• 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

Lability classification of soil organic matter in the northern permafrost region

The large stocks of soil organic carbon (SOC) in soils and deposits of the northern permafrost region are sensitive to global warming and permafrost thawing. The potential release of this carbon (C) as greenhouse gases to the atmosphere does not only depend on the total quantity of soil organic matter (SOM) affected by warming and thawing, but it also depends on its lability (i.e., the rate at which it will decay). In this study we develop a simple and robust classification scheme of SOM lability for the main types of soils and deposits in the northern permafrost region. The classification is based on widely available soil geochemical parameters and landscape unit classes, which makes it useful for upscaling to the entire northern permafrost region. We have analyzed the relationship between C content and C-CO2 production rates of soil samples in two different types of laboratory incubation experiments. In one experiment, ca. 240 soil samples from four study areas were incubated using the same protocol (at 5 C, aerobically) over a period of 1 year. Here we present C release rates measured on day 343 of incubation. These long-term results are compared to those obtained from short-term incubations of ca. 1000 samples (at 12 C, aerobically) from an additional three study areas. In these experiments, C-CO2 production rates were measured over the first 4 d of incubation. We have focused our analyses on the relationship between C-CO2 production per gram dry weight per day (µgC-CO2 gdw−1 d−1) and C content (%C of dry weight) in the samples, but we show that relationships are consistent when using C ∕ N ratios or different production units such as µgC per gram soil C per day (µgC-CO2 gC−1 d−1) or per cm3 of soil per day (µgC-CO2 cm−3 d−1). C content of the samples is positively correlated to C-CO2 production rates but explains less than 50 % of the observed variability when the full datasets are considered. A partitioning of the data into landscape units greatly reduces variance and provides consistent results between incubation experiments. These results indicate that relative SOM lability decreases in the order of Late Holocene eolian deposits to alluvial deposits and mineral soils (including peaty wetlands) to Pleistocene yedoma deposits to C-enriched pockets in cryoturbated soils to peat deposits. Thus, three of the most important SOC storage classes in the northern permafrost region (yedoma, cryoturbated soils and peatlands) show low relative SOM lability. Previous research has suggested that SOM in these pools is relatively undecomposed, and the reasons for the observed low rates of decomposition in our experiments need urgent attention if we want to better constrain the magnitude of the thawing permafrost carbon feedback on global warming.

Kuhry P, Barta J, Blok D, Elberling B, Faucherre S, Hugelius G, Jørgensen C J, Richter A, Santruckova H, Weiss N
2020 - Biogeosciences, 17: 361-379

A systemic overreaction to years versus decades of warming in a subarctic grassland ecosystem

Temperature governs most biotic processes, yet we know little about how warming affects whole ecosystems. Here we examined the responses of 128 components of a subarctic grassland to either 5–8 or >50 years of soil warming. Warming of >50 years drove the ecosystem to a new steady state possessing a distinct biotic composition and reduced species richness, biomass and soil organic matter. However, the warmed state was preceded by an overreaction to warming, which was related to organism physiology and was evident after 5–8 years. Ignoring this overreaction yielded errors of >100% for 83 variables when predicting their responses to a realistic warming scenario of 1 °C over 50 years, although some, including soil carbon content, remained stable after 5–8 years. This study challenges long-term ecosystem predictions made from short-term observations, and provides a framework for characterization of ecosystem responses to sustained climate change.

Walker TWN, Janssens IA, Weedon JT, Sigurdsson BD, Richter A, Peñuelas J, Leblans NI Bahn M, Bartrons M, De Jonge C, Fuchslueger L, Gargallo-Garriga A, Gunnarsdóttir GE, Marañon-Jimenez S, Oddsdóttir ES, Ostonen I, Poeplau C, Prommer J, Radujković D, Sardans J, Sigurðsson P, Soong JL, Vicca S, Wallander H, Ilieva-Makulec K, Verbruggen E
2020 - Nature Ecology & Evolution, 4: 101-108

The Forest Observation System, building a global reference dataset for remote sensing of forest biomass

Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (AGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. AGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. All plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities.

Schepaschenko D, et al, Wanek W, Zo-Bi IC
2019 - Scientific Data, 6: Article 198

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