deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index 4551c22..5d0f180 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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and lignin (15-25\%) \citep{Lynd2002}. Hemicellulose, being the most soluble,  degrades most easily as compared to cellulose and lignin, and is targeted in  the early stages of decomposition. Hemicellulose composition varies  considerably with xylans being most abundant, abundant constituent  themselves composed of differing amounts of xylose, glucose, arabinose, galactose, mannose, and rhamnose \citep{Saha2003}. Xylose is often the most abundant sugar in hemicellulose, comprising as much as 60-90\% of xylan in some plants (e.g hardwoods) \citep{Spiridon2008}, wheat \citep{Sun2005}, and switchgrass  \citep{Bunnell2013}. Microbes that respire sugars proliferate during the  initial stages of decomposition \citep{Garrett1951,Alexander1964}, and  metabolize as much as 75\% of sugar C during the first 5 days of decomposition  \citep{Engelking2007}. In contrast, cellulose decomposition proceeds more  slowly with rates increasing for approximately 15 days while degradation continues for 30-90 days \citep{Hu1997,Engelking2007}. It is hypothesized that distinct microbial functional guilds mediate fresh, plant-derived organic matter decomposition and that these guilds proliferate as they decompose compounds of increasing lability over time \citep{Hu1997,Rui2009,AnneliseHKjoller2002,Bastian2009}. For instance, this  degradative succession hypothesis posits that rapidly growing plant sugar  decomposers proliferate first \citep{Garrett1963,Bremer1994} followed by slow 
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processes (e.g. denitrification \citep{Cavigelli2000}, nitrification  \citep{Carney2004,Hawkes2005,Webster2005}, methanotrophy \citep{Gulledge1997},  and nitrogen fixation \citep{Hsu2009}). However, the complexity of soil  C transformations and the lack of convenient functional diagnostic  genes for describing these transformations has limited progress in characterizing the contributions  of individual microbes to the soil C-cycle. Remarkably, we still lack basic  information on the physiology and ecology of the majority of organisms that  live in soils. For example, contributions to soil processes remain  uncharacterized for entire bacterial phyla such as Acidobacteria, Chloroflexi,  Planctomycetes, \textit{Acidobacteria},  \textit{Chloroflexi}, \textit{Planctomycetes},  and Verrucomicrobia. \textit{Verrucomicrobia}.  These phyla combined can comprise 32\% of soil microbial communities (based on surveys of the SSU rRNA genes in soil) \citep{Janssen2006,Buckley2002} and they are nearly ubiquitous in soil. % Fakesubsubsection:Functional guild membership  Functional guild membership and diversity define connections between microbial 
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\citep{Buckley_2007,9780408708036,Holben1995,Nusslein1999}. As a result, most  applications of SIP have targeted specialized microbial functional guilds of  limited diversity (e.g. methanotrophs \citep{radajewski2000stable}). SIP has  generally proved less useful in analysis of for exploring  theoverall  soil C-cycle because it has lacked the resolution necessary to manage effectively the signal complexity that results from adding components of plant biomass to microbial communities  in soil. High throughput DNA sequencing technology, however, improves the  resolving power of SIP. SIP \citep{Aoyagi2015}.  % Fakesubsubsection:High throughput sequencing  Coupling SIP with high throughput DNA sequencing now enables exploration of 
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the assimilation of $^{13}$C labeled xylose and/or cellulose into bacterial DNA  in an agricultural soil.   Specifically, we addedto soil microcosms  a mixture of nutrient nutrients  and resource  mixture resources  that simulated organic matter derived from fresh plant biomass. biomass to soil microcosms.  All microcosms received the same nutrient and resource mixture amendment  but the identity of the isotopically labeled substrate was varied between treatments. We set up a control treatment where all components were unlabeled, a treatment with  $^{13}$C-xylose, and a treatment with $^{13}$C-cellulose. Soil in microcosms  were samples was sampled  at days 1, 3, 7, 14, and 30 and we assessed which soil  microorganisms had assimilated $^{13}$C into DNA at each sampling point. The experiment was designed to provide a test of the degradative succession hypothesis as applied  to in the context of  soil bacteria, to identify the soil  bacteria that metabolize xylose and cellulose  in soils, cellulose,  and to characterizethe  temporal dynamics of xylose and cellulose metabolism during the degradation of fresh organic matter. in soil.