TY - JOUR
T1 - Microbial functional diversity and carbon use feedback in soils as affected by heavy metals
AU - Xu, Yilu
AU - Seshadri, Balaji
AU - Bolan, Nanthi
AU - Sarkar, Binoy
AU - Ok, Yong Sik
AU - Zhang, Wei
AU - Rumpel, Cornelia
AU - Sparks, Donald
AU - Farrell, Mark
AU - Hall, Tony
AU - Dong, Zhaomin
N1 - Funding Information:
Yilu Xu is thankful to the University of Newcastle and Department of Education and Training, Government of Australia, for awarding her PhD Scholarship. This research was partly supported by an Australian Research Council Discovery–Project ( DP140100323 ).
Publisher Copyright:
© 2019 The Authors
PY - 2019/4
Y1 - 2019/4
N2 - Soil microorganisms are an important indicator of soil fertility and health. However, our state of knowledge about soil microbial activities, community compositions and carbon use patterns under metal contaminations is still poor. This study aimed to evaluate the influences of heavy metals (Cd and Pb) on soil microorganisms by investigating the microbial community composition and carbon use preferences. Metal pollution was approached both singly and jointly with low (25 and 2500 mg kg−1) and high (50 and 5000 mg kg−1) concentrations of Cd and Pb, respectively, in an artificially contaminated soil. In a laboratory incubation experiment, bio-available and potentially bio-available metal concentrations, selected soil properties (pH, electrical conductivity, total organic carbon and total nitrogen), and microbial parameters (microbial activity as basal respiration, microbial biomass carbon (MBC) and microbial functional groups) were determined at two sampling occasions (7 and 49 days). Metal contamination had no effect on the selected soil properties, while it significantly inhibited both microbial activity and MBC formation. Contaminated soils had higher microbial quotient (qCO2), suggesting there was higher energy demand with less microbially immobilized carbon as MBC. Notably, the efficiency of microbial carbon use was repressed as the metal concentration increased, yet no difference was observed between metal types (p > 0.05). Based on the microbial phospholipid fatty acids (PLFA) analysis, total PLFAs decreased significantly under metal stress at the end of incubation. Heavy metals had a greater negative influence on the fungal population than bacteria with respective 5–35 and 8–32% fall in abundances. The contaminant-driven (metal concentrations and types) variation of soil PLFA biomarkers demonstrated that the heavy metals led to the alteration of soil microbial community compositions and their activities, which consequently had an adverse impact on soil microbial carbon immobilization.
AB - Soil microorganisms are an important indicator of soil fertility and health. However, our state of knowledge about soil microbial activities, community compositions and carbon use patterns under metal contaminations is still poor. This study aimed to evaluate the influences of heavy metals (Cd and Pb) on soil microorganisms by investigating the microbial community composition and carbon use preferences. Metal pollution was approached both singly and jointly with low (25 and 2500 mg kg−1) and high (50 and 5000 mg kg−1) concentrations of Cd and Pb, respectively, in an artificially contaminated soil. In a laboratory incubation experiment, bio-available and potentially bio-available metal concentrations, selected soil properties (pH, electrical conductivity, total organic carbon and total nitrogen), and microbial parameters (microbial activity as basal respiration, microbial biomass carbon (MBC) and microbial functional groups) were determined at two sampling occasions (7 and 49 days). Metal contamination had no effect on the selected soil properties, while it significantly inhibited both microbial activity and MBC formation. Contaminated soils had higher microbial quotient (qCO2), suggesting there was higher energy demand with less microbially immobilized carbon as MBC. Notably, the efficiency of microbial carbon use was repressed as the metal concentration increased, yet no difference was observed between metal types (p > 0.05). Based on the microbial phospholipid fatty acids (PLFA) analysis, total PLFAs decreased significantly under metal stress at the end of incubation. Heavy metals had a greater negative influence on the fungal population than bacteria with respective 5–35 and 8–32% fall in abundances. The contaminant-driven (metal concentrations and types) variation of soil PLFA biomarkers demonstrated that the heavy metals led to the alteration of soil microbial community compositions and their activities, which consequently had an adverse impact on soil microbial carbon immobilization.
KW - Heavy metals
KW - Microbial activity
KW - Microbial carbon decomposition
KW - Microbial community composition
KW - PLFAs
KW - Soil organic carbon
UR - http://www.scopus.com/inward/record.url?scp=85061397953&partnerID=8YFLogxK
U2 - 10.1016/j.envint.2019.01.071
DO - 10.1016/j.envint.2019.01.071
M3 - Article
C2 - 30771648
AN - SCOPUS:85061397953
VL - 125
SP - 478
EP - 488
JO - Environmental International
JF - Environmental International
SN - 0160-4120
ER -