VOLUME 7 NUMBER 2 (July to December 2014)

by Olivia C. Cabrera*¹, Cesar L. Villanoy¹, Gil S. Jacinto¹, Lawrence Patrick C. Bernardo^1,2, Charissa M. Ferrera^1,3, Imelda B. Velasquez^1,4, and Rhodora V. Azanza¹

¹Marine Science Institute, University of the Philippines, Diliman, Quezon City, Philippines, 1101
²Department of Civil Engineering, Tokyo Institute of Technology,Ookayama, Meguro-ku, Tokyo, Japan, 152-8552
³Department of Mechanical and Environmental Informatics,Graduate School of Information Science and Engineering, Tokyo Institute of Technology,Ookayama, Meguro-ku, Tokyo, Japan, 152-8552
⁴Hill Laboratories 101c Waterloo Road, Hornby, Christchurch New Zealand

Malampaya Sound is an enclosed bay in Palawan,Philippines. A salinity maximum or saltplug was discovered in the middle of theSound by a field survey in May 2005 and successfullysimulated using a Delft3D numericalmodel of the sound, forced with tide and freshwater discharge atthe lateral boundaries, and evaporation at the surface. Differentconditions to simulate the major monsoonal regimes of 2005(dry inter-monsoon, southwest-wet, and northeast-dry) indicatethat the salt plug persists, although its relative position changeswith the magnitude of freshwater discharge. The salt plug effectivelylimits the exchange of water between the Inner and theOuter Sound, which may account for differences in nutrient levelsand the phytoplankton assemblage during the same survey.Such a thermohaline circulation has important consequences forsediment transport, phytoplankton bloom formation, and accumulationof pollutants in the Sound.