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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #348082
Title: Bacterial community response to a preindustrial-to-future CO2 gradient is limited and soil specific in Texas Prairie grassland

Author
item RAUT, SWASTIKA - Baylor University
item Polley, Herbert
item Fay, Philip
item KANG, SANGHOON - Baylor University

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2018
Publication Date: 9/25/2018
Publication URL: http://handle.nal.usda.gov/10113/6206210
Citation: Raut, S., Polley, H.W., Fay, P.A., Kang, S. 2018. Bacterial community response to a preindustrial-to-future CO2 gradient is limited and soil specific in Texas Prairie grassland. Global Change Biology. 24(12):5815-5827. https://doi.org/10.1111/gcb.14453.
DOI: https://doi.org/10.1111/gcb.14453

Interpretive Summary: The concentration of carbon dioxide (CO2) gas in air is rising as a result of fossil fuel combustion, land-use change, and other human activities. Higher CO2 concentration usually stimulates plant growth over periods of months to years, potentially increasing human production of food and fiber. Longer-term effects of increased CO2 on plant production remains unresolved, however, because CO2-caused changes in plants may lead to changes in soil bacterial communities that decompose dead plant material and regulate nitrogen (N) cycling. Feedback resulting from change in bacterial communities could either enhance or dampen plant growth response to higher CO2. ARS scientists at Temple, TX together with collaborators from Baylor University investigated the response of bacterial communities in three soil types to a gradient in CO2 spanning low levels of the pre-industrial period to elevated concentrations anticipated by mid-century following 10 years of CO2 treatment. Bacteria were isolated from soil on which mixed communities of species common to the tallgrass prairie in central Texas, USA were grown using gene sequencing techniques. Bacterial communities differed between a sandy loam soil and two clay soils, a silty clay and heavy black clay. CO2 effects on bacterial communities also differed among soil types. Bacterial communities differed consistently in composition from low to high CO2 concentration on the silty clay soil only, whereas CO2 effects were limited to specific families of bacteria on the sandy loam and clay soils. By contrast, diversity of bacterial types declined at high soil water content when analyzed using data from all soils combined. Our results indicate that soil properties influence how CO2 affects bacterial groups and, via soil effects on water content, the numbers and relative abundances of bacterial families in soil. Findings imply that soil type will influence plant growth response to CO2 over decades to centuries partly by influencing composition, numbers, and relative abundances of soil bacteria involved in decomposition and N cycling.

Technical Abstract: Rising atmospheric CO2 concentration directly stimulates plant productivity and affects nutrient dynamics in the soil. However, the influence of CO2 enrichment on soil bacterial communities remains elusive, likely due to their complex interactions with a wide range of plant and soil properties. Here, we investigated the response of bacterial communities to a preindustrial-to-future CO2 gradient and seasonal variation in three contrasting soil types. We utilized 16S rRNA gene amplicon sequencing technique for bacterial community characterization. We found that sandy loam soil communities were distinctly clustered, whereas there was a significant overlap between silty clay and clay soils. Seasonal variation had negligible effect on bacterial community structure and composition. Silty clay soil communities were better structured on a CO2 gradient (p<0.001) among three soils, suggesting soil-specific variation in CO2 effects. The abundance of Pirellulaceae family decreased linearly with CO2 in sandy loam soils. Conversely, the abundance of Micromonosporaceae and Gaillaceae families increased with CO2 in clay soils. Both Shannon index (H’) and Faith’s phylogenetic diversity (PD) declined with increasing soil moisture (R2 = 0.16, p < 0.001). Taken together, our results indicate that soil moisture and nutrient properties have a more significant influence on bacterial community structure than CO2 and season.