Distribution of nutrients (nitrate, nitrite, ammonia and ortho-phosphate) content, primary productivity and chlorophyll-a in the Merchang river, Marang, Terengganu

Abstract

Productivity and nutrient content study in the Merchang River, Terengganu were conducted during the pre-monsoon period (October) and monsoon period (January ). Mean nitrate concentration in the surface and bottom water during the first sampling were 1.145 mg/Land 0.792 mg/L respectively while during the second sampling were 0.734 mg/L and 0.689 mg/L respectively. For nitrite, the mean concentration during the first sampling were 0.254 mg/L and 0.221 mg/L respectively while during the second sampling were 0.097 mg/L and 0.072 mg/L respectively. For ammonia the mean concentration during the first sampling were 1.323 mg/L and 0. 776 mg/L respectively while during the second sampling were 2.008 mg/L and 2.137 mg/L respectively. For ortho-phosphate, the mean concentration during the first sampling were 0.743 mg/Land 0.436 mg/L respectively while during the second sampling were 0.962 and 0.854 mg/L (0.440 - 1.963 mg/L) respectively. The mean concentration for chlorophyll-a during the first sampling was 0.026 mg/m 3 while for the second sampling was 0.018 mg/m 3 • Mean net productivity for the first sampling was 382.55 mgC/m3/hr while for the second sampling was 232.55 mgC/m3/hr. There was a good relationship between productivity and nutrient content where increase in productivity will decrease the nutrient content. Nutrient ·content during the pre-monsoon period was found to be higher than that during the monsoon period.