Soil microorganisms and plants are key players in the production and breakdown of organic matter, and together control global biogeochemical cycles of carbon, nitrogen and phosphorus. TER, the Division of Terrestrial Ecosystem Research, aims to advance our fundamental understanding of how plants and soil microorganisms respond to, and in turn shape, their abiotic and biotic environment, and to determine the consequences for the functioning of Earth’s ecosystems.

Research Mission

Primarily dedicated to basic research, TER addresses pressing environmental issues, such as the impact of climate and land-use change on ecosystem functioning and the role of soils in the global carbon cycle and in food security. In doing so, we work on scales from µm (i.e. the scale at which microbes operate) to the biosphere (i.e. where plant and microbial processes become evident), and in ecosystems spanning the Arctic tundra to tropical rainforests. We integrate this scale of thinking with state-of-the-art methods, including stable isotope tracing and biomarker fingerprinting, and are developing novel approaches to estimate gross environmental processes with isotope pool dilution techniques.

We are strongly committed to conduct world-leading research in a motivating and intellectually stimulating environment, and to train our students to become independent and internationally competitive scientists who enjoy research and contribute to society as conscientious citizens.

Uni Wien/Der Knopfdruecker

Research Projects

Soil fluxomics and tracing SOM decomposition at the molecular level

Current Projects TER | Wolfgang Wanek | Andreas Richter

Soil organic matter (SOM) represents a vast store of carbon, exceeding that of the atmosphere by at least 3-fold. Global change effects on the formation and breakdown of SOM therefore can have strong repercussions on the global C cycle and on the Earth’s climate. However much of the controls of SOM decomposition have remained elusive given the lack of approaches to trace gross rates of SOM decomposition on the molecular level.

Pixabay/ Filmbetrachter

Organic matter from plants, microbes and soils typically consists of regular polymers (polysaccharides, proteins, peptidoglycan etc.) and irregular polymers (lignin, humic acids). The breakdown of these compounds by extracellular enzymes yields biologically available compounds (e.g. sugars, amino acids, amino sugars) small enough to be taken up and metabolized by microbial cells. The extracellular cleavage of regular polymers by hydrolytic enzymes and of irregular polymers by oxidative enzymes is considered to be the major bottleneck in organic matter decomposition. While much has been learned about the makeup of the extracellular enzyme complement by meta-genomic approaches, the assessment of their activity in situ has been hampered by the lack of suitable approaches. The only way of estimating in situ rates of extracellular reactions is based on isotope pool dilution assays (IPD), in which the compound produced during organic matter breakdown is isotopically enriched and the isotope dilution thereof is measured over time. Currently IPDs only exist for the extracellular protein and cellulose breakdown, pioneered by our working group but not for most of the other naturally occurring polymers such as peptidoglycans, nucleic acids, lipids and lignin. In this project we develop a universal IPD platform for the simultaneous measurement of gross rates of organic matter depolymerization processes using state-of-the-art High Resolution Orbitrap LC/MS and apply it to investigate major controls of SOM decomposition, such as effects of environmental factors and organic matter quality, across a wide range of soils. At the same time we trace the metabolism of these breakdown products, following isotopomers of carbon (13C, 12C) and nitrogen (15N, 14N) through the soil microbial food web and into soil mineral N and respiratory CO2.

Publications:

  • S. Leitner, W. Wanek, B. Wild, I. Haemmerle, L. Kohl, K.M. Keiblinger, S. Zechmeister-Boltenstern, A. Richter (2012) Influence of litter chemistry and stoichiometry on glucan depolymerization during decomposition of beech (Fagus sylvatica L.) litter. Soil Biology and Biochemistry 50, 174-187.
  • W. Wanek, M. Mooshammer, A. Blöchl, A. Hanreich, A. Richter (2010) Determination of gross rates of amino acid production and immobilization in decomposing leaf litter by a novel isotope pool dilution technique. Soil Biology and Biochemistry 42, 1293-1302.
  • M. Mooshammer, W. Wanek, J. Schnecker, B. Wild, S. Leitner, F. Hofhansl, A. Blöchl, I. Hämmerle, A.H. Frank, L. Fuchslueger, K.M. Keiblinger, S. Zechmeister-Boltenstern, A. Richter (2012) Stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter. Ecology 93(4), 770-782.
  • Wild, B., Schnecker, J., Barta, J., Capek, P., Guggenberger, G., Hofhansl, F., Kaiser, C., Lashchinsky, N., Mikutta, R., Mooshammer, M., Santruckova, H., Shibistova, O., Urich, T., Zimov, S.A., and Richter, A. (2013). Nitrogen dynamics in Turbic Cryosols from Siberia and Greenland. Soil Biology & Biochemistry 67, 85-93

Investigated by: