• CUBE - Computational Systems Biology

  • DOME - Microbial Ecology

  • TER - Terrestrial Ecosystem Research


Latest publications

Rhizospheric microbial community of Caesalpinia spinosa (Mol.) Kuntze in conserved and deforested zones of the Atiquipa fog forest in Peru

Caesalpinia spinosa, tara, is the predominant fog catcher tree in the fog forest of Atiquipa, a biodiversity hotspot ecosystem within the coastal Peruvian desert highly threatened by intense land use over time. We investigated the impact of deforestation, as well as potential effects of the tree age (juveniles vs adults) and the type of tree (recruited vs planted), on the rhizospheric microbial communities of tara growing in contrasting landscapes (conserved vs deforested) of the Atiquipa forest.

We used a phospholipid fatty acids analysis approach to study the microbial community associated with tara. Additionally, we isolated and sought for native rhizospheric bacteria with plant growth promoting (PGPR) traits to be used as potential inoculants for restoration projects.

Deforestation profoundly altered the chemical and biological fertility of soils. All rhizospheric microorganisms were clearly reduced in abundance by deforestation, while the age or the type of trees had no effects. Both, deforestation and tree age influenced the assemblage of microbial communities, which tightly correlated with soil pH and organic matter among other soil properties. Adult trees harboured similar microbial communities in conserved and deforested soils being potential reservoirs of native microorganisms in the degraded areas. Some selected bacterial strains showed high plant growth promoting abilities, and PGPR traits were related with the isolation source of bacteria. The knowledge about key factors structuring the rhizospheric microbiota of tara and the identification of high-performing PGPR strains, provide a solid framework to formulate inocula for their use in restoration programmes in the Atiquipa fog forest.

Cordero I, Ruiz-Diez B, Balaguer L, Richter A, Pueyo JJ, Rincon A
2017 - Applied Soil Ecology, 114: 132-141

Global patterns of phosphatase activity in natural soils

Soil phosphatase levels strongly control the biotic pathways of phosphorus (P), an essential element for
life, which is often limiting in terrestrial ecosystems. We investigated the influence of climatic and soil
traits on phosphatase activity in terrestrial systems using metadata analysis from published studies.
This is the first analysis of global measurements of phosphatase in natural soils. Our results suggest
that organic P (Porg), rather than available P, is the most important P fraction in predicting phosphatase
activity. Structural equation modeling using soil total nitrogen (TN), mean annual precipitation, mean
annual temperature, thermal amplitude and total soil carbon as most available predictor variables
explained up to 50% of the spatial variance in phosphatase activity. In this analysis, Porg could not be
tested and among the rest of available variables, TN was the most important factor explaining the
observed spatial gradients in phosphatase activity. On the other hand, phosphatase activity was also
found to be associated with climatic conditions and soil type across different biomes worldwide. The
close association among different predictors like Porg, TN and precipitation suggest that P recycling is
driven by a broad scale pattern of ecosystem productivity capacity.

Margalef O, Sardans J, Fernández-Martínez M, Molowny-Horas R, Janssens IA, Ciais P, Richter A, Obersteiner M, Asenio D, Peñuelas J
2017 - Scientific Reports, 7: 13

Decoupling of microbial carbon, nitrogen, and phosphorus cycling in response to extreme temperature events

Predicted changes in the intensity and frequency of climate extremes urge a better mechanistic understanding of the
stress response of microbially mediated carbon (C) and nutrient cycling processes. We analyzed the resistance and
resilience of microbial C, nitrogen (N), and phosphorus (P) cycling processes and microbial community composition
in decomposing plant litter to transient, but severe, temperature disturbances, namely, freeze-thaw and heat. Disturbances
led temporarily to a more rapid cycling of C and N but caused a down-regulation of P cycling. In contrast to the
fast recovery of the initially stimulated C and N processes, we found a slow recovery of P mineralization rates, which
was not accompanied by significant changes in community composition. The functional and structural responses to
the two distinct temperature disturbances were markedly similar, suggesting that direct negative physical effects and
costs associated with the stress response were comparable. Moreover, the stress response of extracellular enzyme
activities, but not that of intracellular microbial processes (for example, respiration or N mineralization), was
dependent on the nutrient content of the resource through its effect on microbial physiology and community
composition. Our laboratory study provides novel insights into the mechanisms of microbial functional stress responses
that can serve as a basis for field studies and, in particular, illustrates the need for a closer integration of
microbial C-N-P interactions into climate extremes research.

Mooshammer M, Hofhansl F, Frank AH, Wanek W, Hämmerle I, Leitner S, Schnecker J, Wild B, Watzka M, Keiblinger KM, Zechmeister­‐Boltenstern S, Richter A
2017 - Science Advances, 3: 13