Soil-Easily Extractable Glomalin: An Innovative Approach to Deciphering Its Molecular Composition under the Influence of Seasonality, Vegetation Cover, and Wildfire

Sammanfattning

Easily extractable glomalin (EEG) is a fraction of soil organic matter thought to contain mainly glomalin-related soil glycoproteins produced by mycorrhizal fungi. The EEG has an impact on various soil ecological functions, primarily related to soil aggregation formation and stability as well as water repellence. Here, analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used for studying the molecular composition of soil EEG, and a detailed description of the chemical composition is reported. Samples extracted from Mediterranean soils under different vegetation covers (Pinus halepensis and shrubland species, Rosmarinus officinalis, and Brachypodium spp, predominantly), impacted or not by forest fires and collected at different times, were studied. A total of 139 compounds were identified and grouped based on their probable biogenic origin. The EEG chemical composition is dominated by lipids, aromatic compounds, steranes, and hydroaromatics with a remarkable abundance of compounds from plant origin. Significant EEG structural changes can indicate environmental disturbances such as those after a wildfire. The EEG soil organic fraction is found to be a stable and heat-resistant material in nature if soil temperatures remain below 200-250 degrees C. This study advances the understanding of EEG by providing a detailed molecular characterization and highlighting its role as a stable, heat-resistant component of soil organic matter in Mediterranean ecosystems. The main findings indicate that while EEG is structurally resilient and mostly originates from plant material, its composition is more similar to that of humic acids than to that of glycoproteins.

Nyckelord

soil organic matter; glomalin-related soilprotein; analytical pyrolysis; wildfire; chemometrics

Publicerad i

Environmental Science and Technology
2024, volym: 58, nummer: 51, sidor: 22624-22634
Utgivare: AMER CHEMICAL SOC

SLU författare

• Márquez San Emeterio, Layla

  • Institutionen för mark och miljö, Sveriges lantbruksuniversitet
    
  • Universidade de Evora

Associerade SLU-program

SLU Nätverk växtskydd

UKÄ forskningsämne

Markvetenskap

Publikationens identifierare

• DOI: https://doi.org/10.1021/acs.est.4c10036

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/139850