Estimating nutrient budgets in a coastal lagoon

To estimate nutrient budgets, water samples were collected at 16 sites in Tapong lagoon from January 2004 through April 2005 and the parameters of water quality were analyzed immediately after collection. These data were used to build a box model for calculating nutrient budgets of the lagoon. We estimated the net amount of nutrient fluxes into (coming from creeks) and out (from tidal inlet) of the lagoon and calculated the total amount of nutrient that deposits into the sediment in a full tidal cycle. During January and April, nutrients (including nitrate, nitrite and ammonia) accumulated in the lagoon, but phosphate, total phosphate and suspended solids were flushed out of the lagoon from the tidal inlet. In addition, a huge amount of suspended solids (13–15 tons per tidal cycle) flew from the lagoon to the adjacent ocean through the inlet-outlet channel.