Effects of slope exposure on soil physico-chemical and microbiological properties along an altitudinal climosequence in the Italian Alps.
Due to their sensitivity to changing environmental conditions sub- and alpine soils are often monitored in the context of climate change, usually, however, neglecting slope exposure. Therefore, we set up a climosequence-approach to study the effect of exposure and, in general, climate, on the microbial biomass and microbial diversity and activity, comprising five pairs of north (N)- and south (S)-facing sites along an altitudinal gradient ranging from 1200 to 2400m a.s.l. in the Italian Alps (Trentino Alto Adige, Italy). Soil physico-chemical properties were related to microbiological properties (microbial biomass: double strand DNA yield vs. substrate-induced respiration; diversity of bacterial, fungal and archaeal communities: genetic fingerprinting DGGE vs. real-time PCR; microbial activity: basal respiration vs. multiple hydrolytic enzyme assays) to monitor shifts in the diversity and activity of microbial communities as a function of slope exposure and to evaluate the most determinant chemical parameters shaping the soil microbiota. The exposure-effect on several hydrolytic key-enzymes was enzyme-specific: e.g. acid phosphomonoesterase potential activity was more pronounced at the N-facing slope while the activities of alkaline phosphomonoesterase, pyrophosphate-phosphodiesterase and arylsulfatase were higher at the S-facing slope. Furthermore, this exposure-effect was domain-specific: bacteria (S>N, altitude-independent); fungi (N~S); and archaea (N>S; altitude-dependent). Additionally, the abiotic parameters shaping the community composition were in general depending on soil depth. Our multidisciplinary approach allowed us to survey the exposure and altitudinal effects on soil physico-chemical and microbiological properties and thus unravel the complex multiple edaphic factor-effects on soil microbiota in mountain ecosystems.
Department of Agrifood and Environmental Science, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy; Institute of Microbiology, University of Innsbruck, Technikerstraβe 25d, 6020 Innsbruck, Austria. Electronic address: tommaso.bardelli@unifi.it.
Tommaso
T
Bardelli
Institute of Microbiology, University of Innsbruck, Technikerstraβe 25d, 6020 Innsbruck, Austria. Electronic address: Maria.Gomez-Brandon@uibk.ac.at.
María
M
Gómez-Brandón
Department of Agrifood and Environmental Science, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy; Institute of Microbiology, University of Innsbruck, Technikerstraβe 25d, 6020 Innsbruck, Austria. Electronic address: judith.ascher@unifi.it.
Judith
J
Ascher-Jenull
Council for Research and Experimentation in Agriculture, Via Trieste 23, 34170 Gorizia, Italy. Electronic address: fornasier.flavio@gmail.com.
Flavio
F
Fornasier
Department of Agrifood and Environmental Science, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy. Electronic address: paola.arfaioli@unifi.it.
Paola
P
Arfaioli
Helmholtz Centre for Environmental Research-UFZ, 06120, Halle (Saale), Germany. Electronic address: davide.francioli@ufz.de.
Davide
D
Francioli
Department of Geography, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland. Electronic address: markus.egli@geo.uzh.ch.
Markus
M
Egli
Museo delle Scienze (MUSE), Corso del Lavoro e della Scienza 3, 38122 Trento, Italy. Electronic address: giacomo.sartori@sfr.fr.
Giacomo
G
Sartori
Institute of Microbiology, University of Innsbruck, Technikerstraβe 25d, 6020 Innsbruck, Austria. Electronic address: Heribert.Insam@uibk.ac.at.
Heribert
H
Insam
Department of Agrifood and Environmental Science, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy. Electronic address: giacomo.pietramellara@unifi.it.
Giacomo
G
Pietramellara
Bacteria-fungi-archaea; Microbial communities; Multiple hydrolytic enzyme activities; Soil depth; Soil texture; Subalpine-alpine soils