Glasgow Lake: an early-warning sentinel of lake acidification in Cape Breton Highlands National Park (Nova Scotia, Canada)

• Published in: Hydrobiologia 2008-11, Vol.614 (1), p.299-307
• Main Authors: Gerber, Alexandra M, Ginn, Brian K, Whitfield, Colin J, Dillon, Peter J, Cumming, Brian F, Smol, John P
• Format: Article
• Language: English
• Subjects: Acid deposition; Acidification; Alkalinity; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomedical and Life Sciences; Ecology; Fresh water ecosystems; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Lakes; Life Sciences; National parks; Paleolimnology; Peak load; Plankton; Primary Research Paper; Sulfates; Synecology; Warning systems; Zoology
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-008-9514-x

In contrast to other lakes studied in Cape Breton Highlands National Park (Nova Scotia, Canada), our paleolimnological results indicated that Glasgow Lake has been impacted by acidic deposition starting in the early 1900s. Based on analysis of diatom assemblages, the lake experienced a decrease in diatom-inferred lakewater pH from a pre-industrial pH of ~5.8 to a current pH of 5.3 (2000-2002 measured mean pH = 5.0) as well as a decrease in diatom-inferred Gran-alkalinity. In this study, diatom-based paleolimnological techniques were used in conjunction with a dynamic biogeochemical model (MAGIC) to assess both the timing and extent of the acidification trend, as well as determine a probable explanation as to why this lake, and none of the other 15 Cape Breton Highlands lakes studied for paleolimnology thus far, acidified under a peak non-marine sulphate deposition load of 43.6 mmolc m⁻² year⁻¹ in the mid-1970s. Steady-state models estimate that Glasgow Lake had the lowest buffering capacity of six study lakes and estimated critical sulphate loading of