The Spatial Factor, Rather than Elevated CO(2), Controls the Soil Bacterial Community in a Temperate Forest Ecosystem

The global atmospheric carbon dioxide (CO(2)) concentration is expected to increase continuously over the next century. However, little is known about the responses of soil bacterial communities to elevated CO(2) in terrestrial ecosystems. This study aimed to partition the relative influences of CO(2), nitrogen (N), and the spatial factor (different sampling plots) on soil bacterial communities at the free-air CO(2) enrichment research site in Duke Forest, North Carolina, by two independent techniques: an entirely sequencing-based approach and denaturing gradient gel electrophoresis. Multivariate regression tree analysis demonstrated that the spatial factor could explain more than 70\% of the variation in soil bacterial diversity and 20\% of the variation in community structure, while CO(2) or N treatment explains less than 3\% of the variation. For the effects of soil environmental heterogeneity, the diversity estimates were distinguished mainly by the total soil N and C/N ratio. Bacterial diversity estimates were positively correlated with total soil N and negatively correlated with C/N ratio. There was no correlation between the overall bacterial community structures and the soil properties investigated. This study contributes to the information about the effects of elevated CO(2) and soil fertility on soil bacterial communities and the environmental factors shaping the distribution patterns of bacterial community diversity and structure in temperate forest soils.

Duke Scholars

Author Ram Oren Environmental Sciences and Policy