Soil microbial communities are important drivers of major ecosystem processes such as decomposition and biogeochemical cycling. Understanding the mechanisms that alter microbial community function is key to predicting the stability of ecosystems in the face of global change.
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How does N fertilization alter the abundance of extracellular DNA (eDNA) in soils?
In high N conditions there is no selective pressure on bacteria to be able to carry out biological nitrogen fixation (N2 to NH3) and the genes that maintain this metabolic process are merely expensive to maintain. But in low N conditions (no fertilizer) the ability to fix N may be the difference between life and death.
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I am measuring the abundance of eDNA at two field sites (KBS LTER resource gradient & GLBRC Marginal lands) both sub-divided into fertilized and unfertilized treatments. Recent studies are just starting to uncover the role of relic or free DNA in muddling analyses of community composition, but there is yet to be any work exploring how soil treatments alter the abundance of eDNA. Manipulating nutrient concentration is a particularly interesting treatment because the consumption of DNA for nutrients is well documented, but cell lysis or decreases in the active microbial biomass is also a common side effect of fertilization. While measuring eDNA has many implications for microbial and soil ecology, I am ultimately interested in understanding how much eDNA is available for natural transformation into in-tact cells.
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