Climate change in the polar regions has been described as very dramatic in recent decades. Better
understanding and modeling the Earth´s climate system requires improving our knowledge of carbon, water
and energy exchange between terrestrial ecosystems and the atmosphere (IPCC, 2007). In severe climatic
conditions of Antarctica birds play an important role in transportation of organic matter to the coastal
landscapes. This study is aimed at studying structural and molecular composition of organic matter in soils
of King George and Ardley islands (South Shetland Islands). We revealed that redistribution of guano
components significantly affects the speed of soil cover spatial development and formation of new
polypedons. We found that the humic acids (HAs) of the cryoturbated, buried areas had lower amounts of
alkyl aromatic and protonized aromatic compounds. In contrast, the HAs from the surface layers contain
less alkyl carbon components. Our data showed that the portion of aromatic compounds is little higher in
soils under materials transported by birds compared to soils developed under bryophyta or lichens
communities. This is probably because birds use mainly remnants of Deschampsia antarctica (with high
portion of phenyl-propanoic organic precursors) for nest building. Comparison of the 13C-NMR spectra of
the HAs and the bulk SOM revealed that humification occurs in the Antarctic and results in accumulation of
aromatic and carboxylic compounds and reductions in alkylic ones. This indicates that humification is one of
the ways of soil organic matter stabilization.