Yueyue Shen Biomi 2911 Lab Report – Nitrogen Cycling 1. Hypothesis: there are relatively more nitrate reducing bacteria in pond water, compared to creek water. The hypothesis is based on the knowledge that nitrate reducing bacteria use anaerobic respiration, and the fact that creek water has more concentration of dissolved oxygen. It is reasonable to believe that the hypothesis is true because nitrate bacteria uses denitrification (a process that only occurs in anoxic environment) and creek water flows & contains more oxygen as opposed to pond water, which remains stagnant. Since nitrate reducing bacteria requires anoxic environment because they use nitrate as the final e- acceptor rather than oxygen, creek water is less favored, meaning that more nitrate reducing bacteria should grow in pond water. The data from the table refutes this hypothesis, because the percentage of NR/PCA for pond water is lower (118%) than that of creek water (132%); if the information were to support the hypothesis, the % for pond water should have been higher. One possible reason for getting this
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This note was uploaded on 10/24/2010 for the course BIOMI 2911 at Cornell.