Microbial biomass carbon and enzymes-degraders of carbohydrates in polar soils from the area of Livingston Island, Antarctica

Polar soils under different vegetation cover from Livingston Island (Antarctica) were studied analyzing indicators of carbohydrates decomposition in soils: organic carbon, biomass carbon, total nitrogen, C:N ratio, cellulase, amylase, and invertase activity. The highest values of microbial biomass in soils were indicated for sites with vegetation cover while the lowest values in soils without vegetation, which correlate with the content of total organic carbon and the C:N ratio. The highest percentage of biomass carbon compared to the total organic biomass carbon is obtained for two sites with mosses, and the lowest in sites without vegetation, followed by the sites with lichens. Cellulase activity is highest in polar soils with moss cover. Amylase activity depends more strongly on the type of vegetation. The highest amylase activity is detected in soils under algae cover and the lowest in soils without vegetation. Invertase activity is limited by the extreme soil and climatic conditions of Antarctica. A very strong, positive correlation is found between total carbon and total nitrogen. The relationship between total carbon and the C:N ratio, as well as between biomass carbon and amylase activity, is moderate, and positive. The higher dependence of amylase activity from organic carbon with microbial origin correlates with higher values of the enzyme amylase compared to the enzyme cellulase. There is a strong (cellulase) and very strong (amylase) positive relationship between the activity of enzymes and the combination of factors: total carbon, total nitrogen, C: N ratio and biomass carbon.