pH profiles from diatom stratigraphies in sediment cores of selected lakes of new brunswick and Nova Scotia,Canada

Diatom-inferred pH profiles have been constructed using the log x index for three lakes in Nova Scotia and four lakes in New Brunswick, Canada. The profiles cover the last 150 yr, including the past 70 to 80 yr when acid precipitation was increasing. The diatom-inferred pH changed from 6.1 to 5.3 for an unbuffered lake and from 6.3 to 6.1 for the buffered lake near Halifax, Nova Scotia, during the past 70 yr but no change in pH occurred in an unbuffered lake situated in the south of the province. Since 1900, the acidity of two unbuffered lakes in New Brunswick has changed from 6.5 to 6.1 and 6.2 to 5.7. There was no change in pH for the naturally-buffered lake and a third unbuffered lake in New Brunswick. The study suggests that there was a decline in pH of lake water in some unbuffered lakes of New Brunswick and Nova Scotia.