• Global Warming:

    the threat of a permafrost Carbon – climate feedback

  • We develop and improve

    stable isotopes techniques for ecological applications

  • Plants, fungi and bacteria interact

    at the root-soil interface

  • Probing the future:

    Climate Change experiments

  • Soil is fundamental to human life

  • Tropical rainforests

    hold the key to global net primary productivity

TER News

Latest publications

Comparable canopy and soil free-living nitrogen fixation rates in a lowland tropical forest

Biological nitrogen fixation (BNF) is a fundamental part of nitrogen cycling in tropical forests, yet little is known about the contribution made by free-living nitrogen fixers inhabiting the often-extensive forest canopy. We used the acetylene reduction assay, calibrated with 15N2, to measure free-living BNF on forest canopy leaves, vascular epiphytes, bryophytes and canopy soil, as well as on the forest floor in leaf litter and soil. We used a combination of calculated and published component densities to upscale free-living BNF rates to the forest level. We found that bryophytes and leaves situated in the canopy in particular displayed high mass-based rates of free-living BNF. Additionally, we calculated that nearly 2 kg of nitrogen enters the forest ecosystem through free-living BNF every year, 40% of which was fixed by the various canopy components. Our results reveal that in the studied tropical lowland forest a large part of the nitrogen input through free-living BNF stems from the canopy, but also that the total nitrogen inputs by free-living BNF are lower than previously thought and comparable to the inputs of reactive nitrogen by atmospheric deposition.

Van Langenhove L, Depaepe T, Verryckt LT, Fuchslueger L, Leroy JDC, Moorthy SMK, Gargallo-Garriga A, Ellwood MDF, Verbeeck H, Van Der Straeten D, Peñuelas J, Janssens IA
2021 - Science of The Total Environment, 754: Article 142202

Empirical support for the biogeochemical niche hypothesis in forest trees

The possibility of using the elemental compositions of species as a tool to identify species/genotype niche remains to be tested at a global scale. We investigated relationships between the foliar elemental compositions (elementomes) of trees at a global scale with phylogeny, climate, N deposition and soil traits. We analysed foliar N, P, K, Ca, Mg and S concentrations in 23,962 trees of 227 species. Shared ancestry explained 60–94% of the total variance in foliar nutrient concentrations and ratios whereas current climate, atmospheric N deposition and soil type together explained 1–7%, consistent with the biogeochemical niche hypothesis which predicts that each species will have a specific need for and use of each bio-element. The remaining variance was explained by the avoidance of nutritional competition with other species and natural variability within species. The biogeochemical niche hypothesis is thus able to quantify species-specific tree niches and their shifts in response to environmental changes.

Sardans J, Vallicrosa H, Zuccarini P, Farré-Armengol G, Fernández-Martínez M, Guille P, Gargallo-Garriga A, Ciais P, Janssens IA, Obersteiner M, Richter A, Peñuelas J
2021 - Nature Ecology & Evolution, 5: 184-194

Acidobacteria are active and abundant members of diverse atmospheric H2-oxidizing communities detected in temperate soils

Significant rates of atmospheric dihydrogen (H2) consumption have been observed in temperate soils due to the activity of high-affinity enzymes, such as the group 1h [NiFe]-hydrogenase. We designed broadly inclusive primers targeting the large subunit gene (hhyL) of group 1h [NiFe]-hydrogenases for long-read sequencing to explore its taxonomic distribution across soils. This approach revealed a diverse collection of microorganisms harboring hhyL, including previously unknown groups and taxonomically not assignable sequences. Acidobacterial group 1h [NiFe]-hydrogenase genes were abundant and expressed in temperate soils. To support the participation of acidobacteria in H2 consumption, we studied two representative mesophilic soil acidobacteria, which expressed group 1h [NiFe]-hydrogenases and consumed atmospheric H2 during carbon starvation. This is the first time mesophilic acidobacteria, which are abundant in ubiquitous temperate soils, have been shown to oxidize H2 down to below atmospheric concentrations. As this physiology allows bacteria to survive periods of carbon starvation, it could explain the success of soil acidobacteria. With our long-read sequencing approach of group 1h [NiFe]-hydrogenase genes, we show that the ability to oxidize atmospheric levels of H2 is more widely distributed among soil bacteria than previously recognized and could represent a common mechanism enabling bacteria to persist during periods of carbon deprivation.

Eichorst S, Giguere A, Meier D, Herbold C, Richter A, Greening C, Woebken D
2021 - ISME Journal, 15: 363-376

Lecture series

Microbial ecology of nitrogen cycling in paddy soils

Yong-Guan Zhu
Research Centre for Eco-Environmental Sciences & Institute of Urban Environment, Chinese Academy of Sciences
09:00 h
Lecture Hall HS 5, UZA2 (Geocentre), Althanstrasse 14, 1090 Vienna

How to meet the Paris 2°C target: Which are the main constraints that will need to be overcome?

Ivan Janssens
Centre of Excellence of Global Change Ecology, University of Antwerp, Belgium
12:00 h
Lecture Hall HS2 (UZA 1), Althanstraße 14, 1090 Vienna

Soil C dynamics –when are microbial communities in control?

Naoise Nunan
Institute of Ecology and Environmental Sciences IEES Paris, France
12:00 h
Lecture Hall HS2 (UZA 1), Althanstraße 14, 1090 Vienna