• Our new home,

    from summer 2021

  • 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

Phosphorus limitation reduces microbial nitrogen use efficiency by increasing extracellular enzyme investments

Microbial nitrogen use efficiency (NUE), which reflects the proportion of nitrogen (N) taken up to be allocated to microbial biomass and growth, is central to our understanding of soil N cycling. However, the factors influencing microbial NUE remain unclear. Here, we explored the effects of climate factors, soil properties, and microbial variables on microbial NUE based on a survey of soils from 11 locations along a forest transect in eastern China. We found microbial NUE decreased with the ratio of acid phosphatase (AP) activity versus microbial growth rate. This suggested that increased microbial phosphorus acquisition decreased microbial NUE due to increasing investment in AP. However, microbial NUE increased with soil organic carbon content, because soil organic carbon is the source of material and energy for microbial growth and metabolism. Soil pH and mean annual temperature indirectly affected microbial NUE through their effects on the ratio of AP activity relative to microbial growth rate and soil organic carbon content, respectively. Our results improve our understanding and prediction of microbial NUE on a large spatial scale and emphasize the importance of phosphorus in affecting microbial metabolic efficiency.

Sun L, Li J, Qu L, Wang X, Sang C, Wang J, Sun M, Wanek W, Moorhead DL, Bai E, Wang C
2023 - Geoderma, 432: Article 116416

Seasonal fluctuations of extracellular enzyme activities are related to the biogeochemical cycling of C, N and P in a tropical terra-firme forest

Extracellular enzymes (EE) play a vital role in soil nutrient cycling and thus affect terrestrial ecosystem functioning. Yet the drivers that regulate microbial activity, and therefore EE activity, remain under debate. In this study we investigate the temporal variation of soil EE in a tropical terra-firme forest. We found that EE activity peaked during the drier season in association with increased leaf litterfall, which was also reflected in negative relationships between EE activities and precipitation. Soil nutrients were weakly related to EE activities, although extractable N was related to EE activities in the top 5 cm of the soil. These results suggest that soil EE activity is synchronized with precipitation-driven substrate inputs and depends on the availability of N. Our results further indicate high investments in P acquisition, with a higher microbial N demand in the month before the onset of the drier season, shifting to higher P demand towards the end of the drier season. These seasonal fluctuations in the potential acquisition of essential resources imply dynamic shifts in microbial activity in coordination with climate seasonality and resource limitation of central-eastern Amazon forests.

Schaap KJ, Fuchslueger L, Quesada CA, Hofhansl F, Valverde-Barrantes O, Camargo PB, Hoosbeek MR
2023 - Biogeochemistry, in press

Does long-term soil warming affect microbial element limitation? A test by short-term assays of microbial growth responses to labile C, N and P additions

Increasing global temperatures have been reported to accelerate soil carbon (C) cycling, but also to promote nitrogen (N) and phosphorus (P) dynamics in terrestrial ecosystems. However, warming can differentially affect ecosystem C, N and P dynamics, potentially intensifying elemental imbalances between soil resources, plants and soil microorganisms. Here, we investigated the effect of long-term soil warming on microbial resource limitation, based on measurements of microbial growth (18O incorporation into DNA) and respiration after C, N and P amendments. Soil samples were taken from two soil depths (0–10, 10–20 cm) in control and warmed (>14 years warming, +4°C) plots in the Achenkirch soil warming experiment. Soils were amended with combinations of glucose-C, inorganic/organic N and inorganic/organic P in a full factorial design, followed by incubation at their respective mean field temperatures for 24 h. Soil microbes were generally C-limited, exhibiting 1.8-fold to 8.8-fold increases in microbial growth upon C addition. Warming consistently caused soil microorganisms to shift from being predominately C limited to become C-P co-limited. This P limitation possibly was due to increased abiotic P immobilization in warmed soils. Microbes further showed stronger growth stimulation under combined glucose and inorganic nutrient amendments compared to organic nutrient additions. This may be related to a prolonged lag phase in organic N (glucosamine) mineralization and utilization compared to glucose. Soil respiration strongly positively responded to all kinds of glucose-C amendments, while responses of microbial growth were less pronounced in many of these treatments. This highlights that respiration–though easy and cheap to measure—is not a good substitute of growth when assessing microbial element limitation. Overall, we demonstrate a significant shift in microbial element limitation in warmed soils, from C to C-P co-limitation, with strong repercussions on the linkage between soil C, N and P cycles under long-term warming.

Shi C, Urbina-Malo C, Tian Y, Heinzle J, Kendo SK, Inselsbacher E, Borken W, Schindlbacher A, Wanek W
2023 - Global Change Biology, 29: 2188-2202

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