Changes of Soil Dissolved Organic Matter and Its Relationship with Microbial Community along the Hailuogou Glacier Forefield Chronosequence

Abstract

Glacier-retreated areas are ideal areas to study soil biogeochemical processes during vegetation succession, because of the limited effect of other environmental and climatic factors. In this study, the changes of soil dissolved organic matter (DOM) and its relationship with microbial communities along the Hailuogou Glacier forefield chronosequence were investigated. Both microbial diversity and DOM molecular chemodiversity recovered rapidly at the initial stage, indicating the pioneering role of microorganisms in soil formation and development. The chemical stability of soil organic matter enhanced with vegetation succession due to the retaining of compounds with high oxidation state and aromaticity. The molecular composition of DOM affected microbial communities, while microorganisms tended to utilize labile components to form refractory components. This complex relationship network between microorganisms and DOM components played an important role in the development of soil organic matter as well as the formation of stable soil carbon pool in glacier-retreated areas.

Mercury Accumulation and Sequestration in a Deglaciated Forest Chronosequence: Insights from Particulate and Mineral-Associated Forms of Organic Matter

“…POM is readily more bioavailable, but usually contains larger and insoluble molecules and therefore requires depolymerization prior to assimilation. − In contrast, components in MAOM tend to be more nutrient dense (higher N as shown in Figure B). Once dissociated from the minerals, MAOM can be quickly assimilated or decomposed. , The chemistry and nutrient of the plant input control the quality of POM for microbiota uptake. , The litters of coniferous forests have low N contents (Figure S12) and high levels of recalcitrant and nonbiodegradable components . Compared to POM, MAOM in the coniferous forest chronosequence is likely to be more useful to microbiota as a labile carbon and nutrient source.…”

“…The negative correlations between δ 202 Hg and δ 15 N, and between Δ 199 Hg and δ 15 N (Figure A,B) reflect the input mixing of throughfall and litterfall. The increase of litterfall and throughfall input during vegetation succession increases nutrient input and chemical stability of soil organic matter, and microbial community diversity, as well as promotes Hg and N fixation in the organic soil . Therefore, variation of δ 202 Hg in soil organic matter depends on the δ 202 Hg shifts in each source endmember.…”

“…18,19 The litters of coniferous forests have low N contents (Figure S12) and high levels of recalcitrant and nonbiodegradable components. 73 Compared to POM, MAOM in the coniferous forest chronosequence is likely to be more useful to microbiota as a labile carbon and nutrient source. 24,25 Correlation analysis between N and Hg isotopic signatures provides additional insights into Hg accumulation and sequestration processes.…”

“…The increase of litterfall and throughfall input during vegetation succession increases nutrient input and chemical stability of soil organic matter, and microbial community diversity, as well as promotes Hg and N fixation in the organic soil. 73 Therefore, variation of δ 202 Hg in soil organic matter depends on the δ 202 Hg shifts in each source endmember. Figure 5C depicts the positive correlation between δ 202 Hg and δ 15 N in the coniferous forest chronosequence.…”

Natural Disinfection-like Process Unveiled in Soil Microenvironments by Enzyme-Catalyzed Chlorination

“…Redissolved extracts were directly infused into a 15 T Bruker SolariX FT-ICR mass spectrometer via an electrospray ion source (Bruker) operated in the negative ionization mode. 44 Detailed instrumentation settings are provided in Text S4. Each sample was analyzed in instrumental duplicates, with DOM formulas assigned in duplicates retained for analysis.…”