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Linking soil bacterial biodiversity and soil carbon stability

Linking soil bacterial biodiversity and soil carbon stability

leshyk illustration single and multiple pulse

Native soil carbon (C) can be lost in response to fresh C inputs, via the “priming effect,” a phenomenon observed for decades yet still not understood. Using dual-stable isotope probing, Ecoss research showed that priming involves changes in the diversity and composition of two functional bacterial groups: a single-substrate pulse of added glucose suppressed native soil C loss and reduced bacterial diversity (shown here as the large pile of one dominant bacterial taxon per each of the two soil communities), whereas repeated substrate pulses stimulated native soil C loss and increased diversity. Increased diversity after repeated C amendments contrasts with resource competition theory, and may be explained by increased predation (roundworms, amoebae, etc. shown at bottom) as evidenced by a decrease in bacterial 16S rRNA gene copies, implying an overall reduction in bacterial populations.

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