Kenneth Fortino edited ResultsOMMineralization.tex  over 7 years ago

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\subsubsection{Organic Matter}  The sediments added to the microcosms in the litter experiment had a dry bulk density that ranged between 0.25 to 0.26 g ml\textsuperscript{-1} thus we added between 25 and 26 g dry mass of sediment to the bottles. The organic matter content of those sediments ranged between 12.7 and 12.9\% so the sediments in the microcosms contained between 3.18 and 3.23 g of organic matter each. The microcosms that received leaf litter each received between 0.04 and 0.08 additional g of organic matter with the added leaf litter, which would be the equivalent of 11.3 to 22.7 g coarse organic matter m\textsuperscript{-2}.   The percent carbon of the surface sediments ranged between 3.05\% and 3.41\% with a median of 3.18\%. The bulk sediments ranged between 3.12 and 4.27\% C with a median of 3.29 \%. The difference between the bulk sediment \% carbon and the surface sediment \% carbon was small with a range of --0.13 to 1.13\% and a median of 0.09\%. Only 3 samples departed more than 0.5\% and in all of these the bulk sediment had greater \% C. The bulk and surface sediment \% C of the same bottle were uncorrelated (r = -0.12) and the leaf litter or nutrient additions had no effect (p >0.05) on the \% C of either the surface or bulk sediment.  The \% N in the sediments was very highly correlated with the \% C of the same sediment sample (r = 0.968) and therefore, the \% N of the bulk and surface sediments showed the same patterns as the \% C. The \% N of the surface sediments ranged between 0.28 and 0.32\% with a median of 0.29\%. The \% N of the bulk sediments (median = 0.31\%, range = 0.29 to 0.40\%) was overall slightly greater than the surface sediments with a median difference of 0.01\% and only 2 samples out of 14 with greater \% N in the surface sediment. As with the \% C, there was no effect (p > 0.05) of the leaf litter or nutrient additions on the \% N of either the surface or bulk sediments.   The C:N of the sediments was constrained and only ranged between 10.48 and 11.27 across all of the bulk and surface sediment samples. There was no effect (p > 0.05) of added leaf litter or nutrients on the C:N of either the bulk or surface sediments. The C:N of the added leaf litter ranged 15.22 to 17.36 with a median of 16.16 which was significantly greater than the median C:N of either the surface or bulk sediments (p < 0.0001) and was not affected by the nutrient addition (p = 0.248).  The sediments added to the microcosms in the leached litter experiment had a dry bulk density between 0.10 and 0.11 g ml\textsuperscript{-1}, which was less than those used in the leaf experiment and likely due to the fact that the sediment slurry was not settled before being added to the microcosm. The organic matter content of the sediments used in the leached litter experiment was nearly identical to those used in the litter experiment and ranged between 12.1 and 12.4\%. As a result the sediments of each microcosm contained between 1.23 and 1.39 g of organic matter. The microcosms that received leaf litter each received between 0.04 and 0.05 g of coarse organic matter with the added litter, which would be the equivalent of 10.8 to 13.5 g of coarse organic matter m\textsuperscript{-2}.