TY - JOUR
T1 - Bacterial community structure and function change in association with colonizer plants during early primary succession in a glacier forefield
AU - Knelman, Joseph E.
AU - Legg, Teresa M.
AU - O'Neill, Sean P.
AU - Washenberger, Christopher L.
AU - González, Antonio
AU - Cleveland, Cory C.
AU - Nemergut, Diana R.
N1 - Funding Information:
The authors thank Eran Hood for acting as a lead collaborator in facilitating both laboratory and fieldwork surrounding this project in Juneau, Alaska. Sasha Reed lent invaluable advice in quantifying nitrogen fixation. David Bru and Laurent Philippot at INRA Dijon, France, provided nifH standards for qPCR analysis. Additional thanks to Steve Schmidt, Bill Bowman, Ned Friedman, Lee Stanish and members of the Knight and Townsend labs at the University of Colorado, who contributed important insights and help with regards to this research. We also thank Josh Schimel and two anonymous reviewers for their input on the content and communication of this study. This work was supported by National Science Foundation (NSF) grants.
PY - 2012/3
Y1 - 2012/3
N2 - Plants directly interact with the soil microbial community through litter inputs and root exudates, and these interactions may be particularly important in nutrient poor soils that typically characterize early ecosystem development. However, little is known regarding how plant-microbe interactions may actually drive ecosystem processes in early succession, a perspective this study helps to define. We investigated how soil microbial communities develop and interact with the establishment of the first plants in the recently exposed soils of the Mendenhall Glacier forefield near Juneau, AK, USA. We sampled soils from under two different plant species (alder, Alnus sinuata and spruce, Picea sitchensis) and from unvegetated areas; all samples were collected along a single soil transect that had been exposed for 6 years. The presence or absence of vegetation as well as the type of plant (i.e., alder vs. spruce) structured the soil microbial community. Furthermore, asymbiotic nitrogen (N) fixation rates, which were greater in vegetated soils, correlated with differences in bacterial community composition. Although soil microbial community composition varied with vegetation type, soil nutrient and carbon (C) pools did not correlate with bacterial community composition. Moreover, pH did not significantly vary by vegetation type, yet it was the only soil parameter that correlated with bacterial community composition. Vegetation type explained more of the variation in bacterial community composition than pH, suggesting that plant acidification of soils only partly explains the observed shifts in bacterial communities. Plant specific differences in bacterial community structure may also relate to the chemical composition of litter and root exudates. Our research reveals differences in the bacterial community composition of vegetated soils, and how such differences may promote shifts in fundamental biogeochemical processes, such as rates of asymbiotic N fixation, in early stages of primary succession where low N availability may limit bacterial and plant growth and thus constrain ecosystem development. As such, this suggests that plant-soil microbe interactions in themselves may drive processes that shape the trajectory of primary succession.
AB - Plants directly interact with the soil microbial community through litter inputs and root exudates, and these interactions may be particularly important in nutrient poor soils that typically characterize early ecosystem development. However, little is known regarding how plant-microbe interactions may actually drive ecosystem processes in early succession, a perspective this study helps to define. We investigated how soil microbial communities develop and interact with the establishment of the first plants in the recently exposed soils of the Mendenhall Glacier forefield near Juneau, AK, USA. We sampled soils from under two different plant species (alder, Alnus sinuata and spruce, Picea sitchensis) and from unvegetated areas; all samples were collected along a single soil transect that had been exposed for 6 years. The presence or absence of vegetation as well as the type of plant (i.e., alder vs. spruce) structured the soil microbial community. Furthermore, asymbiotic nitrogen (N) fixation rates, which were greater in vegetated soils, correlated with differences in bacterial community composition. Although soil microbial community composition varied with vegetation type, soil nutrient and carbon (C) pools did not correlate with bacterial community composition. Moreover, pH did not significantly vary by vegetation type, yet it was the only soil parameter that correlated with bacterial community composition. Vegetation type explained more of the variation in bacterial community composition than pH, suggesting that plant acidification of soils only partly explains the observed shifts in bacterial communities. Plant specific differences in bacterial community structure may also relate to the chemical composition of litter and root exudates. Our research reveals differences in the bacterial community composition of vegetated soils, and how such differences may promote shifts in fundamental biogeochemical processes, such as rates of asymbiotic N fixation, in early stages of primary succession where low N availability may limit bacterial and plant growth and thus constrain ecosystem development. As such, this suggests that plant-soil microbe interactions in themselves may drive processes that shape the trajectory of primary succession.
KW - 16S rRNA gene sequencing
KW - Colonization
KW - Deglaciation
KW - Glacier forefield
KW - NifH gene
KW - Nitrogen fixation
KW - Plant-microbe interactions
KW - Pyrosequencing
KW - Soil microbial community
KW - Succession
UR - http://www.scopus.com/inward/record.url?scp=84455170926&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2011.12.001
DO - 10.1016/j.soilbio.2011.12.001
M3 - Article
AN - SCOPUS:84455170926
SN - 0038-0717
VL - 46
SP - 172
EP - 180
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
ER -