Decomposition of Urea by the Larger Particulate Fraction and the Free Bacteria Fraction in a Pond Water

✍ Scribed by Mr. Yasuhiro Satoh; Dr. Takahisa Hanya

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 447 KB
• Volume: 61
• Category: Article
• ISSN: 1434-2944
• DOI: 10.1002/iroh.19760610606

✦ Synopsis

Abstract

An aliquot of a water sample taken from an artificial pond on the campus of the Faculty of Science, Tokyo Metropolitan University, was filtered with Whatman GF/C glass fiber filters. Urea was added to the filtered and unfiltered waters, respectively to a final concentration of around 10 μg‐at‐N/l. These samples were kept in 10 liter glass bottles, which were kept on the surface of the pond with rope. Changes in the concentrations of urea, ammonium, nitrate, nitrite, and the number of bacteria were traced from 15 June through 13 July, 1973.

The urea added to the unfiltered water decreased to about 1 μg‐at‐N/l within first three days. The decrement of the urea seemed to proceed as a first‐order reaction with rate constant of 0.73 day^−1^. On the other hand, the urea added in the filtered water kept nearly the initial concentration for 18 days. As the number of bacteria in the filtered and unfiltered water were not significantly different, decrease of the urea in the unfiltered water may be ascribable to the participate fraction removed by the filtration. The urea was not decomposed by free bacteria.