TY - JOUR

T1 - Does long-term soil warming affect microbial element limitation?

T2 - A test by short-term assays of microbial growth responses to labile C, N and P additions

AU - Shi, Chupei

AU - Urbina-Malo, Carolina

AU - Tian, Ye

AU - Heinzle, Jakob

AU - Kwatcho Kengdo, Steve

AU - Inselsbacher, Erich

AU - Borken, Werner

AU - Schindlbacher, Andreas

AU - Wanek, Wolfgang

N1 - Funding Information: This study was funded by the Austrian Science Fund (FWF; project I 3745). We sincerely thank Christian Holtermann for field site maintenance; Margarete Watzka, Sabine Maringer, Sabrina Pober and Ludwig Seidl for technical and material support; Shasha Zhang for experimental guidance; and Marilena Heitger for laboratory assistance.

PY - 2023/4

Y1 - 2023/4

N2 - 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.

AB - 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.

KW - carbon

KW - co-limitation

KW - long-term soil warming

KW - microbial growth

KW - nitrogen

KW - nutrient limitation

KW - phosphorus

KW - soil microbes

UR - http://www.scopus.com/inward/record.url?scp=85146926877&partnerID=8YFLogxK

U2 - 10.1111/gcb.16591

DO - 10.1111/gcb.16591

M3 - Article

C2 - 36622092

AN - SCOPUS:85146926877

VL - 29

SP - 2188

EP - 2202

JO - Global change biology

JF - Global change biology

SN - 1354-1013

IS - 8

ER -