The fate of ¹³C¹⁵N labelled glycine in permafrost and surface soil at simulated thaw in mesocosms from high arctic and subarctic ecosystems

TY - JOUR

T1 - The fate of 13C15N labelled glycine in permafrost and surface soil at simulated thaw in mesocosms from high arctic and subarctic ecosystems

AU - Ravn, Nynne Marie Rand

AU - Elberling, Bo

AU - Michelsen, Anders

N1 - CENPERM[2017]

PY - 2017/10/1

Y1 - 2017/10/1

N2 - Background and aim: Nutrient distribution and carbon fluxes upon spring thaw are compared in mesocosms from high arctic and subarctic ecosystems dominated by Cassiope tetragona or Salix hastata/Salix arctica, in order to evaluate the possibility of plant and microbial utilization of an organic compound in thawing permafrost and surface soil. Methods: Double labeled glycine (13C15N) was added to soil columns with vegetation and to permafrost. During thaw conditions ecosystem respiration 13C was measured and 13C and 15N distribution in the ecosystem pools was quantified one day and one month after glycine addition. Results: Near-surface soil microbes were more efficient in the uptake of intact glycine immediately upon thaw than plants. After one month plants had gained more 15N whereas microbes seemed to lose 15N originating from glycine. We observed a time lag in glycine degradation upon permafrost thaw, in contrast to surface soil thaw. Conclusions: Our results suggest that both arctic plants and microorganisms acquire amino acids released upon spring and permafrost thaw. Despite indications of more efficient utilization of added substrate in the High Arctic than the Subarctic, we conclude that patterns of nutrient distribution are similar and predictions based on subarctic data valid for high arctic settings.

AB - Background and aim: Nutrient distribution and carbon fluxes upon spring thaw are compared in mesocosms from high arctic and subarctic ecosystems dominated by Cassiope tetragona or Salix hastata/Salix arctica, in order to evaluate the possibility of plant and microbial utilization of an organic compound in thawing permafrost and surface soil. Methods: Double labeled glycine (13C15N) was added to soil columns with vegetation and to permafrost. During thaw conditions ecosystem respiration 13C was measured and 13C and 15N distribution in the ecosystem pools was quantified one day and one month after glycine addition. Results: Near-surface soil microbes were more efficient in the uptake of intact glycine immediately upon thaw than plants. After one month plants had gained more 15N whereas microbes seemed to lose 15N originating from glycine. We observed a time lag in glycine degradation upon permafrost thaw, in contrast to surface soil thaw. Conclusions: Our results suggest that both arctic plants and microorganisms acquire amino acids released upon spring and permafrost thaw. Despite indications of more efficient utilization of added substrate in the High Arctic than the Subarctic, we conclude that patterns of nutrient distribution are similar and predictions based on subarctic data valid for high arctic settings.

KW - Carbon and nitrogen isotopes

KW - Carbon dioxide

KW - Glycine

KW - Permafrost thaw

KW - Plant-microbe interactions

KW - Tundra

U2 - 10.1007/s11104-017-3322-x

DO - 10.1007/s11104-017-3322-x

M3 - Journal article

AN - SCOPUS:85023775768

SN - 0032-079X

VL - 419

SP - 201

EP - 218

JO - Plant and Soil

JF - Plant and Soil

IS - 1-2

ER -