Mineral composition of the Nostoc commune soil cyanoprokaryota in the Baikal region

The Nostoc commune Vaucher ex Bornet et Flahault soil cyanoprokaryote is a filamentous organism forming macroscopic colonies on the soil surface. This organism is capable of oxygenic photosynthesis and atmospheric nitrogen fixation, thereby contributing to the nitrogen and carbon balance of ecosystems and participating in the processes of disturbed soil recovery. The present study aimed to determine the content of mineral elements (Ca, Mg, K, Na, Cu, Fe, Mn, Zn, Cd, Pb) in N. commune thalli growing in herbaceous plant communities of the Baikal region in areas of various anthropogenic disturbance, and to establish the effect of soil acidity on the accumulation of these elements. The elemental composition was determined by emission flame photometry and atomic absorption spectroscopy. To the best of our knowledge, the accumulation of Ca, Mg, K, Na, Na, Cu, Fe, Mn, Zn, Cd, and Pb in regional samples of N. commune were determined for the first time. The investigated thalli were found to contain significant amounts of Ca, Mg, K, Na, and Fe. The species can be referred to calciphiles in terms of its ability to accumulate Ca (up to 27,440 mg center dot kg-1 abs. dry weight) and to grow on neutral and alkaline soils. N. commune outperforms vascular plants in terms of Fe accumulation (on average, 2112 mg center dot kg-1). Significant differences were observed in the content of the studied elements in N. commune collected from different sites. N. commune thalli growing in the vicinity of a highway contained Pb, Cu, Zn, Cd, Ca, Mg, and Na in increased amounts. Under lower soil acidity, the species was found to accumulate more Ca, Mg, and Cd. Under increased soil acidity, N. commune thalli accumulate Fe, Mn, and K. A significant correlation between the content of these elements in N. commune and the acidity of the upper soil horizons was revealed.