This study aims to assess the influences of land use on nutrient concentrations in Kelantan river basin (southern South China Sea), in addition to the effects of monsoon seasons on nutrient concentrations. The dissolved inorganic and organic nutrients in this river were demonstrated to be related to land use during the study period. The middle and lower reaches of the river, which are surrounded by urban areas with high population densities, have enhanced levels of both dissolved inorganic and organic nutrients. Increased rainfall decreased most of the nutrient concentrations in Kelantan river basin, probably due to the dilution effect. According to The Malaysia National Water Quality Standards (NWQS) classification, the mean concentrations of dissolved inorganic phosphorus, nitrite and nitrate in Kelantan river basin fell into Class 1, which is considered at natural levels in the water column.
The contribution of inorganic and organic nutrients to the growth of a North American isolate of the mixotrophic dinoflagellate, Dinophysis acuminata