TY - JOUR
T1 - Increased temperatures alter viable microbial biomass, ammonia oxidizing bacteria and extracellular enzymatic activities in Antarctic soils
AU - Barnard, Sebastian
AU - van Goethem, Marc W.
AU - de Scally, Storme Z.
AU - Cowan, Don A.
AU - van Rensburg, Peet Jansen
AU - Claassens, Sarina
AU - Makhalanyane, Thulani P.
N1 - Generated from Scopus record by KAUST IRTS on 2023-10-23
PY - 2020/1/1
Y1 - 2020/1/1
N2 - The effects of temperature on microorganisms in high latitude regions, and their possible feedbacks in response to change, are unclear. Here, we assess microbial functionality and composition in response to a substantial temperature change. Total soil biomass, amoA gene sequencing, extracellular activity assays and soil physicochemistry were measured to assess a warming scenario. Soil warming to 15◦C for 30 days triggered a significant decrease in microbial biomass compared to baseline soils (0◦C; P < 0.05) after incubations had induced an initial increase. These changes coincided with increases in extracellular enzymatic activity for peptide hydrolysis and phenolic oxidation at higher temperatures, but not for the degradation of carbon substrates. Shifts in ammonia-oxidising bacteria (AOB) community composition related most significantly to changes in soil carbon content (P < 0.05), which gradually increased in microcosms exposed to a persistently elevated temperature relative to baseline incubations, while temperature did not influence AOBs. The concentration of soil ammonium (NH4+) decreased significantly at higher temperatures subsequent to an initial increase, possibly due to higher conversion rates of NH4+ to nitrate by nitrifying bacteria. We show that higher soil temperatures may reduce viable microbial biomass in cold environments but stimulate their activity over a short period.
AB - The effects of temperature on microorganisms in high latitude regions, and their possible feedbacks in response to change, are unclear. Here, we assess microbial functionality and composition in response to a substantial temperature change. Total soil biomass, amoA gene sequencing, extracellular activity assays and soil physicochemistry were measured to assess a warming scenario. Soil warming to 15◦C for 30 days triggered a significant decrease in microbial biomass compared to baseline soils (0◦C; P < 0.05) after incubations had induced an initial increase. These changes coincided with increases in extracellular enzymatic activity for peptide hydrolysis and phenolic oxidation at higher temperatures, but not for the degradation of carbon substrates. Shifts in ammonia-oxidising bacteria (AOB) community composition related most significantly to changes in soil carbon content (P < 0.05), which gradually increased in microcosms exposed to a persistently elevated temperature relative to baseline incubations, while temperature did not influence AOBs. The concentration of soil ammonium (NH4+) decreased significantly at higher temperatures subsequent to an initial increase, possibly due to higher conversion rates of NH4+ to nitrate by nitrifying bacteria. We show that higher soil temperatures may reduce viable microbial biomass in cold environments but stimulate their activity over a short period.
UR - https://academic.oup.com/femsec/article/doi/10.1093/femsec/fiaa065/5818763
UR - http://www.scopus.com/inward/record.url?scp=85084932596&partnerID=8YFLogxK
U2 - 10.1093/FEMSEC/FIAA065
DO - 10.1093/FEMSEC/FIAA065
M3 - Article
SN - 1574-6941
VL - 96
JO - FEMS MICROBIOLOGY ECOLOGY
JF - FEMS MICROBIOLOGY ECOLOGY
IS - 5
ER -