Role of Temperature and Organic Degradation on the Persistence of ...

Four different statistical analyses were performed using Statistical Analysis S<strong>of</strong>tware (SAS)
program version 9.1 (SAS Institute Inc., Cary, NC, USA) on samples collected from both active
<strong>and</strong> inactive sites, as well as feeds used at the active sites.
An analysis <strong>of</strong> variance using a General Linear Model (GLM) was performed on samples
collected from active sites with the site as a block effect.
The second analysis consisted <strong>of</strong> correlating means <strong>of</strong> isotopic signatures <strong>of</strong> δ 13 C <strong>and</strong> δ 15 N at
active sites versus δ 13 C <strong>and</strong> δ 15 N signatures <strong>of</strong> the feed.
A comparison between sediment stable isotope data collected at active versus inactive sites was
performed using the GLM procedure via mixed model analysis <strong>of</strong> variance, assuming samples
within sites were collected r<strong>and</strong>omly.
The fourth analysis compared the variances <strong>of</strong> isotopic signatures <strong>of</strong> δ 13 C <strong>and</strong> δ 15 N at active <strong>and</strong>
inactive sites using the Brown <strong>and</strong> Forsythe’s test for homogeneity <strong>of</strong> variance method, assuming
samples within sites were collected r<strong>and</strong>omly.
2. 3. Results
The values <strong>of</strong> δ 15 N for samples taken from active sites were significantly different between
sample locations within a site (F value =17. 60, Pr>F= 0.0015, DF = 5) as well as measurements
taken between the sites (F value= 9.4, Pr> F= 0.001, DF = 5).
No significant differences were found between δ 13 C values <strong>of</strong> sediment samples taken within a
particular site (F value = 0.08, Pr > F =0.788, DF = 5) as well as among sediment samples from
different active sites (F value 0.43, Pr > F= 0.820, DF = 5).
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