Abstract:
The coastal waters in Southern Central and East South Vietnam are in eutrophicated status.
Nitrate and COD were the main factors that determine the eutrophication. Organic
substance budget is high. Among the heavy metals zinc usually has the concentrations
higher than critical value described in Vietnamese Fishery Water Standard (1995). HAB
were sometimes recorded. It usually prevails in hot dry season when the high water
temperature and weak dynamic regime can accelerate the mineralization of organic matter
and stimulate excystment of dinoflagellate cysts. High concentration of zinc may also
contribute to the occurrence of HAB. However, up to now the knowledge on the relation
between water quality and red tide phenomenon is not enough and there is no effective
approach for the prediction of this phenomenon established. Therefore, comprehensive
studies are necessary for the waters that are potentially threaten by HAB in order to prevent
this phenomenon and/or to minimize its consequences.