Effect of anthropogenic acidification on a mountain lake zooplankton in an area with acid-sensitive bedrock (the Tatra Mountains, central Europe): Comparison of a 40-year research with a paleolimnological record
Abstract
Many lake areas of Europe and North America suffered from anthropogenic acidification during the last century. While the causes (acid deposition, low buffering geology) and consequences (degradation of both the water chemistry and biota) have been well understood, the onset of this process in particular sites remains unclear.
For that reason, we combined recent data on chemistry and zooplankton with a paleolimnological study of subfossil Cladocera in a lake (Starolesnianske pleso) in the Tatra Mountains (the Carpathians massif, Slovakia/Poland). Longterm research of acidification and recovery from acidification in Tatra lakes started in 1978.
By that time, 42 % of lakes were already acidified. Starolesnianske pleso is an alpine lake of glacial origin, with weathered granite in the background and a predominantly meadow watershed.
Once strongly acidified, it has been undergoing fast chemical recovery and the first signs of biological recovery from acidification since 1990-1995. The only records on its zooplankton prior acidification come from 1909-1913 (Stanislaw Minkiewicz).
A sediment core, covering the period of the last 3,500 years, was analyzed for chemistry, LOI, and subfossil Cladocera remains. Despite climatic changes in the last millennia, the record showed a very stable cladoceran fauna, poor in species, over the time, with the only statistically significant change at the beginning of the 20th century, which we associate with acidification.
Data on the zooplankton (Cladocera, Copepoda, and Rotifera) from the limnological monitoring (the last 40 years), though, allow to see a more dramatic and more detailed situation, which contributes to a better understanding of the phenomena: during the peaking acidification in the 1980s, the zooplankton were extinct except for one acid-tolerant cladoceran species, while a return of a copepod crustacean started the recovery. The combination of both the approaches provides a complex record and reference/detailed data where no other information is available.