Recent trends of carbonate parameters in a mariculture area ofBolinao, Pangasinan, Philippines

In the last 3 years, monitoring of the carbonate parameters from a fixed station in Bolinao, Pangasinan has been carried out as an addition to the water quality monitoring conducted in waters affected by mariculture activities. Samples were collected daily and analyzed for nutrients namely NO₃^-, NO₂^-, PO₄^-, NH₄⁺, Si(OH)₄; chlorophyll-a; and carbonate parameters namely total alkalinity (TA) and pH. Other carbonate parameters such as pCO2, dissolved inorganic carbon (DIC), aragonite saturation and Revelle Factor were calculated using the CO2Sys program. The 3-year data showed seasonal variability of TA and DIC, supersaturation of CO₂ parameters during dry season and undersaturation in wet season relative to the atmosphere. The variability can be attributed to mixing of seawater with riverine water and precipitation during wet season and biological activity in the dry season. The 3-year data showed a decrease in TA by 0.13 unit per year which suggests a decrease in the buffering capacity of Bolinao waters. On the other hand, pH data gave an estimate of -0.0002 pH unit per year or a decrease in the rate of acidification for these waters.