Program     Biogeochemical processes in land-ocean interfaces, surface estuaries, subterranean estuaries and sediment-water interface       Poster Distribution and Behaviour of Nutrients in Kelantan River Estuary during Different Monsoon Seasons P-C2-04-S Md Nasir, Fatin Adlina* , Institute of Oceanography and Environment, Universiti Malaysia Terengganu Suratman, Suhaimi, Institute of Oceanography and Environment, Universiti Malaysia Terengganu Dung Le Quang, Institute of Oceanography and Environment, Universiti Malaysia Terengganu Presenter Email: eyna_nasir@yahoo.com Nutrients input to estuarine has increased significantly globally in tandem with anthropogenic activities, which correspond to the rising of human populations and leads to eutrophication. Eutrophication is major water pollution, which can alter food webs and causes loss of submerged aquatic vegetation. Thus, this study was designed to determine the distributions and behaviour of nutrients in Kelantan River Estuary area (southern water of South China Sea) during different monsoon seasons. Surface and bottom water samples were collected using “Van Dorn Sampler” along the salinity gradient and the nutrients concentration analysed colorimetrically. Nutrient such as nitrate, nitrite, ammonia, and phosphate are determined to be critical indicator of water quality in this estuary. This study shows all nutrients behaved in a non-conservative manner in the study area during all monsoon seasons. Highest concentration of inorganic nutrients was observed during monsoon seasons. This may happened, due to the input from strong seasonal land runoff. In addition, there were also strong water turbulence, which resulted in resuspension of nutrients in bottom sediment and lead to the increase of nutrients in the surface water. The results from this study highlighted the importance in understanding the nutrient compounds behaviour for future protection of the estuary. Keywords: Nutrients, distribution, behaviour, Kelantan River Estuary

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