Acidity of twelve northern New England (U.S.A.) lakes in recent centuries |
| |
Authors: | Ronald B Davis Dennis S Anderson Stephen A Norton Mark C Whiting |
| |
Institution: | (1) Department of Plant Biology and Pathology, University of Maine, 04469-5722 Orono, ME, USA;(2) Institute for Quaternary Studies, University of Maine, 04469-5711 Orono, ME, USA;(3) Department of Geological Sciences, University of Maine, 04469-5711 Orono, ME, USA;(4) Present address: Maine Department of Environmental Protection, Bangor Regional Office, 106 Hogan Road, 04401 Bangor, ME, USA |
| |
Abstract: | Studies of sediment cores from 12 acidic lakes in granitic, forested and uninhabited catchments in northern New England, U.S.A. produced diatom-inferred pH (IpH) 5.2 to 5.8 and alkalinity (Ialk) –12 to 31 µeq l–1, with slowly declining values at some lakes, for one to four centuries prior to logging. Increases of IpH (0.05 to 0.60) and Ialk (5 to 40 µeq l–1) correlate with logging in the catchments in the early-1800s to early-1900s. Recovery to pre-logging IpH and Ialk correlates with forest succession toward conifers, and is completed in the late-1800s to mid-1900s. Beginning at 1915–1920 (4 lakes), 1930–1950 (4 lakes) and 1965–1970 (4 lakes), IpH and Ialk start decreasing below pre-logging values due to atmospheric acidic deposition, leading to respective total decreases of 0.10 to 0.45 (X=0.25) and 5 to 25 µeq l–1 (X=15). Inputs of anthropogenic Pb, Zn, V, polycyclic aromatic hydrocarbons, and soot from the atmosphere are first detectable in early- to late-1800s sediment, and Cu in late-1800s sediment, increase rapidly in the late-1800s to mid-1900s, and level off or decrease since the 1960s — partly due to emission controls. Decreasing Ca, Mn, and possibly Zn relative to other metals and normalized to organic content, and increasing flux of Fe to the lakes, indicate soil and water acidification after 1900.This is the fourteenth of a series of papers to be published by this journal which is a contribution of the Paleoecological Investigation of Recent Lake Acidification (PIRLA) project. Drs. D. F. Charles and D. R. Whitehead are guest editors for this series. |
| |
Keywords: | acidification alkalization pH alkalinity diatoms sediment chemistry New England catchment effects land use logging acidic deposition air pollutants |
本文献已被 SpringerLink 等数据库收录! |
|