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
Creators: name: Shi, Chupei
name: Urbina-Malo, Carolina
name: Tian, Ye
name: Heinzle, Jakob
name: Kwatcho Kengdo, Steve
name: Inselsbacher, Erich
name: Borken, Werner
name: Schindlbacher, Andreas
name: Wanek, Wolfgang
Publisher: name: Zenodo
Year: 2023
Subjects: subject: 18O incorporation into microbial DNA
subject: Microbial element limitation
subject: Temperate forest ecosystem
subject: Soil Sciences
subject: FOS: Agriculture, forestry and fisheries

description: 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 (<sup>18</sup>O 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 (&gt;14 yrs 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 hours. 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.
description: ExcelFunding provided by: Austrian Science Fund<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100002428<br>Award Number: I 3745
description: Please refer to the accompanying README file and the published paper: Shi, C., Malo, C., Tian, Y., Heinzle, J., Kengdo, S. K., Inselsbacher, E., Borken, W., Schindlbacher, A., &amp; Wanek, W. (2023). 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. Global Change Biology. Accepted.