De Groot, A.

Rousseau, M.

Siegenthaler, A.

Skidmore, A.K.

English

de Groot, A. Arjen

University of Twente Research Information

Soil acidification is a major driver of soil biodiversity and functions. While European forests recovered from soil acidification in the 1980s1, it is re-emerging as a threat in areas of intense agriculture, urbanization, and traffic. Acidification shifts forest community toward acid-tolerant bacteria, and reduces both diversity and enzymatic activities, influencing, in turn, nutrient cycling. Acidification studies usually involve acidification or liming experiments across a wide pH range. However, whether trends observed so far still hold in natural conditions under severe acidification is unknown. We compared two European temperate forests (ongoing acidification vs. recovery system from acidification) and explored the effect of past and present severe acidification on soil bacterial diversity, community, and functions.Email: m.s.d.rousseau@utwente.nl @melo_rousseauCharacterization of soil bacterial profiles in extremely acidic forest soilsMélody Rousseau1, Arjen de Groot2, Andjin Siegenthaler1 & Andrew Skidmore11University of Twente, The Netherlands & 2Wageningen UR, The NetherlandsReferences1. Dirnböck et al. (2018). Environmental Research Letters, 13(12)2. Extracted and adapted from David CasMor work3. Lauber et al. (2009). Applied and Environmental Microbiology, 75(15)4. Wang et al. (2019). Annals of Microbiology, 69• The effect of severe acidification on bacterial richness, community structure, and functions is important, even at the extreme of the gradient. Soil pH is still a driver in highly acidic forests. • Increase in cellulose degradation may result in soil carbon loss and thus may participate in carbon release in the atmosphere4. • Nitrate, the plant-usable form of nitrogen, is limited in acidic soils. Reduction and loss of nitrogen fixation could negatively impact forest health by losing bacteria capable of metabolizing nitrate. • Further monitoring soil pH and biodiversity indicators is important, especially for regions subjected to high acidification pressure. Methodology2 & study areas                                                   DNA metabarcodingPCR amplification515F/806RSequencingNovaseqTaxonomical and functionalassignmentDNA extractionConclusionIntroduction• Significant changes in bacterial richness, community structure, and functions with acidification were detected for both forests. • Similar patterns were observed across forests, with severe acidified soils characterized by a lower bacterial richness, an increased cellulolytic potential, and a reduced nitrogen fixation potential. • Bacterial loss in Bavarian NP (recovery forest) was greater compared to Veluwe NP (ongoing acidification) with acidification. With a greater range of soil pH, Bavarian NP may have more richer and diverse bacterial communities due to less physiological constraint at higher pH3.Figure 1. Bacterial communities in both forests changed withacidification and clustered according to their pH values (PERMANOVA[Bray-Curtis]: p < 0.001).Bavarian NPVeluwe NPFigure 2. ASV (Amplicon Sequence Variant) richness decreased with acidification for bothforests. A similar loss of richness with acidification was observed for coniferous and deciduousstands in Bavarian NP but not in Veluwe NP.Bavarian NP Veluwe NPFigure 3. Relationships between soil pH and relative abundance of taxa involved in cellulosedegradation (cellulolysis) and nitrogen fixation for Bavarian NP (A-B) and Veluwe NP (C-D).Cellulolysis CellulolysisNitrogen fixation Nitrogen fixationResults & Discussion

Characterization of soil bacterial profiles in extremely acidic forest soils

https://ris.utwente.nl/ws/files/320530738/Poster_V003.pdf

Characterization of soil bacterial profiles in extremely acidic forest soils

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