During the preparation of an estimator for the nitrate level, a correlation was found between the pH and the nitrate concentration. This was taken as another indicator that the DO would actually have short-term effects on the nitrate concentration. However, the correlation that was found was only valid for mid-to-long term variations since it was based on data sampled at a rate of two times per week. Naturally, this correlation could not really “guarantee” anything about the variations on a time scale of hours. Also, the correlated variation between nitrate and pH could not be proved to be dependent on the DO-level, this was just assumed. The tests above did primarily confirm that the assumptions about the ammonium levels dependency on the DO was correct, at least for the DO interval used in the tests. This could be stated because the variation in the ammonium level was shown to be well correlated to the variations in DO level. Actually, they seemed to vary in a proportional fashion. The tests did not confirm the nitrates DOdependency to the same degree. The pH was indeed shown to be well correlated to the DO, but since the pH could vary for other reasons than a changing nitrate level – correlation is not causation – the variations in nitrate could not be confirmed to be dependent on the DO.
Published on Nov 9, 2011