Microbial characteristics of soils on a latitudinal transect in Siberia

Abstract

Soil microbial properties were studied from localities on a transect along the Yenisei River, Central Siberia. The 1000 km‐long transect, from 56°N to 68°N, passed through tundra, taiga and pine forest characteristic of Northern Russia. Soil microbial properties were characterized by dehydrogenase activity, microbial biomass, composition of microbial community (PLFAs), respiration rates, denitrification and N mineralization rates. Relationships between vegetation, latitude, soil quality (pH, texture), soil organic carbon (SOC) and the microbial properties were examined using multivariate analysis. In addition, the temperature responses of microbial growth (net growth rate) and activity (soil respiration rate) were tested by laboratory experiments. The major conclusions of the study are as follows: 1. Multivariate analysis of the data revealed significant differences in microbial activity. SOC clay content was positively related to clay content. Soil texture and SOC exhibited the dominant effect on soil microbial parameters, while the vegetation and climatic effects (expressed as a function of latitude) were weaker but still significant. The effect of vegetation cover is linked to SOC quality, which can control soil microbial activity. 2. When compared to fine‐textured soils, coarse‐textured soils have (i) proportionally more SOC bound in microbial biomass, which might result in higher susceptibility of SOC transformation to fluctuation of environmental factors, and (ii) low mineralization potential, but with a substantial part of the consumed C being transformed to microbial products. 3. The soil microbial community from the northernmost study region located within the permafrost zone appears to be adapted to cold conditions. As a result, microbial net growth rate became negative when temperature rose above 5 °C and C mineralization then exceeded C accumulation.

Evaluating carbon dynamics and microbial activity in arctic soils under warmer temperatures

“…In the Cz mineral horizon, microbes were likely unable to metabolize the more recalcitrant C compounds, especially under conditions of low N availability, compared with soil richer in organic material. Sˇantruckova´et al (2003) also noted that microbial activity was lower in soil with a low SOM and N content and high lignin content. Additionally, changes in the C/N ratio also influenced soil microbial metabolic diversity and activity (McKinley et al 2005).…”

Patterns and regulating mechanisms of soil nitrogen mineralization and temperature sensitivity in Chinese terrestrial ecosystems

“…The lower Q 10 at lower latitudes might result from the adaptation of microorganisms to the increased temperature in these regions (Santruckova et al, 2003;Wang et al, 2007). Tjoelker et al (2001) reported that the Q 10 values of soil C mineralization were significantly negatively correlated with soil temperature, and decreased with increasing soil temperature in experiments conducted at different latitudes (arctic, cool-temperate zone, temperate zone, and tropical zone).…”

“…It is assumed that TN and SOM have a strong influence on the Q 10 values of soil N mineralization by regulating the substrates supply of microorganisms. As lower temperatures limit litter decomposition, high-latitude regions always have a higher SOM content (Santruckova et al, 2003), resulting in a consequent increase of Q 10 with latitude. Zheng et al (2009) demonstrated that Q 10 tended to be higher in ecosystems with higher SOM contents, and the quality and quantity of SOM have also been shown to influence its decomposition (Fierer et al, 2005;Knorr et al, 2005).…”

Soil moisture and land use are major determinants of soil microbial community composition and biomass at a regional scale in northeastern China

“…Previous studies have reported that soil texture, organic matter content, N availability and pH exhibited dominant effects on soil microbial community composition, while climatic effects were weaker but still significant at regional scales (Šantrucková et al, 2003;Brockett et al, 2012;Yang et al, 2013;Tsiknia et al, 2014). For example, Tsiknia et al (2014) identified soil total organic C, pH and geographic distance as the most important determinants of microbial community abundance at the watershed scale in Greece.…”