Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Long-term trends in the chemistry of precipitation and lake water in the Adirondack region of New York, USA

Conference ·
OSTI ID:617897
; ;  [1]
  1. Syracuse Univ., NY (United States); and others
Long-term changes in the chemistry of precipitation (1978-94) and 16 lakes (1982-94) were investigated in the Adirondack region of New York, USA. Time-series analysis showed that concentrations of SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +} and basic cations have decreased in precipitation, resulting in increases in pH. A relatively uniform rate of decline in SO{sub 4}{sup 2-} concentrations in lakes across the region (1.81 +/- 0.35 {mu}eq L{sup -1} yr{sup -1}) suggests that this change was due to decreases in atmospheric deposition. The decrease in lake SO{sub 4}{sup 2-} was considerably less than the rate of decline anticipated from atmospheric deposition. Model calculations suggest that this discrepancy in watershed S budgets may be due either: (1) underestimates of dry deposition of S, or (2) internal release of S from weathering or mineralization of organic S in soil. The discrepancy in watershed S budgets cannot be explained by the release of previously adsorbed SO{sub 4}{sup 2-} from soil. Despite the marked declines in concentrations of SO{sub 4}{sup 2-} in Adirondack lakes, there has been no systematic increase in pH and ANC. The decline in SO{sub 4}{sup 2-} has corresponded with a near stoichiometric decrease in concentrations of basic cations in low ANC lakes. A pattern of increasing NO{sub 3}{sup -} concentrations that was evident in lakes across the region during the 1980`s has been followed by a period of lower concentrations. Currently there are no significant trends in NO{sub 3}{sup -} concentrations in Adirondack lakes.
OSTI ID:
617897
Report Number(s):
CONF-970145--
Country of Publication:
United States
Language:
English