High concentrations of silicate-silicon can potentially stimulate the growth of benthic diatoms, which covers the coral and
bottom sediments. Concentrations of ammoniumnitrogen (NH+4 -N) and orthophosphate-phosphorus (PO3 – 4 -P) in Ranong and Phang Nga waters were slightly low compared to the values in the Gulf of Thailand. Concentrations of PO3 – 4 -P in Ranong was markedly high (0.34–0.77 µM) compared to the value obtained from the same area in 199224