Fig. 3: Response of diatom assemblages in Shuanghu Lake to changes in ice cover duration.
From: Ecological shift in a remote alpine lake in inland Asia induced by European air pollutants
a Variations in the abundance of small benthic fragilarioids and b A. minutissima from Shuanghu Lake before the 1870s, along with c the Shannon index (alpha diversity) of diatom spices, were mainly influenced by changes in ice cover duration. This relationship is supported by winter temperature reconstructions based on d tree-ring data in East Asia over the past 700 years41, where the grey line represents annual temperature variations and the pink line indicates the 130-point smoothing, as well as e the cellulose δ18O record from the Big Black peatland in the Altai Mountains19,42. f The DCCA results (green line) and the RSI (blue bars) of the diatom assemblages in Shuanghu Lake indicate an ecological shift around 1870 CE. The grey/yellow shaded bars indicate the periods of reduced ice cover duration and the new regime of diatom assemblages, respectively. The grey dots and square at the top correspond to ten AMS 14C dates with a 1σ uncertainty interval, and a 210Pb/137Cs date from Shuanghu Lake, respectively22. The red triangles in e represent the five 14C dates from the Big Black peatland42.
