Dados do Trabalho

Título

Soil Microbial Communities Change after Drying/Wetting and Freeze/Thawing Cycles.

Resumo

Climate change has impacted soil drying/rewetting (D/W) and freezing/thawing (F/T) events. The frequency of drought and freezing impact biological and physical soil conditions as there are one of the main drivers of soil carbon (C) turnover. Here we tested: i) 1 and 4 D/W and 4 F/T cycles will increase the SOM decomposition of readily available C due to increased extracellular enzymes and soil cellullobiotic bacterial communities. Thermogravimetric analysis (TGA) and Fourier Transform Infrared (FTIR) spectroscopy were used to assess the SOM quality. Enzyme activity (eight exoenzymes) related to SOM decomposition was evaluated, and a diversity analysis of microbial communities by DGGE electrophoresis was performed. The TGA pyrolysis showed the highest weight loss of polysaccharides (high abundance) in D/W, and FTIR showed the highest lignin signal intensity in F/T, indicating that it could weather the selection of complex organic matter to feed the communities decrease. Enzymes Peroxidase increased with D/W, and glycine aminopeptidase increased with F/T cycles. Cellulolytic bacteria (CFU) grew with D/W, closely related to increased peroxidase activity. DGGE analysis shows that D/W cycles critically affect microbial communities, with a 15 % shift from F/T cycles similar to No cycles in a short period. The enzyme activity of POD (p <0.01) was the most important of the enzymes affecting the microbial structure. Our findings suggest water cycles have a crucial effect on this pristine forest soil organic matter accumulation.

Palavras-chave

Dry/wet Freeze/thaw cycles, Soil enzymes, Microbial communities.

Instituição financiadora

This study was funded by ANID FONDECYT postcoctoral N◦ 3230428 and ANID Anillo N◦ ACT210060.

Agradecimentos

Earthshape project, Göttingen university, Hannover Uiversity, Tübingen University. Proyecto ANILLO FIRING.