The effects of monsoon on the distribution of inorganic nitrogen and total nitrogen in water of Setiu Lagoon, Terengganu, South China Sea

Abstract

The distribution of inorganic nitrogen and total nitrogen in Setiu Lagoon, Terengganu has been study during South West monsoon, Inter-monsoon, and North East monsoon. Three sampling times had been done from September to December 2006. Fourteen sampling stations were established and the water samples from each of these stations were taken. The first sampling was done on 8 September 2007. The mean value of total nitrogen during first sampling was 66.38 ± 17.67-µM .The second sampling was conducted on the 21 October 2007. The mean value of total nitrogen during second sampling was 48.94 ± 28.7 µM. The third sampling was carried out on 29 December 2007 and the mean value of total nitrogen was 98.95 ± 9.9 µM. Total nitrogen had showed no significant difference (p> 0.05) among stations during the first, second and third sampling. Somehow, total nitrogen indicated a significant difference (p< 0.05) between the first, second and third sampling. The total nitrogen had decreased from the South West monsoon to Inter-North East monsoon and then increased back during North East monsoon season. Generally, the nitrogen level is higher than the phosphorus level in the Lagoon. The N: P ratio for the first, second and third samplings were 33:1, 5:1, and 22:1 respectively.