Post-glacial acidification of two alpine lakes (Sudetes Mts., SW Poland), as inferred from diatom analyses

Abstract

Past environmental changes in mountain lakes can be reconstructed with the use of subfossil diatoms from post-glacial sediments. This study applied such an analysis to two mountain lakes in the Sudetes Mts. in Poland: Mały Staw (MS) and Wielki Staw (WS). Cores 882 cm long (MS) and 1100 cm long (WS) taken from the centre of each lake in 1982 were used to study the long-term acidification history of these lakes. Changes in vegetation indicate that the initial phase of MS started at the end of the Pleistocene. WS sediments began to accumulate shortly after that, at the beginning of the Holocene. The majority of the diatom assemblages are typical of oligotrophic acidic lakes located in alpine and arctic regions. A pH reconstruction based on diatoms (DI-pH) showed long-term acidification dating to almost the beginning of the lakes' existence. Natural acidification began after the deglaciation, and the most intensive acidification continued to the end of the mid-Holocene. Through the whole period studied, pH decreased by 1.4 in MS and 0.9 in WS. After a period of relatively stable lake water pH, it decreased rapidly during the last few decades of the 20 th century, due to anthropogenic pollution: pH declined by 0.7 in MS and 0.3 in WS. Mały Staw, being shallower, smaller, and with a larger drainage basin than Wielki Staw, is more sensitive to acid deposition; this accounts for the difference in pH.

Pogórze Przemyskie Landscape Park Complex as a Habitat for Rare and New to Poland Pinnularia Species

“…Distribution in Poland: the species is rare in Poland(Siemińska 1964, Siemińska, Wołowski 2003, reported from various locations including a now-extinct peat bog near Krakow(Rumek 1946), the Widawka River(Ligowski 1988), the Kryniczanka Stream(Starmach 1989), and a peat bog in Magdalenowo (Lesiak, Sitkowska 1981). In recent years, the species has only been identified in Holocene sediments from the Mały Staw in the Karkonosze Mountains(Sienkiewicz 2005(Sienkiewicz , 2016.Ecology and distribution worldwide:The species is rare and occurs zonally as a zonal element in the Palaearctic region, often in isolated locations. It prefers waters with low electrolyte content(Krammer 2000).…”