Effects of Temperature and Moisture Manipulation on Biological Activity of Northern and Southern Taiga Peat Soils

Wetland ecosystems play a significant role in organic carbon conservation; one meter layer of peat soils store over 30 percent of terrestrial organic carbon (Lal, 2008). Ecosystems have different sensitivity to climate change in different nature zones (IPCC, 2014) due to various moisture and temperature regime.The aim in this work is to define effect of temperature and moisture on mineralization rate in peat soils in Northern and Southern taiga.The samples of Cryic Histosol (WRB, 2014) were taken from Northern Taiga (65°18'52" N, 72°52'32" E). The samples of Fibric Histosol (WRB, 2014) were taken from Southern Taiga (55°40'04" N 36°42'49" E). In laboratory conditions, samples were brought to certain soil moisture (SM): 30, 60, 80, 100 % (Gritsch, 2015), temperature of incubation was ranging from 5 to 25 ◦C (equal-time method).In all the cases basal respiration (BR) was growing with increasing of temperature. Samples of Cryic Histosol are more sensitive to changes both in temperature and moisture. BR varies from 0.58 ±0.26 (30% SM and 5 ◦C) to 13.53±0.22 mg C-CO2/g/h (100% SM and 25 ◦C). Q10 coefficient varies from 4.64 to 2.82 respectively (this coefficient demonstrates differences in the temperature sensitivity of soil respiration (Kirschbaum, 1995)). For samples of Fibric Histosol BR varies from 0.75±0.01 (30% SM and 5 ◦C) to 6.14±0.26 mg C-CO2/g/h (100% SM and 25 ◦C). Q10 coefficient varies from 2.70 to 2.18 respectively.Influence of moisture and temperature on biological activity in all of the cases was statistically confirmed, but interaction of factors is significant only for Cryic Histosol. According to the results, Cryic Histosol is more sensitive to temperature and moisture change, than Fibric Histosol. Peat soils in the northern area are subjected to more rapid organic carbon mineralization after a change of hydrothermal regime, than southern peat soils. In conclusion, Q10 coefficient variation indicates that soils with low soil moisture are more sensitive to temperature changes.