Algae and cyanobacteria in soils polluted with heavy metals (Northwest Russia, Murmansk region)

Abstract

The analysis of algae and cyanobacteria in Albic Podzols affected by emissions of the copper–nickel plant Pechenganikel in the forest-tundra of the Arctic region was carried out. The main pollutants contained in the emissions and entering the soil are sulfur compounds and heavy non-ferrous metals. Algae and cyanobacteria were identified in soil samples collected in three zones differing in their distance from the pollution source: the zone of strong pollution (at a distance of 3 km southwest from the source of the emission), the zone of medium pollution (5-7 km), and the zone of weak pollution (16-25 km). In total, 61 species of eukaryotic algae and 2 species of cyanobacteria were found. In the studied soils, several species of algae were found with a high frequency, apparently resistant to unfavorable natural and anthropogenic factors: Chloromonas sp., Neocystis brevis, Parietochloris alveolaris, Pseudococcomyxa simplex, Stichococcus bacillaris, Interfilum terricola, Leptosira cf. obovata, Myrmecia bisecta, Nostoc muscorum. Algae from the Chlorophyta division predominated in all soils studied. Yellowgreen algae and diatoms were found only in the zone of strong pollution and were represented by a very small number of species. The presence of Microthamnion kuetzingianum, which is resistant to high acidity and heavy metals concentration, can be useful as an indicator of severe heavy metal contamination. Our study confirmed sensitivity of Vischeria magna to soil contamination with heavy metals. In long-term aspect, the species diversity of algae has increased by 35% in the soils influenced by the Pechenganikel plant in comparison with the data obtained 30 years ago, which probably indicates a certain decrease in anthropogenic load on the adjacent territories.