The Biogeography of Forest Soil Microbial Functional Diversity Responds to Forest Types across Guangxi, Southwest China

Vegetation and soil have spatial distributions at different scales, while the spatial distribution of soil microorganisms and factors driving their distribution are still unclear. We aimed to reveal the spatial pattern of microbial functional diversity and to identify its drivers in forest soils at a regional scale. Here, we performed an investigation of microbes across several forest types covering an area of 236,700 km2 in Guangxi, southwest China. We examined a total of 185 samples for soil microbial functional diversity using Biolog EcoPlates. The soil microbial functional diversity had strong spatial heterogeneity across the Guangxi region. The distribution of microorganisms in forest soils was mainly determined by total nitrogen, available N, and C:N ratio, and stand age. We found that coniferous forests, especially pine forest, exhibited lower functional diversity, but the reverse was true for deciduous broadleaf forest/mixed evergreen and deciduous broadleaf forest. Our findings suggested that a heterogeneous distribution of microbial functional diversity in forest soils is related to forest types in Guangxi, China. In conclusion, high soil microbial functional diversity is favored in subtropical forests with looser soil structure, lower soil C:N ratio, greater total soil nitrogen and available nitrogen concentration, and broad-leaved tree species.

Metagenomics-informed soil biogeochemical models projected less carbon loss in tropical soils in response to climate warming

A major challenge of quantifying feedback between microbial communities and climate is the vast diversity of microbial communities and the intricacy of soil biogeochemical processes they mediate. We overcome this challenge by simplifying the representation of diverse enzyme functions from metagenomics data. We developed a dynamic allocation scheme for enzyme functional classes (EFCs) based on the premise that microbial communities act to maximize acquisition of limiting resources while minimizing energy expenditure for acquiring unlimited resources. We incorporated this scheme into a biogeochemical model to explicitly represent microbial functional diversity and simulate responses of microbially-mediated soil biogeochemical processes to varying environmental and nutrient conditions. Representing microbial functional diversity and environmental acclimation improved predictions of the stoichiometry of microbial biomass and mitigated the sensitivity of soil organic carbon to warming in nutrient-deficient regions. Our results indicate the importance of microbial functional diversity and environmental acclimation for projecting climate feedbacks of nutrient-limited soils.

Metagenomics-informed soil biogeochemical models projected less carbon loss in tropical soils in response to climate warming

A major challenge of quantifying feedback between microbial communities and climate is the vast diversity of microbial communities and the intricacy of soil biogeochemical processes they mediate. We overcome this challenge by simplifying the representation of diverse enzyme functions from metagenomics data. We developed a dynamic allocation scheme for enzyme functional classes (EFCs) based on the premise that microbial communities act to maximize acquisition of limiting resources while minimizing energy expenditure for acquiring unlimited resources. We incorporated this scheme into a biogeochemical model to explicitly represent microbial functional diversity and simulate responses of microbially-mediated soil biogeochemical processes to varying environmental and nutrient conditions. Representing microbial functional diversity and environmental acclimation improved predictions of the stoichiometry of microbial biomass and mitigated the sensitivity of soil organic carbon to warming in nutrient-deficient regions. Our results indicate the importance of microbial functional diversity and environmental acclimation for projecting climate feedbacks of nutrient-limited soils.

Soil Microbial Functional Diversity under the Single-Season Influence of Traditional Forest Management in a Sessile Oak Forest of Central Europe

This one-year study focuses on the responses of a soil environment to the implementation of traditional forest management practices in oak–hornbeam stands with the following treatments: cut (C), cut + litter raking (CR), cut + grazing (CG), cut + litter raking + grazing (CRG) and control (Ctrl). The cut was conducted in 2018 through extremely heavy thinning. In autumn of 2017 and 2018, we sampled the soils, focusing on microbial functional diversity (FD) assessments using BIOLOG EcoplateTM. After one season, the FD was the highest in the Ctrl stand and the lowest in the CRG stand. Furthermore, we detected significant seasonal differences in soil reaction, nitrate nitrogen content, phosphatase activity and microbial biomass among the treatments. In particular, the Ctrl stand was defined via FD indices and biochemical and biological soil properties that contrasted mainly with those of the CRG stand defined by the content of mineral nitrogen forms. The soil properties did not differ substantially in the remaining treatments. Of the 31 carbon sources defining FD, 6 were treatment-specific (putrescine, L-arginine, L-serine, L-threonine, D-cellobiose and glycogen), while the remaining carbon sources mainly displayed either uniform high or low activity across the treatments.

Soil microbial functional diversity responses to different vegetation types in the Heilongjiang Zhongyangzhan Black-billed Capercaillie Nature Reserve

Purpose The soil microbial community is an important bioactive component of terrestrial ecosystems. Its structural and functional diversity directly affects carbon and nitrogen processes. This study aimed to investigate the variations in the functional diversity of soil microbial communities in forests with different types of vegetation. Methods We selected three typical vegetation types, larch (LG), black birch (BD), and larch and black birch mixed (LGBD) forests, located in the Heilongjiang Zhongyangzhan Black-billed Capercaillie Nature Reserve. The Biolog-Eco microplate technology was selected to perform these analyses. Result Our results showed clear differences between microorganisms in the three typical forests. The average well colour development (AWCD) change rate gradually increased with incubation time. The BD type had the highest AWCD value, followed by LGBD; the LG forest type had the lowest value. The difference in the soil microbial alpha diversity index between BD and LG was significant. A principal component analysis showed that PC1 and PC2 respectively explained 62.77% and 13.3% of the variance observed. The differences in the soil microbial carbon-source utilisation patterns under different vegetation types were mainly caused by esters and carbohydrates. Redundancy analysis showed that soil microbial functional diversity was strongly affected by soil physicochemistrical properties (e.g. organic carbon, total nitrogen and pH). Conclusion These results provide a reference for further exploring the relationship between forest communities and soil microbes during the process of forest succession.

Soil Microbial Functional Diversity Responses to Different Vegetation Types in the Heilongjiang Zhongyangzhan Black-billed Capercaillie Nature Reserve

Purpose: The soil microbial community is an important bioactive component of terrestrial ecosystems. Its structural and functional diversity directly affects carbon and nitrogen processes. This study aimed to investigate the variations in the functional diversity of soil microbial communities in forests with different types of vegetation. Methods: We selected three typical vegetation types, larch (LG), black birch (BD), and larch and black birch mixed (LGBD) forests, located in the Heilongjiang Zhongyangzhan Black-billed Capercaillie Nature Reserve. The Biolog-Eco microplate technology was selected to perform these analyses. Result: Our results showed clear differences between microorganisms in the three typical forests. The average well-colour development (AWCD) change rate gradually increased with incubation time. The BD type had the highest AWCD value, followed by LGBD; the LG forest type had the lowest value. The difference in the soil microbial alpha diversity index between BD and LG was significant. A principal component analysis showed that PC1 and PC2 respectively explained 62.77% and 13.3% of the variance observed. The differences in the soil microbial carbon-source utilization patterns under different vegetation types were mainly caused by esters and carbohydrates. Redundancy analysis showed that soil microbial functional diversity was strongly affected by soil physicochemistrical properties (e.g. organic carbon, total nitrogen, and pH). Conclusion: These results provide a reference for further exploring the relationship between forest communities and soil microbes during the process of forest succession.