PRIMARY PRODUCTIVITY OF THE ESTUARINE WATERS OF LUN MASLA AND LUN PADIDU RIVERS, MALAPATAN, SARANGANI PROVINCE

A study was conducted to determine the productivity of Lun Masla estuary and its adjacent Lun Padidu estuary with the objectives to determine the rate of production, to measure the NPP and GPP; to determine the carbon content; to identify the phytoplankton present in the area, and to measure the physicochemical parameters of the respective estuaries. Water sampling was done using the Light and Dark Bottle Method for three consecutive months from March 20, 2017 to May 15, 2017 every 7 am-9 am only. Morning sampling shows that the dissolved oxygen level in each site is considerably good condition as it does not decline below 6 mg/L in the whole duration of the study. Lun Masla has an average NPP of 0.7mg/L while Lun Padidu has 0.2mg/L and an average GPP of 0.27 mg/L and 0.3mg/L respectively. The carbon content of Lun Masla is 4.22 C mg/m^3/hr and for Lun Padidu is 4.68 C mg/m^3/hr. A total of 23 species of phytoplankton were found in the respective areas sampled only once for the whole duration of sampling. There were two species of phytoplankton which were enlisted in the harmful algal blooms namely Prorucentrum lima and Pseudo-nitzschia australis. The estuaries were classified as Class SB base on their physicochemical parameters in accordance to the DAO 2016-08 Standard for water quality classification.