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Type: Journal article
Title: Assessing long-term pH change in an Australian river catchment using monitoring and palaeolimnological data
Author: Tibby, J.
Reid, M.
Fluin, J.
Hart, B.
Kershaw, A.
Citation: Environmental Science and Technology (Washington), 2003; 37(15):3250-3255
Publisher: Amer Chemical Soc
Issue Date: 2003
ISSN: 0013-936X
Statement of
John Tibby, Michael A. Reid, Jennie Fluin, Barry T. Hart, and A. Peter Kershaw
Abstract: Reviews of stream monitoring data suggest that there has been significant acidification (>1.0 pH unit at some sites) of Victorian streamwaters over the past 3 decades. To assess whether these declines are within the range of natural variability, we developed a diatom model for inferring past pH and applied it to a ca. 3500-yr diatom record from a flood plain lake, Callemondah 1 Billabong, on the Goulburn River, which has among the most substantial observed pH declines. The model has a jackkniffed r 2 between diatom inferred and measured pH of 0.77 and a root mean square error of prediction of 0.35 pH units. In the pre-European period, pH was stable (range 6.5-6.7) for approximately 3000 yr. Since European settlement around 160 yr ago, diatom-inferred billabong pH has increased significantly by >0.5 units. We hypothesize that this increase in pH is related to processes associated with land clearance (e.g., increased base cation load and decreased organic acid load). There is no evidence of the recent monitored declines in the Callemondah record, which may indicate that that flood plain lakes and the main stream are experiencing divergent pH trends or that the temporal resolution in the billabong sediment record is insufficient to register recent declines.
Keywords: Diatoms
Acid Rain
Environmental Monitoring
Population Dynamics
Hydrogen-Ion Concentration
Geologic Sediments
Models, Theoretical
Reference Values
Description: Copyright © 2003 American Chemical Society
DOI: 10.1021/es0263644
Published version:
Appears in Collections:Aurora harvest 6
Environment Institute publications
Geography, Environment and Population publications

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