TY - JOUR

T1 - Freezing–thawing cycles affect organic matter decomposition in periglacial maritime Antarctic soils

AU - Matus, Francisco

AU - Mendoza, Daniela

AU - Nájera, Francisco

AU - Merino, Carolina

AU - Kuzyakov, Yakov

AU - Wilhelm, Kelly

AU - Boy, Jens

AU - Aburto, Felipe

AU - Jofré, Ignacio

AU - Dippold, Michaela A.

N1 - Funding Information: The authors sincerely appreciate the logistic support from INACH project RT_17_23 and MEC 80180029 (ANID-Chile). The authors are also grateful to the RUDN University Strategic Academic Leadership Program and the Universidad de La Frontera.

PY - 2023/4

Y1 - 2023/4

N2 - Antarctic King George Island is the fastest-warming area in the Southern Hemisphere. Organic matter inputs are scarce in this area, as they are derived from lichens, mosses, avian faeces, and minor inputs from two vascular plant species, Deschampsia antarctica É. Desv. and Colobanthus quitensis (Kunth) Bartl. Here, we examined the effects of freezing and thawing (FT) cycles on the priming effect (PE). We hypothesised that soil microorganisms preferentially use freeze-preserved soil organic carbon (SOC) exposed after thawing as an important energy source, resulting in intense PE. Two soils with contrasting clay contents were characterised by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and incubated with and without 13C-glucose for 21 d. CO2 and 13CO2 were recorded from soil (i) without FT, (ii) one FT, and (iii) three FT cycles (− 18/12 °C). SOC exhibited low aromaticity stretching at 920 cm−1 and 1650 cm−1. Glucose-derived CO2 was maximal (26 ± 2.2 mg g−1 C) in the control soil without FT and decreased to 8.6 ± 0.1 mg g−1 C after three cycles. Glucose induced an intensely positive PE, 41–64% of basal respiration for a single FT cycle and 72–76% for no cycles. However, after three FT cycles, there was null or negative PE (− 9.5–0.4%). On average, the SOC content after net C balance increased with freezing frequency from 103 ± 14 to 212 ± 7. mg C kg−1 in low clay forming soil and from 129 ± 14 to 156 ± 2 mg C kg−1 in high clay forming soil and declined with increasing PE in both soils (R2 = 0.87, p < 0.01). Diminution in freezing frequency because of global warming will increase the positive PE, affecting the C sequestration of incipient SOC formation in maritime Antarctic soils. Graphic abstract: [Figure not available: see fulltext.]

AB - Antarctic King George Island is the fastest-warming area in the Southern Hemisphere. Organic matter inputs are scarce in this area, as they are derived from lichens, mosses, avian faeces, and minor inputs from two vascular plant species, Deschampsia antarctica É. Desv. and Colobanthus quitensis (Kunth) Bartl. Here, we examined the effects of freezing and thawing (FT) cycles on the priming effect (PE). We hypothesised that soil microorganisms preferentially use freeze-preserved soil organic carbon (SOC) exposed after thawing as an important energy source, resulting in intense PE. Two soils with contrasting clay contents were characterised by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and incubated with and without 13C-glucose for 21 d. CO2 and 13CO2 were recorded from soil (i) without FT, (ii) one FT, and (iii) three FT cycles (− 18/12 °C). SOC exhibited low aromaticity stretching at 920 cm−1 and 1650 cm−1. Glucose-derived CO2 was maximal (26 ± 2.2 mg g−1 C) in the control soil without FT and decreased to 8.6 ± 0.1 mg g−1 C after three cycles. Glucose induced an intensely positive PE, 41–64% of basal respiration for a single FT cycle and 72–76% for no cycles. However, after three FT cycles, there was null or negative PE (− 9.5–0.4%). On average, the SOC content after net C balance increased with freezing frequency from 103 ± 14 to 212 ± 7. mg C kg−1 in low clay forming soil and from 129 ± 14 to 156 ± 2 mg C kg−1 in high clay forming soil and declined with increasing PE in both soils (R2 = 0.87, p < 0.01). Diminution in freezing frequency because of global warming will increase the positive PE, affecting the C sequestration of incipient SOC formation in maritime Antarctic soils. Graphic abstract: [Figure not available: see fulltext.]

KW - Antarctic soils

KW - Carbon isotope applications

KW - Extreme environment

KW - Initial soil development

KW - Organic matter balance

KW - Priming effect

UR - http://www.scopus.com/inward/record.url?scp=85151321731&partnerID=8YFLogxK

U2 - 10.1007/s10533-023-01032-z

DO - 10.1007/s10533-023-01032-z

M3 - Article

AN - SCOPUS:85151321731

VL - 163

SP - 311

EP - 325

JO - BIOGEOCHEMISTRY

JF - BIOGEOCHEMISTRY

SN - 0168-2563

IS - 3

ER -