Plant- or microbial-derived? A review on the molecular composition of stabilized soil organic matter

Soil Biology and Biochemistry, Journal Year: 2021, Volume and Issue: 156, P. 108189 - 108189

Published: March 1, 2021

Language: Английский

---

Microbial necromass as the source of soil organic carbon in global ecosystems

Soil Biology and Biochemistry, Journal Year: 2021, Volume and Issue: 162, P. 108422 - 108422

Published: Sept. 14, 2021

Language: Английский

---

Clarifying the evidence for microbial‐ and plant‐derived soil organic matter, and the path toward a more quantitative understanding

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(24), P. 7167 - 7185

Published: Aug. 31, 2022

Predicting and mitigating changes in soil carbon (C) stocks under global change requires a coherent understanding of the factors regulating organic matter (SOM) formation persistence, including knowledge direct sources SOM (plants vs. microbes). In recent years, conceptual models have emphasized primacy microbial-derived inputs, proposing that microbial physiological traits (e.g., growth efficiency) are dominant controls on quantity. However, quantitative studies challenged this view, suggesting plants make larger contributions to than is currently recognized by paradigm. review, we attempt reconcile these perspectives highlighting variation across estimates plant- versus may arise part from methodological limitations. We show all major methods used estimate plant substantial shortcomings, uncertainty our current estimates. demonstrate there significant overlap chemical signatures compounds produced microbes, roots, through extracellular decomposition litter, which introduces into use common biomarkers for parsing SOM, especially mineral-associated (MAOM) fraction. Although review contributed deeper limitations with constrain light advances, suggest now critical time re-evaluate long-standing methods, clearly define their limitations, develop strategic plan improving quantification SOM. From synthesis, outline key questions challenges future research mechanisms stabilization pathways.

Language: Английский

---

From energy to (soil organic) matter

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(7), P. 2169 - 2182

Published: Jan. 3, 2022

In this concept paper, we propose a new view on soil organic matter (SOM) formation: microorganisms use most of the organics entering as energy rather than source carbon (C), while SOM accumulates residual by-product because microbial investment in its decomposition exceeds gain. During initial stages decomposition, nominal oxidation state C (NOSC) remaining litter decreases, and content increases. This reflects rapid mineralization available compounds with positive neutral NOSC (carboxylic acids, sugars, some amino acids). Consequently, drops to -0.3 units, rate decreases due relative accumulation aromatic aliphatic (which are hydrolized later) entombment necromass. Ultimately, incompletely decomposed plant residues will have 1%-2.5% more per unit litter. The linear decrease density broad range substances by 106 kJ mol-1 upon is supported experimental data decomposition. Preferential recycling energy-rich reduced (lipids, aromatics, certain sugars) degradation oxidized acids) also energetically enrich SOM. Despite high content, availability stored lower explains why not fully mineralized (thermodynamically unfavorable), especially absence provide (e.g., bare soil). Energy from activates decomposers mine nutrients (the main ecological function priming effects) nutrient 2-5 times higher that results only 0.4%-5% year-1 litter-derived being sequestered SOM, whereas stores 1%-10% total energy. Thus, captured photosynthesis reason utilize matter, whereby merely storage mediator fluxes.

Language: Английский

---

Soil Organic Matter Characterization by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR MS): A Critical Review of Sample Preparation, Analysis, and Data Interpretation

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(14), P. 9637 - 9656

Published: July 7, 2021

The biogeochemical cycling of soil organic matter (SOM) plays a central role in regulating health, water quality, carbon storage, and greenhouse gas emissions. Thus, many studies have been conducted to reveal how anthropogenic climate variables affect sequestration nutrient cycling. Among the analytical techniques used better understand speciation transformation SOM, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) is only technique that has sufficient resolving power separate accurately assign elemental compositions individual SOM molecules. global increase application FTICR MS address complexity highlighted challenges opportunities associated with sample preparation, analysis, spectral interpretation. Here, we provide critical review recent strategies for characterization by emphasis on collection, data Data processing visualization methods are presented suggested workflows detail considerations needed molecular information derived from MS. Finally, highlight current research gaps, biases, future directions improve our understanding chemistry within terrestrial ecosystems.

Language: Английский

---

Tradeoffs among microbial life history strategies influence the fate of microbial residues in subtropical forest soils

Soil Biology and Biochemistry, Journal Year: 2020, Volume and Issue: 153, P. 108112 - 108112

Published: Dec. 16, 2020

Language: Английский

---

Phospholipid fatty acids in soil—drawbacks and future prospects

Biology and Fertility of Soils, Journal Year: 2021, Volume and Issue: 58(1), P. 1 - 6

Published: Dec. 4, 2021

Abstract The current opinion and position paper highlights (1) correct assignation of indicator phospholipid fatty acids (PLFA), (2) specificity recycling PLFA in microorganisms, (3) complete extraction detection PLFA. straight-chain 14:0, 15:0, 16:0, 17:0 occur all i.e., also fungi not only bacteria. If the phylum Actinobacteria is excluded from group Gram-positive bacteria, remaining bacteria belong to bacterial Firmicutes, which should be considered. 16:1ω5 used as an for biomass arbuscular mycorrhizal (AMF) there no experimental evidence that they marked amounts Gram-negative Fungal embrace AMF-specific 16:1ω5. In presence plants, ergosterol instead 18:2ω6,9 18:1ω9 fungal indicators Mucoromycotina, Ascomycota, Basidiomycota. majority are fully specific a certain microbial group. This problem might intensified by processes during decomposition unknown extent. Soil handling conditions further optimized. reliability accuracy gas chromatographic separation need regularly checked against unintentional variations. analysis will still interest over next decades important independent control DNA-based methods.

Language: Английский

---

Microbial Necromass in Soils—Linking Microbes to Soil Processes and Carbon Turnover

Frontiers in Environmental Science, Journal Year: 2021, Volume and Issue: 9

Published: Dec. 14, 2021

The organic matter of living plants is the precursor material stored in terrestrial soil ecosystems. Although a great deal knowledge exists on carbon turnover processes plant material, some (SOM) formation, particular from microbial necromass, are still not fully understood. Recent research showed that larger part original converted into biomass, while remaining modified by extracellular enzymes microbes. At end its life, biomass contributes to molecular imprint SOM as necromass with specific properties. Next appropriate environmental conditions, heterotrophic microorganisms require energy-containing substrates C, H, O, N, S, P, and many other elements for growth, which provided nutrients contained SOM. As easily degradable often scarce resources soil, we can hypothesize microbes optimize their energy use. Presumably, able mobilize building blocks (mono oligomers fatty acids, amino sugars, nucleotides) stoichiometry This contrast mobilizing only consuming new synthesis primary metabolites tricarboxylic acid cycle after complete degradation substrates. Microbial thus an important resource SOM, mining could be life strategy contributing priming effects providing growth cycles. Due needs microorganisms, conclude formation through depends flux. However, details variability use decay cycles yet understood linked fields science. Here, summarize current gain, use, decay, relevant processes, e. g. pump, C storage, stabilization. We highlight factors controlling contribution implications efficiency (CUE) identify process-based modelling understanding these various types under different climates.

Language: Английский

---

Initial soil formation by biocrusts: Nitrogen demand and clay protection control microbial necromass accrual and recycling

Soil Biology and Biochemistry, Journal Year: 2022, Volume and Issue: 167, P. 108607 - 108607

Published: Feb. 15, 2022

Language: Английский

---

Pathways of biogenically excreted organic matter into soil aggregates

Soil Biology and Biochemistry, Journal Year: 2021, Volume and Issue: 164, P. 108483 - 108483

Published: Nov. 5, 2021

Soil organisms are recognized as ecosystem engineers and key for aggregation in soil due to bioturbation, organic matter (OM) decomposition, excretion of biogenic OM. The activity is beneficial quality, functions, nutrient cycling. These attributions based on field-scale observations that link the presence spatiotemporal changes properties can be traced back formation aggregates. This pathway encompasses a cascade processes so far not discussed comprehensively. A more general approach needs consider feedback loops between biota, active release OM by excretion, interaction with constituents, organo-mineral associations, how these become incorporated aggregated structures. Especially function biogenically excreted OM, which quite complex composition, controversial it permits or inhibits aggregation. review analyzes various roles may take an agent. We will show its depends interplay numerous factors, including environmental conditions, variety producers, composition availability type interacting mineral phase. affect aggregate three different ways: (I) bridging agent promotes surface modifications attraction, (II) separation favors formation, mobility, transport associations their further inclusion into aggregates, (III) gluing mediates stability, after external force provokes close particles. conclude takes functional simultaneously varying extent across scales. Hence, involved modification particles, enmeshment particles (im-)mobilization, facilitating All hierarchy factors comprising local community's conditions immediate environment.

Language: Английский

---