Chuck Pepe-Ranney edited Results.tex  almost 10 years ago

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We evaluated alpha diversity in all treatments for both the plankton and the biofilm communities using rarefaction curves. Rarefaction curves showed bacterial and algal OTU richness was consistently higher in the biofilm compared to the planktonic communities (Figure 4). However, for both the algal community and bacterial community analysis the biofilm and planktonic communities had the fewest OTUs in the highest C:P treatment (500) (Figure 4).  \subsubsection{Community membership biofilm versus plankton}  Membership in addition to OTU richness was different among plankton and biofilm treatments. Bacterial community membership between the plankton and biofilm communities was notably different for all treatments except for the highest carbon treatment where the plankton and biofilm communities at day 17 were more similar to each other than any other community (Figure 5). Algal plankton and biofilm communities were also composed of different OTUs however the similarity among algal plankton and biofilm communities in the highest carbon treatment was not observed as it was for the bacterial communities (Figure 5). In bacterial libraries, sequences were distributed into 636 total OTUs. 58\% of quality controlled sequences fell into the top 25 OTUs in order of decreasing sum of relative abundance across all samples. Highest absolute OTU relative abundance mean ratios grouped by environment type (plantonic versus biofilm) were found for OTUs enriched in planktonic samples (with respect to biofilm) (Figure 6) which is consistent ith the higher alpha diversity in biofilm communities compared to planktonic communities. That is, sequence counts were spread across a greater diversty of taxa in the biofilm libraries compared to the planktonic libraries. Of the top five OTUs ordered by absolute environment type OTU mean ratios, one is annotated as in the \textit{Bacteroidetes}, two \textit{Gammaproteobacteria}, one \textit{Betaproteobacteria} and one \textit{Alphaproteobacteria}; all five are enriched in the planktonic liraries relative to biofilm. Table 1 lists the top 25 OTUs ordered by absolute environment type mean ratios. Only five bacterial OTU centroid sequences for the top 25 environment type enriched OTUs (ordered by absolute environment type mean ratio) share high sequence identity (>= 97\%) with cultured isolates (Table 1). Environment type OTU mean ratios are consistent with positions of OTUs in the sample ordination space (see Figures 5 and 6).