by Tatyana MOISEENKO, RAS Corresponding Member, RAS Institute of Water Management
Since arctic and high-mountain lakes (tarns) have been spared direct anthropogenic, man-caused effects, we can learn a good deal about global changes of the environment by studying lacustrine bottomset beds (deposits). The pollution of the upper layers of the atmosphere and the cross-border transfer of air masses from industrial centers have touched off substantial ecological changes in these what looks like vestal bodies of water.
Paleoecological studies of lakes figure prominently in major international programs: PEP (Pole-Equator-Pole) for Europe and Africa, CAPE (Circumpolar Ambience in Past Epochs), MOLAR (Mountain Lakes Research), LIMPACTs (Limnetic impact of human activity), among others. This approach has proved highly productive. The available fresh data show up the aftereffects of the booming industries in Europe, namely the pollution of high-mountain lakes in the Alps, Tatra Mountains and Pyrenees with oxides, heavy metals and radionuclides.
WATER "MEMORY LAYERS"
Now why in particular high-mountain and arctic lakes? How do they help diagnose global environmental changes? The thing is that their water catchment area
contains no immediate, direct pollutants (say, contributed by industrial or agricultural sources). That is why we can speak of the decisive impact of the cross-border transport of substances on the chemical composition of water, one that is formed by atmospheric precipitation often contaminated by heavy metals, acidiferous toxic organic substances and radionuclides. Such lakes have little, if any, soil and plants capable of retaining or digesting contaminants. Thus actually all polluting agents get into water.
The low temperatures as well as the ultrafresh and oligotrophic nature of these bodies of water diminish their self-purification capacity, and hence impurities get accumulated in bottomset beds (deposits). According to MOLAR data, the rate of ... Read more