions of calcium or other elements were altered and the...

It is especially difficult to obtain an overview of the literature on acid precipitation and its effects on freshwater ecosystems because this research covers disciplines in meteorology, chemistry, biology, geology, and hydrology. In addition, much of the work done in Scandinavia is not published in international journals and thus not included by major abstract services. Furthermore, many of these reports are written in Swedish and Norwegian and are, therefore, of little use to non-Scandinavian scientists.

Acid precipitation is altered by interaction with rocks, sediment and soil. A calcareous region buffers even the most intense loading at pH ~8; an alumino silicate region with unconsolidated sediment buffers acid loadings at pH ~6.5; alumino silicate outcrops are generally acidified. Either FeOOH or alumino silicates are probable H+ ion sinks in noncalcareous sediments. Glacially derived sediment is more important than bedrock in assimilation of acid precipitation in Shield areas. Toxic metal concentrations are dependent upon sediment metal concentrations and the pH of water.

The Cedar Creek Basin (39th N parallel 92nd W meridian) was studied for the period June 1952 through August 1954 to observe the effects of both continuous and periodic acid effluent flows on aquatic communities. The acid strip-mine effluent contained ferric and ferrous iron, copper, lead, zinc, aluminum, magnesium, titratable acid, and elevated hydrogen ion concentration, and was toxic to many of the aquatic organisms. In the areas of Cedar Creek, subjected to continuous acid flow, planktonic and benthic species had become adapted to the severe conditions and varied in abundance and...

Data collected since 1965 at a network of 9 stations in the northeastern United States show that precipitation is most acid in the growing season (May-September) and least acid in winter (December-February). For the Hubbard Brook station in New Hampshire, where the mean hydrogen ion content of precipitation ranges between 46 μeq/l in winter and 102 μeq/l in summer, the seasonal pattern in acidity correlates closely with seasonal differences in sulfur deposition from the atmosphere. As summer precipitation passes through the forest canopy, hydrogen ion concentrations are lowered by an...

Many soil processes and properties may be affected by a change in chemical climate such as that caused by acidification of precipitation. The effect of additions of acid precipitation depends at first on the extent to which this acid is really absorbed by the soil and on the changes in substances with actual or potential acidity leaving the soil. There is for instance the possibility that added sulphur dioxide or sulphuric acid may leave the soil either as sulphate ions or as gaseous hydrogen sulphide. In the latter case there is no net acidification. Acidity due to uptake of nitrogen...

Recent measurements of the pH of precipitation leave no doubt that rainfall is acidic. Evidence will be presented that precipitation is a weak acid system. The results of this research indicate the need to establish standard sampling procedures to provide uniform sampling of precipitation

The acidity of precipitation in rural, forested areas of the northeastern United States is dominated by the strong mineral acids, sulfuric and nitric. Weak acids have a negligible effect on the measured acidity (pH) of precipitation. These conclusions are based on total acidity titrations and detailed analysis of organic and inorganic components in precipitation.

Being downwind of eastern and midwestern industrial centers, the Hubbard Brook Experimental Forest offers a prime location to monitor long-term trends in atmospheric chemistry. Continuous measurements of precipitation chemistry during the last 10 years provide a measure of recent changes in precipitation inputs of hydrogen ion. The weighted average pH of precipitation during 1964-65 to 1973-74 was 4.14, with a minimum annual value of 4.03 in 1970-71 and a maximum annual value of 4.21 in 1973-74. The sum of all cations except hydrogen ion decreased from 51 μeq/l in 1964-65 to 23 μeq/l in...

Sequential rain and snow sampling has been performed at Burlington and Concord, Massachusetts. The samples have been collected during 1974 and 1975 in one-quarter inch and one inch rain equivalents and chemical analysis performed on the aliquotes. Meteorological data was documented at the time of collection.