Genetic Linkage of Soil Carbon Pools and Microbial Functions in Subtropical Freshwater Wetlands in Response to Experimental Warming

Abstract

dRising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands.

Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests

“…Hyvonen et al (2007) reported that elevated N deposition may lead to a decrease in the mineralization rate and accumulation of C. SOC is a complex mixture of dissolved organic C (DOC), LOC, and ROC. DOC and LOC are direct reservoirs of readily available substrate and important for ecosystem functioning as substrates for CO 2 production (Goldberg et al, 2008;Wang et al, 2012).…”

Changes in heavy metal mobility and availability from contaminated wetland soil remediated with combined biochar-compost

“…In addition, compost is also a kind of high quality organic fertilizer which can replenish various nutrients, increase microbial biomass and improve soil physicochemical properties (Clemente et al, 2012;Mackie et al, 2015;Schulz et al, 2013;Huang et al, 2008). Biochar, a solid residue from biomass pyrolysis under low oxygen conditions, has also gained increasing literature mainly because of polyaromatic and microporous structures, the large specific surface area, various surface functional groups and high cation exchange capacity (Keiluweit et al, 2010;Wang et al, 2012Wang et al, , 2013aXu et al, 2014;Liang et al, 2015a;Tang et al, 2014a). These characteristics make biochar sorb heavy metals easily and thus reduce soil ecotoxicity Tang et al, 2012;Yang et al, 2015;Wang et al, 2015bWang et al, , 2017.…”

Differential responses of carbon‐degrading enzyme activities to warming: Implications for soil respiration

“…The critical roles of cellulase and ligninase in mediating SOM decomposition suggest that climate warming may affect SR through its effects on EEAs, yet we still lack direct evidence. Cellulase and ligninase are synthesized by specific groups of microorganisms (Burns et al, 2013;Carreiro et al, 2000;Wang et al, 2012), and it may take years for microbial communities to adapt to environmental changes . Thus, responses of cellulase and ligninase activities to warming may vary over time.…”