The aim of this work was to describe changes in fatty acid profiles of fungi growing under artificial
conditions of oxygen depletion. In total, 133 fungal strains belonging to eight orders were isolated from
cattle impacted soils and tested. The analysis of the ten most frequent fatty acids revealed significant
shift in fatty acids composition as a result of decreasing oxygen level. Taxonomic- as well as aerationdependent
changes in the amounts of fungal biomarker fatty acids (18:19 and 18:26,9) were found.
Therefore,the ratio ofthese two fatty acids could be considered as an indicator of anaerobic, microaerobic
or aerobic conditions in soil. Moreover, fatty acid-based estimation of fungal biomass in soils should be
performed as a sum of both biomarker fatty acids and with respect to the soil characteristics as well as
to the composition of fungal community.